Influence of Adult Size on Mate Choice in the Solitary and Gregarious Parasitoids, Cotesia marginiventris and Cotesia flavipes

Female and male mate choice in relation to adult size were examined for the solitary and gregarious parasitoids, Cotesia marginiventris (Cresson) and Cotesia flavipes Cameron, respectively. In addition, male precopulatory behaviors were observed for evidence of male competition or a large-male advantage in mate acquisition. Male parasitoids are not known to offer female mates direct benefits, but females that mate high quality males may obtain indirect benefits, such as offspring that are more successful in obtaining mates. Female choice experiments for C. marginiventris found that large males approached females first more frequently than small males, and that females mated large males significantly more often than small males. Male choice experiments for C. marginiventris did not demonstrate a male preference for female size. In contrast, female choice experiments with C. flavipes found that females mated equally with large or small males, while male choice experiments showed that males attempted copulation and mated more frequently with smaller females. Male competition was not observed in the gregarious species C. flavipes, but competition in this gregarious parasitoid could be moderated by dispersal.