Cannibal Spiders “Sing” to Each Other to Recognize Other Spiders of the Same Species and Avoid Becoming Dinner
There is plenty of cannibalism in the spider world, with one species of spiders that only prey on other spiders. However, this particular species has pretty bad eyesight, so there is a danger that they could eat one of their own species if not careful. They aren’t aiming to eat their own species, as this would cause obvious problems for the continued survival of the species. Eating member of your own species has quite a few drawbacks such as eating a possible mate or other spiders eating possible mates, causing missed mating opportunities, a higher risk of disease, as well as the obvious one of accidentally eating one of your own relatives. The spider species Palpimanus has a much higher risk of accidentally eating one of their own since they are specialized hunters, only preying on other spiders. So how do they avoid cannibalizing members of their own species? A recent study revealed that Palpimanus spiders likely use sound to recognize one another and avoid eating other members of the same species.
Since Palpimanus spiders have very poor eyesight they rely on touch and vibration instead to interpret what is going on around them. They can also make noise that sounds similar to buzzing chirps when they rub their facial appendages against the ridged surface of their jaws. In a recent study researchers placed two Palpimanus spiders in the same enclosure to see if they could recognize each other or one of them would end up eating the other one. When they put two of these spiders together the spiders usually would touch each other with their front legs and make a chirping sound. Both spiders walked away unharmed in this situation. However, a few smaller spiders that did not chirp did end up as dinner for the bigger spider.
The researchers then tried amputating some of the spiders’ facial appendages, rendering them unable to chirp. When they placed them in the same container as another spider of the same species that was bigger, the bigger spiders turned out to be four and a half times more likely to eat the smaller spider when they couldn’t chirp than when they could. This demonstrated that the spiders do, in fact, use sound to recognize each other and avoid eating their own species.
Have you ever heard a spider make noise such as chirping? What did you think it was doing?