Sticky sex

The “love dart” that garden snails stab their partners with before sex helps
them retain sperm, say Canadian biologists. Land snails are hermaphrodite, and
when acting as females destroy sperm from undesirable partners using a
sperm-digesting gland. To save their sperm from that fate, the “male” snail
tries to stab its partner with a mucus-coated calcium carbonate dart before
mating. A chemical in the mucus makes the snail close off the entrance to the
sperm-eating gland. David Rogers and Ronald Chase of McGill University in
Montreal found that as a result, stabbed snails retained more than twice as much
sperm…