PROGENY AND SEX ALLOCATION DECISIONS OF THE POLYEMBRYONIC WASP COPIDOSOMA-FLORIDANUM

1. The reproductive biology of the polyembryonic encyrtid wasp Copinos oma floridanum was examined in a series of laboratory experiments and related to observations from field collections. Females laid one or tw o eggs per host, producing broods comprised of all males, all females, or both sexes (mixed). Each egg produced multiple embryos that develo ped into either precocious larvae that never became adult or reproduct ive larvae that developed into reproductive adults. 2. The age of the host-egg when it was parasitized was found to have a substantial effec t on offspring clutch sizes and sex ratios. (i) The clutch sizes and o verall survivorship of female and mixed broods decreased with increasi ng host-egg age, whereas male clutch sizes and survivorship were relat ively unaffected by host-egg age. (ii) Offspring sex ratios (proportio n males) of mixed broods were higher in older host-eggs. (iii) Body si zes of males and females were negatively correlated with clutch size. Larger females had higher fecundities and larger males had greater mat ing abilities. 3. Host-egg age also affected competitive asymmetries b etween males and females. In young host-eggs, female precocious larvae were much more abundant than males and were instrumental in reducing the number of males in mixed broods. In older host-eggs, the numbers o f male and female precocious larvae were much lower, and were approxim ately equal. As a result, sex ratios of mixed broods in older host egg s were closer to equality. 4. Ovipositing females responded to host-eg g age and host encounter rates when making oviposition decisions. Fema les laid more female eggs in younger hosts and more mixed broods in ol der hosts. Females laid more mixed broods when encounter rates were lo w and more female broods when encounter rates were high.