Voracious larvae of two recently discovered beetles can latch onto frogs, toads, and other amphibians many times their size, then devour them. How the bugs entice their prey and survive their attacks, however, wasn’t known until now.
Researchers have witnessed the worm-like larvae of predatory Epomis ground beetles in action. The fingertip-sized larvae perform a dazzling dance to lure large prey to their doom.
“The amphibians don’t stand a chance. They can’t ignore the moving larvae because, if they do, something is wrong with their instincts,” said entomologist Gil Wizen of the University of Toronto, leader of a study about the deadly bugs published Sept. 21 in PLoS ONE.
“Normally amphibians eat small larvae, so the larvae seem to be taking their revenge here,” he said.
A scanning electron microscope’s view of Epomis ground beetle larvae. The spiked mandibles help the larvae both dazzle and latch onto their prey. Top: E. dejeani. Bottom: E. circumscriptus. (G. Wizen et al./PLoS ONE)
In 2005, Wizen and his colleagueAvital Gasith of Tel Aviv University found a toad in Israel with the larvae of a ground beetle species calledEpomis dejeani latched onto its skin. They brought the duo back to the lab and learned the larvae — unlike any other beetle species — fed exclusively on amphibians to grow into adulthood.
Years later, they discovered that adults of E. dejeani and a second species, E. circumscriptus, could also dine on much larger amphibians.
How the larvae of either species latched onto the amphibians and reduced them to “only a pile of bones,” however, wasn’t known. So Wizen and Gasith closely monitored hungry Epomis larvae after introducing a toad, frog, or salamander into their cage.