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Soldier beetles

Quick facts 

  • Large numbers of soldiers beetles may be seen in gardens in the summer.
  • Adults are active from late July to September.
  • Adult beetles are found on flowers and leaves of many plants, especially ones with yellow flowers such as goldenrod, helianthus, coneflower, tansy, zinnia, marigold and globe thistle.
  • They are harmless to plants and are beneficial as pollinators.
  • There is no need to control them. Just ignore them and they will go away on their own.

How to identify soldier beetles

(Chauliognatha pennsylvanicus)

Adults

A dull orange insect with one black patch on each of its wing covers sitting on a flower with orange petals
Adult soldier beetle
  • About ½ inch long, yellowish to tannish-brown with soft wing covers.
  • Black head, black legs with a black spot behind the head and an oval, black spot on each wing cover.
  • Wing covers do not completely cover the body, leaving abdominal segments exposed.
  • The head is clearly visible and they have chewing mouth parts.
  • Soldier beetles are related to fireflies but do not have the light-producing organs that fireflies have.

Larvae

  • Larvae look like mini alligators and are usually dark colored.
  • They can grow up to ¾ inch long.

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

Life cycle

An dull yellow-orange insect with one black patch on each of the wings
  • 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 look like wasps in flight.
  • They can also look like 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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