HAMILTON, Ont. September 11, 2009The smell of recent death or
injury that repels living relatives of insects has been
identified as a truly ancient signal that functions to avoid
disease or predators, biologists have discovered. David Rollo,
professor of biology at McMaster University, found that corpses
of animals, from insects to crustaceans, all emit the same death
stench produced by a blend of specific fatty acids. The findings
have been published in the journal Evolutionary Biology. Rollo
and his team made the discovery while they were studying the
social behavior of cockroaches. When a cockroach finds a good
place to live it marks the site with pheromone odours that
attract others. In trying to identify the precise chemicals
involved, Rollo extracted body juices from dead cockroaches. "It
was amazing to find that the cockroaches avoided places treated
with these extracts like the plague," says Rollo. "Naturally, we
wanted to identify what chemical was making them all go away."
The team eventually identi