Harari, A.R., USDA-ARS, Gainesville, FL, United States, Volcani Center, Entomology, Beit Dagan 50250, Israel
Handler, A.M., USDA-ARS, Gainesville, FL, United States, USDA-ARS, 1700 S.W. 23rd Drive, Gainesville, FL 32608, United States
Landolt, P.J., USDA-ARS, Gainesville, FL, United States, USDA-ARS, 5230 Konnowac Pass Road, Wapato, WA 98951, United States

In the beetle Diaprepes abbreviatus (L.) females are larger on average than males, as indicated by elytra length. Size-assortative matings were observed in wild populations in Florida and in laboratory mating experiments. We tested three mechanisms for this size-assortative mating: (1) mate availability; (2) mating constraints; and (3) mate choice. We found that mate choice influenced size-assortative mating by: (1) large and small males preferring to mate with large females; (2) large males successfully competing for large females, leaving small males to mate with small females; and (3) females accepting large males as mates more readily than small males. Males increased their reproductive success by mating with larger, more fecund females. They transferred protein to females during mating.