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
Bob Grant

From 2017 to 2022, Bob Grant was Editor in Chief of The Scientist, where he started in 2007 as a Staff Writer.

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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,...

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