In the comments, Vladimir Dinets asks a deceptively simple question:

A quick question: why do so many tropical ants sting, while those in Boreal latitudes never do?

My first response is that Vladimir’s premise isn’t quite right: after all, the jack jumper stinging me above is from temperate, not tropical, Australia, and some of the boreal Myrmica do sting. But the general pattern holds: most of the stinging ants are tropical, and we are much more likely to be stung by an ant in warmer climates than in cold ones.

I have some thoughts on this observation (related to an old post of mine), including the notion that this may be one of those ultimately unknowable deep evolutionary puzzles, but before I launch into it I’d like to hear your opinions.

What do you think? Why do more ants sting in the tropics?