LIFE under the waves can get pretty crowded when you are a sea squirt vying
for space on the rocks. But these sea creatures have a novel weapon—they
use their sperm to sabotage the eggs of other kinds of sea squirt. According to
a marine biologist in California, this may be the first example of sperm
competition between species.
Sea squirts spend most of their life clinging on to rocks, and many are
broadcast spawners: females and males release eggs and sperm into the water,
where they mix and fertilise. Any egg that is fertilised by more than one…
