33-44 Elsevier Scientific Publishing Company ...

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Sep 14, 1982 - Division of Social Sciences; University of 1'innesota, Morris; Morris, MN, ... Relations at the University of Minnesota, Morris, for their kind ...
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Behavioural Processes, 8(1983) 33-44 Elsevier Scientific Publishing Company, Amsterdam - Printed in The Netherlands

EFFECTS OF VARIED PRIOR MANIPULATORY OR CONSUMMATORY BEHAVIOURS ON NUT OPENING, PREDATION, NOVEL FOODS CONSUMPTION, NEST BUILDING, AND FOOD TABLET GRASPING IN RATS;, 1 ERNEST D. KEMBLE, SUZANN C. WIMMER, AND AMY P. KONKLER 1 Division of Social Sciences; University of 1'innesota, Morris; Morris, MN,

56267 (U.S.A.) (Accepted 14 September 1982) !::

ABSTRACT Kemble, E. D., Wimmer, S. C. and Konkler, A. P., 1983. Effects of varied prior manipulatory or consummatory behaviours on nut opening, predation, novel foods consumption, nest building, and food tablet grasping in rats. Behav. Processes: 8: 33-44. Varied manipulatory-gnawing experience with nonfood objects facilitated later nut opening and insect predation in rats. Varied food consumption, which minimized manipulation, facilitated the hulling and consumption of sunflower seeds. Both treatments weakly facilitated forepaw food tablet grasping but neither treatment altered novel foods consumption or nest building. The data suggest that these two forms of prior experience contribute differentially to some later behaviours depending upon the sensory-motoric demands of the task and/or upon the intensity of food related stimulation.

INTRODUCTION Although motor-sensory processes such as visually-guided placing (e.g., Held and Hein, 1963) seem to be essential components in the behavioural and neuroanatomical effects of varied sensory experience (e.g., Bennett and Ellis, 1968; Ferchmin, Bennett, and Rosenzweig, 1975), their role in foraging behaviour has received limited attention.

Recently Collier and Rovee-Collier (1981) have

shown that the preliminary manipulation required by some foods (e.g., unshelled seeds) adds appreciably to their foraging cost in rats.

Some recent evidence

also suggests that such processes may contribute to foraging diversity as well. Galef (1980) found that the development of underwater diving for chocolates was more strongly facilitated by prior swimming experience, which did not require t

diving, than by prior consumption of chocolate.

In a comparison of two closely

related subspecies of deer mice (Peromyscus maniculatus borealis, Gray (1981) found that

f·~·

f·~·

blandus),

borealis, presumed to have evolved in a more varied

foraging environment, chose not only a greater variety of foods but also more

*The authors would like to thank Ms. Peggy Palmer and the Office of University Relations at the University of Minnesota, Morris, for their kind photographic assistance.

0376-6357/83/0000---0000/$03.00 © 1983 Elsevier Scientific Publishing Company

I 34 varied instrumental activities (e.g., climbing, digging, swimming) by which the foods could be obtained.

The present experiments explore the differential ef-

fects of varied manipulatory-gnawing or food consumption experiences on a number of subsequent behaviours.

EXPERIMENT lA Inexperienced squirrels initially gnaw at hazelnut shells over much of their surface and without regard to shell grain.

Gnawing is later restricted to fur-

rows which are parallel with shell grain and are eventually combined with prying movements of the incisors (Eibl-Eibesfeldt, 1963).

It is suggested that

this development of nut opening reflects an interaction between an innate, perhaps squirrel-specific, behaviour and learning.

Landry (1970), however, sug-

gests that the highly omnivorous diets of rodents reflect their possession of common, primitive gnawing adaptations.

Thus, other rodents might show similar

approaches when confronted by a novel food resource such as hazelnuts. suc·h skills might also generalize to related food items.

Further,

The first experiment

examines the acquisition and generalization of nut opening by rats.

METHOD The subjects were 16 experimentally naive albino female rats supplied by the Holtzman Co. periment.

(Madison, WI) and wei~hing 246-282 g at the beginning of the ex-

The rats were individually housed and, except where noted, had ad

libitum access to Purina Lab Chow and water. all rats were deprived of food.

Twenty-four hours before testing

Each of eight (Experimental) rats then receiv-

ed a single hazelnut (1.9-2.5 cm dia, 2.6-4.1 g). 15 min intervals for 6 h.

The nuts were inspected at

When a hazelnut was opened and its contents consumed,

the shell was removed and replaced with a fresh nut. for examination. the following day.

All shells were retained

At the end of 6 hall food was removed from the cages until This procedure was repeated for five days during which

hazelnuts were the sole food source.

During this period the remaining eight

(Control) rats were treated identically but were given single small (l .5-2.5 g) pieces of Purina Lab Chow five times during each 6 h access period.

All rats

were then given three days ad libitum access to Purina Lab Chow and water, food deprived for 24 h, and given a single pecan (2.0-2.4 cm dia, 3.4-4.2 cm length, 5.5-7.0 g).

The pecans were examined at 15 min intervals for 3 h.

to open and to consume the pecan were recorded.

Latencies

Pecans were replaced when 85-

90% of the nutmeat (estimated) was consumed.

RESULTS The results of this and subsequent experiments were compared by analyses of

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variance and t-tests utilizing two-tailed probability values.

There was a

steady increase in the number of hazeJnuts opened and c 0.10) and began nutmeat consumption

Althovgh the Gnawing Group

(!'.

> 0.10) somewhat more

rapidly than Control rats, these differences were not statistically significant. The latencies of the Consumption Group did not differ significantly from those of the Control Group (all !'._s > 0.10).

When compared to the Gnawing Group, la-

tency to begin consumption was marginally elevated in the Consumption Group

(J:. = 1.86, d.f. = 15, 0.05


0.10).

Both measures showed substan-

tial reductions on the second trial (pursuit, X

34.5 vs 16.3s; kill, X = 20.3

vs 13.3 min;£.= 5.38 and 7.71, d.f. = 1, 30, P < 0.05).

There were no group

differences, trial effects, or interactions in latency to consume the crickets (X = 7.5-26.5 min; all Fs < 1.0, all Ps > 0.10).

There were significant group

differences in the number of escapes by crickets during the initial trial. These results are summarized in the left column of Table 2.

There was a signi-

ficant decline in the number of escapes permitted on the second trial (£. = 5.16, d.f. = 1,30, .!'_ < 0.05).

As can be seen in Table 2, Groups Mand P permitted

fewer escapes than the remaining groups on the initial trial (£. = 3.01, d.f. 3, 30,

.!'.

< 0.05).

Subsequent comparisons revealed that Group M differed signi-

fjcantly from Group C (Jc.= 2.39, d.f. = 19, P < 0.05) while Group P performance was only marginally reduced (Jc.= 1.82, d.f.

15, 0.05