EVALUATION OF DEFENSIVE BEHAVIOR OF

EVALUATION OF DEFENSIVE BEHAVIOR OF HONEYBEE (Apis mellifera L.) COLONIES AGAINST THE ATTACKING OF ORIENTAL HORNET (Vespa orientalis L.) By

YASSER YEHIA MOHAMMED IBRAHIM B.Sc. Agric. Sci. (Economic Entomology), Fac. Agric., Cairo Univ., 1997 M.Sc. Agric. Sci. (Economic Entomology), Fac. Agric., Cairo Univ., 2002

THESIS Submitted in Partial Fulfillment of the Requirements for the Degree of

DOCTOR OF PHILOSOPHY In

Agricultural Sciences (Economic Entomology) Department of Economic Entomology and pesticides Faculty of Agriculture Cairo University

EGYPT 2009 1

APPROVAL SHEET EVALUATION OF DEFENSIVE BEHAVIOR OF HONEYBEE (Apis mellifera L.) COLONIES AGAINST THE ATTACKING OF ORIENTAL HORNET (Vespa orientalis L.) Ph.D. Thesis In Agric. Sci. (Economic Entomology) By


Approval Committee Dr. ABD EL-MONEAM MOHAMED EL-HEFNEY……………… Professor of Economic Entomology, Fac. Agric., Al Azhar University

DR. OSAMAA MOHAMED NAGEB ELANSARY………………… Professor of Economic Entomology, Fac. Agric., Alexandria University

DR. MOHAMED ATTIA EWIES ……………………………………………

Professor of Economic Entomology, Fac. Agric., Cairo University

DR. MOHAMMAD ABD ALWAHAB ABD ALFATTAH…......... Professor of Economic Entomology, Fac. Agric., Cairo University Date: 2

/

/

SUPERVISION SHEET

EVALUATION OF DEFENSIVE BEHAVIOR OF HONEYBEE (Apis mellifera L.)COLONIES AGAINST THE ATTACKING OF ORIENTAL HORNET (Vespa orientalis L.) Ph.D. Thesis In Agric. Sci. (Economic Entomology) By


SUPERVISION COMMITTEE DR. MOHAMMAD ABD ALWAHAB ABD AL-FATTAH Professor of Economic Entomology, Fac. Agric., Cairo University

DR. MOHAMMAD ATTIA EWIES Professor of Economic Entomology, Fac. Agric., Cairo University

DR. AHMED ABD EL-HALEAM EL-SHEMY Professor of Economic Entomology, Fac. Agric., Cairo University \

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Name of Candidate: Yasser Yehia Mohammed Degree: Ph.D. Title of Thesis: Evaluation of defensive behavior of honeybee Apis mellifera l. colonies against the attacking of oriental hornet Vespa orientalis l. Supervisors: Dr. Mohammed Abd Al-Alwahab Dr. Mohammed Atia Ewias Dr. Amad Abd Al Haleam Department: Economic Entomology and Pesticides Branch: Economic Entomology Approval: / / ABSTRACT This study was conducted to study the population fluctuation of oriental hornet during its active season (August- November) was weekly determined using modified screen trap fixed on empty brood box provided with some sealed honey combs for two successive seasons, 2007 and 2008. The obtained results revealed that the total numbers of trapped hornet were, 41242.5 individuals/trap and 9577.9 individuals/trap during 2007 and 2008 respectively. The highest mean numbers of hornet individuals was recorded during October, for the two studied seasons represented 41.9% and 65.7% of the total trapped hornets. The highest wiped out colonies due to direct attack of hornet was occurred during October (29.03 % & 17.65%) for the two observed years, respectively. The percentage of the total destroyed honeybee colonies during hornet active seasons were 45.16% and 35.29% of the total wiped out colonies during each year. Many of the survived colonies, after hornet active season, were weak and unable for wintering. The percentages of finished colonies from them were 5.65% and 2.94% as a latent negative effect of hornet. The percentage of total wiped out colonies were 50.81% and 38.24% for the two successive years in Giza region Key words: Honeybee, Orintal hornet, defensieve behaviour, attacking, loss 4

DEDICATION This thesis is dedicated to my wonderful parents, who have raised me to be the person I am today. You have been with me every step of the way, through good times and bad. Thank you for all the unconditional love, guidance, and support that you have always given me, helping me to succeed and instilling in me the confidence that I am capable of doing anything I put my mind to. Thank you for everything. This thesis is dedicated also to my soul mate and confidant, for always being there for me. Thank you for your continual love, support, and patience as I went through this journey. I could not have made it through without you by my side. I love you! . 5

ACKNOWLEDGEMENT I wish to express my sincere thanks, deepest gratitude and appreciation to Dr. Mohammad Abd alwahab Abd Al-Fattah Professor of Economic entomology, Faculty of Agriculture, Cairo University for suggesting the problem, supervision, continued assistance and their guidance through the course of study and revision the manuscript of this thesis. Sincere thanks to Dr. Mohammad. Attia Ewais and Dr. Ahmed Abd El-Haleam ElShemy Professors of Economic entomology, Faculty of Agriculture, Cairo University for sharing in supervision. Grateful appreciation is also extended to all staff members of Experimental station apiary, Faculty of Agriculture, Cairo University. Special deep appreciation is given to my father, my mother, my wife my son and my sisters.

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INTRODUCTION Vespa and Vespula genera that belong to the Vespinae subfamily (Hymenoptera) are commonly called wasps. Vespa orientalis L. (oriental hornet) and Vespula germanica (F.) (yellowjacket) are social wasps. The Vespula spp. can be easily distinguished from the insects of genus Vespa by their small size (Bilò et al., 2005). Wasps are predatory–carnivorous insects feeding mainly their brood with animal proteins (insects, pieces from fresh or spoiled meat and fish) while the adults are fed with carbohydrates (nectar, honeydew and ripe fruits). Bee hives constitute places where the wasps can find the best combination of proteins from animal origin (bees or larvae) and carbohydrates (nectar and honey). According to De Jong (1979) some social wasps are quite dynamic enemies of honey bees which in some cases may cause serious damages to bee-colonies. The large wasp V. orientalis has been reported as being an insect particularly dangerous to the bee colonies (Edwards, 1980; Shoreit, 1998). Mayer et al. ,1987) indicates that yellowjackets [Vespula pensylvanica (Saussure), Vespula vulgaris (L.) and V. germanica] eat bee brood, rob honey and sometimes kill the queen or the colony. Stringer (1989) also reported that V. germanica and V. vulgaris compete with honeybees for honeydews, resulting in a considerable decrease in the annual honey production. The oriental wasp, Vespa orientalis L. is considered one of the most important insect pests affecting honeybee industry in Egypt. Furthermore, it attacks many fruit trees, especially grapes and dates The wasps attack foraging workers and guard bees at hive entrances 7

and resulted weakening strong colonies and minimizing their productivity. In some circumstances, the wasps enter the hive and carry off both larvae and pupae. The wasps bite and discard the head and the abdomen of the adult bee and flies back to their nest with the thorax to feed the wasp larvae. The population activity of the wasps varied greatly according to the prevailing weather factors. In Egypt, many authors mentioned that the activity of oriental wasps is very low in winter, spring and early summer and gradually increase to reach the peak of abundance in the autumn particularly during October. The number of wasps starts to fall off gradually during the second half of November and disappeared in the middle of December. Different types of traps either baited or not baited for capturing oriental wasps were used by Ibrahim and Mazeed (1967) they tested seven types of traps that currently used in Egypt. They found that the wooden trap recommended by Ministry of Agriculture in Egypt with honey baits was the most efficient one followed by the ordinary tin-can trap. Ahmed (1999) recorded that using Ministry of Agriculture trap exhibited a highest fitness for the high season of hornet population than the hanged trap (Abou- Elezz trap). Also, he found that the poison bait having 10 gm Lannate 90% mixed with 1Kg honey gave speed action on capture the wasps. Irrespective of the high nutrient contents of yeast cultures (Candida tropicalis) of protein, amino acids and vitamins, they emerges special odor during their growth especially in liquid culture that attracts honey bee workers to feed on it. The aim of this work studing the realtionship between predator (Vespa orientalis L.) and prey ( Apis mellifera) in some point as followed: 8

1- Seasonal abundance of hornet population 2- Fluctuation of hornet numbers attacking honeybee colonies 3- Relationships between oriental hornet and some races of honeybees and their descendant hybrids 4- Impact of hive bottom board modification on hornet-bees relationship 5- Impact of Honeybee colony strength on hornet-bees relationship 6- Seasonal number and percentage of wiped out colonies due to direct attack and negative latent effect of oriental hornet

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REVIEW OF LITERATURE 1. Ecological studies of hornets Sharkawi (1964) recorded that the normal distribution and the population density of oriental hornet begins with a slight increase in number during August. In September, a big jump in their number occurs, and then the insect activity reaches its peak in October. The number of hornets starts to fall off gradually during the second half of November and disappeared in the middle of December. on Japanese hornets which are followed by a description of the nesting habits of nesting V. mandarin, with diagrams and photographs of nests, and tables giving the size and numbers of brood cells and numbers of different brood stages. The annual cycle and behavior patterns are then described. Its peculiar habits when compared with other Vespa species. They studied the following points: 1. Exclusively subterranean nests. 2. Conical and irregular comb surface and in complete nest envelope. 3. Mating front of nests. 4. Frequent food exchange between workers outside the nest. Visits to apiaries and attacks by different species of hornets on honeybees are discussed. In Japan the attacks of V. Mandarinia differ from those of the other species consisting of 3 phases hunting, slaughter and nest occupation.

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Brar et al. (1985) reported that Vespa Orientals visited colonies Apis mellifera from July to December, with peak population in August and October. The number of hornets caught in apiaries varied from 18 to 74. Few hornets visited apiaries during mornings and evenings, whereas In the middle of the day 30-51 hornets were observed during the peak population period. Sharma and Raj (1988) in India showed that survey o f A . mellifera apiaries revealed the presence of 5 species of predatory wasps V e s p a m a n d a r i n , V . V e l u t l n e a u r o r a , V . t r o p i c , V . o r i e n t a l i s t a n d V . bawls. Maximum attacks of V. mandarin, V velutina auraria -and V tropica were recorded during the beginning of October and the end of November. Matsuura (1988) studied the attacking and damage caused by hornets of the genus Vespa to Apis mellifera colonies in Japan with or without hornet traps, and in wild colonies. He recorded that the most common species, V. mandarinia, visited apiaries from mid / late August to late November, with mass attacks throughout the period except in the last month. During the study, all the 106 colonies in hives without hornet traps were extirpated by mass attacks involving 2-18 hornets (mean 7 .9). The mean number of hornets killed during an attack was 1.8, whereas about 15000 worker honeybees were killed. In 6 cases the queen and some young workers abandoned the hive before being exterminated. Of 35 wild colonies, 31 were destroyed by

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mass attacks. V. mandarin also attempted such attacks on hives with traps but were unable to enter the hive. Ishay and Lior (1990) in Israel made observations o n t h e activities of workers of V. orientalis during flight to and from the nest, o n f u l l y a c t i v e d a ys i n m o n t h s o f m a x i ma l c o l o n y a c t i v i t i e s . T h e y recorded two types of flight out of the nest: flight for removal of dug-up soil and f light f or f oraging of building mater ials and f ood f rom the field. The flight activity is gaussian and in accordance with the int ensity of solar radiation. The study suggests that there is strong competition

among

the

digger

hornets

for

flight

opportunities during periods of highest insulation intensity. Due to the correlation between the flight of digger hornets and the intensity of sun radiation, it is assumed that hornets do make use of solar energy for flight purposes. Si ha g (1992 a, b) stated that V . o ri e nt al is st ar te d to vi si t a n A . mellifera apiary in June and continued until October-November. The wasps preyed on guard bees at hive entrances, and after mid-July they a l s o c a p t u r e d b e e s f r o m flowers

in

December -Ma y.

The

average

population

density of the wasps in an apiary was 7.5 in June -mid-July and 3.5 from mid-July to Sept-Oct. The average numbers of wasps caught daily during 1989-1990 were 30/h, of the 28 A. mellifera colonies and 12 colonies were lost due to hornet effect.

