Effects of Intermating Interval on Spermatophore Size and Sperm Number in the Simultaneously Hermaphroditic Land Snail Arianta arbustorum

We examined the effect of intermating interval on spermatophore size and number of sperm delivered in the simultaneously hermaphroditic land snail, Arianta arbustorum . Snails that remated after 6–7 d transferred smaller spermatophores which contained fewer sperm than snails that remated after eight and more days. This indicates that individuals of A. arbustorum need at least 8 d to completely replenish their sperm reserves after a successful copulation. We suggest that the interval between two copulations is also influenced by the energy costs of the long-lasting courtship behaviour with extensive mucus production.