Common Name: Carabid Ground Beetle
Scientific Name: Various
Class / Order / Family: Insecta/Coleoptera/Carabidae
Members of this family get their common name from their general habit of occurring on the ground, usually beneath something. They are worldwide in distribution and occur throughout most of the United States.
Adults about 1/16-1 3/8″ (12-35 mm) long, body elongate, somewhat flattened in form. Color usually uniformly black and shiny, but some species patterned or brightly colored. Head at eyes nearly always narrower than pronotum. First abdominal segment divided by hind coxae, and hind trochanter (segment between coxa and femur) much enlarged and kidney-bean shaped. Antennae inserted between eyes and base of mandibles, usually threadlike. Legs usually long, slender. Larvae vary from dirty white to dirty yellow to almost black in color. Thoracic legs 5-segmented, with 2 claws. Mandibles biting but without a blood groove. Abdomen 10-segmented and without any dorsal hooks.
(1) Other beetles (order Coleoptera) lack kidney-bean-shaped trochanter of hind legs.
(2) Cockroaches (order Blattodea) lack hardened front wings or elytra.
Relatively little is known about carabid biology. Eggs of some species are laid in specially constructed cells. The larvae have 3 instars and pupation takes place in the ground. The life cycle (egg to egg) takes one year in most cases, and adults live for 2-4 years.
Ground beetles are terrestrial and typically found on the ground, usually under something such as stones during the daytime. A few species climb trees in search of food and may be seen during the daytime. Many species and in great numbers, come to lights at night. Most species are nocturnal or active at night. They typically enter structures by crawling under door thresholds or will fly in through open doors, windows, etc. at night when lights are on.
Ground beetles are a nuisance pest. They give off a very unpleasant odor when handled or crushed. With few exception both adults and larvae are predaceous, so they are a beneficial group. Insects make up a large portion of their diet, including the larvae of many undesirable pest species such as cutworms and other caterpillars, beetle larvae, and maggots. Some feed on dead organic material.
Preventative control consists mainly of removing objects under which ground beetles can hide during the day from within several feet of the building’s perimeter. Changing exterior light bulbs from white to less attractive yellow or sodium vapor lamps helps. Pesticide application as a band treatment of the building’s foundation wall and perimeter out 6-10 feet (1.8-3 m) is helpful. Wettable powder and micro encapsulated formulations of repellent pesticides (pyrethrins or pyrethroids) are best. Ebeling in his book “Urban Entomology, ” gives the following: :”A successful control measure has been to install an electric light above a container filled with water, with detergent added, about 50 ft. (15 m) from the house.” The beetles are attracted to the light and then fall into the water and drown; don’t forget to add the detergent.