Harris asked artificial intelligence to tell the spiders apart from images of preying mantises, wasps and other insects. The spider abdomens fooled the computer about 5 percent of the time.
"One of the species is actually named Maratus vespa," she said. "Vespa is Latin for wasp. So we're not the first scientists to see the faces of invertebrate predators in these little spiders."
Spiders are notoriously cannibalistic. Courting males walk a fine line between seducing females and ending up as a snack.
Harris said mimicking a predator might give females just enough pause to halt a deadly ambush so the male can begin his courting display.
"Our hypothesis is the males are trying to exploit the females' anti-predator response of freezing when scared. This would help him capture the female's attention without immediately becoming prey himself," Harris said.
Harris presented her findings at the Society of Integrative and Comparative Biology conference this month.
Featured image at top: A jumping spider's raised abdomen looks so much like the angular head of a preying mantis or wasp that it fooled a computer some of the time. Photo/Jurgen Otto/www.peacockspider.org