NPIPM:Carabidae
Authors: Ashley Mueller, Buyung Hadi
Beetles comprise the largest order of insects. Adults have four wings; the outer wings are hardened to protect the hind wings. Although beetles have wings, not all beetle species are able to sustain flight. Adults and larvae have well-developed chewing mouthparts, which can cause economic damage, depending on the species. In urban areas, the pest status of beetles is usually based on larval feeding habits.
Beetle development stages include egg, larva, pupa, and adult. The length of the life cycle depends on the species. Beetles in the larval, pupal and adult stages are capable of overwintering if they are in protected areas. Beetles often lay their eggs on or near a food source for larvae. Proper storage of organic materials and sanitation are the primary methods of beetle management. Additionally, surveying stored foods and organic materials regularly for all stages of beetle life cycle is a good beetle management practice.
Identification
Ground beetles (various species) can range anywhere from 1/8 to 1 inch in length and come in various shapes and colors. They have broad, hard wing covers with parallel lines or ridges running down the wing covers. The front segment of the thorax is narrower than the abdomen, and the head is even narrower. Antennae are present on the head. Most beetles are black or dull brown, but some species are iridescent with vibrant greens or blues.
Habitat
Adult ground beetles and larvae are often found outdoors under logs, bark, and stones laying on the ground. When disturbed, the adults run rapidly. Although they have wings, they rarely fly. Adults are nocturnal, seeking pray at night. However, some species are attracted to lights. Sometimes, ground beetles do find their way indoors. They prefer damp environments, such as a basement or cellar. Their time in a building is often short, and they do not reproduce indoors.
Life Cycle and Seasonal History
Outdoors, adult ground beetles can be found in the spring, summer, and fall. If ground beetles enter the home, it is most likely in mid- to late-summer. During the winter months, ground beetles remain in either the larva or adult stage. With warmer temperatures, adults emerge in the spring to mate and scatter. Single eggs are laid into the soil, and the larvae hatch and develop through several stages. The pupal stage follows the larval stage. Development to adult is complete in about one year.
Human Interaction and Urban Impact
Ground beetles are beneficial insects because they are predators of other significant pests such as caterpillars and insect larvae. They do not damage structures, furniture, or clothes. Even though they are capable of biting, they are generally not harmful to humans or pets. If they occur in high numbers indoors, they can be a nuisance.
Prevention and Management Approaches
Prevent beetles from entering the home or building by sealing around windows and doors and by making sure screens on windows and doors are in good condition. Do not stack firewood near the home, and cut and maintain grass that sits near the home.
If a ground beetle is found indoors, it can be captured in a small container and placed outdoors. No chemicals should ever be applied to eradicate these beneficial beetles.
Other Online Resources
For information regarding labels of chemical control options, please visit NPIC MAPL
