Significance of constraints on genital coevolution: Why do femaleDrosophilaappear to cooperate with males by accepting harmful matings?

Abstract

The mechanisms driving the coevolution of male and female genital morphologies are still debated. Female genitalia in Drosophila species bear membranous "pouches" or hardened "shields," which the male genital armature contact during copulation. Although shield-like structures likely serve to mitigate the effects of harmful mating, some authors have suggested that soft pouches, which do not prevent male genitalia from inflicting wounds, represent a congruent sensory organ. To elucidate the evolutionary forces responsible for the development of such organs, I examined the effects of artificial damage to various genital parts of female Drosophila erecta on reproductive success. Despite a high survival rate among females, damage to the ovipositor plate resulted in frequent failure of insemination and in the embedment of eggs into the substrate. Damage to the vaginal shield resulted in increased mortality and frequent failure of egg embedment, with an egg blocking the vagina under the damaged shield in some females. Wounding of the pouch had less of an effect on both mating and oviposition success, suggesting that the structure "lures" the male trauma-causing organs to areas where the resultant wounds do not interfere with insemination or oviposition. These data show that the dual functions of female genitalia (mating and oviposition) mediate genital coevolution.

An innovative ovipositor for niche exploitation impacts genital coevolution between sexes in a fruit-damaging Drosophila

“…In many insect species, the selection of oviposition sites is an essential factor that determines the early lifetime performance of offspring, while the ovipositor and/or its surrounding structures are contacted by male genitalia and determines the posture of the body during copulation. This is clearly the case in most Drosophila species in which ovipositors are grasped or covered by periphallic organs during copulation [25,29,30]. The contact between ovipositor and/or its surrounding structure and male genitalia during copulation is observed in many other insects, including longhorn beetles [31], crickets [32] and a dung fly species, in which the ovipositors are heavily injured during copulation [33].…”

Mechanical incompatibility caused by modifications of multiple male genital structures using genomic introgression inDrosophila*

“…Instead, the mechanical cause of structural incompatibility by posterior lobe divergence most likely involves wounding of the female body (Masly and Kamimura ). Wounding of the female body during copulation is a widespread phenomenon in Drosophila (Kamimura , , ). During copulation, the posterior lobes intercalate between the female abdominal segments to establish stable coupling until 10 min after genital coupling (Jagadeeshan and Singh ; Kamimura and Mitsumoto ).…”

Resolving Between Novelty and Homology in the Rapidly Evolving Phallus of Drosophila

“…To study the evolution of the phallic processes in the melanogaster species subgroup we used the following subset of described species, representing all major complexes: D. santomea (Lachaise et al, 2000), D. teissieri (Tsacas, 1971), D. orena (Tsacas & David, 1978), D. erecta (Tsacas & Lachaise, 1974), D. melanogaster (Meigen, 1830) from the melanogaster species subgroup and the following outgroup species D. biarmipes (Malloch, 1924) from the suzukii subgroup, D. ananassae (Doleschall, 1858), and D. malerkotliana (Parshad & Paika, 1964) from the ananassae subgroup. Previous work has investigated the function of the copulatory anatomy of all species we analyzed (Kamimura, 2007(Kamimura, , 2016Muto et al, 2018;Yassin & Orgogozo, 2013)…”