New Book Excerpts #4: Bison Wasps

Today’s choice titbit from my NEW BOOK is a homage to the Bison Wasps; tiny, tropical and downright outrageous characters that exploit ant nests. To me, they’re the epitome of the mesmerising diversity in forms we see among the insects. Again, there’s another stunning illustration by Carim Nahaboo.

“Even by insect standards, bison wasps (Kapala spp.) are outlandish, preposterous even – a perfect example of why there can be no creator. To come up with these, the creator would have to be out of their mind on horse tranquilisers. Through the lens of natural selection though, what appears outlandish in our eyes makes much more sense.

These wasps, about 25 known species, with many more still to discover, are mainly from the neotropics where they are parasitoids of ants. Beyond their overall shape, from their relatively enormous thorax to the delicate stalked abdomen, perhaps their oddest characteristic are the horns that sprout from their thorax. Without any knowledge of the biology of these animals you might say that they look like a bit of an impediment, but they do have an important function. They are actually tiny handles the host ants use to carry the adult wasp from the nests when it emerges after developing in the nest within one of the ant larva.

To get inside the nest in the first place is a tortuous process, beset with all manner of pitfalls. The worker ants are on high alert for anything that doesn’t belong in their nest, so these wasps have evolved a complex way of avoiding detection. They deposit their eggs on plants near the nest and the tiny, active larvae that hatch have to surreptitiously hitch a ride on a worker ant or potential prey that the ants are likely to catch and bring back to the nest…”