bombardier beetles
awild | December 5, 2008
Metrius contractus
Oregon, USA
Many biologists are familiar with the Bombardier Beetles in the ground beetle tribe Brachinini, as their defensive tactic of aiming an explosive spray has been studied extensively. The Brachinini are even celebrated by creationists as animals that couldn't possibly evolve.
As it turns out, though, bombardiers have evolved at least twice. The second, less known radiation comprises the subfamily Paussinae, also in the Carabidae, and as we'd expect from an independent origin the spray dispersing mechanism is different, using a flange instead of a nozzle. …