Heritability of body mass, a sexually selected trait, in an arctiid moth (Utetheisa ornatrix)

In the moth Utetheisa ornatrix (Lepidoptera: Arctiidae), females mate prefe rentially with larger males. Large body mass is advantageous to both sexes: large males sire more young than small males, and large females have highe r fecundity than small females. Were me report that body mass is heritable in both sexes, indicating that by choosing larger males females obtain gene tic benefits for their offspring. Choosy females also receive extra nutrien t and defensive alkaloid by way of their partner's spermatophores, but thes e gifts do not affect the heritability of body mass. These results indicate that by exercising mate choice female Utetheisa receive both direct phenot ypic and indirect genetic benefits.