Random mating with respect to relatedness in the simultaneously hermaphroditic land snail Arianta arbustorum

A previous study showed negative effects of inbreeding on reproductive success in the simultaneously hermaphroditic land snail Arianta arbustorum. Different mechanisms of inbreeding avoidance such as kin recognition, sex-biased dispersal patterns, and variation in mating systems have evolved in a variety of organisms. We performed mate-choice tests to examine whether individuals of A. arbustorum discriminate between full-sibs and non-sibs from the same population, and whether incestuous matings reduce the snails' subsequent reproductive success. Snails mated randomly with respect to degree of relatedness, indicating a lack of inbreeding avoidance by selective mating. Snails which mated with full-sibs did not differ in number of eggs, hatching success of eggs, and number of offspring produced from those mated with unrelated conspecifics. Our results indicate that there is no kin recognition mechanism in A. arbustorum. We suggest that multiple mating with different partners, as observed in the field, may reduce inbreeding effects in this species.