Tuesday, 28 October 2003

This presentation is part of : Display Presentations, Section Cd. Behavior and Ecology

The adaptive significance of sibling egg cannibalism in the Coccinellidae: Comparative evidence from three species

Angela K. Grant and J.P. Michaud. Kansas State University, Entomology, 1232 240th Ave, Hays, KS

Egg cannibalism is common among aphidophagous coccinellids that lay clustered eggs. Neonate larvae may improve their survival probability by cannibalizing sibling eggs prior to dispersal in search of prey. Egg-clustering facilitates sibling egg cannibalism and may represent a form of maternal care that improves the survival of early-hatching larvae. We examined sibling egg cannibalism behavior and its consequences in three aphidophagous coccinellid species that lay clustered eggs: Cycloneda sanguinea L., Harmonia axyridis Pallas, and Olla v-nigrum Mulsant. Cannibalizing larvae of all three species delayed dispersal from clusters and consumed all late-hatching and/or non-viable eggs within clusters before dispersing. There was significant variation among species in 1) the proportion of eggs laid singly versus in clusters, 2) the synchrony of egg hatch within clusters, and 3) the proportion of eggs cannibalized by early-hatching larvae. Both male and female larvae that cannibalized eggs molted to the second instar sooner than did their non-cannibalizing counterparts in all three species, and this translated into reduced total developmental time for both sexes in H. axyridis, but only for males in C. sanguinea and only for females in O. v-nigrum. Female cannibals were heavier as adults than were non-cannibalizing females in H. axyridis and O. v-nigrum, but males had similar weights. Therefore, our results revealed substantial life history benefits for sibling egg cannibalism behavior in all three species, although in many cases the benefits were sex-specific.

Species 1: Coleoptera Coccinellidae Cycloneda sanguinea
Species 2: Coleoptera Coccinellidae Harmonia axyridis
Species 3: Coleoptera Coccinellidae Cycloneda sanguinea
Keywords: egg cannibalism, development

Back to Display Presentations, Section Cd. Behavior and Ecology
Back to Posters

Back to The 2003 ESA Annual Meeting and Exhibition