Host discrimination in insects has a large influence on fitness. For seed feeders, the accuracy with which females select their host plant and the number of eggs laid on the seed will affect the survival and development of progeny. It is expected that females evolve a behavior that maximizes the amount of resources per offspring. Previous studies with non-seed limited bruchids have shown that females tend to distribute eggs uniformly among seeds and prefer to oviposit on seeds upon which a lower than average number of eggs have been previously laid. Utilizing two populations of the seed beetle, Stator limbatus, we examine female fecundity and egg laying patterns by exposing females to seeds of Acacia gregii containing hatched or unhatched eggs at varying densities. We found that fecundity and dispersion of eggs decrease with increasing egg density. The type of eggs did not significantly influence either total fecundity or egg dispersion. The two populations under study responded similarly to each treatment. These results agree with the hypothesis that females distribute eggs among seeds less uniformly as more eggs are laid and as the density of eggs on the seeds increase.
Species 1: Coleoptera Chrysomelidae Stator limbatus
Species 2: Fabales Fabaceae Acacia gregii (catclaw)
Keywords: egg dispersion, oviposition behavior
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