A short clip from the BBC program “Ant Attack

Driver ant males are astoundingly strange creatures. They are larger, more muscular, more exaggerated than most other male ants. The reason is likely linked to the behavior shown in the above video: males must first be accepted by a gauntlet of choosy workers.

A classic paper by Franks and Hoelldobler (1987) describes the theory. This preference of workers for bulkier males- and a corresponding slaughter of smaller or otherwise unsuitable ones- drives an evolutionary trajectory towards increasing monstrosity. It’s an ant version of the peacock’s tail.