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Experimental Tests of the Optimal Diet in Two Social Insects
Diane W. Davidson
Behavioral Ecology and Sociobiology
Vol. 4, No. 1 (1978), pp. 35-41
Published by: Springer
Stable URL: http://www.jstor.org/stable/4599187
Page Count: 7
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1. Experimental studies of dietary specialization in two species of harvester ants (genus Pogonomyrmex) reveal correspondence to several qualitative predictions of optimal diet theory. 2. If the proportions of available seed types are held constant while overall abundance is varied, dietary specialization in colonies of P. barbatus is enhanced in more productive environments. 3. Colonies of P. rugosus take a narrower range of prey types as distance to the foraging area increases. 4. Ants appear to rank prey (barley particles) on the basis of size (caloric value), and the order of incorporation of prey types in the diet of P. rugosus corresponds to the sequence of profitabilities of these food types. Contrary to the predictions of theory, partial preferences are expressed by ant colonies of both species and may be explained in part by within-colony worker variation in the choices of individual workers, as well as by a possible requirement for workers to continuously sample the resource environment. Trends in dietary specialization at the colony level with changes in resource density and distance probably reflect the summed responses of individual workers that evaluate the resource environment and alter their diets in the predicted way.
Behavioral Ecology and Sociobiology © 1978 Springer