The effect of male size, age, and mating behavior on sexual selection in the seed beetle Callosobruchus maculatus

We use laboratory mating experiments to examine the effect of male size, ag e, and mating behavior on fecundity selection and sexual selection in the s eed beetle, Callosobruchus maculatus (Coleoptera Bruchidae), a species in w hich females are larger than males. Female C. maculatus gain a fitness adva ntage, in the form of increased lifetime fecundity, from mating with large males (which contribute larger ejaculates), but the partial correlation bet ween male size and fecundity is weaker than the partial correlation between female size and her fecundity. Large males had a mating advantage relative to small males, both when a single male was presented to a female and when two males were present. However, this did not appear to be due to females rejecting male courtship attempts, but instead may be due to male-male comp etition. When females were mated to two males sequentially, neither the siz e of the first male nor the size of the second male influenced whether or h ow quickly a female remated. None of the other potential bases for sexual s election - male age, male mating experience, and male courtship persistence - appeared to influence male mating success. We discuss how patterns of se xual selection on body size and sexual size dimorphism in C. maculatus diff er from patterns of sexual selection and dimorphism in another seed beetle, S. limbatus.