THE 鈥渓ove darts鈥� that the common garden snail, Helix aspersa,
shoots into its partner鈥檚 skin during mating are coated with a pheromone that
helps ensure its sperm are successful.
The sharp calcareous darts are exchanged between hermaphrodite snail partners
in a prelude to several hours of mating. Now, in a study to appear in a
forthcoming issue of the Journal of Experimental Biology, Joris Koene
and Ronald Chase at McGill University in Montreal have shown that an extract of
the mucus covering the dart makes the female copulatory canal more accessible
for sperm and closes off an organ that digests sperm.
鈥淢ultiple matings before egg laying are common, so the pheromone can give the
dart shooter鈥檚 sperm an advantage over that stored from previous partners,鈥�
Koene says.
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