Somewhere in the subtropical region of Western Australia, a male spider is balanced atop a leaf. He senses the movements of a female spider on the other side. Although he can't see the potential new mate, he can tell she's there — and he has a decision to make.
Rushing to her side of the leaf could mean he'll be attacked. Doing nothing could mean missing an opportunity for some sexy time. So this male, a member of the Jotus remus species, strikes a compromise: He extends the heart-shaped paddle on one of his third legs over the edge of the leaf and offers a friendly wave. Check out the action in this video:
"If she approaches and stays still, he'll jump over to the other side of the leaf and mate with her immediately," says David Hill, who co-authored the study published in the January 2016 issue of Peckhamia.
What's really unusual is that this tiny male spider — about the size of a grain of rice — hasn't seen the female spider until this amorous moment, but has still been able to sense whether her posture is quiescent or defensive and then use this information to determine his course of action in the courtship and mating ritual.
"Interestingly, he seems to be very aware of her position even if he can't see her," Hill says.
"The whole behavior really is totally remarkable, since it was never observed in any other spider as far as I am aware," says Jurgen Otto, who was the first to identify, name and record the jumping spider. "I was completely surprised to see it and the game-like nature of it, seemingly playing some kind of 'peek-a-boo.'"
Otto discovered the spider after camping in Barrington Tops, which is about four hours from Sydney, Australia. "I unpacked our gear and sitting on my tent bag, I found a jumping spider that at first did not seem unusual. Then I noticed its legs and that they were widened or paddle-shaped at their tips," he says. "That's when I got curious."
Two days, later, Otto drove back to the camping spot, searched for six hours and was about to give up when he decided to take one last look. "And there I got lucky," he says. "I found more individuals and was sure it came from there."
Otto spent months studying the Jotus remus and partnered with Hill to write a paper detailing its paddle-waving mating ritual.
"I saw the male doing this strange thing, hiding on the other side of a leaf and sticking out its paddle-shaped leg and waving it at the female," Otto says, "then he scuttled to a different part of the leaf and did it again. It went on and on. I kept watching this for days, filming in the process. It was so entertaining to watch."
Indeed it is. We'll leave you with one more video of this arachno-Casanova: