Most wasps do not have ant heads for butts. So, if you were a researcher digging through a museum collection and found a wasp with an ant head for a butt, you might be surprised. The researchers describing this wasp shouted, "ay, caramba," apparently.
Image: Ilari Sääksjärvi, Zoological Museum at the University of Turku, Finland
Scientists from the Zoological Museum at the University of Turku, Finland found the first and only specimen of the so-called Clistopyga caramba wasp at The Natural History Museum, University of San Marcos, Lima, Peru. The specimen looked so bizarre, they thought it must have been deformed, but nope, they and other entomologists eventually agreed it was a new species, according to a paper published in the journal Zootaxa in September of 2015. Not many others seem to have written about it since then, so now is as good a time as any to talk about ant head wasp butts.
Mimicry isn't all that rare in the animal kingdom — plenty of critters mimic scarier species to avoid being eaten, or less-scary species to create a false sense of security. Take the hoverflies that mimic bumblebees, for instance. Or alligator snapping turtles, which have wormlike tongues to lure prey into their mouths. But this wasp truly shocked the scientists. From the paper:
The specific name caramba refers to the Spanish exclamation "¡Ay, caramba!", used to express astonishment. This word well describes our feelings when we saw this species for the first time.
The Natural History Museum of the University of San Marcos first collected this specimen in the region where the Andes meet the Amazon rainforest in Peru. The date of collection is unknown. The researchers hypothesise several potential functions for C. caramba's ant head butt. Certain jumping spider species fear ants, so the C. caramba wasp might use a tactic called Batesian mimicry to scare the spiders away... and then feast on their eggs. Alternately, the wasp might use the ant head to lure in hungry passersby, and then attack and immobilise them.
The scientists recognise it's not ideal to identify a species from one specimen, and that it's hard to guess the function of an appendage from looks alone — they now need to actually gather some hard evidence. But this wasp looked so weird they felt they needed to share it with a world. You would probably also show your butt to the world if it looked like an entirely different animal.