Before any beetle talk, my heartfelt thanks goes out to the fabulous Mark Jones, my longtime friend and author of The Daily Shim Sham (check out his blog!) for the awesome artwork in this post! Hopefully Mark will continue to grace my blog with his brilliant artistry – fingers crossed!
So! Onto the beetles!
Amphibians often feast on beetle larvae, but there are some beetles that have evolved the ability to fight back. During their larval lifestage, ground beetles (Carabidae) in the genus Epomis feed exclusively on amphibians. How do the larvae accomplish this? Oh, they simply suck the body fluids out of the frogs, like small beetle vampires. This predator-prey role reversal is extremely rare – especially when the predators (beetles) are much, much smaller than the prey (amphibians).
A recent study was just published that reported how the beetle larvae are luring the amphibians to their deaths. Basically, the larvae entice the amphibians with their dancing mouthparts.
The antennae and mandibles of the larvae move in a sort of dance that the frogs find irresistible, which makes perfect sense since the frogs are adapted to notice larval movements as their own prey. Once the larvae have danced alluringly for the amphibians, they attach themselves to the frogs and suck them dry. The researchers of the recent paper repeated these observations several times. In one of the trials, the frog ate a larva and kept it in its stomach for 2 hours. Then, the frog regurgitated it and the beetle larva immediately latched onto the amphibian and turned into Nosferatu.
It does not appear that the amphibians have yet evolved any defenses against the vampiric beetles. Hopefully, they’ll soon employ some tiny garlic wreaths.
Wizen G, Gasith A. (2011) An Unprecedented Role Reversal: Ground Beetle Larvae (Coleoptera: Carabidae) Lure Amphibians and Prey Upon Them. PlosOne. 6(9): 1-6.