Ground Beetle

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Ground beetles are one of the most common groups of beetles in North America with more than 2,600 different species.

Fast Facts

Color Most are black or brown and iridescent, although some species can be brightly colored, including blues, greens, and reds.
Size Most ground beetles are small to moderate sized insects, about 1/8 – 1/2″ long.
Appearance Ground beetles vary in size and shape, but most are oval and elongated.

Diet

Being predators, ground beetles prey on invertebrate pests, including caterpillars, fly maggots, aphids, slugs, and even other beetles. Any insect or worm with a soft body is susceptible to being the ground beetle’s next meal.

Habitat

Ground beetles are active at night and are occasionally attracted to lights. They hide during the day and are typically found on the ground under leaves, logs, stones, loose bark, and in grassy areas. When exposed, ground beetles move quickly to find shelter but rarely fly.

Life Cycle

Ground beetles develop and mature by undergoing complete metamorphosis from egg to adult. Females typically produce one generation of offspring each year and lay their eggs individually in the soil. Ground beetles emerge as adults shortly after completing the pupal stage of the life cycle, which occurs in the soil. Full development from egg to adulthood can take place within a single season. Adult ground beetles typically live for one to four years and are usually most active between the months of April and October.

Damage

Ground beetles are not harmful to people (although they may pinch the skin if mishandled) nor do they cause damage to buildings, food, or clothing. They are just a nuisance when they are found indoors. In most cases, only a few ground beetles are found in buildings at any given time, although there are times when large numbers will enter structures. Ground beetles are relatively short lived indoors and do not reproduce there.

Since ground beetles are occasional invaders, they are typically seen from spring to fall and enter homes most frequently during the middle or end of summer. Attracted to light, ground beetles are noticeable when they congregate around well-lit structures. Since ground beetles do not breed indoors, they leave behind few other signs of an infestation.

Prevention & Control

Ground Beetle Prevention

If you encounter a large number of ground beetles, you can reduce their numbers through a number of non-chemical steps:

  • Seal and repair potential entry points, such as cracks in the foundation, gaps and spaces around doors, ground level windows and similar areas.
  • Thin out or remove wood mulch or other organic mulch that is directly adjacent to the foundation.
  • Stack firewood away from the home.
  • Remove stones, leaves, boards, and other nearby debris.
  • Cut or remove tall grass and weeds around the home.
  • Minimize the use of lighting immediately next to the structure or switch the lights from bright white to yellow to minimize attracting ground beetles.
Ground Beetle Control

In most cases, you will only encounter just a small number of ground beetles indoors. The only necessary control is physical removal by capturing them in a container or removing them with a vacuum. Sticky traps may also be effective if places in areas where ground beetles are most commonly found, especially along walls.

If a ground beetle infestation occurs, count on a professional pest management service to take care of the problem knowledgeably and successfully.