“…Many hermaphroditic animals have been shown to mate multiply, mostly under laboratory conditions (e.g., Jordaens, Dillen, & Backeljau, ), but in a few cases also in the field (e.g., Anthes, Putz, & Michiels, ). Moreover, in the majority of studied hermaphroditic species, multiple paternity within broods or clutches, providing a minimum estimate of the degree of polyandry in a population (Anthes, Häderer, Michiels, & Janicke, ; Dunn & Lifjeld, ; Griffith, ; Uller & Olsson, ), turned out to be common (e.g., Angeloni, Bradbury, & Burton, ; Henry, Bousset, Sourrouille, & Jarne, ; Janssen & Baur, ; Lorenzi, Schleicherová, & Sella, ; Pongratz & Michiels, ; Proestou, Goldsmith, & Twombly, ). Finally, in two species of simultaneously hermaphroditic freshwater snails, sexual selection has been measured explicitly and proved to be quite similar in strength and direction to corresponding values of gonochoric species (Anthes et al., ; Pélissié, Jarne, & David, ).…”