Instant attraction

SIZE might not matter so much when it comes to fertilising eggs under water,
say biologists in Australia. Fertilisation can be a hit-or-miss affair for
marine animals that release eggs and sperm into the water, and bigger eggs are
thought to make bigger targets for sperm to hit. But now it seems that the
chemicals some eggs produce to attract sperm are just as important. Jon
Havenhand at Flinders University in Adelaide and his colleagues tracked sperm as
it fertilised sea-squirt eggs. The eggs released a sperm-attracting chemical
into the water, which made fertilisation 45 times more likely than would…