Spiders, Prey Leave DNA

A study of black widow spiders suggests that the arachnids leave traces of their own genetic material and DNA from prey in their sticky webs.

Bob Grant
Nov 30, 2015

WIKIMEDIA, BROCKEN INAGLORYResearchers have developed a method for noninvasively sampling DNA from spiders and their prey items simply by harvesting genetic material left on the arachnids’ sticky webs. Scientists who studied captive black widow spiders (Latrodectus spp.) at an Indiana zoo reported their results last week (November 25) in PLOS One. “In the past, identification of spiders has relied on morphology, especially looking at the genitalia of spiders because they’re very different between different species of spider,” study coauthor Charles Xu, a graduate student at the Erasmus Mundus Master Program in Evolutionary Biology in Europe, told BBC News. “But there are a lot of errors associated with these kinds of methods, and now with the advent of new genetic technologies we can more accurately identify these species.”

Xu and his colleagues found that they could extract spider mitochondrial DNA and genetic material from the spiders’ prey,...