ABSTRACT

In the leaf beetles (Coleoptera: Chrysomelidae) males and females mate with multiple partners and form prolonged associations that last for hours or even days. In some species, males exhibit elaborate courtship behaviors while riding on females' backs before, during, or after insemination. Females often respond to copulation attempts by positioning their abdomens out of reach of the male's genitalia or by kicking males with their legs. Examination of internal events suggests that females control the ability of males to fully evert their genitalia and inseminate. Females of some species also emit sperm during or after copulation. Experimental work indicates that the spermathecal muscle plays a role in sperm retention and fertilization of eggs, suggesting that females control emission and retention of the male's sperm. Comprehensive analysis of the fitness consequences of prolonged and multiple mating has not been attempted for any species in the Chrysomelidae. Although mateguarding appears to be one important function of prolonged pairing, prolonged pairing can increase proportional paternity even when it does not reduce the likelihood of remating by the female. An intriguing body of evidence suggests that cryptic female choice may occur in the leaf beetles, where females accept, retain, and use sperm of males of preferred phenotypes. The hypothesis that females exert postmating female choice by manipulating retention and use of sperm should occupy significant numbers of behavioral ecologists in the coming decade.