How mating moths elude spider's web
By Roger Highfield
BIOLOGISTS have discovered the first example of a
sexually-transmitted chemical that protects females from
The male rattlebox moth (Utetheisa ornatrix) gives a
potent chemical with his sperm to protect his partner for
life against predatory spiders, according to a team from
Cornell University, Ithaca, New York.
"This classy moth gives his bride a gift she can
really use - a life assurance policy, if you will - that
keeps paying off every time her life is in danger,"
said Prof Thomas Eisner, who reports the find today in
the Proceedings of the National Academy of Sciences.
"We have added one more item to that very short
list, 'What are males good for?' " he said.
"They evidently donate more than sperm."
The adult male obtains the chemical by eating
rattlebox plants while in the larval stage. One taste of
the chemical-laden female moth is enough to make a spider
cut loose its intended prey from the web.
A derivative of the chemical is released from two
brushes on the male's abdomen during the courtship dance,
Prof Eisner added, so the female has a way of sensing
which suitor offers the best defence.