Soldier beetles

Quick facts 

Large numbers of soldiers beetles (Chauliognatha pennsylvanicus) may be seen in gardens in the summer.

  • Adults are active from late July to September.
  • Adult beetles are found on flowers and foliage of many plants, especially ones with yellow flowers such as goldenrod, helianthus, coneflower, tansy, zinnia, and marigold and globe thistle.
  • They are harmless to plants and are beneficial as pollinators.

How to identify soldier beetles

Adults

A dull orange insect with one black patch on each of its wing covers sitting on a flower with orange petals
Soldier beetle
An dull yellow-orange insect with one black patch on each of the wings
Soldier beetle
  • They are about ½ inch long, yellowish to tannish brown with soft wing covers.
  • They have a black head, black legs with a black spot behind the head and an oval, black spot on each wing cover.
  • Their wing covers do not completely cover the body, leaving a couple of abdominal segments exposed.
  • Their head is clearly visible and like other beetles they have chewing mouthparts.
  • Soldier beetles are related to fireflies but lack the light-producing organs that fireflies possess.

Larvae

  • Larvae look like mini alligators and are usually dark colored.
  • They can grow up to 3/4 inch long.

Adult soldier beetles are noticeable, but larvae are rarely seen.

Life cycle of soldier beetles

Soldier beetles live through winter as larvae.

  • During spring they are active in leaf litter, plant debris, loose soil and other areas where high humidity occurs.
  • They mainly feed on insect eggs and larvae.
  • Larvae transform into pupae in early summer with adults first emerging in late July.
  • They are active through August and into September.
  • Adults will lay eggs some time at the end of the summer.
  • Larvae hatch from the eggs and they remain in this stage for the winter.
  • There is one generation a year.

Behavior and habits of soldier beetles

Four orangish beetles with black patches feeding on the pollen from yellow flowers
Soldier beetles on a tansy flower

Soldier beetles are very active and readily fly.

  • They resemble wasps in flight.
  • They can also resemble bees by moving quickly and often between flowers.
  • Because of their frequent contact with flowers, soldier beetles are important pollinators.
  • Soldier beetles are often seen mating on flowers.

Soldier beetles protect themselves by secreting defensive chemical compounds to make them a less attractive target for predators.

Their yellowish color is thought to signal that they don't taste good.

Soldier beetles are beneficial insects

Soldier beetles mainly feed on pollen and nectar.

  • They do NOT damage flowers or other plants and are also harmless to people.
  • They are beneficial because they are predators (larvae) and pollinators (adults).

There is no need to control them. Just ignore them and they will go away on their own.

Jeffrey Hahn, Extension entomologist

Reviewed in 2018

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