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Ugolini and Ishay (1992) described the pattern of f l i g h t s c it ed w it h ne st di gg i ng of V. or ie nt al is , ba se d on observation made in Israel in the field in the summer the outgoing and return flights are perpendicularly to the wind direction, the arc is made with the wind and its length is almost constant. The possible of these flights is discussed. Chang et al. (1 99 3) identif ied the visiting wasps in an apiar y in T aej on, Korea Rep ubl ic. The y recorde d 4 f ameless, 5 gene ra and 12 s p e c i e s . T h e n u m b e r s o f c a p t u r e d V e s p a m a n d a r i n i a , V c r b r o a n d vespula vulgaris were 280, 296 and 269 respectively. V. mandarinia visits peaked at 10.00h to 11.00 h and 15.00-16.00 h as 27 and 20 individuals, respectively, in mid-September, however, in late September and in early October the visiting peak time was from 12.00 to 13.00 h with 23 and 35 c aptured, respectivel y. There are no sig nificant relationship between visiting wasps and weather. Abrol (1994) studied the activity of V. velutina in 2 apiaries, the first one with 10 Apis mellifera colonies and the second with A. Cerullo colonies. The wasps were active from April to November, with a peak in August- September. Diurnal activity showed a peak between 09.00h and 13.00h, af ter which it declined wasps, hovered near hive entrance and caught returning foragers, and they also caught bees as they foraged on flowers.

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Ishay (2004) stated that Oriental hornet Vespa orientalis (Hymenoptera, Vespinae) flies outside its nest only in the daytime and never in the dark. Oriental hornets can be anaesthetized by means of diethyl ether, following which they awake spontaneously within about ≥1 h. However, when the anaesthetized hornets are exposed to direct irradiation they awake much faster and immediately fly out and this is within the temperature range for their normal activities (20–400C). Light exerts an effect not only on intact hornets, but also on their main body parts, the head, thorax or gaster, or a torso without a head or without a gaster. These body parts also ‘awake’ from ether anesthesia when illuminated, especially by ultraviolet (UV) B or shorter light wavelengths. Ishay et al. (2004) found that of the various wavelengths of sunlight, UV was the most contributory to the active cuticular voltage generation. Throughout the warm season of the year the active period in colonies of social hornets and wasps colony members exit from the dark nest during the daytime and fly to the field under the hot sun for various foraging purposes, ultimately returning to the nest. Thus, each hornet, queen, worker or drone, probably undergoes daily cyclical process of electric charge and discharge in the exterior part of their integument, cuticle, which lasts up to 30-40 min. Such photoelectric phenomenon was detected in both live, ether-anaesthetized hornets and dead hornets; albeit in the latter the electric values recorded were lower. The present study addresses the possible impact of the phenomenon on vespan daily life.

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Sverdlov and Ishay (2004) measured voltage values from the cuticle of live specimens of the Oriental hornet Vespa orientalis (Hymenoptera, Vespidae) The relevant measurements were taken between the two tips of their bodies at various hours of the day and were made on a total of 90 worker hornets. Recorded voltage values varied within a range of 60-180 mV. The lower values measured during the morning hours and the afternoon and the highest values during the noon hours. The distribution of the voltage values in hornets measured at various hours in the daytime closely resembled that of the global radiations (in W/m2) on the same days the measurements were taken. 2. Biological studies of hornets Sandman (1940) dugs out the comb of vespa c r a b r o a n d transferred it to a box together with the queen, where lie could observe the w ho le s oc ia l a ct iv it y of t he ne st f r o m s ta rt to en d. He t in ed th e departure of the queen and found that it left the nest sufficiently long for him to get the comb out and hang it in a box with a wire passed through it before the queen came back. He placed a small mirror in the botton of the box so that the inside of the comb could be seen in it. He observed the queen's work for about three days. On the fourth day it left the nest and did not appear again. It could be probably not with an accident. Sharkawi (1964) stated that the studying of hornets’ biology depends on establishing a colony in a place easy to observe but with the same characteristics of the natural one which was in a dark cavity of a hole. A mud walls built with compartments like the natural cavities of 15

nests to use in this experiments. Attempts were made to accommodate queens after hibernation or queens with their embryo nests, but they were not successful. El-Deeb et al.(1 96 5) mentioned a comparative study of the external morphology and the internal anatomy of the alimentary canals and the reproduction systems of worker, queen and drone of hornet, Vespa orientails, Also the life - cycle and the damage caused by this wasp to apiaries and fruits, was discussed. Ishay and Schwarz (1965) specified a detailed account on the interrelations between the queen and workers of V. orientalis. Inter alia, it had been pointed out that during pauses between ovipositions, while the queen is resting on the surface of the comb, the workers approach and arrange in a circle about her. Some of the workers proceed to lick the body and particularly the head of the queen, whereas others commence tapping their abdomens against the surface of the comb. These tapping sounds, although produced by workers within the nest, are clearly audible outside the nest, even at distances of 1-1.5 meters from it. Isha y

(1968)

me ntioned

that

d uri ng

the

active

su mmer sea son hornet workers in such groups develop ovaries, build one or more combs into which they oviposite, and subsequently nurse and brood jointly - not so usually, in the case of horn et queens kept in groups, for although a single small comb was built occasionally by one of the queens only rarely did more than one queens participate in the building. Neither did queens tend to feed on proteins stored 16

in their fat body to produce the eggs; the queens in their natural habitat were unable to capture insects as a source of the necessary proteins. Waf a et al. (1969) studied the biological aspects of the larval stages of the oriental hornet, Vespa orentalis, Fab . The mean periods of t h e f i v e l a r v a l i n s t a r s i n t h e q u e e n w e r e 1 , 1 , 2 , 3 a n d 8 d a y s , respectively, while in the worker they were 1 , 1 , 1 1/2 , 1 1/2 and 4 1/2 days, respectively, and in the male, large variations were observed according to the cell size. Spradbery (1971) studied the nests of Vespula vulgaris and V. germanica. The seasonal changes in population structure of the 89 colonies collected are described. The ovaries of queens developed after emergence from hibernation. Daily oviposition exceeded 200 in July, declining to 100 during August and September. The direct linear relationship between numbers of eggs and of pupae suggests that oviposition rate may be influenced by pupal density. In August building of queen cells (31 % wider) superseded the building of worker cells. More queens were produced per year than by any other social Hymenoptera. Adult males emerged f rom late July to mid -August, and adult queens emerged f ro m late Augus t to e arl y Septe mber. Approxi ma tel y 16 000 adults per colony were produced by the end of the season. Wafa and Sharkawi (1972) in Egypt recorded the biology and life history of V. orientalis. The 5 larval instars occupied 1, 1, 2, 3 and 8 days in the queen;1, 1, 1.5, 1.5 and 4.5 days in workers (mean f i g u r e s ) . T h e d e v e l o p m e n t a l p e r i o d o f 17

m a l e s v a r i e d c o n s i d e r a b l y , according to cell size. The prepupal stage occupied 6.5, 4 and 6 da ys, respectively for queen, worker-and drone. The pupaI stages were 13.5, 8.5 and 12 days. Archer (1972) collected 27 nests and studied p h a s e s o f development: worker brood only (A); male and worker brood (D); queen larvae, male and worker brood (C); queen cocoon's or virgin queen in, or having been produced by, the nest (D). Nests in period (D) either had only female reproductive’s or male and female, in which case the, nests were larger and had a greater number and proportion of large cells the daily worker emergence rates were 36-54 (A); 96176 (B, C); 104-156 (D). The daily average oviposition rates were estimated to be-78 (A); 185 (B); 157 (C), 149, of which 36 were laid in large cells, (D). Cell-building was at its maximum (90-157 cells / day) in period B and most foraging was in (C) and (D). The larger nests in perio d (D) produced workers of larger size a n d m o r e n e w q u e e n s ( 1 1 2 0 ) t h a n s m a l l n e s t s ( 7 4 6 q u e e n s ) . I t i s suggested that this variability is due to), weather conditions and differing rater of worker mortality, particularly in periods (A) and (B). Isha y (1976) stated that the abilit y of hornet workers to build geotropically oriented sterns combs has now been tested in containers of various geometrical shapes. It was found that hornets display negative geotropism, but the capacity to discriminate the zenith (the highest point in the 18

container) is not fully developed at emergence but improves with time during the first 3 days of life. Ishay and Perna (1979) stated that among Vespinae both the queen and workers build cells of a typical architectural design which are suitable for rearing a brood. In the case of Vespa orientalis, but not in the species V. crabro, Paravespula vulgaris, P. germanica, Dolichovespula saxonica, or D. media, groups of workers of various ages which are kept in artificial breeding boxes in the absence of a queen continue to build new cells and even entire combs. Workers which are deprived of a queen build worker cells but not queen cells. The construction commences from a central point where the workers had congregated for a while. The site of construction can be preselected by intentionally directing the workers to rest in a particular spot Once the building has been initiated, the workers will persist building in the same spot over and over again, even after any imposed limitation has been removed. Motro et al. (1979) measured ovaries development i n yo u n g w o r k e r s o f V . o r i e n t a l i s t ha t h a d b e e n k e p t in q u e e n l e s s g r o u p s f r o m t h e mo me n t o f emergence. The mean length of the oocytes increased over the test period and there was a more marked increase in the coefficient of variation

with

time,

which

reflected

the

increasing

v a r i a b i l i t y i n o o c yt e s s i z e w i t h i n c r e a s e d a g e o f t h e w o r k e r s . I n p a r a l l e l e x p e r i m e n t t h ey m e a s u r e d o v a r i e s development in older workers that had been separated i n t o qucenless groups only after growing up in a normal nest 19

(i.e.. in a nest containing a fertilized, ovipositing queen as well as adults and brood at various ages). Kadymov (1981) studied the biology of V. crabro in large beekeepi ng enterprises. T he period of emb r yo nic develop men t lasted 5-6 days, the larval period, 9 days, and pupal period 14 days. The workers began foraging a few days after emergence Adults fed on honey, r i p e f r u i t , b e r r i e s , s a p , h o n e y d e w , f l i e s , l o c u s t s , d e a d l i z a r d s a n d f r o g s and other food of animal origin. The maximum numbers of hornets was o b s e r v e d i n A u g u s t a n d S e p t e m b e r . I t w a s i n t h i s p e r i o d t h a t t h e y attacked honeybee colonies with the greatest frequency, inflicting great damage to the bees. The bees were not passive during these attacks and s u c c e s s f u l l y killed hornets by stinging them. In the autumn, a new generation of male and female hornets emerged, and the males perished after mating. The workers died with the onset of cold weather. Fertilized females hibernated in sheltered habitats. Martin (1991) i n J a p a n c o l l e c t e d 4 1 n o r ma l c o l o ni e s o f V e s p a basalia over a period of two years were used to develop a simulation model which attempted to predict the daily changes in a typical colony of this species. Cell building rate, egg laying

rate,

type

of

egg

laid

(worker

/ male/ queen),

developmental periods of the brood and workers. Yamane (1992) showed that a mature nest of Vespa basalia smith from Taiwan appears to be one of the largest hornet nests so far recorded. The nest was completely enveloped and 21

had a moderately pointed roof cone and three vertical slit-like entrance holes on the side. It had 15 round combs with a total of 40,000 cells. The adults collected with the nest totaled 558 workers, 579 males and 535 new queens. The greater part of the adult, however, including most workers, escaped at the time of collection. The number of workers, males and queens which the colony had produced (including cocooned stages) were 37.000, 3900 and 3400, respectively. The colony did not appear to be near the end of its productivity, so that it was likely to have produced many more males and queens. Martin (1995) studied 134 Vespa affinis colonies and data collected from these colonies was used to build a computer model which predicted the daily growth of a colony. The model was used to compare the development between small and large colonies of Vespa affinis. Observed data and model- generated values are in good agreement. The timing of events was similar in all colonies, despite large variations in size. Slow colony growth is due to the failure of worker to build new cells, while differences between species depend on the ability of the queen to lay eggs. The greatly reduced numbers of sexual produced by small colonies were most likely to result from incidents occurring earlier rather than later in the nesting season. Ishay et al. (2002) found that social wasps belonging to subfamily: Vespinae (Hymenoptera) build brood combs made up of hexagonal cells, all of which have their outlet facing in the direction of the gravitational force. These combs are built of organic and/or mineral matter, each grain of which is enwrapped in saliva secreted by the 21

building hornets. The enwrapping hornet saliva hardens rapidly into a tough polymer that binds together the building materials collected from the surroundings. The combs are intended to rear the brood from egg to imago. The comb cell walls possess electric properties which in part have already been elucidated. It has been established that the cell walls behave like a thermoelectric material in that with rise in temperature between 20-30°C Ishay et al. (2006) found that a thermogenic center has been found in the dorsal part of the first thoracic segment in social wasps Vespa orientalis and Paravespula germanica (Hymenoptera, Vespinae),. The temperature in this region of the prothorax is higher by 6–90C than that at the tip of the abdomen, and this in actively flying hornets outside the nest (workers, males or queens) as well as in hornets inside the nest that attend to the brood in the combs. Ishay et al. (2006) found that the temperature in the nest of V. orientalis (as measured between the brood combs) is a stable 29±1◦C. In the summer, when the heat in the field rises and so also the temperature in the hornets nest, which is usually constructed subterraneanly, worker hornets, and occasionally also young queens beating their wings and arranging in circles (or in lines) around the nest entrance, with their heads directed outwards. The number of wing beating hornets depends of course on the size of the nest population but per same nest and day it is in correlation with the time of day, considering that the warmest hours of the day in the summer are the afternoon hours, few ventilating workers found in the morning hours,

