Parental investment in two solitary wasps Ancistrocerus adiabatus and Euodynerus foraminatus (Eumenidae: Hymenoptera)

Summary Females of the solitary eumenid wasps Ancistrocerus adiabatus and Euodynerus foraminatus control the adult size of their offspring by the amount of food provded to the larvae. For both species, larger females provision more offspring and collect more food than smaller females. Males of E. foraminatus, upon emergence as adults, fight for control of the nest area. The winning brother remains at the nest and mates with his sisters as they emerge several days later. Males of A. adiabatus are not as agonistic as males of E. foraminatus so that a number of males may remain near the natal nest. When females nest near each other, male-male interactions increase, and the likelihood of sibling mating decreases. Under conditions of clumped nesting, females make larger offspring and invest more in males than when nesting in isolation.