Everyone likes a little music with their romance. Even, as it turns out, spiders.
New research finds that the “purring” wolf spider, aka Gladicosa gulosa, can send out an auditory call that's practically a love song to any nearby female spider.
The sounds are created by males causing leaves to vibrate. While it's not unusual for spiders to use vibration to signal each other, what is unusual in this case is that those physical vibrations are accompanied by actual airborne sounds, according to the study presented last week at the annual meeting of the Acoustical Society of America.
To human ears, the spider signals sound like a gentle thrum or patter. But to a female wolf spider, it's like having John Cusack standing outside the window with a boombox cranking out "In Your (Eight) Eyes."
New Scientist posted two audio clips. This first is just the spider vibrations, converted to audible sound:
The second is of the actual audible sound:
"It's very quiet, but it's what you would hear if you were in the room with a courting spider," study co-author George Uetz of the University of Cincinnati told New Scientist. "The sound is at a level that's audible by human hearing at about a meter (roughly 3 feet) away."
The sounds are so delicate that they will only carry when the spiders are on certain surfaces, such as leaves.
"On granite or wood or dirt, you get little to no vibration and almost no sound," co-author Alexander Sweger of the University of Cincinnati, who discovered the sounds with Uetz, told the BBC. "But on a leaf, or paper or parchment, you get vibration and you get the airborne sound."
Since spiders don't have ears and can't "hear" the sounds in any traditional sense of the word, the researchers believe the audio travels through the air, then causes the leaf the female is standing on to vibrate, which she then feels.
"We think that's how she 'hears' the sound," Sweger told New Scientist. "Spiders have very sensitive structures all over their bodies for detecting vibration, even at low levels, so we're working on the hypothesis that they detect a surface vibration induced by the airborne sound."
The noises aren't the only unusual thing about spider sex. At least one type of spider is known to chew off its own genitals after copulating.