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but their number increasing steadily toward the hottest time of day, usually about 3–4 in the afternoon. Marian Plotkin et al. (2009) found that yellow-colored part in V. orientalis contains within pockets in the cuticle granules possessing a yellow pigment. These yellow granules (YG) are formed about 2 days prior to eclosion of the imago, and their production continues for about 3 days posteclosion. Xanthopterin is the main component of the granule and lends it its yellow color. Xanthopterin produces a characteristic excitation ⁄ emission maximum at 386 ⁄ 456 nm.

3. Behavioral studies of hornets Imms (1938) reported the material used in the nest of Vespa species construction consists of wood particles which are rasped from palings, fences, dead trees, etc., by means of the mandibles. They worked up with the aid of saliva and masticated to form a substance which, when dry, has a paper like consistency. Free (1970) found that wasps individuals while foraging on dead adult and pupal honeybees, showed little conformity in the order in which they dismembered their prey, they attempted to take as large load as possible, and preferred abdomen and thorax parts than head. Wasps always removed some appendages from the thorax, especially the hind and middle legs, but the presence of these appendages did not encourage foraging or facilitate recognition of the prey. Pupae were preferred to newly emerged bees, and newly emerged bees to old bees. Archer (1972b) made laboratory tests, single or small numbers of workers found comb without brood less attractive than comb with cocoon caps or small or large numbers of larvae. Records collected 23

over three years from 6 observation nests shoed that in all cases a dominant comb, which carried a large percentage of workers than any other comb and usually the queen if present, was soon established. This comb always which contain brood, was nearest or near the entrance, and received most foragers, workers grouped on it more frequently than on other combs, grouping behavior of workers on comb was related to background temperature. Below 19.50 C and above 270C. No grouping behavior was observed, between these temperatures grouping caused comb temperature to increase to 29-32.5 0C. Grouping was noted without a queen but never in the absence of foraging. The attention a larva received from workers increased as the number of workers on its comb increased. Sakagami and Matsumura (1972) stated that the annual cycle is divided into the phases pre-nesting solitary, co-operative and social, dissolution of the nest, hibernation. Behavior in attacking colonies of A. mellifera , A. cerana, and those of other social wasps is described. Unlike V. mongolica for instance V. mandarinia attacks a selected A. mellifera colony, a group of 20-30 wasps acting together. In the south of Japan such a group will kill 5000-25000 bees out of a population of 15000-30000, only 1 or 2 of the wasps occupy and guard the hive, carrying of the prey during the next few days. The attacks on A. mellifera , which cause severe losses to beekeepers, are considered as an arising from an exceptional coincidence of ecological conditional in the area. Ishay (1973) observed that the behavior of hornets V. orientalis kept in boxes was observed. After incubation for 4-6 days at 80C young 24

unfertilized queen, between 1 and 60 days old, built combs and laid eggs. Queens normally need 5-6 months of diapauses between emergence and cell building. Worker spontaneously built combs attached to the roof by stalk, as they do in nests. Similar combs were built by workers after the amputation of their wings and incubation for some days at 80C, or living with a fertilized queen, or fed with queen pheromone. Ishay (1976) studied cell building activities of Vespa orientalis queenright and quennless colonies were allowed to oviposite into cells and raise brood within comb cells that were smaller than, equal to, or larger than normal. In both groups queens were willing to oviposite into cells larger than those normally used during the same season. Worker, however, attempted to rectify the dimensions of cell different from normal. Experimental transfer of eggs and first to third instar larvae from worker cells to queen cells resulted in the development of queens. The reverse transfer resulted in the production of workers. Transfer resulted in the production of workers were made on the comb building activities of intact hornets and those with wings amputated in various ways. Intact hornets build pedicles suspended from the roof of the breeding box and were built vertical instead of horizontal axis. Hornets without wings also built combs against the wall, but without pedicels. Cooling or feeding wingless hornets with queen pheromone caused them to revert to normal cell construction. He suggests that wing amputation upsets sensory feedback of spatial resulting in deviation in the orientation of construction.

25

Macdonald and Matthews (1976) studied the colonies of both species Vespula vidua and V. consobrina which they are typically subterranean., but are also found in decaying logs and stumps. Mature nests consist of about 1000-2500 cells, and contain a single worker cell comb. Colonies contain 100-400 workers at their peak. Archer (1977) studied foraging activity of Paravespula vulgaris in the field ,using fixtures over the entrance holes of underground nests. Departing foragers carried earth, nest waste, or nothing. Incoming foragers carried pulp (for nest building), flesh (to fed larvae), or a complementary or partially full crop or liquid and a few had no load. Partial liquid loads were also carried by 28% of pulp carriers. No correlation was found between worker size and weight of flesh or pulp load, but there were significant correlation between worker size and weight of earth and liquid loads. Grinfel (1977) showed that active nests of Polistes gallica removed from lofts were fixed inside wooden boxes 20X20X20 cm. these carnivorous wasps fed themselves and their larvae (by mouth), on food containing proteins, and also on some carbohydrates foods such as nectar, honeydew and the juice of ripe fruits. Morse (1980) stated that bees may be attacked by Vespids both in the field and at the entrance of the colony. In some circumstances the wasps may enter the hive and destroy larvae and pupae, although the pupae are preferred. Generally, only the thorax of the bee is eaten. Wasps bite of the head and the abdomen of the bee and flies back o its nest with the thorax to feed the larvae.

26

Archer and Phipps (1982) stated that in late summer and winter 1979-1980, from a single subterranean colony of V. germanica numerous wasps interfered in hive management, prevented honeybees from foraging efficiently, and robbed small colonies. Feeding syrup to the bees attract wasps, which were able to enter hives unmolested at temperature below 100C when the bees clustered and left entrances unguarded. The wasps took honey or sugar syrup from unsealed combs, wood pulp and water from the hive walls, and the contents of the honey sac of dead bees. Wasps were observed foraging at temperature from 1 to 60C until January, when the nest was dug up. The structure and contents of the nest are described. Ishay et al. (1984) found that the activity of controlled V. orientalis queens was very low. In fact, control queen immobile throughout the observation periods and they were at least four hours during day (at night queens hardly move even under natural conditions). Under conditions of light and heat, the queens commenced becoming active (started to feed, build, and quarrel or attempt to fly within the breeding boxes, in contrast with the queens treated with heat alone which were already week after the start of the treatment, the queens behaved the same expect than under heat and light as for exposure to light only. Ross et al. (1984) found that horsemeat (based carnivore food) Nebraska Brands Feline Food (NBFF) much more attractive to worker of Vespula germanica (F.) and V. maculifrons (Buysson) than several meat based pet foods currently used in toxic baits abatement programs. Solvent extract made from NBFF were also strongly attractive, with the 27

ethanol fraction being the most attractive. The combined extract fractions of NBFF were as attractive as whole NBFF. Performance of relatively unattractive meat products was enhanced after addition of various extract fractions made from NBFF. Possible applications of extract fractions as alternatives to chemical lure i.e. heptyl butyrate, was discussed as they relate to yellow jacket abatement. Jianding et al. (1985) found that hornets which preyed on honeybees in Fujian province China were identified as Vespa mandrinia, V. bicolor, V. basalis, V. tropica baemetodes, V. ducalis and V. offinis. The life histories of these species are described, and details are given on overwintering, nesting, colony development, foraging and feeding habits. Experiment on control methods showed that the most effective method was smear captured hornet with poisonous dust at the rate of 1-29 mg per hornet. Matsuura (1985) compared the giant hornet, Vespa orientalis, with other Japanese hornets. This hornet affects congeneric species in two ways, as a competitor in seeking common food sources and as a predator. The vespine species attack consists of three phases hunting, killing and nest occupation. The attacks have been done on honeybee colonies since the introduction of Apis mellifera into Japan. A. mellifera has no effective defence, such as possessed by A. cerana. Ono el al. (1985) observed the mating behavior of Vespa mandarinia at Machide-Shi, Tokyo and at two places in Kumamoto prefecture, from the middle of October to November in 1983 and 1984. In most cases, the nests were in underground cavities or hollow trees and the entrance was surrounded by a pile of excavated soil pellets. 28

Many males were attracted to the vicinity of the nest entrance and flew from around 10:00 to 13:00h. When a sexual mature new queen left the nest entrance, some of the waiting males tried to copulate with her. The distance from the nest entrance to the mating site was mainly within 2m. No sign of attempted mating between males and workers or other males leaving the nest was observed. An ether extract of workers was used to attract 347 males during the mating season. This suggests that worker aggregation pheromone is closely related to attraction of males to the nest entrance. Aggregation pheromones activity was found in all three casts. A queen specific sex pheromone, which induced the typical mating behavior of males, was extracted from young queens. No. such activity was observed in extract of workers and males. Muzaffer and ahmed (1986) found that Vespa basalis, V. orientalis, V. tropica, V. velutina V. pruthii and Vespula germanica preyed upon Apis mellifera and A. cerana in Pakistan. Vespa pruthii and V. basalis were the most important and caused heavy losses by feeding on adult bees and their broods. Honey reserves were also taken, and this was particularly damaging during the near flowerless dry season(July to October). A. mellifera was comparatively more susceptible to attack than was A. cerana. Plastic jars placed on top of the hive containing 50% solution of sucrose collected large numbers of wasps and hornets and provided some degrees of control, particularly of V. pruthii . Vincent (1988) studied the population of the western yellow jacket, Vespulla pennsylvanica, regulary declined in Hawaii in December despite the warm winter. This decline may be correlated 29

with the significant shortening of daylight and the decrease of solar radiation in August and September. Sakai (1989) noticed that the hornet, Vespa simillima xanthoptera, attack A. mellifera and A. cerana colonies from jun. until mid Nov. they attacked A. mellifera colonies more easily than A. cerana at hive entrance of the latter, guards vibrated their abdomens. A. cerana killed hornets by balling to produce a high temperature. A. mellifera killed hornets by stinging them. When hive of A. cerana was caged with a net that interrupted the workers flight, hornets learned to prey on these bees. Ishay and Ganor (1990) showed that brood combs of Vespa oreintalis were collects in Israel to examine the comment or mortar used by adults to glue together organic or mineral building material used in their construction. The cement is secreted in the saliva of adults of the vespid, hardening within seconds to form fibers or plates, this saliva derived spittle overlay and united the building particles laminally and vertically. Within the brood cell, the larval cocoon was largely fastened to and supported by the cell walls and was composed of a network of silk fibers and interlinking flat surfaces. On the outside of the cocoon fibers were spherical button like structure that were very rich in phosphorus. The chemical composition of the adult salivary cement and the larval cocoon fibers were similar: both contained the elements P, Mg, Cl, K and Ca. Shah and Shah (1991) showed that during Vespa vulutina attack A. mellifera colonies, up to 150 workers from a loose cluster at and around the hive entrance. When a hornet approaches the cluster, one or 31

two bees may leave the cluster and walk rather aggressively towards the hornet, but this behavior does not repel the hornet, which seizes one of these bees and flis off with it. Guard bees seldom attack the hornets and appear incapable of sezining and holding a captured hornet finally enough for it to be killed. A. mellifera workers particularly during the honey flow, take off slowly, making a couple of circles above the hive before flying off. This makes them easy prey. Woyke (1992) Studied defense behavior of an African bee colony was studied in order to determine recommendations for handling A. m. adansonii bees (when and how) without being stung. The number of stings left in a leather ball suspended 50 cm in front of the hive entrance for 1 min was therefore counted as well as the number of workers returning to the hive over a 5-min period. A typical pattern of diurnal defensive behavior was observed. During the nonproductive period, i.e. the summer rainy season, one peak of defensive behavior was observed in the morning. During the period of honey flow, i.e. the winter dry season, 2 peaks occurred, one early in the morning and the other late in the evening. A highly positive correlation existed between flight activity and defensive behavior. Abrol (1994) noticed that Apis cerana workers resisted wasp attacks by creating shimmering movments at the hive entrance and by balling behavior against individuals’ wasps. Apis mellifera workers also killed wasps but their defensive behavior was not so well organized as that of A. cerana. For both species, the number of wasps killed was significantly and positively correlated with honeybee colony population. 31

