(ANIMAL SCIENCE/WEIRD ANIMAL FACTS) If you want to stay alive, you have to “twerk” for it—at least if you’re a male black widow spider.
Scientists discovered that upon entering a female’s web, a male spider will pause and vibrate his abdomen up and down, while keeping the rest of his body relatively still—much like Miley Cyrus’ notorious dance move. Read on to learn more about this amusing phenomenon. — Global Animal
National Geographic, Karl Gruber
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.
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.”
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.
Their results showed that black widow males sent just the right vibrations to black widow females to keep them docile.
“The vibrations 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.
For hobo spiders, however, 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.
But when researchers turned up the volume of the vibrations made by the black widow males, the female black widows attacked.
This explains why the male spiders keep their twerking at a low key: “The males ‘twerk’ to avoid triggering a female’s predatory instinct, or even to turn it off,” Vibert said.
Talk about a labor of love.
More National Geographic: http://newswatch.nationalgeographic.com/2014/01/16/black-widows-spiders-mating-sex-animals-science/