Anatomy of male and female genitalia of (Say, 1831) (Coleoptera, Chrysomelidae, Bruchinae) in interaction.

Armatures of the male intromittent copulatory structures have been surmised to increase male fitness by imposing physiological costs on female re-mating. Female kicking could, consequently, be a counterstrategy to avoid wounding or to prevent males from mating. The membranous endophallus of male (Say, 1831) is armed with denticles.

Functional morphology of immature mating in a widow spider.

Background: Mating generally occurs after individuals reach adulthood. In many arthropods including spiders, the adult stage is marked by a final moult after which the genitalia are fully developed and functional. In several widow spider species (genus Latrodectus), however, immature females may mate a few days before they moult to adulthood, i.