Akre and Mayer (1994) showed that strong colonies of honeybees are relatively free from attack by yellow jacket perdition only becomes serious in the late autumn when bees are limited in activity by temperature, but yellow jacket colonies are at the highest population. Defense used by A. cerana japonica consists of balling during which between 180 and 300 workers gather into a tight ball around the attackers for up to 20 min. Any hornets inside was killed by the 460C. This defense was usually successful although some colonies are destroyed by wasps. This defensive techniques suggests that heaters installed at honeybee hives entrances might repel hornets trying to enter the colony. Ishay and Letvtov (1994) showed that hornet workers (Vespa orientalis, Hymenoptera, Vespidae) were anesthetized by diethylether, and their sleeping period was monitored. Sleep duration in hornets was found to be inflounced by pre exposure to horizontal rotation or to hypo and hypergravity, by volatile fractions of their own venom and by the size of their habitat. Coster and Turillazzi (1995) reported that Parischnogaster alternate build two distinct types of nest which differ in substrate and other characteristics. Both types of nest were examined and compared for overall dimensions, cell size and building material. Significant differences between the two types of nests were found in cell size and percentage of inorganic and organic material. A significant difference was also found in the wing size of the inhabitants. Yildirim and Ozbek (1995) mentioned that the vespine (2521 specimens) collected during 1970- 1991 from various parts of Turkey, 32

comparing 12 species and supspecies, were recorded Dolichovespula adulterine, D. norwegica, D. saxonica, Vespa austrica and Vespa crabro germane were new records for Turkey. Vespa orientalis was very common in vineyards of fruit growing areas, in some places becoming a serious pest on ripened and bruised fruit including apples, grapes, mulberries, peaches and apricots. Dani et al. (1996) suggested that in social wasps of the genus polistes the Dufour's gland involved in kin recognition. In fact, the same hydrocarbons occurring on the cuticle are found in the gland secretion. In P. dominulus the composition of the glandular is more similar in foundresses belonging to the same colonies than in heterocolonial

founderesses.

P.

dominulus

colonies

were

experimentally presented with previously treated dead nonspecific females. These lures had been derived of their epicuticular lipids and coated with epiculticular. Lipids, the Dufour’s gland secreation are involved in nestmate recognition. Koeniger et al. (1996) observed Colony defense and predatory behavior of Vespa multimaculata entrance of a natural nest site of Apis nuluensis. When V. multimaculata was present, guard bees frequently performed body shaking behavior: bees lifted the tip of the abdomen slightly spreading the wings and exposed the Nasonov gland. The oscillation of the abdomen tip had an amplitude of 83° (SD = 50°; n = 84) and its duration was 0.08 s (SD = 0.01; n = 84). The individual behavior resulted in the rapid formation of a group of guard bees and induced body shaking of neighboring bees. The hunting V. multimaculata workers hovered about 5-10 cm in front of the nest and 33

blocked the direct flight path of bees returning to the nest. Returning foragers are regularly diverted from the nest entrances and attracted to the body shaking guard bees where they land beyond the reach of hovering V. multimaculata. During a period of 12 h one V. multimaculata worker caught 14 bees. At the end of the observation we brought the hornet (tethered to a wire) into contact with a group of bees at the nest entrance. The A. nuluensis guard bees immediately balled and killed the hornet with heat. Suzuki (1996) showed that the social behavior of confound dresses was described for P. stigma, the queen founders performed cell initiation, oviposition and received more flesh pellets from returned foragers. Foraging was for pulp to initiate cells and not for other materials. The queen and subordinates tended to rub different parts of the nest., suggesting different functions. Although subordinates as a whole did all tasks for the colony, contributions to each task were very different among individuals. Some foragers initiated new cells and oviposited as well as the queen. Their oviposition was not interrupted by the queen, but all their eggs were eaten by her resulting in functional monogyny. Some foragers started flesh foraging later than others which disappeared in the early period. A part of cofounders did not substantively work for the colony. Changes in the time allocated to various spatial positions were distinctive among individuals, depending on their social activity. Breed et al. (2004) stated that One key advantage of eusociality is shared defense of the nest, brood, and stored food; nest defense plays an important role in the biology of eusocial bees .Recent studies on 34

honey bees, Apis mellifera, have focused on the placement of defensive activity in the overall scheme of division of labor, showing that guard bees play a unique and important role in colony defense. Guzman-novoa et al. (2004) analyzed the relationships of the guarding, stinging, pursuing and alarm pheromone responses of two types of bees: European (EHB) and Africanized honey bees (AHB). Single type (source colonies) and two-type (EHB and AHB cofostered) colonies were used. Of co-fostered bees, AHB comprised 81% of those that stung during the first 10 s. But from 10 to 30 s, AHB and EHB were equally likely to sting. However, when tested in their own colonies, two of the three EHB types did not sting and did not pursue in any of the eight trials conducted, whereas all three AHB types did in all trials. Moreover, AHB represented 90% of bees that stung observers during an 18-day observation period (25% of which were recently seen guarding). There was a relationship between pursuing and stinging of the six source colonies and the guarding behavior of co-fostered individuals from those sources. Results suggest that the more defensive bee types guard longer and may affect the thresholds of response of less defensive bees, recruiting them to sting. Results also suggest that the individual performance of different defensive tasks cause interactions that result in increased colony response. Guzman-novoa et al. (2005) studied the defensive behavior of 52 hybrid honeybee (Apis mellifera L.) colonies from four sets of crosses and compared with that of European and Africanized bee colonies. Colonies containing F1 hybrid workers were obtained through 35

reciprocal crosses between European and Africanized bees. The total number of stings deposited by workers in a moving leather patch in 1 min was recorded. In each of the four sets of crosses, bees from hybrid colonies of Africanized paternity left more stings in leather patches than bees from hybrid colonies of European paternity. Results strongly suggest paternal effects of African origin increasing the defensive behavior of hybrid colonies. Although some degree of dominance was observed for high-defensive behavior in one of the four sets of crosses involving European paternity Abrol (2006) studied defensive behavior of Apis cerana F. against predatory wasps Vespa velutina and Vespa magnifica. The honeybee Apis cerana showed a well organized defense and killed more number of predatory wasps by exhibiting well organized balling behavior as compared to Apis mellifera L. The bee mortality was higher when fewer wasps visited the apiary due to an unorganized defense. However, when the intensity of attack was severe, fewer bees and more wasps were killed due to an organized defense. Tan et al., (2007) studied the behavior of vespine wasps, Vespa velutina in China using native Apis cerana and introduced A. mellifera colonies. When the wasps are hawking, A. cerana recruits threefold more guard bees to stave off predation than A. mellifera. The former also utilizes wing shimmering as a visual pattern disruption mechanism, which is not shown by A. mellifera. A. cerana foragers halve the time of normal flight needed to dart into the nest entrance, while A. mellifera actually slows down in sashaying flight manoeuvres. V. velutina preferentially hawks A. mellifera foragers when both A. 36

mellifera and A.cerana occur in the same apiary. The pace of wasphawking was highest in mid-summer but the frequency of hawking wasps was three times higher at A. mellifera colonies than at the A. cerana colonies. The wasps were taking A. mellifera foragers at a frequency eightfold greater than A. cerana foragers. The final hawking success rates of the wasps were about three times higher for A. mellifera foragers than for A. cerana. The relative success of native A. cerana over European A. mellifera in thwarting predation by the wasp V. velutina is interpreted as the result of co-evolution between the Asian wasp and honeybee, respectively. Papachristoforou et al. (2007) reported that Cyprian honeybees, Apis mellifera cypria, kill their major enemy, the Oriental hornet, Vespa orientalis, in a different way by asphyxia- balling, in which the Cyprian honeybees mob the hornet and smother it to death. Volynchik et al. (2007) stated that during the active season, extending from June to October, hornets emerge from their nest in the field in all the daytime hours. In the beginning of the season, when the number of workers is relatively small, the number of exits from the nest is fairly uniform numerically throughout the day. However, with the increase in hornet population from July onwards, the number of workers emerging from the nest entrance around noon (1100–1300 h) is by 1–2 orders of magnitude greater than the number of those emerging in the morning or evening hours. This disparity persists till September or October, at which time the workers revert to behave as in the beginning of the season. It appears, therefore, that in this period hornet activities outside the nest are coordinated with the meteorological 37

conditions, and in this regard, the highest correlation is with the ultra violet B (UVB) radiation level and to a lesser extent with the temperature. Presumably, also, the greater noon-hour activity in the nests of hornets in the field stems from the digging hornets benefiting from the greater availability of solar energy at noon, mainly that of UVB radiation. Abdel-Gahny et al. (2008) surveyed Two wadi systems in the southwestern part of the St Katherine Protectorate for one year to record the seasonal abundance and food preference of the most common troublesome household pests in Bedouin villages, the oriental hornet Vespa orientalis and cockroaches (Blattodea). There was no significant difference between wadis in wasp and cockroach abundance, even though they differ in altitude, Bedouin density and type of tourism impact. The wasp was abundant from April to November, peaking during August, and disappearing between December and March. Kastberger et al. (2008) found that Giant honeybees (Apis dorsata) nest in the open and have evolved a plethora of defense behaviors. Against predatory wasps, including hornets, they display highly coordinated Mexican wave-like cascades termed ‘shimmering’. Shimmering starts at distinct spots on the nest surface and then spreads across the nest within a split second whereby hundreds of individual bees flip their abdomens upwards. However, so far it is not known whether prey and predator interact and if shimmering has antipredatory significance. This article reports on the complex spatial and temporal patterns of interaction between Giant honeybee and hornet 38

exemplified in 450 filmed episodes of two A. dorsata colonies and hornets (Vespa sp.). Detailed frame-by-frame analysis showed that shimmering elicits an avoidance response from the hornets showing a strong temporal correlation with the time course of shimmering. In turn, the strength and the rate of the bees’ shimmering are modulated by the hornets’ flight speed and proximity. The findings suggest that shimmering creates a ‘shelter zone’ of around 50 cm that prevents predatory wasps from foraging bees directly from the nest surface. Thus shimmering appears to be a key defense strategy that supports the Giant honeybees’ open-nesting life-style. Indu et al. (2009) made an attempt to study the seasonal incidence of predatory wasp in Apis mellifera colony having different number of frames at G. B. Pant University of Agriculture & Technology, Pantnagar. All the three species of wasps i.e. Vespa tropica haematoides, Vespa orientalis and Polistis hebraeus commenced their visit over the colonies from July (early rainy season) and started to decline from the month of November. Maximum activity of predatory wasp was recorded between last fortnight of September (late rainy season) to first fortnight of October (early autumn season) during both the years. No wasp was recorded during winter, spring and summer season during study. Correlation study revealed that there was significant positive correlation between the wasps’ population and minimum temperature (r = 0.287), maximum humidity (r = 0.380) and minimum (r = 0.434) humidity. Positive correlation was also recorded between wasp population and number of frames in the hive. 39

Volynchik et al. (2009) describes the daily activities of the Oriental hornet (Vespa orientalis) workers older than 48 hours as observed in an Artificial Breeding Box (ABB) in our laboratory at the peak of the active season. These workers were picked randomly from a population of a single nest that was enabled to free egress into the field. The study points to the existence of polyethism in the nest of V. orientalis with the adult worker hornets, separating them into three groups in accordance with the frequency and nature of their exits from the nest, and the tasks which they perform. This polyethism was not age-dependent. Recordings were made of the following vespine activities: the frequency of exits to the field during various hours of the day and the various roles undertaken by the hornets. Also investigated was the assignment of tasks among the hornets and the preference given to some tasks over others. The general organization of traffic and other movements in the colony is discussed.

