Attack of the Alluring Larvae

We usually think of vertebrates eating insects, but not as often about insects eating living vertebrates. However,Wizen and Gasith recently report in PLoS ONE on a couple of interesting beetle species that feed on amphibians. The larvae of two species of ground beetles, Epomis circumscriptus and Epomis dejeani are able to lure frogs and salamaders for dinner.

Most amphibians are predators that feed on insects. They are attracted to movements of potential prey. The Epomis larvae goad the amphibian predators by waving their antennae and mouthparts in an enticing dance. The amphibians hungrily approach, hoping to dart out their long sticky tongues and devour a tasty insect.

However, the Epomis beetle larvae are quick to dodge the attacking tongue. After a miss the larvae jump on the frog or salamander and initiate feeding. The larvae kill the prey and consume all but the bones.

Wizen and Gasith report that 70 percent of the beetle larvae they observed successfully avoided the predator’s tongue and attached to the body. Of the other 30 percent, all but one was rejected by the amphibian predator. When the larvae are spit out, they quickly attach to the amphibian and kill it. Apparently, the larvae must taste bad.

Epomis Larva Attaches to a Frog and Eats It
Image: Screen shot from PloS One Video
(See citation or follow link above.)

One larva that was eaten by a frog, survived in its stomach for two hours. The frog eventually regurgitated the larva which immediately attached itself to the frog and devoured. it.

Check out the article, it has some cool video of beetle larvae attacking frogs.

Citation: Wizen G, Gasith A (2011) An Unprecedented Role Reversal: Ground Beetle Larvae (Coleoptera: Carabidae) Lure Amphibians and Prey upon Them. PLoS ONE 6(9): e25161. doi:10.1371/journal.pone.0025161