When talking about beetles, many of us don't think of them as being threatening creatures. Spiders for example, are the object of ancient fear even though the majority of them are quite harmless. But some beetles are far from innocent.
Ground beetles (family Carabidae), are known to be excellent predators from their larval stage onward. The larger ground beetle species in the tribe Anthiini are fast moving, equipped with powerful mandibles and the incredible ability of ejecting a caustic spray in self-defense. This noxious secretion is produced by pygidial glands located in their abdomen, and can be extremely unpleasant as I once experienced.
The day I met Termophilum burchelli, also known in South Africa as "oogpister" ("eye pisser"), it was not a friendly encounter. I saw a beautiful insect (with warning colours I enthusiastically ignored), rushing towards the thick bushes, so I ran and caught it bare handed. Not only was I bitten by the poor terrified creature....but I also had my face covered by an unpleasant acidic spray that made it burn terribly. I immediately ran into the house with my eyes barely opened to wash it off with water. Here is the "culprit" on the run:
Another beetle that packs a punch (and was underestimated by me) is the bombardier ant's guest beetle (Cerapterus sp.). Like most paussines, they are myrmecophiles (associated with ants, hence common name), living among the ant's brood on which immature and adult beetles feed. The glandular hairs from their body and antennae, produce an aromatic secretion that is attractive to ants, allowing them to live within their nest. But it is their defense mechanism that really blows my mind. If molested, these formidable beetles can bombard a boiling-hot chemical spray from their abdomen in visible, and incredibly, audible explosive bursts, like a mini atomic weapon.
During reproduction time, mature males leave the ants nest and are often attracted to lights, the reason why some of them would find their way into my old house in Tembe. In summer our house used to get so crowded with insects that we would spend hours photographing and relocating them (my paradise!). So when I saw those cute little beetles climbing on the wall I grabbed one of them without hesitation and had a strange sensation; my finger tips felt burnt and were stained brown. Not certain of what had just happened, I took it outside to have a better understanding. Poking it gently, it sprayed a gaseous cloud from all around its abdomen - just like a cartoon with mini atomic cloud and "puff" sound and all. Not only is the gas an irritant, but it is hotter than boiling water. It is believed that they use their hard wing covers (elytra) as a surface to bounce the hot spray to make this defensive cloud around their bodies. Definitely one of the most awesome little beetles out there. It packs a punch, and earns respect!