To win the affection of females, male jumping spiders put on an intricate performance. While their dance moves have been studied for decades, it's only recently that researchers have realized the males also “sing” to their potential lovers.
KQED reports: “By rubbing together their two body segments, the males create vibrations that travel through the ground. The female spiders can ‘hear’ the male songs through ear-like slits in their legs, called sensilla … Far from being random noise, each spider song is composed of a specific series of thumps, scrapes and buzzes, called motifs, all synched to the spider’s movement.”
Check out this fascinating video detailing the dance and the accompanying song:
While the spiders’ song is particular to the species, each male adds his own spin or embellishments. It's perhaps these personal touches that make or break the interaction. Perform in a way she doesn’t like, and the female may just make you her next meal. Around 7 percent of courtships end in the female cannibalizing the poor male. When researchers prevented the males from being able to perform their vibration song, the rate of cannibalism quadrupled. So those little touches to the song or dance had better impress ... life depends on it!
While the song is a critically important part of the courtship performance, it’s meaning to the female remains a mystery. Why females accept or reject males is still a mystery to researchers studying these tiny arachnids.
“The common assumption is that successful courtship behavior demonstrates health and vigor to a potential mate. But when it comes to jumping spiders, that assumption doesn’t tell the whole story,” writes KQED.
Males that seem less robust at first glance may do just as well as seemingly more fit males, so the question is, exactly what are females paying attention to during the performance? Learning more about what she wants will reveal clues about the evolution of this and perhaps other species.
“You can endlessly look at the male,” Erin Brandt, a graduate student in environmental science at UC Berkeley, told KQED, “but the females have all the power. They’re driving the evolution of the system.”