|Big Headed Ground Beetle|
On our WOLF School field trip to Bull Mills last week, one of the boys grabbed this beetle, a courageous act considering the size of it's jaws. This is a big headed ground beetle (BHGB), Scarites subterraneous. It is just as dangerous as it looks, if you happen to be a caterpillar, maggot, ant, aphid, slug or even a snail. The student risked only a small painful pinch.
Most of the 40,000 species of ground beetles in the Carabidae family are carnivores in both life stages. That is not a typo. Recall that there are 390,000+ beetles in the order Coleoptera, leading Haldane to comment that the Creator must have been “inordinately fond of beetles.” The Carabidae family includes the bombardier beetles which can spray defensive gases and chemicals including formic acid out their posterior glands, giving meaning to the term "bad gas."
|BHGB on the move|
We frequently get the "What good are .......(fill in the blank)?" question as if all of nature is supposed to meet our human needs. Ground beetles are good for farmers and vegetable gardeners as they are fast predators and relish the wireworms (click beetle larvae) that attack corn and potatoes. Some species also eat seeds of lawn and garden pest plants like lambsquarter, pigweed, foxtail, and crabgrass. The larval forms are also efficient predators and can move quickly as seen in this video.
|Dorsal view of BHGB playing dead - Note jaws|
Back to BHGB; it is one of the largest ground beetles and its range extends from the US to Central America and the Caribbean. It is fairly distinctive because it has a wide, flat head and prothorax and a narrow, articulated “waist” between the prothorax and abdomen. The closest match is a stag beetle except for the lack of clubbed antennae. If touched, they often "play dead" by folding in their legs and arching their backs.