Forget Miley Cyrus: When it comes to twerking, spiders can save their lives by shaking their booties, a new study says.
Scientists have found that male black widows move their bodies in a certain way to let females know of their presence—and avoid becoming their next meal. (Also see “Surprise! Male Spiders Eat Females, Too.”)A male black widow (right) must tread carefully to avoid being eaten by the bigger female. Photograph by Sean McCann
The male, “upon entering a female’s web, will pause and vibrate its abdomen up and down, keeping the rest of its body quite still,” said Samantha Vibert, an entomologist at Simon Fraser University in Canada, who led the study published January 16 in the journal Frontiers in Zoology.
Female black widow spiders are not the friendliest mates, even according to spider standards: They will pretty much eat anything moving on their web, prey or spider. So it pays to clearly identify yourself as a mate, not a morsel.
Males do this by jerking the female’s web, transmitting friendly vibrations that give the female a simple message: “Please don’t eat me! I’m here to mate.” (Read about 7 other animals that use vibrations to communicate.)
This is a smart move, since the female’s web “functions as an extension of the spider’s exquisitely tuned sensory system, allowing her to very quickly detect and respond to prey coming into contact with her silk,” said study co-author Catherine Scott, also at Simon Fraser.
So by making movements on the web that are unlike those of a fly or cricket, the male has figured out a lifesaving communication strategy.
In the lab, researchers recorded vibrations made by black widow males, hobo spider males, and common prey species.
The vibrations of the male black widows were played back to female black widows, vibrations of the male hobo spiders were played back to female hobos, and both species’ females were exposed to vibrations from prey. The team observed the females’ reactions throughout the experiments.
For hobo spiders, no twerk was detected and their vibes did not differ much from those of prey. This is likely due to the fact that, unlike black widow males, which are much smaller than their females, male hobo spiders are about the same size as females and usually don’t get the cannibal treatment.
However, “the vibrations produced by courting black widow males were very different from those produced by prey,” explained Vibert. “They were long-lasting and of very low amplitude, just like a constant humming,” she said.
Their results suggest that black widow males sent just the right vibrations to black widow females to keep them docile. (See “Male Spiders Give ‘Back Rubs’ to Seduce Their Mates.”)
Talk about a labor of love.