Size-assortative mating, male choice and female choice in the curculionid beetle Diaprepes abbreviatus

In the beetle Diaprepes abbreviatus (L.) females are larger on average than males, as indicated by elytra length. Size-assortative matings were observ ed in wild populations in Florida and in laboratory mating experiments. We tested three mechanisms for this size-assortative mating: (1) mate availabi lity; (2) mating constraints; and (3) mate choice. We found that mate choic e influenced size-assortative mating by: (1) large and small males preferri ng to mate with large females; (2) large males successfully competing for l arge females, leaving small males to mate with small females; and (3) femal es accepting large males as mates more readily than small males. Males incr eased their reproductive success by mating with larger, more fecund females . They transferred protein to females during mating. (C) 1999 The Associati on for the Study of Animal Behaviour.