The mucus of a land snail love-dart suppresses subsequent matings in darted individuals

We studied a mating behaviour of simultaneously hermaphroditic land snails, the so-called shooting of love-darts, whereby a snail drives its love-dart(s) into its mating partner. It has been shown that the dart transfers some of its mucous coating into the partnerʹs blood and that mucus from the dart increases sperm storage. However, whether the mucus affects the sperm recipient in other ways is unclear. We tested the hypothesis that mucus transfer by sperm donors in dart-bearing snails Euhadra quaesita suppresses subsequent matings and promotes oviposition in their partners. We found that the intermating interval was longer in stabbed snails than in ones not stabbed and that snail pairs injected with mucus subsequently mated less often than control pairs. The number of snails that laid eggs did not differ between treatments. These findings show that the dart mucus can suppress subsequent matings in its recipients. Sperm donors may possess advantages in sperm competition with both previous and prospective sperm donors by shooting the love-dart coated with the dart mucus.