Sex signals help spiders snare prey

CARDIFF U. (UK) — Insects using vibration to attract a mate might get more than they bargained for: killer spiders are able to intercept the signals to zero in on their prey.

Predators are known to exploit the sight, sound, and smell communications of their prey—but scientists believe this is the first time they have discovered predators including spiders can pick up secretive vibrational signals and use them to their advantage.

“Vibrational signaling is a widespread form of sexual communication between animals,” write William Symondson, professor of biosciences at Cardiff University and postdoctoral fellow Meta Virant-Doberlet.

“By observing this behavior we have been able to see, for the first time, that spiders are able to exploit sexual vibrational communication signals as a mean of tracking down their prey.”

The findings were published in the journal Molecular Ecology.

The scientists made the discovery by observing the behavior of one spider species Enoplognatha ovate—a relative of the highly poisonous Black Widow spider.

When recordings of male leafhopper vibrational signals were played, spiders began homing in on the signal and searching for food.

Males apparently are at an additional disadvantage—the spiders seen to have a preference for them over females, probably because of the louder, more complex signals used by males during courtship.

“Predators have evolved to intercept the signals of their prey but until now this was thought to be limited to visual, acoustic and chemical ways of communicating,” the researchers say.

“This new discovery represents a previously overlooked strategy for prey location and a major unrecognized driver in the evolution of both predators and prey.

“This is a very significant scientific advance, opening up a whole new area for scientific investigation. Vibrational signalling is widespread amongst invertebrates and it is highly likely that many predators have evolved to exploit it.”

The study received funding from the European Union.

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