The trade-off between flight capability and reproduction is well known in adult males of insects with wing dimorphism but the reproductive advantage of short-winged (SW) males over long-winged (LW) males appears to vary across insect taxa. In the present study, we determined the difference in the mating ability of SW and LW males of Velarifictorus ornatus (Orthoptera: Gryllidae) in order to evaluate whether the SW male morph has a reproductive advantage. We found that the choice of a mate depended on the female. Compared with LW males, SW males had an obvious mating advantage when both SW and LW males courted females simultaneously, and that dealation significantly enhanced the mating ability of LW males. Losing the ability to produce songs reduced the mating advantage of SW males, thereby indicating that the greater mating advantage of SW males was related to the attractiveness of the song. In addition, the difference in the mating ability of LW and SW males was not related to body size or age. These results indicate that SW males of V. ornatus have a mating advantage over their LW counterparts because their underdeveloped flight muscles allow them to devote more resources to reproduction., Lv-Quan Zhao, Huai-Lin Chai, Hong-Jun Wu, Dao-Hong ZhuU., and Obsahuje bibliografii
Ptomascopus morio of both sexes are attracted to vertebrate carcasses, a necessary resource for reproduction. The stage during reproduction that resource defense was most intense and the hypothesis that large beetles were better competitors and sired a larger share of the offspring were supported and tested. Male-male aggression (pushing, biting and mounting) was commonly observed before and during oviposition, but rarely after the larvae hatched. Few female-female aggressive interactions were observed at any time. Parentage analysis of the offspring of six groups of two males and two females each reproducing on a separate carcass revealed that the large males sired more of the offspring than small males. Paternity analysis, using AFLP markers, revealed that larger males had higher paternity than smaller males, but the number of eggs produced by each female did not differ between large and small females. This suggests that competition among males is intense until the end of oviposition and that resident (large) males can acquire more mates and sire more offspring than smaller males; competition among females was not evident at any time.