Death stench: Ancient warning signal to avoid disease, predatorsSeptember 12th, 2009 - 4:13 pm ICT by IANS
Toronto, Sep 12 (IANS) Dead animals, from insects to crustaceans, emit the same death stench. This smell acts as a signal to other insects to avoid disease or predators, biologists have discovered.
David Rollo, professor of biology at McMaster University, found that dead insects emit the same death stench produced by a blend of specific fatty acids.
Rollo and his team made the discovery while studying the social behaviour 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 identified the specific chemicals that signaled death.
Furthermore, they found that the same fatty acids not only signalled death in ants, caterpillars, and cockroaches, they were equally effective in terrestrial woodlice and pill bugs that are actually not insects but crustaceans related to crayfish and lobsters.
“Because insects and crustaceans diverged more than 400-million years ago it is likely that most subsequent species recognise their dead in a similar way,” a McMaster’s release said.
“Recognising and avoiding the dead could reduce the chances of catching the disease, or allow you to get away with just enough exposure to activate your immunity,” Rollo said.
Likewise, he added, release of fatty acids from dismembered body parts could provide a strong warning that a nasty predator was nearby.
The findings were published in Evolutionary Biology.
Tags: ants, biologists, caterpillars, cockroach, cockroaches, david rollo, dead animals, dead cockroaches, dead insects, evolutionary biology, fatty acids, mcmaster university, million years, odours, pill bugs, predators, social behaviour, stench, warning signal, woodlice