title: Hidden female physiological resistance to male accessory gland substances in a simultaneous hermaphrodite.
abstract: To increase fertilization chances compared with rivals, males are favoured to transfer accessory gland proteins to females during mating. These substances, by influencing female physiology, cause alteration of her sperm usage and remating rate. Simultaneously hermaphroditic land snails with love-darts are a case in point. During courtship, a love-dart is pierced through the partner's body wall, thereby introducing accessory mucous gland products. This mucus physiologically increases paternity by inhibiting the digestion of donated sperm. The sperm, which are packaged in a spermatophore, are exchanged and received in an organ called the diverticulum. Because of its length, this organ was previously proposed to be a female anatomical adaptation that may limit the dart interference with the recipient's sperm usage. For reproductive success of the donor, an anatomically long spermatophore, relative to the partner's diverticulum, is beneficial as sperm can avoid digestion by exiting through the spermatophore's tail safely. However, the snailEobania vermiculatapossesses a diverticulum that is three times longer than the spermatophore it receives. Here, we report that the love-dart mucus of this species contains a contraction-inducing substance that shortens the diverticulum, an effect that is only properly revealed when the mucus is applied to another helicid species,Cornu aspersumThis finding suggests thatE. vermiculatamay have evolved a physiological resistance to the manipulative substance received via the love-dart by becoming insensitive to it. This provides useful insight into the evolution of female resistance to male manipulations, indicating that it can remain hidden if tested on a single species.
authors.affiliation: Section of Animal Ecology, Department of Ecological Science, Faculty of Earth and Life Sciences, VU University Amsterdam, De Boelelaan 1085, Amsterdam 1081 HV, The Netherlands m.lodi@vu.nl.|Naturalis Biodiversity Center, Vondellaan 55, Leiden 2332 AA, The Netherlands.
authors.forename: Monica
authors.identifier: 0000-0002-6757-0433
authors.initials: M
authors.lastname: Lodi
authors.affiliation: Section of Animal Ecology, Department of Ecological Science, Faculty of Earth and Life Sciences, VU University Amsterdam, De Boelelaan 1085, Amsterdam 1081 HV, The Netherlands.|Naturalis Biodiversity Center, Vondellaan 55, Leiden 2332 AA, The Netherlands.
authors.forename: Joris M
authors.initials: JM
authors.lastname: Koene
mesh_terms: D000818:Animals; D005075:Biological Evolution; D005260:Female; D005306:Fertilization; D006372:Helix, Snails / Q000033:anatomy & histology / Q000502:physiology*; D008297:Male; D012726:Sexual Behavior, Animal; D013093:Spermatogonia / Q000166:cytology / Q000378:metabolism; D013094:Spermatozoa / Q000166:cytology / Q000378:metabolism
keywords: Allohormone; Antagonistic coevolution; Diverticulum; Love-dart; Sexual conflict; Sexual selection