4. Methods used for controlling hornets Sharkawi (1964) in Egypt described several types of control methods against Vespa orientalis in the apiaries of Fayom regoin, among these metho ds ; capturing hor ne ts gathered o n exp os ed hone y co mb s; emplo yme nt of bo ys who killing the h o rnets b y using pal m lea ves or staks. He mentioned that these methods gave good results. Ibrahim and Mazeed (1967) studied seven types of trap currently used in U.A.R. The traps were distributed at random in the apiary and the daily numbers of hornets caught in each trap were recorded. The honey baited traps are 41

considerably more efficient than the unbaited trap. The wooden trap of the M inistry of Agriculture was the most efficient one followed rather closely by the ordinary tin – can trap, if the costs of these two above mentioned traps were taken into consideration, the ten – can trap showed to be more preferred than the wooden. Also they studied eight kinds of insecticides DDT 5% , 10% , Toxaphene 20% , Agoocids 3,7, Sulphur, Phosphate rock and Talc powder. They tested as dusts on the hornets in the laboratory. The results both cotton dust (DDT. 10 - BHC 25 – Sulphur 4) and Agrocid – 7 were superior to all the other insecticides. On the other hand, Sulphur and• Phosphate rock were the most inferior materials. Grant et al. (1968) studied the ground, cooked h o r s e m e a t c ontai ning 1 % chl ordan e WP, in protect ed dispensers, repleni shed at weekly or more frequent intervals, controlled Vespa pensylvanica and V. vulgaris. Foraging adults carried the poisoned bait back to the nests, thus killing many of the larvae. Trap records showed their population s were below annoyance levels at picnic sites in both open and wooded areas.. Comparison with control sites showed that the reduction in population at least sites was due to the poisoning. Rogers and Lauret (1968) modified a plastic – treated 1gallon (gal = 3.785 liters) round cardboards carton to form an efficient, economical trap. Wasps .entered peripheral holes in the bottom to get the bait, than w e n t t o w a r d s t h e o v e r h e a d 41

s k yl i g h t s h o w i n g t h r o u g h ' t h e w i n d o w – screen top, but had to crawl through a 0.72 inch (1.27 cm) hole in the apex of a screen cone, then become trapped between the cone and top, and soon died. A flap cut in the side was opened for case in rebating. The top was removed to empty dead wasps. Wafa et al. (1969) tested seven insecticides applied by means of p o i s o n e d h o n e y b a i t s i n t h e c h e m i c a l c o n t r o l w o r k . D a t a o b t a i n e d revealed that DDT + lindane gave the best results of the chlorinated h y d r o c a r b o n s , w h i l e E n d r i n ' a n d T o x a p h e n e v e r y s h o o e f f e c t e d t h e hornets in the cage conditions. Malathion gave the best results. Honey bait with Dipterex gave a slightly less effect. Lebaycid was less efective than Malathion and Dipterex. Davis et al. (1975) showed that twelve, s ynthetic attractants for wasps, Vespula spp., were only marginally attractive to honey bees (Apis mellifera), alfalfa leaf-cutter bees (Megachile pacifica panzer and alkali bee Nomia melanderi). Traps baited with these wasp attractants can therefore provide a useful control measure against wasps without hanging bees. Higo (1983) tried a trap described for capturing hornets, which is a predator of honeybees in Japan. The trap, whic h is baited fermented honey, has 4 entrances at the bottom of a steel can and on top metal grids of a mesh size which allows honeybees to escape. In 12 traps placed in I0 apiaries from mid – August to November, over 10000 of xanthoptera 42

workers were caught, and also about 100 V. mandarinia and 8 V. analisinsularis Sharma

et

al.

(1985)

observed

Vespa

Mandarinia

,V.tropica,V. vulutina and V. basalis attacking colonies of Apis mellifera and A. cerana in kangra. They kill many foragers and bee colonies tend to abscond. A control method was tested: powdered aluminum phosphide was fixed to the abdomen of captured hornets so that they would take it into their nest. It was partially successful, but further modifications to the method are deeded. Another method successful against V. mandarinia was to fit over the hive entrance a box with a 1-cm diameter entrance hole. Muzaffer and Ahmed (1986) in Pakistan studied the five species of hornets Vespa baslis, Vespa orientalis, V. tropica haematodes, V. velutine pruthii and Vespula germanica preyed upon Apis mellifera and A. cerana V.pruthil and V.. basalis were the most important and caused heavy losses by feeding on adult bees and their brood. Honey reservers were also taken and this was particularly damaging during the near flowerless dry season (July to October). A. mellijera was comparatively more susceptible to attack than was A. cerana they showed that Plastic jars placed on top of hives containing a 50% solution of sucrose collected large numbers of wasps and hornets and provided some degree of control. Orlov et al. (1988) mentioned that the trapping apparatus described is effective in collecting aculeate social 43

insects, and notably hymenoptera such as Vespa orientalis, without damaging either them or the nets. The body of the trap consists of a tube fitted over the flight hole of the nest curving and tapering into a long, tubular detachable and interchangeable co l le ct or ma d e of a i r - pe r mea le ma t er i al . Th e a pp ar a tu s i s pl ac ed in position between 22 and 24 hour, and on emerging in the morning the insects enter. Mishear et al. (1 989) con cluded th at a mong f ive overripe f ruits tested as bait for Vespa spp. in apiary, pear trees attracted the

maximum

number

of

wasps

when

compared with other fruit. Feeding of poisoned bait provided to the wasps in cages reveled that L.T 50 values were 180.9, 62.1 and 28.8 min at 100 – 200 and 300 mg. fenitrotion

Kg-1

Jaggery,

respectively.

In

the

newly

developed "capsule cup" technique, more wasps shared one load of poison bait on the thorax of a wasp, but the total number of wasps killed did not decrease. With the increase in concentration of bait there was corresponding decrease in L.T 50. A load of 110 mg poison bait could easil y kill 30 35 wasps. In the two field experiments by sending 25 and 16 loads of poisoned bait, respectively, nests of V. cincta were completely destroyed. Stringer (1989) controlled wasp by using insecticides, poison baits and nest destruction. Recently, the Entomology Division propagated and released a biological control agent called sphecophage vesparum. This is a solitary wasp about the 44

size of a flying ant, which lives entirely within wasp nests. This parasites use to laid his eggs on wasp pupae, eggs hatch into larvae which feed on the pupae and destroy them. The adult parasitoid emerges within the nest and lays more eggs on other wasp pupae. Sphecophaga does not infest bee hives. Shah and Shah (1991) found that killing hornet queens

in

earl y

spring,

destroying

hornet

nests

and

employing a person to swat hornets at the hive entrances are the measures widely advocated for controlling hornets. But none of these methods are very effective. They used a glass jar, was half field a mixture of fermented honey and water (50: 50 w/w) as a trap, was found effective control measure. They used this trap for 11 days, from 5 to 15 October 1988. Various baits, e.g. meat, fish, fermented hone y a nd rott en f ruit were used and the average nu mber of hornets upped per day was two (range 0-5) As an alternative, they adopted the following procedure. They used a hornet trap, and plac ed on top of hive in t he apiar y. Hornets entering the jar to feed on the liquid were drowned. I n o n e o n l y 1 8 3 h o r n e t s w e t c a p t u r e d . B e c a u s e o f t h i s e n c o u r a g i n g result, 12 jars were placed on hives at various locations in the apiary. Hornets were removed from the jars every evening and counted. In a 10-day period (18-27 October), 11483 hornets were drowned. Donovan (1992) showed that the most obvious approach is to find and kill nests by using fumi dust. If nests can be 45

readily found, wasps can be locally reduced to nonpestiferous levels or even eliminated. As a result, apiaries and even substantial areas around them may become bee safe. E d w a r d e t a l . ( 19 9 4 ) s t u d i e d t h e f l u c t u a t i o n i n M a l a i s e i n t h e period between 1991 to 1993 and they found that yellow jacket numbers fluctuated greatly between years, as occurs in other habitats. A split — plot analysis revealed that

diflubenzuron

decreased

worker

number

in

the

application year but not in the post application year and revealed no effect of trap site on worker sample size. Roger and Daniel (1994) showed that there are six procedures that are used in Japan for combating hornets. These include killing individual workers with a stick or swatter, destroying nests, toxic baits, trapping by using baits, trapping at the hive entrance using a series of baffles that permit honey bee workers. To pass but trap hornets, and using protective screens. Klein and Zarabi (2000) stated that the oriental hornet, Vespa orientalis, causes damage by destroying beehives and by reducing or even inhibiting the flight of the bees. Considerable losses are thus caused to beekeepers and to crops that require pollination by bees. The hornet has become a serious pest in pear and apple orchards. Also, severe problems are experienced in Israel’s vineyards. The females feed on grapes and remove the juice. The clusters are damaged and, perhaps equally important, the remaining grapes are susceptible to fungal attack. They also found that Destruction of hibernating queens 46

had no effect on hornet population. Indeed, culling of winter queens may even result in an increase in the number of wasp nests by reducing the competition for suitable nest sites in the spring. Destruction of colonies within the nests remains one of the principal methods of hornet control but Trapping remains one of the oldest and still effective methods for control of wasp workers. Traps are easily constructed from netting and contain suitable bait without toxic materials. This method reduces hornet populations, but does not solve the problem. Bacandritsos et al. (2006) compared three improvised types of traps (wood-glue, plastic bottle, double chamber) in combination with two different animal baits (fish and meat), free of insecticides, in order to control the populations of the wasps in apiaries. The experiments were conducted during the summers from 2001 to 2004. The traps were placed in three apiaries located in the Attica region of Greece. The results showed that the use of the wood-glue trap in combination with the fish as a bait was a reliable solution for controlling the wasps in apiaries. Special attention should be paid to the time the fresh bait is placed because the performance of the traps is the best early in the day. Also the baits should be changed regularly (every 1-2 days) because the decomposition reduces the total number of wasps captured. Gomaa and Abd El-Wahab (2006) studied at Dirut location, Assiut governorate during 2003 seasons Seasonal abundance of the oriental wasps (Vespa orientalis L.) and the efficiency of liquid culture of yeast (Candida tropicalis) as bait to it. They found that the oriental wasps started to appear in the first week of April and gradually decreased to the minimum levels during June (late spring) and July 47

(earlier summer). Then, the activity of wasps increased gradually from the second week of August to the fourth week of September. Total numbers of wasps reached the highest values in October followed by September and November and then the number of oriental wasps decreased until disappeared at the fourth week of December. The modified traps recommended by Ministry of Agriculture were baited with 100% of 1.26×105 freshly prepared yeast liquid culture (Candida tropicalis) captured the highest mean numbers of oriental wasps after 24 hr. and 7 days during the active period of wasps (September, October and November).

