Flesh-eating flies map forest biodiversity
DNA in insects' guts reveals inventory of rare mammals.
04 January 2013
The blowflies and flesh flies that settle on dead animals aren't just feasting on the carrion — they're sampling their DNA. Scientists in Germany have now shown that this DNA persists for long enough to be sequenced, providing a quick and cost-effective snapshot of mammal diversity in otherwise inaccessible rainforests.
Researchers stumbled on the grisly cataloguing technique while studying a form of anthrax that kills chimpanzees in Côte d'Ivoire. They started sampling flies to see whether the insects could harbour the anthrax bacterium after feasting on infected bodies, but soon realized “that detecting mammal DNA from flies could also be an extremely cool tool for assessing biodiversity”, says team leader Sébastien Calvignac-Spencer, an evolutionary biologist at the Robert Koch Institute in Berlin.
By baiting nets and traps with meat, the team collected carrion flies from Taï National Park in Côte d'Ivoire and Kirindy Reserve in Madagascar, and found that 40% of them carried mammal DNA. The researchers sequenced this material to identify 16 mammals in Côte d'Ivoire, including six of the nine local primate species, as well as Jentink’s duiker (Cephalophus jentinki) — an endangered antelope of which fewer than 3,500 remain. In Madagascar, the team identified four mammal species — including two lemurs — representing one in eight of all the island’s mammals. The work will appear on 7 January in Molecular Ecology1.