CORLEY, L.S.*; STRAND, M.R.: Regulation of Caste Fate in the Polyembryonic Wasp Copidosoma floridanum

Striking morphological differentiation among individuals structures the complex societies found in insects such as termites, bees, and ants. Castes have also evolved in other insects such as aphids, thrips and polyembryonic wasps. Copidosoma floridanum is a polyembryonic parasitoid wasp that produces two castes during development from a single egg. Polyembryonic development results in a single brood containing approximately 1000 reproductive larvae that develop into adult wasps and 50 precocious larvae that function as soldiers. We examined how the single egg proliferates and responds to environmental factors to produce two castes in C. floridanum. We conducted transplantation experiments of wasp embryos from all developmental stages into unparasitized hosts from all developmental stages. By transplanting wasp embryos of a particular stage into different host environments, we partitioned the effects of the intrinsic properties of the embryos from the extrinsic factors (i.e. — the host environment) influencing caste fate. Our results indicate that both intrinsic and host environmental factors affect caste formation in this species.