From SOTT:

You may want to think twice before vacuuming up any pesky cobwebs you find around your home — these messy spider lairs may contain valuable information (valuable to scientists, that is).

A spider’s sticky web contains traces of the critter’s DNA, as well as the DNA of whatever prey that was unlucky enough to get stuck in the web, according to a new study, which found that these tiny samples of DNA can be amplified and sequenced in a lab. In other words, an empty spider web isn’t a mystery; it’s a clue that can tell scientists what kind of spider built the web and what prey it snagged in its trap.

Knowing exactly which species of spider built a web in a certain area, as well as knowing what that spider feasted on, is important information for researchers in a variety of fields — from conservation ecology to pest management, said study lead author Charles C.Y. Xu, a graduate student in the Erasmus Mundus Master Programme (MEME) in evolutionary biology, a joint program hosted by four European universities and Harvard University in the United States.

“There’s a variety of different methods to study [spiders],” Xu told Live Science. To collect specimens, researchers try everything from beating (literally beating on a tree until spiders and other insects fall from it) to the aspiration method, which is when a researcher sucks a spider or insect into a glass vial through a rubber tube.

But genetic sequencing, which is becoming less expensive, enables new methods…

Continue Reading