One of the first things a gardener must learn is that they mustn't kill every insect that wanders into their garden. There are good bugs and bad bugs and most times the good bugs are free insecticide. They like to dine on some of the garden's worst pests, so encouraging them is essential. The tribe of Calosoma beetles are all great hunters and the genus occurs around the world.
Calosoma sayi is a large, beautiful black beetle that is especially fond of caterpillars. Its favorite meal is the caterpillar of the dreaded Gypsy Moth, Lymantria dispar and similar species. These beetles are also quite fond of army worms and any gardener who has any experience with those beasts, should welcome them with open arms. They are quick and agile beetles and are often seen scurrying along the ground or along tree branches. It is native to eastern and central North America, Mexico and portions of Central American and the Caribbean.
The Black Caterpillar Hunter is a nocturnal beetle and is often drawn to lights, where it is often an equal opportunity predator and tends to pounce on any prey. It isn't poison, however, it does produce a foul odor if agitated and its strong jaws can produce a little nip if it decides to bite. However, this beetle isn't aggressive and it prefers to run and hide instead of staying and fighting when challenged.
It is identified by its black body that is often 'punched' with small dots of red or gold lines and some even have a bluish metallic sheen along their edges. Their pronotum (the section between the head and the abdomen) is larger than the head and is quite distinctive, looking like a large collar of sorts. The body is often at least an inch (28mm) long and with its long legs, appears even larger.
This insect is beneficial to farmers, as it maintains excellent populations in corn and soybean fields, feeding on larvae of a number of agricultural pests. Methyl-parathion and methomyl are agricultural insecticides that are toxic to Calosoma sayi, however, farmers who use them, report that if done before the adults emerge, the effects are minimal.
Adults can live 2 or 3years in good conditions, overwintering under fallen logs and leaf debris. Eggs are laid one at a time in the soil and the larva overwinter, before emerging in late spring or early summer as adults.
It is important to recognize the residents of your garden. By encouraging beneficial insects, you can help establish a stable ecosystem on your property which will result in using fewer insecticides and poisons. When there is a natural balance, everything thrives. If pests show up in larger numbers than your friendly predators can dispose of, please take precautions when applying poisons to mitigate their effects on the the good guys. Hand-picking is an excellent way of eliminating destructive insects and their eggs and no harm to the environment or desirable bugs. As always, think before you spray!