Natural Enemies Gallery

Spider Mite Rove Beetle

Hosts or Prey

Plant-feeding spider mites (family Tetranychidae)

Identification

The adult is black and about 1/25 inch (1 mm) long. It has shortened wing covers that expose the abdominal segments when viewed from above. Characteristically, Oligota adults have a pointed abdomen that curves upward at the rear end and a head that is bent downward or under the body so the head is not apparent when viewed from above.

Eggs are oval, yellowish to pale orange, and a little over 1/100 inch (0.3 mm) long. Oligota eggs commonly are hidden beneath the skins of mites. The female rove beetle covers her eggs with the skins immediately after she lays her eggs.

Larvae are cylindrical, elongate, pale yellowish, and covered with fine spines. Larvae have distinct segments and a prominent black spot (hardened dorsal plates) on top the eighth abdominal segment, near the rear end. At maturity larvae are less than 1/10 inch (2.5 mm) long.

The pupa is oblong and occurs in a silk cocoon in topsoil. It initially is yellowish, then turns orange or reddish, and blackens shortly before the adult emerges.

Lookalikes

At least 10 Oligota species occur in the United States. At least two species, O. oviformis and O. parva are present in California.

Life Cycle

Rove beetles develop through four life stages: egg, larva, pupa, and adult. Adult females lay eggs singly near colonies of plant-feeding mites, commonly along leaf veins or in leaf depressions on the underside leaves. The hatching larvae develop through three or four increasingly larger instars.

Development from the egg to an egg-laying adult occurs in 3 to 4 weeks at warm temperatures. Oligota oviformis has multiple generations per year.

Habitat

Oligota oviformis occurs mostly in coastal areas, including in avocado and citrus groves. Both adults and larvae feed almost exclusively on spider mites of all stages, including citrus red mite, persea mite, and twospotted mite. A larva consumes about 20 mites per day during its approximately 2 weeks development time. Adult Oligota eat about 10 mites per day during their lifespan of approximately 1 month.

Species

Over 1,200 species of rove beetles are known from the California. It is the largest family of beetles in the state. Most rove beetles are predators or parasites of tiny arthropods in organic debris and topsoil or feed on decaying organic matter, fungi, or pollen. Prey of particular species includes ants, aphids, bark beetles, immature flies, mites, or termites.

More Information

Scientific classification:

  • Phylum: Arthropoda
  • Class: Insecta
  • Order: Coleoptera
  • Family: Staphylinidae
Adult rove beetle, Oligota oviformis, a predator of spider mites.
Adult rove beetle, Oligota oviformis, a predator of spider mites. Credit: Jack Kelly Clark, UC IPM Program
Larva of the spider mite predator, Oligota oviformis.
Larva of the spider mite predator, Oligota oviformis. Credit: Jack Kelly Clark, UC IPM Program
Pupa of the rove beetle, Oligota oviformis, a predator of spider mites.
Pupa of the rove beetle, Oligota oviformis, a predator of spider mites. Credit: Jack Kelly Clark, UC IPM Program
Pupa of the rove beetle, Oligota oviformis, a predator of spider mites
Pupa of the rove beetle, Oligota oviformis, a predator of spider mites Credit: Jack Kelly Clark, UC IPM Program