Bulletin of Pure and Applied Sciences. Vol.31 A (Zoology),Issue (No.1) 2011:P.1-6 www.bpas.in
LIFE CYCLE AND LARVAL PERFORMANCE OF THE JOKER BYBLIA ILITHYIA (LEPIDOPTERA: RHOPALOCERA: NYMPHALIDAE) FROM SOUTHERN ANDHRA PRADESH V. Prasanna Kumar, P. Harinath and S.P.Venkata Ramana* Department of Zoology, Yogi Vemana University, Kadapa-Andhra Pradesh – India *Corresponding author e- mail:
[email protected]
Received on 5 February 2011: Accepted on 23 May 2011
ABSTRACT The Joker butterfly, Byblia ilithyia was multivoltine, and breeds almost throughout the year with high frequency during the periods from September to December. The life cycle from egg to adult emergence was relatively short spanning over 22 - 27 days. Successful development of adults, larvae and pupae are from 80 – 100% during the said period. Short life cycle and high success development of life stages suggest the production of 12 -13 broods in the season. The different stages from egg to adult emergence of Byblia ilithyia on Tragia plukentii was discussed in detail. Nutritional indices consumption index (CI) and approximate digestibility (AD) increase as the larvae aged, while growth rate (GR) increases, efficiency of conversion of digested food (ECD) and efficiency of conversion of ingested food (ECI) are inversely related as age increased. Keywords: Instars, Tragia plukentii, population index, nutritional indices.
INTRODUCTION Butterflies are one of the most fascinating creatures symbolically representing beauty and grace. Byblia ilithyia (Drury) from Nymphalidae was endemic to India and Sri Lanka with weak flight sails fluttering close to ground (Kehimkar, 2008). There was an increasing interest all over the world in butterfly conservation. Lack of complete zoological knowledge of the concerned species including the breeding habitat was considered to be the reason for such declines and extinctions (New et al.1995). In India exact status of several species of butterflies are not clearly known and where there was accelerated distribution of forests and other natural areas giving to urbanization (Venkata Ramana, 2011). This strategy requires complete knowledge of life cycle, larval performance in respect of food utilization and growth and adult nectar resources and other habitat conditions for its successful implementation. Now we describe here the life cycle and ecobiology of Byblia ilithyia.
V. Prasanna Kumar, P. Harinath and S.P.Venkata Ramana*
MATERIALS AND METHODS Field areas were searched for the reproductive activity of Byblia ilithyia during 2011-2012 was found laying eggs on Tragia plukentii. The eggs with the leaf material were brought to the laboratory and incubated and further development stages were recorded. Young leaves were supplied daily to growing larval instars. Details of larval, pupal stages and the adult emergence were recorded from close observations. Searches were made every month for recording different life stages, eggs, larvae and pupae on 50 plants of Tragia plukentii to work out the population index.
RESULTS These butterflies are weak flyers largely available where food plants were abundant. Adults were found laying eggs throughout the year with an abundance during September – December. Tragia plukentii serves as a larval host and it lays eggs on the young leaves singly.
ADULT The adults are found on dry and open grassy plains with a wing span of 4555 mm, flying weak, close to stems and branches where food plant grows. It is mostly confined to Indian peninsular. Male and female look alike with slight variations. Males are bright tawny with narrow black markings in male, dark brown in female. A row of large white spots present between the two bands with a wing span of 45 – 55 mm. Life cycle stages The egg was yellow in color with prominent ridges from anterior to posterior end. Anterior end was with pointed tip and posterior end was flattened attached to the young stems. The egg decolorizes before hatching. The larva feeds on the shell of the egg after hatching and it takes 3 to 4 days for hatching. The first instar larva was dark brown in colour with segmented body. The head bears two tri radiated horny antennae. The entire body on dorsal side and lateral side was covered with tri radiate horns. This stage remains for 2-3 days and grows to a length of 3.0 mm to 8.0 mm (7.8±0.07mm). The second instar larva changes from dark brown to green colour. Dark patches along the dorsal side from anterior region to posterior region are present. The tri radiate horns on the dorsal side are darker than on the lateral sides. This stage remains for 2-3 days and grows up to a length of 10.3 mm – 12.8 mm (12.7 ±0.005). The third instar larva again changes to dark brown in colour. Almost all the horns too get darker. This stage remains for 2 – 3 days and grows to a length of 17.2 to 18.3mm (18. ±0.005mm). In the fourth instar white bands develop on the dorsal side from anterior end to the posterior patches with broken bands except the last segment. This stage remains for 2-3 days and larva grows to a length of 23.4 to 24.5mm (24.3 ±0.005). The fifth instar larva in this stage remains darker colour changes to slight purple colour. The horns on the lateral sides were shredded off before swirls itself. It remains for about 4-5 days before it pupates and larva grows up to 30.0 – 31.5 mm (31.2 ± 0.02). The final larval stage passes through the pre pupal stage where it remains for one day and after that it develops the shell around it and remains for 5 days before the adult emerges out from the pupa. The entire life cycle from egg to adult emergence completes in 22 - 27 days.
2
LIFE CYCLE AND LARVAL PERFORMANCE OF THE JOKER BYBLIA ILITHYIA (LEPIDOPTERA: RHOPALOCERA: NYMPHALIDAE) FROM SOUTHERN ANDHRA PRADESH
Figure-1: Population index of eggs, larvae, pupae of Byblia ilithyia based on the searches of 50 Tragia plukentii plants.
Fig.2: Relationship between food consumption and growth in Byblia ilithyia
Larval body weight (mg / day)
1.00
.75
.50
.25
0.00 0.00
.25
.50
.75
1.00
Total food consumption (mg / day)
Population Index The numerical frequency of the natural occurrence of the life stages – eggs, larvae and pupae, on the host plant are given in figure-1. All the stages were spotted out throughout the year in the study locality. However, there was a higher frequency of occurrence of the life stages during September to December which corresponds with the winter season
3
V. Prasanna Kumar, P. Harinath and S.P.Venkata Ramana*
Table – 1: Food consumption of Byblia ilithyia larva on Tragia plukentii leaves. Instar No
Weight of food ingested (mg)
Wt.of faeces(mg)
Wt.gain by larva (mg)
I
0.0552
0.006
0.011
II
0.064
0.013
0.042
III
0.0832
0.037
0.067
IV
0.092
0.077
0.089
V
0.161
0.119
0.128
Table – 2: Food utilization efficiencies of Byblia ilithyia larva on Tragia plukentii leaves Instar No
GR
CI
AD
ECD
ECI
(mg/day/mg)
(mg/day/mg)
%
%
%
I
2.526
0.092
88
36.75%
64.37
II
2.928
0.048
75
54.25%
64.62
III
3.761
0.030
34
68.24%
51.12
IV
5.022
0.019
22.5
72.75%
47.62
V
5.906
0.026
16
77.5%
46.62
Nutritional indices Quantitative data of food ingested, the faeces, weight gain by larvae, growth rate & consumption index were given in Table-1. and Table-2. There is vast increase in the consumption of food from instar I to V. The weight gain by larva increased from instar I to instar V. The instar growth rate increased & consumption index decreased as age increases from instar I to instar V. Regression of weight gained by larva against the food consumed per day showed a straight line relationship between these two variable with r value (r=0.93) and t value (t =2.137) at 0.05 level correlation (Fig.2). The AD values decreased from Instar I to instar V, the ECD values increased where as ECI values shown a decline from instar I to V.
DISCUSSION:
4
LIFE CYCLE AND LARVAL PERFORMANCE OF THE JOKER BYBLIA ILITHYIA (LEPIDOPTERA: RHOPALOCERA: NYMPHALIDAE) FROM SOUTHERN ANDHRA PRADESH
The increasing food consumption at successive instars was in inverse relationship with consumption index & growth rate. There was gradual increase in the food consumption from instar to instar. The increased food consumption and growth rate was considered to accumulate energy rich fat to meet the metabolic requirements of non feeding pupal and adult stages (Waldbauer 1968; Downer and Mathew 1976; Slansky and Scriber 1985). The GR values increased & CI decreased with the age of larvae. The values of GR increased from a low of 2.52 to 5.906 the later from a high of 0.92 to 0.026. The decline in CI as the larvae aged may be related to the increase in body size of the larvae or to be the increase in conversion efficiency of ingested food to body mass. So the high consumption index of early instars was due to low conversion efficiency (Slansky and Scriber 1985).The AD values decreased from instar I to instar V. The values of food ECD increase from early to late instars; an inverse relationship is expected between assimilation efficiency AD and efficiency of conversion of digested food or net conversion efficiency ECD (Slansky and Scriber, 1985). The decrease in AD with age was due to less selective feeding by older larvae, which for leaf chewers like butterfly larvae results in the consumption of higher proportion of indigestible fiber. Food quality influences growth efficiencies (Scriber and Feeny, 1979). The resulting ECI may increase, decrease or show little change depending on the extent to which the changes in AD and ECD compensate each other.
ACKNOWLEDGEMENT The senior author Dr. S.P. Venkata Ramana Asst. Professor, Dept. of Animal sciences, Y.V. University, greatly acknowledge to CSIR, New Delhi for financial support through a major research project.
REFERENCES 1. Downer , R.G.H. and Mathews, J.R. 1976. Patterns of lipid distribution and utilization in insects. Amer. Zoolo. 16: 733 – 745. 2. Kehimkar, I. (2008). The book of Indian Butterflies. Bombay natural history society, Oxford University press, Oxford, New York. pp. 497. 3. New, T.R., R.M. Pyle, J.A. Thomas, C.D. Thomas, and P.C. Hammona. (1995). Butterfly conservation and management. Annul Review of Entomology, 40: 57-83. 4. Owen, D.F. (1971). Tropical Butterflies. Clarendon Press. 5. Scriber, J.M. and Feeny, P. 1979. Growth of herbivorous caterpillars in relation to feeding specialization and to the growth form of their food plants. Ecology. 60: 829 – 850. 6. Slansky, F. and Scriber, J.M. 1985. Food consumption and utilization. pp 85- 163. In : Comprehensive insect Physiology, Biochemistry and pharmacology, Eds. Kerkut, G.A. and Gilbert, L.I., Pergamon, Oxford. 7. Venkata Ramana, S.P. (2011). The Flying jewels – Butterflies. Sri Venkateswara publications, Kadapa. A. P. pp.95. 8. Waldbauer, G.P., 1968. The consumption and utilization of food by insects, Advances in Insect Physiology, 5: 229 – 288.
5
