Alternative Female Choice Tactics in the Scorpionfly Hylobittacus apicalis(Mecoptera) and Their Implications

Females of the scorpionfly Hylobittacus apicalis choose mateson the basis of material benefits (nuptial arthropod prey size)and probably on the basis of genetic benefits males deliverat mating. Females feed on the male's prey throughout copulation.They prefer males with large prey as mates and often refusemales who present small prey. That females may value male geneticquality is suggested by differences in ability of males to obtainlarge prey, which if inherited would influence offspring fitness,and by females often terminating mating with males with smallprey before they transfer any sperm or a complete ejaculate.Females hunt only when males with prey are not available becausehunting exposes individuals to predators. Female Hylobittacusapicalis exhibit alternative mate choice tactics, which arecondition-dependent in expression and probably comprise a conditionalstrategy. Body size, recent feeding history, and male availabilitydetermine how discriminating an individual female actually is,and these conditions may determine the value of material andgenetic benefits in mate choice decisions. The results suggestthat female choice controls male behavior. When females becomechoosy, males are forced to obtain rare large prey despite theincreased risks to males associated with this behavior. The implications of the findings on H. apicalis are discussedin relation to condition dependent female choice patterns inother species and the evolutionary maintenance of female choice.