RT Journal Article SR Electronic T1 Postmating sexual selection and the enigmatic jawed genitalia of Callosobruchus subinnotatus JF bioRxiv FD Cold Spring Harbor Laboratory SP 116731 DO 10.1101/116731 A1 Merel M. van Haren A1 Johanna Liljestrand Rönn A1 Menno Schilthuizen A1 Göran Arnqvist YR 2017 UL http://biorxiv.org/content/early/2017/03/14/116731.abstract AB Insect genitalia exhibit rapid divergent evolution. Truly extraordinary structures have evolved in some groups, presumably as a result of post-mating sexual selection. To increase our understanding of this phenomenon, we studied the function of one such structure. The male genitalia of Callosobruchus subinnotatus (Coleoptera: Bruchinae) contain a pair of jaw-like structures with unknown function. Here, we used phenotypic engineering to ablate the teeth on these jaws. We then experimentally assessed the effects of ablation of the genital jaws on mating duration, ejaculate weight, male fertilization success and female fecundity, using a double-mating experimental design. We predicted that copulatory wounding in females should be positively related to male fertilization success. However, we found no significant correlation between genital tract scarring in females and male fertilization success. Male fertilization success was, however, positively related to the amount of ejaculate transferred by males and negatively related to female ejaculate dumping. Ablation of male genital jaws did not affect male relative fertilization success but resulted in a reduction in female egg production. Our results suggest that postmating sexual selection in males indeed favors these genital jaws, but not primarily through an elevated relative success in sperm competition but by increasing female egg production.