48

MATERIALS AND METHODS The present work was carried out the apiary of The Agriculture Experimental station, Faculty of Agriculture, Cairo University under the environmental conditions of Giza region throughout years of 20062008. Two local races of honeybee, which reared under supervision of Agriculture Ministry of Egypt, were used in producing the pedigree hybrids from them to be used in this study. These races were local Carniolan (Apis mellifera carnica pollmman) and local Italian, (Apis mellifera ligustica spinola). The descendant pedigrees from each of them were reared till the fourth hybrid. The required queens of each hybrid were artificially reared by grafting method.

1. Fluctuation of oriental hornet population during its active season To determine weekly population fluctuation of oriental hornet during its active season, screened traps were used. Each trap was made of wooden bars and wire screen with diameters of 50 X 30 X 30 cm. The trap was placed on the top of open Langstroth brood box hold over hive stand. Eight traps each having 3 combs of capped honey or empty wax comps with sugar syrup were placed in the site of the experimental apiary. These traps established and baited from the first week of August until the last week of November through the two years of study due to the peak of activity of hornet. The hornets attracted and caught within the given traps were weekly collected and counted.

49

2. Wiped out honeybee colonies due to direct attack and latent negative effect of oriental hornet The number of wiped out honey bee colonies during the period from August to November (hornet active season) and during December and January (latent negative effect) was weekly recorded and calculated as a percentage of the initial started number before hornet appear for each season. All beekeeping ordinary procedures were done to investigate colonies including feeding, varroa control by Apistan strips from beginning of September and full wintering. 124 and 102 moderate colonies, (each had from 7-10 combs covered with bees and 4-7 brood combs) were observed during 2007and 2008, respectively. 3. Relationship between honeybee and oriental hornet This study was conducted at the apiary of experimental station, Faculty of Agriculture, Cairo University during three successive years 2006, 2007 and 2008 to study the relationship between honeybee Apis mellifera and the predatory hornet (oriental hornet) Vespa orientalis during hornet active season (August to November) During the first year, 2006, three main points were studied as follows: 1- Relationship between predatory hornet and honeybees. Genetically undefined 40 honeybee colonies were chosen to study their relationship with the oriental hornet during the period of (11-8 to 30-10, 2006) 2- Impact of honeybee colony strength on attacking hornet features. 51

Genetically undefined 20 honeybee colonies were chosen and divided into 10 strong colonies (with population rang 1700024000 individual)) and moderate colonies (with population rang 8000-11000 individual) 3- Impact of modified bottom board on hornet- bees relationship. Genetically undefined 20 honeybee colonies were chosen and divided into 10 colonies modified by eliminating the alighting board by vice verse the hive stand and provide the hive with a small entrance in the hive bottom board with diameter 5 Width – 1 High and 10 ordinary common hives The following parameters were studied for all the previous study points 1- Total numbers of attacking hornets during 3 min. for each colony and repeated each two hours from 8000 hour until 1800 hour 2- Total numbers of honeybee preyed by direct attack of oriental hornet 3- Total trials numbers made by attacking hornets During the second year, 2007, two main points were studied as follows: 1- Relationship between predatory hornet and honeybees. Thirty two descendant honeybee hybrid colonies from Carniolan and Italian races + eight genetically undefined colonies with total 40 colonies were determined to study its relationship with the oriental hornet during the period of (16-8 to 14-11, 2007) 51

2- Thirty two descendant honeybee hybrid colonies from Carniolan and Italian races prepared as followed In this experiment, two types of descendant hybrids were tested. The first descendant hybrid produced from the origin of Italian race as a mother queen while the second one produced from the origin of Carniolan race as a mother queen. These two honeybee races and their hybrids were mainly spread all over the region of study, (Giza region). Newly emerged virgin queens were reared from the mother colonies of each race according to Dolittle Method during March, 2006. These virgin queens were introduced into small mating nuclei and left for free mating. After 3-4 weeks from the beginning of egg laying of the newly mated queens, young larvae from their F1 offspring were reared as a queen. From offspring of hybrid F1 mated queens, the hybrid F2 virgin queens were reared as mentioned above. The same procedure was followed until obtained the offspring of hybrid F3during July and august, 2006. This experiment was conducted from September, 2006 for all descendant hybrids using a new open mated queen which simultaneously reared from each of the origin race and their descendant hybrids to offer offspring of F1, F2, F3 and F4 at the same time March, 1

local carniolan and Italian virgin queen x unknown drones

April, 15

carniolan and Italian F1 offspring F1 virgin queen x unknown drones 52

June, 1

carniolan and Italian F2 offspring F2 virgin queen x unknown drones

July, 15

carniolan and Italian F3 offspring F3 virgin queen x unknown drones

September, 1 carniolan and Italian F4 offspring Four prepared honeybee colonies were headed by one type of the descendant carniolan and Italian hybrids, so, 32 colonies similar in their strength and food stores were established During the Second year, 2008, two main points was studied as follows: During hornet active thirty two descendant honeybee hybrid colonies from Carniolan and Italian races prepared as previously described For all the previous study points the followed parameters were calculated 1- Hornet capture rate (CR) Hornet capture rate was calculated from total no. of honeybee preys divided by total no. of attacking hornets CR= total no. of preys/ total no. of attacking hornets 2- Hornet capture efficiency (CE) Hornet capture efficiency was calculated from total no. of preys divided by total trials no. CE= total no. of preys/ total hornets trials 3- Honeybee defensive efficiency (DE) Defensive efficiency of honeybee was calculated as follows DE= (1-CR) X 100 53

4- Total predation/day Total honeybee preys / day was calculated as follow No. of hornets/day X CR Statistical analysis of the findings was carried out by applying one-way ANOVA and paired and independent sample t-test. P value of P < .001 was determined as the significant level using ASSISTAT version 7.5 beta (2008).

54

RESULTS AND DISCUSSIONS 1. Seasonal abundance of hornet population Weekly and monthly count of trapped hornets caught by traps in 2007and 2008 are shown in Table (1).The total numbers of trapped hornet during 2007 were, (41242.5 individuals/trap) higher with about 4.3 times than those trapped during 2008,(9577.9 individual/trap). Gradual increase in hornet population was occurred in the following weeks by the first week of August to reach its climax (4725.1 and 1850 hornet/trap) in the second week of October of both 2007 and 2008 seasons, respectively. On the other hand, the numbers of trapped hornets were noticeably declined from the 3 rd. and 1 st. Week of November during the previous seasons respectively, Fig (1). The highest mean numbers of hornet individual was recorded during October, for the two studied seasons where represented 41.9% and 65.7% of the total trapped hornets, Fig (1) The obtained results indicated that the oriental hornet individuals started to appear in pronouncing figures in the apiaries of Giza region in the second half of summer season (August) during the two studied years. These numbers were exponentially increased throughout the followed month to reach the highest peak in the second week of October. These finding are confirmed by the previous reports, under the same circumstances of Wafa,,1956, wafa et al., 1969 and Ibrahim & Mazeed, 1967). They stated that the population density of the oriental hornet, V. orientalis was very low during spring and early summer, then it gradually increased to attained its peak of abundance in September and October. In upper Egypt,( Ahmed, 1999 and Gomaa & 55

Abd El-wahab, 2006) recorded the highest hornet population in the third week of October. Also , El-Sherief (2003) in lower Egypt demonstrated that the highest trapped numbers of hornet workers were recorded during September while the new generation of hornet queens was in a maximum account during October Abdel-Gahny et al. ( 2008).

56

Table 1.Weekly average no. of oriental hornet V. orientalis /trap during active seasons of 2007 and 2008. Month

Week st

August

September 51

October

November

Total

1 week 2 nd week 3 rd week 4 th week Total 1 st week 2 nd week 3 rd week 4 th week Total 1 st week 2 nd week 3 rd week 4 th week Total 1 st week 2 nd week 3 rd week 4 th week Total

Hornet average no./ trap % 2008 0.76 0.0 3.04 15.0 4.37 112.0 5.59 245.3 13.75 372.3 5.80 412.0 7.16 645.3 7.42 637.3 7.19 629.0 27.58 2323.6 8.41 1059.0 11.46 1850.0 10.88 1787.0 11.18 1600.0 41.94 6296.0 11.31 431.0 4.27 87.0 0.78 38.0 0.39 30.0 16.74 586.0 9577.9

2007 311.5 1252.2 1801.5 2304.0 5669.3 2393.2 2953.1 3061.1 2966.5 11373.9 3469.1 4725.1 4489.2 4612.0 17295.4 4663.9 1760.0 320.0 160.0 6903.9 41242.5 57

% 0.00 0.16 1.17 2.56 3.89 4.30 6.74 6.65 6.57 24.26 11.06 19.32 18.66 16.71 65.73 4.50 0.91 0.40 0.31 6.12

52

Fig.1. Weekly average no. of oriental hornets /trap during active seasons of 2007 and 2008. 58

2. Relationships between predator, Vespa orientalis, and honeybee colonies during hornet active season, 2006. a. Fluctuation of hornet numbers attacking honeybee colonies The fluctuation in numbers of hornet attack against honeybee colonies throughout day time hours of its active season, 2006 were recorded in Tables (2&3). It appears that there were a wide variation within each observed day, so, the weekly means of each observed period were monitored for the all season. In general, the individuals of V. orientalis showed attack the honeybee colonies from early morning to the dusk during its active season; except early 2nd and 3rd week of August and last week of October periods of the season where the attacking activity is concentrated within mid-day. During August, there is no attack of hornet extended from early morning till the mid day (1200 h.) for the 1st week and from early to 1000 h. for the 2nd week. For the two periods weeks no attack was observed through late afternoon, (from 1600- 1800 h.). With the end of the 3rd week, the attacking hornets were arranged during the daytime hours which done occurred two concentrated peaks, the first and the major at periods 1000-1200 h.,(0.92 individual/colony/3min.), and the second at 16001800 h. periods, as shown in Table (3) and Fig (2). During September, the capture attempts alternated between the periods of 1000-1200 h. and 1600-1800 h. for the first three weeks, Table (3) and Fig (2). From the 4th week of September to the end of October, the enormous skirmish of hornet changed to the afternoon periods which extended from 1400 h. to the end of the day. They concentrated, mostly, near the evening. The highest attacking peaks 59

were at 1600 h. for both the 4th week of September (1.66 hornets/colony/3min.), and 1st week of October, (1.57 hornets/ colony/ 3min.), and at 1800 h. for the 2nd and 3rd weeks of October, (1.74 and 1.06 hornet/colony/3min., respectively). Dependant on the means of periods throughout daytime, the highest

numbers

of

hornet

attack

during

August

was

0.5

hornet/colony/3min., at 1400 h. during September, 1.05 hornet/ colony/3min. at 1600 h. and during October, 1.24 hornet/colony/ 3min. at 1800 h. as revealed in Table(3) and Fig (2). Data presented in Table (2) appear the daily mean number of hornet, Vespa orientalis, attacked honeybee, Apis mellifera, colonies during its active season, (August, September and October months), in Giza region, 2006. The number of attacking hornets increased with the progression season. However, these attacking hornets were fluctuated from day to day and from week to another. This fluctuation cleared in a form of weak and strong attacking sorties of hornets towards the honeybee colonies throughout the active season of this hornet. The number of hornets of the weakest sortie of attacking was 0.66 hornet/ colony/ 2 hours, (4.00 hornet/ col./ day) which occurred during August 11, while it was 20.06 hornet/ col./ 2 hours, (120.40 hornet/ col./ day) for the strongest skirmish during August 16. The lowest number of hornets for the week attacking wave was 6.94 hornet/ col. / 2 hours, (41.60 hornet/ col. / day) which occurred at the September 16. However, the highest number of hornets recorded for the strongest attacking sortie was 46.94 hornets/ col. / 2 hours, (281.60 hornet/ col. / 61

day) during September 26. During October, the colonies of honeybees were received the most attacking aggressiveness of hornets where the lowest number of them was accounted by 1.56 hornet/ col. / 2 hours (9.40 hornet/ col. / day) at the last week of October. The highest hornet number of the strongest attacking wave was 76.26 hornet/ col. / 2 hours (457.60 hornet/ col. / day) at the first week of October. With the starting of the fourth week of October, 2006, a sharp decline in the number of hornets that attack honeybee colonies was observed as shown in Table (4) and Fig. (3). It is also noticed from results in Table (4) that, each colony of honeybees exposed to a total number of attacking hornets valued by 260.44 hornet/ col. / 2 hours (1562.8 hornet/ col. / day) during August, while increase to 808.60 hornet/ col. / 2 hours (4851.27 hornet/ col. / day) during September and 931.1 hornet/ col. / 2 hours (5586.60 hornet/ col. / day) during October. Therefore, the honeybee colony was attacked with an average of 12000.60 hornet/ season. It is noteworthy that the hornet numbers of the weakest sortie during September (41.60 hornet/day) was increased than those occurred during August, (4.00 hornet/day) by about 9.5 times. However, this case which recorded during October, (9.4 hornet/ day) was higher than those occurred during August 2.35 times but lower than September with about 4.4 times. On the other hand, this rate increased in hornet numbers for the strongest sortie which were 2.4 times for September and 3.9 times for October than August and was about 1.6 times for October than September. 61

