Using the Smell of Rotting Meat to Find New Species
Posted by Richard Conniff on January 14, 2013
Science magazine online recently reported a bizarre technique for finding new species: By the smell of their rotting flesh. The idea is to let carrion flies do the work of field biologists:
Even today, the distribution and abundance of many animal species remains poorly documented, and figuring out a habitat’s who’s who is no easy task. The terrain can be vast and difficult to traverse, and many creatures are secretive by nature. Traditionally, biologists have searched for the animals themselves, or for burrows, nests, footprints, droppings, and other traces—and all that searching can be time-consuming and costly. In recent years, they’ve been turning to labor-saving methods, such as setting out microphones, cameras, and traps that snag hairs, or studying animal DNA left behind in water or soil.
But why not just let someone else do the searching? Carrion flies—which include blowflies (family Calliphoridae) and flesh flies (family Sarcophagidae)—live around the world in virtually every terrestrial habitat occupied by vertebrates. Best of all, they’re abundant and much easier to capture than vertebrates—even dead ones.
“In the rainforest, many animals die each and every day, but it’s really rare to find a carcass,” says Sébastien Calvignac-Spencer, an evolutionary biologist at the Robert Koch Institute in Berlin and lead author of the new study.
Calvignac-Spencer and colleagues collected carrion flies in two tropical habitats: Taï National Park rainforest in Côte d’Ivoire and dry, deciduous Kirindy forest in Madagascar. They began by analyzing flies they captured under mosquito nets shrouding dissected mammal carcasses of known species, showing that DNA from the carcasses could be retrieved from the flies.
They then trapped 115 flies at random in the two forests and found that 40% contained identifiable DNA fragments from a total of 20 mammal taxa, two bird species, and an amphibian. In Kirindy, the catch represented 13% of the documented mammal community. In Taï, the mammals aren’t fully cataloged, but the scientists turned up DNA from six out of nine known primate species and one very rare antelope, they report this week in Molecular Ecology. Those results are “remarkable” for a modest sample, according to a commentary in the same issue.
You can read the full article by Rebecca Kessler here. She also mentions recent research using leeches for the same purpose. Visit this website for more information on the dashing field biologist in the photo.