It’s getting closer to her. Subtle vibrations run up her brown legs, and the starlit flashes of the cricket’s movement reach her eight night-vision eyes. But she can’t strike yet. Too early, and the slender cricket will jump away with its powerful rear legs. Too late, and the cricket will discover her and change course. It’s so close. Not yet. A twitch. Not yet…

Now.

The wolf spider uncoils in a sudden flash of legs and fangs, and with an agile lunge that her ancestors have practiced for millions of years, she grabs the cricket by the abdomen and drives her venom-filled jaws into its body. The cricket frantically tries to buck and throw her off, but it’s too late. She patiently clamps down as the toxin takes what remains of the cricket’s strength, and it is over. 

Many spiders hunt by building a web and waiting for prey to fly in. Not her. Wolf spiders (Family: Lycosidae), like their mammalian namesake, hunt on the move. They use their superb night vision to prowl through forests, fields, and meadows looking for food [1]. Their quick legs let them dart to cover before predators like birds catch them. Their ferocity in hunting down pest insects like grasshoppers also makes wolf spiders a welcome sight in agricultural fields (but don’t worry, they’re harmless to people). In fact, wolf spiders are so common throughout the world that you’ve probably seen one without even knowing it.

But I bet you haven’t heard them sing.

Well, it’s not a song per se. In some species of wolf spiders, males attract females by repurposing their bodies into a full rock-n-roll drum kit. The male starts by striking his smaller front legs into the ground to create a drumroll, then lets loose with its brush-covered forelegs for a striking flourish, turning its abdomen into a kickdrum [2]. It’s something that needs to be heard to be believed.

This flashy drumming isn’t just for kicks. Nori Choi, Eileen Hebets, and their team at the University of Nebraska-Lincoln found that the more sophisticated a male wolf spider’s drum solo – the faster his flourishes – the more popular he was with attracting mates [3, 4]. This is a phenomenon called sexual selection, where one sex prefers a signal from the other sex that’s tricky to produce. Sexual selection has led to extravagant sage grouse displays, giant rhinoceros beetle horns, bright colors and dances in male peacock spiders and, apparently, a spider with a killer drum solo.

Due to their hunting tactics, wolf spiders largely spend their lives on the move, and that means the kids are too. When a mother wolf spider lays eggs, she’ll carry them on her abdomen in a special sack. And once the spiderlings hatch, they all pile onto her back like it’s some sort of oversized minivan. Mom will carry them around until they’re strong enough to fend for themselves. One day, there’ll be a whole new generation of hunters and drum enthusiasts, coming soon to a woody grassland near you.

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Jacob Johnson is a third-year animal behavior PhD student at UC Davis studying how animals respond to rapid environmental changes. When he’s not chasing birds or ants, he enjoys playing jazz saxophone, running board game nights, and writing about nature. His first book, Are You There God? It’s Me, Darwin, will be available late next year.

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References:

[1] Nyffeler, M., & Benz, G. (1988). Feeding ecology and predatory importance of wolf spiders (Pardosa spp.) (Araneae, Lycosidae) in winter wheat fields. Journal of Applied Entomology, 106(1–5), 123–134. https://doi.org/10.1111/j.1439-0418.1988.tb00575.x

[2] Hebets, E., Stratton, G. E., & Miller, G. (n.d.). Habitat and courtship behavior of the wolf spider Schizocosa retrorsa (Banks) (Araneae, Lycosidae). The Journal of Arachnology, 8.

[3] Choi, N., Adams, M., Fowler-Finn, K., Knowlton, E., Rosenthal, M., Rundus, A., Santer, R. D., Wilgers, D., & Hebets, E. A. (2022). Increased signal complexity is associated with increased mating success. Biology Letters, 18(5), 20220052. https://doi.org/10.1098/rsbl.2022.0052

[4] Parri, S., Alatalo, R. V., Kotiaho, J. S., Mappes, J., & Rivero, A. (2002). Sexual selection in the wolf spider Hygrolycosa rubrofasciata: Female preference for drum duration and pulse rate. Behavioral Ecology, 13(5), 615–621. https://doi.org/10.1093/beheco/13.5.615

[Edited by Meredith Lutz]