On the basic means of hourly and daily numbers of hornets attack, honeybee colonies during its active season, it could be noticed that hourly means were 6.2 hornet/ colony, 13.48 hornet/colony and 15.02 hornet/colony during August, September and October, respectively. The corresponding daily means were 74.42 hornets/colony, 161.71 hornets /colony and 180.21 hornets/colony for the previous months, respectively. So, as mentioned above, the hornet population in the apiary site was remarkably increased with a rate of 1.17 times (117.4%) during September and with a rate of 1.42 times (142.3%) during October when both were compared with August population. The rate of increase in the population density of hornets during October than September was low and valued about 0.11 times, (11.4%). It is, also, clear from monitoring the weekly means of hornet attacking activity over honeybee colonies that there is a gradual increase through the investigated period as shown in Table (4) and Fig (3). The lowest rate of hornet attack was 4.77 hornet/ hour which recorded for the second week of August. The highest rate was 23.62 hornets/ hour for the first week of October. A slight fluctuation in the weekly mean number of attacking hornets from the beginning of season, (second week of August) till the end of the first week of September. Then, a continuous increase in the attacking hornets from the second week of September until the end of the first week of October as shown in Fig (3). Afterward the attacking rate of hornets was gradually reduced to the end of October.

62

Table 2. Daily mean no. of hornets/3 min. attacking honeybee colonies at two hour intervals during hornet active season (11 -8 to 31- 10, 2006) August.

57

Days 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29

800 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.25 0.21 0.29 0.37 0.18

1000 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.40 0.11 0.21 0.50 1.00 0.61 0.59 0.92 0.78 0.98 0.89

1200 0.05 0.21 0.44 0.37 0.47 0.74 0.55 0.29 0.47 0.44 0.89 0.21 0.37 0.63 0.43 0.41 0.42 0.39 0.44

1400 0.05 0.26 0.79 0.72 0.68 1.11 0.95 0.53 0.37 0.68 0.47 0.37 0.68 0.68 0.40 0.29 0.17 0.32 0.39

September. 1600 0.00 0.05 0.16 0.61 0.46 1.16 0.66 0.11 0.00 0.00 0.00 0.00 0.00 0.00 0.19 0.57 0.96 0.27 0.50

1800 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.28 0.20 0.11 0.31 0.34

800 0.28 0.42 0.11 0.06 0.24 0.21 0.60 0.36 0.43 0.54 0.65 0.66 0.89 0.77 0.66 0.15 0.13 0.66 0.73 0.43 0.49 0.52 0.45 0.39 0.35 0.18 0.28 0.36 0.21

1000 0.19 0.30 0.16 0.24 0.27 0.21 0.45 0.67 0.62 0.56 0.51 0.80 0.97 0.74 0.70 0.08 0.89 0.62 0.79 0.84 0.71 1.10 0.78 0.46 1.01 0.92 0.69 0.83 0.78

1200 0.28 0.42 0.16 0.18 0.30 0.25 0.52 0.55 0.73 0.70 0.66 0.69 0.66 0.66 0.68 0.14 0.58 0.43 0.34 0.46 0.48 0.87 1.06 1.25 0.97 1.08 1.16 1.07 0.94 63

1400 0.22 0.32 0.26 0.40 0.36 0.28 0.68 0.65 0.25 0.29 0.34 0.41 0.57 0.46 0.39 0.11 0.63 0.58 0.48 0.56 0.60 1.19 1.05 0.92 1.25 1.31 1.12 1.14 0.92

October. 1600 0.56 0.67 0.55 0.65 0.66 0.59 1.11 1.14 0.48 0.45 0.42 0.67 0.85 0.64 0.59 0.46 1.17 1.19 1.27 1.22 1.18 1.63 1.61 1.59 1.79 1.95 1.77 1.72 1.65

1800 0.27 0.44 0.21 0.32 0.38 0.29 0.05 0.50 0.56 0.40 0.23 0.73 0.90 0.57 0.57 0.10 0.95 0.20 0.34 0.65 0.45 1.52 1.13 0.73 1.56 1.60 1.17 1.29 1.17

800 0.53 0.37 1.50 2.03 0.92 0.00 0.03 0.05 0.04 0.08 0.07 0.04 0.16 0.29 0.42 0.20 0.24 0.33 0.27 0.32 0.28 0.24 0.16 0.19 0.12 0.00 0.00 0.00 0.00

1000 1.11 0.94 1.29 2.40 1.43 0.63 0.64 0.66 0.41 0.18 0.42 0.49 1.77 1.62 1.48 1.11 0.45 0.96 1.23 1.40 1.29 1.18 0.70 0.86 0.59 0.00 0.00 0.00 0.00

1200 0.95 0.94 0.80 1.74 1.21 0.66 0.55 0.45 0.43 0.21 0.33 0.44 1.25 0.95 0.66 0.89 0.53 0.59 0.81 0.84 0.76 0.68 0.42 0.51 0.34 0.41 0.33 0.13 0.00

1400 1.55 1.23 0.92 2.47 1.65 0.84 0.74 0.65 0.98 1.12 0.89 0.87 1.58 1.12 0.66 1.08 0.58 0.62 0.94 0.60 0.38 0.16 0.30 0.25 0.76 0.53 0.16 0.08 0.00

1600 0.64 1.88 2.11 1.37 1.46 1.75 1.70 1.65 1.17 0.59 1.12 1.33 2.23 1.50 0.76 1.48 0.74 0.75 1.24 1.06 0.53 0.00 0.53 0.35 0.00 0.39 0.11 0.03 0.00

1800 0.91 1.56 1.95 1.43 1.34 1.73 1.69 1.64 1.05 0.37 1.00 1.25 3.16 2.49 1.81 2.75 2.34 2.08 2.44 0.68 0.34 0.00 0.34 0.23 0.00 0.00 0.00 0.00 0.00

30 31

0.16 0.26

1.19 1.09

0.45 0.42

0.38 0.28

0.36 0.66

0.24 0.22

0.37 -

0.94 -

0.94 -

64

1.23 -

1.14 -

1.04 -

0.00 0.00

0.00 0.00

0.00 0.00

0.00 0.00

0.00 0.00

0.00 0.00

Table 3. Weekly mean no. of hornets/3 min. attacking honeybee colonies at two hour intervals during hornet active season (11 -8 to 31- 10, 2006) Day time Weeks

800

1000

1200

1400

1600

1800

1

0.00

0.00

0.40

0.65

0.44

0.00

2

0.00

0.40

0.47

0.54

0.02

0.00

3

0.25

0.92

0.42

0.32

0.50

0.24

0.08± 0.125 c

0.44± 0.442 ab

0.43± 0.178 ab

0.50± 0.265 a

0.32± 0.348 b

0.08± 0.125 c

1

0.29

0.31

0.33

0.40

0.74

0.31

2

0.59

0.62

0.62

0.35

0.57

0.51

3

0.49

0.82

0.60

0.73

1.32

0.75

4

0.31

0.80

1.06

1.13

1.66

1.22

0.42± 0.215 c

0.63± 0.282 b

0.64± 0.3169 b

0.63± 0.362 b

1.05± 0.489 a

0.68± 0.453 b

1

0.68

1.14

0.91

1.26

1.57

1.53

2

0.16

0.94

0.65

1.04

1.27

1.74

3

0.25

1.01

0.64

0.48

0.65

1.06

4

0.02

0.08

0.17

0.22

0.07

0.00

0.31± 0.460 c 0.28± 0.233 b

0.90± 0.581 ab 0.64± 0.388 ab

0.67± 0.351 b 0.57± 0.255 ab

0.85± 0.526 b 0.65± 0.353 ab

1.02± 0.652 ab 0.80± 0.571 a

1.24± 0.944 a 0.67± 0.635 ab

August mean

58

September mean

October mean mean / week

Mean /3 min. 0.25± 0.161 0.24± 0.069 0.44± 0.041 0.31± 0.137 B 0.40± 0.144 0.54± 0.188 0.78± 0.289 1.03± 0.110 0.67± 0.2898 A 1.18± 0.348 0.96± 0.538 0.68± 0.310 0.09± 0.086 0.83± 0.466 A 0.60± 0.175

Hornets /2 hours

Hornets /day

10.00

59.94

9.54

57.26

17.68

106.06

12.40

74.42

15.82

94.95

21.74

130.45

31.4

188.34

41.18

247.09

26.96

161.71

47.24

283.45

38.58

231.50

27.26

163.60

3.76

22.60

30.04

180.21

24.02

144.11

Means designated with the same letter in the same column are not significantly different at 0.05 level of probability. 65

66

1.4 August mean

September mean

October mean

1.2

Hornet No.

1

0.8

0.6

59

0.4

0.2

0 8

10

12

14

16

18

Day time

Fig. 2. Monthly mean no. of hornets/3 min. attacking honeybee colonies at two hour intervals during hornet active season (11 -8 to 31- 10, 2006).

67

Table 4. Total daily mean no. of hornets attacking honeybee colonies during hornet active season from (11 -8 to 31- 10, 2006) August. Day

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 Total Mean

September.

Hornets /2 hours

Hornets /day

Hornets /2 hours

0.66 3.46 9.26 11.34 10.74 20.06 14.40 6.20 8.26 8.20 10.46 7.20 13.66 12.80 14.26 17.34 18.20 17.60 18.26 18.54 19.54 260.44 12.40± 5.53

4.00 20.80 55.60 68.00 64.40 120.40 86.40 37.20 49.60 49.20 62.80 43.20 82.00 76.80 85.60 104.00 109.20 105.60 109.60 111.20 117.20 1562.80 74.42± 33.17

12.00 17.14 9.66 12.34 14.74 12.20 22.74 25.80 20.46 19.60 18.74 26.40 32.26 25.60 23.94 6.94 29.00 24.54 26.34 27.74 26.06 45.54 40.54 35.60 46.20 46.94 41.26 42.74 37.80 37.74 808.60 26.95± 11.59

Hornets /day

October. Hornets /2 hours

72.00 37.94 102.80 46.14 58.00 57.14 74.00 76.26 88.40 53.40 73.20 37.40 136.40 35.66 154.80 34.00 122.80 27.20 117.60 17.00 112.40 25.54 158.40 29.46 193.60 67.66 153.60 53.14 143.60 38.60 41.60 50.06 174.00 32.54 147.20 35.54 158.00 46.20 166.40 32.66 156.40 23.86 273.20 15.06 243.20 16.34 213.60 15.94 277.20 12.06 281.60 8.80 247.60 3.94 256.40 1.56 226.80 0.00 226.40 0.00 0.00 4851.20 931.10 161.71± 30.04± 69.55 20.32

68

Hornets /day

227.60 276.80 342.80 457.60 320.40 224.40 214.00 204.00 163.20 102.00 153.20 176.80 406.00 318.80 231.60 300.40 195.20 213.20 277.20 196.00 143.20 90.40 98.00 95.60 72.40 52.80 23.60 9.40 0.00 0.00 0.00 5586.60 180.21± 121.9

total hornets/co l./ season

350.40 394.40 455.20 616.00 514.00 378.00 357.60 245.60 235.20 204.80 215.20 271.60 550.00 460.00 432.40 575.60 455.60 397.60 484.80 411.60 362.40 406.80 423.20 386.00 435.20 438.40 380.40 371.40 336.40 337.60 117.2 12000.60 387.12

August.

September.

October.

6000

61

TOTAL hornets /day

5000 4000 3000

2000 1000 0 Hornets/day

Fig. 3 . Total daily mean no. of hornets attacking honeybee colonies during hornet active season 2006

69

b. The capture efficiency of hornet during its active season The capture efficiency (CE) of hornet attacking honeybee colonies during the different hours of the day time was recorded in Table (5 & 6). The highest capture efficiency of hornet was noticed during the periods from 1200 to 1600 h. in early season, (August). The weekly mean of each observed periods was ranged from 6.14% to 30.12% at 1200 h., from 10.76% to 29.75% at 1400 h., and from 0.0% to 44..94% at 1600 h. during various weeks of August. The mean values of the previous periods were 19.32%, 20.6% and 21.35% respectively, Table (6). During September this efficiency had a narrow range of variation between the observed periods. It was ranged from 10.05% to 16.8% at 1000, from 15.53% to 21.15% at 1200, from 11.77% to 15.77% at 1400, from 9.06% to 18.92% at 1600 and from 5.91% to 19.99% at 1800 during September. The corresponding figures during October were from 1.14% to 16.09%, 5.05 to 17.63%, 3.68% to 17.06%, 2.27% to 16.22% and 0.0% to 7.13% respectively. The monthly mean values of the tested activity periods were 6.83% & 8.57, 14.09% & 8.89%, 17.76% & 10.87, 13.32% & 11.96, 13.48% & 8.34% and 11.18% & 4.05% for 800, 1000,1200,1400,1600 and 1800 h. of September and October, respectively. It is noticed that the capture efficiency was positively affected by the number of attacking hornet especially during August and September. The “r” values were 0.7258, 0.4077, respectively. 71

However, this influence was negative, (-0.4905) during the daytime of October, which reflect the great competition between hornets against the bee prey. This competition caused increase the total number of attempts made by hornet to catch one bee, So, the “r” value between number of hornet attack and the total attempts/hornet was positive, (0.5236) during this month. Data in Table (5) revealed the hourly and daily percentage of hornet capture efficiency, (CE), from honeybee colonies during different months of active season, 2006. The daily mean of CE were highly fluctuated during the beginning (August) and ending (October) of hornet active season, while it was more stable during the middle, (September), of season. This efficiency of hornet ranged from 2.86% (in August, 14) to 26.18% (in August, 28) during August. In similar, it ranged from 1.49% in (in October, 28) to 25.68% (in October, 1) during October. However, during September, less difference was observed between the lowest hornet CE, (5.29% in September, 16) and the highest ones, (18.56% in September, 29). The weekly mean percentage of hornet CE during August was ranged from 2.82% to 15.53% with a mean value of 11.62% for this month. During September, the CE of hornet is nearly similar during different weeks of this month. It was ranged from 11.14% to 13.81% with a mean value of 12.78%. During October, This hornet character start to decline from first week of this month, (mean 13.2%) toward the end of the season, (2.02%). So, the mean percentage of hornet capture efficiency was the lowest (8.85%) for October month. Therefore, from the above results, it 71

appears that the mean capture efficiency of the oriental hornet, V. orientalis, during its active season under the circumstances of study was 11.08%.

72

Table 5. Daily means of hornets capture efficiency (CE) at two hour intervals during hornet active season (11 -8 to 31- 10, 2006) days

65

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31

August

October

September

800

1000

1200

1400

1600

1800

800

1000

1200

1400

1600

1800

800

1000

1200

1400

1600

1800

0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 30.3 0.00 0.00 8.50 5.00 0.00 0.00

0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 4.70 4.80 3.60 5.50 38.50 16.40 10.50 8.10 9.00 6.30 8.80

0.00 0.00 0.00 7.20 5.00 20.00 10.80 12.70 51.30 20.00 10.30 14.60 28.20 14.90 20.00 20.00 20.00 38.50 21.30 38.50 52.60

0.00 0.00 31.60 5.20 10.40 15.60 12.50 10.50 21.30 6.30 49.20 68.50 30.90 21.50 38.50 9.30 0.00 76.90 0.00 10.50 13.90

0.00 0.00 0.00 0.00 0.00 0.00 0.00 23.80 0.00 8.30 93.80 63.50 76.10 49.20 12.70 8.30 6.10 21.30 62.50 11.20 11.60

0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 3.80 5.20 4.10 4.00

10.30 6.10 0.00 0.00 8.30 0.00 5.70 0.00 16.10 6.10 7.60 9.00 5.20 6.20 8.50 0.00 0.00 7.20 7.80 9.40 5.00 10.60 14.00 10.30 8.00 0.00 12.70 8.60 10.40 11.80 -

21.70 15.20 10.60 6.10 8.70 11.80 34.50 12.90 30.90 12.80 0.00 12.90 8.20 6.80 8.80 0.00 7.90 21.10 22.70 15.60 13.60 8.90 12.90 15.90 12.20 13.10 14.40 9.80 34.50 18.10 -

12.00 10.00 20.80 31.30 15.20 15.20 13.10 15.20 15.20 23.30 22.50 18.50 35.70 34.50 19.60 0.00 18.00 14.90 17.40 17.70 15.90 12.70 12.10 15.50 12.40 12.10 15.80 12.10 18.40 36.00 -

22.20 15.90 8.80 5.00 7.60 10.40 11.90 12.40 31.30 25.60 23.30 10.50 12.70 10.00 12.80 0.00 8.60 10.10 14.00 10.70 9.60 16.20 13.90 12.30 15.00 6.50 8.40 12.40 15.20 26.50 -

14.90 14.60 12.30 7.60 12.80 11.30 21.70 8.90 10.20 20.80 21.50 9.60 18.00 19.60 19.80 31.70 7.00 12.50 8.70 6.80 8.90 10.10 9.40 7.00 12.60 16.70 11.50 11.00 18.20 8.20 -

5.70 3.60 11.80 11.00 5.50 6.80 0.00 7.30 7.90 5.90 4.70 10.90 8.30 4.40 5.20 0.00 7.60 23.30 46.00 17.10 16.70 13.90 15.40 21.00 13.30 12.10 15.40 13.40 14.60 6.70 -

27.40 20.80 31.60 16.20 9.00 0.00 0.00 0.00 0.00 23.30 0.00 0.00 18.90 6.50 3.90 14.30 11.50 5.80 7.50 11.90 14.10 17.20 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00

13.90 19.00 17.00 22.70 20.50 10.40 8.80 16.40 7.50 6.40 7.20 8.00 4.30 5.00 5.90 5.40 25.30 7.30 6.00 7.50 6.10 4.60 9.00 0.00 4.60 0.00 0.00 0.00 0.00 0.00 0.00

51.70 9.80 3.50 18.50 15.80 7.10 9.00 25.60 18.00 16.30 19.80 9.60 4.30 6.10 7.70 6.30 8.70 8.20 7.20 5.60 6.10 6.60 3.80 8.70 6.10 0.00 5.20 9.00 0.00 0.00 0.00

51.70 9.30 3.20 19.70 16.80 10.00 8.80 16.90 5.90 4.20 6.70 7.60 23.30 15.60 11.70 19.10 11.20 11.50 15.40 3.80 3.40 13.50 3.80 27.00 5.10 0.00 9.70 0.00 0.00 0.00 0.00

4.30 6.40 9.30 15.60 10.80 8.30 5.50 4.70 17.90 15.00 6.10 6.40 28.70 9.00 3.60 43.20 0.00 9.60 13.50 2.80 1.90 0.00 1.90 0.00 0.00 0.00 9.10 0.00 0.00 0.00 0.00

5.10 6.10 8.80 14.20 11.40 5.00 3.70 2.90 4.30 2.50 3.20 3.40 10.20 6.60 4.00 7.30 5.10 5.00 6.00 3.80 3.80 0.00 3.80 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00

73

Table 6. Weekly means of hornets capture efficiency (CE) at two hour intervals during hornet active season (11 -8 to 31- 10, 2006) Day time Weeks 800

1000

1200

1400

1600

1800

Mean /3 min.

1

0.00

0.00

6.14

10.76

0.00

0.00

2.82± 2.35

2

0.00

2.66

21.71

29.75

44.94

0.00

16.51± 8.45

3

6.26

13.94

30.12

21.29

19.10

2.45

15.53± 7.33

2.08± 3.61 b

5.53± 7.40 b

19.32± 12.17 a

20.06± 9.51 a

21.35± 22.55 a

0.80± 1.41 b

11.62±7.63 AB

1

3.81

15.19

16.58

11.77

13.03

6.45

11.14± 2.15

2

7.34

10.05

21.15

15.77

18.92

5.91

13.19± 3.83

3

7.71

14.68

15.53

11.87

9.06

19.99

13.14± 3.43

4

8.82

16.84

17.48

13.74

12.19

13.78

13.81± 3.23

September mean

6.83± 2.17 c

14.09± 2.91 b

17.76± 2.44 a

13.32± 1.89 b

13.48± 4.12 b

11.18± 6.68 b

12.78±1.16 A

1

13.14

16.09

17.63

17.06

8.11

7.13

13.20± 6.30

2

8.34

6.22

11.01

11.75

16.22

5.18

9.79±3.89

3

8.51

8.23

6.86

11.21

3.71

3.42

6.99±2.12

4

0.00 8.57± 9.61 ab 6.19± 7.63 b

1.14 8.89± 6.91 ab 9.97± 8.66 ab

5.05 10.87± 9.87 a 15.73± 11.41 a

3.68 11.96± 10.38 a 14.77± 13.75 a

2.27 8.34± 6.54 ab 13.75± 16.97 a

0.00 4.50± 3.57 b 6.06± 7.19 b

2.02±1.69

August mean 66

October mean mean / week

74

8.85±5.43 B

11.08± 6.13

Means designated with the same letter in the same column are not significantly different at 0.05 level of probability.

25.00

Capture efficency

20.00

15.00 August September

10.00

October

67 5.00

0.00 8

10

12

14

16

18

Day time

Fig.4. Monthly mean no. of hornets capture efficiency (CE) at two hour intervals during hornet active season (11 8 to 31- 10, 2006) 75

c. Capture rate (CR) of honeybee workers by hornet. Data in Tables (7 & 8) indicate to the rate of captured honeybee per the individual oriental hornet through its active season, 2006. It is appeared that the capture rate of hornet was varied and fluctuated from day to day, from week to week and from month to month. The daily mean value ranged from 0.08 bees, (August, 27) to 0.34 bees,( August, 15) during August. This value ranged from 0.17 to 0.55% during September, (expect the day of Sep., 16). The rate of capture during September increased with about 1.62 to 2.13 times than those occurred during August. During October, the daily mean of capture rate ranged from 0.15% to 0.71. This rate raised than that recorded during August with about 1.9 to 2.1 times as shown in Table (7) and Fig (5). On the base of weekly mean of capture rate, there is a gradual increase in this feature from the beginning of observation until reached the highest peak in the second week of October,(0.40 bees) then, decreased again toward the end of the season. So, the monthly means of hornet capture rates were 0.18, 0.32 and 0.35 for August, September and October, respectively. The mean capture rate at any time of its active season was 0.29 bees. Concerning the capture rate (CR) of hornet throughout daytime of active season, it is observed that this rate followed the same trend of number of attacking hornets and its capture efficiency. However, it significantly affected by the capture efficiency than the number of hornet attack. The “r” values between CE and PR were 0.9892, 0.9044 and 0.9522 during August, September and October, respectively. The 76

relation with attacking hornet numbers were positive but not significant during August, (r=0.7293) and September, (r=0.5347), while it was fairly negative, (r=-0.0785) during October. Therefore, the highest rates were occurred during the periods from 1200 hour to 1600 hour through hornet season. Partial regression coefficients confirmed, also, the results between CR and CE, (0.810) with important with 0.812, while it was, (0.304) with important 0.188. It is, also noticed that highly significant positive correlation was found between the hornet capture efficiency (CE) and the predation rate during different months of its active season. These correlation coefficient, (r) were 0.6641, (n=21 and p