During the final stages of courtship, helicid land snails pierce each other
with calcareous 'love darts'. This bizarre sexual device has been claimed
to be a nuptial gift or an indicator of the readiness of a 'shooter' to mat
e. However, these explanations are not supported by new work, which shows i
nstead that mucus introduced with darts paralyses the female reproductive t
ract, allowing sperm to avoid female digestion and so make it in greater nu
mbers to the sperm storage sacs. Love darts increasingly look like male ins
truments that are designed to manipulate females, although a role in mate c
hoice cannot be excluded.