True Bug Trichopoda Parasitoid / Home and Landscape / UC Statewide IPM Program (UC IPM)

Hosts or Prey

True bugs (Heteroptera) of relatively large size, such as squash bug

Identification

Adults, mature larvae, and puparium (coverings of the pupae) are 1/3 to 1/2 inch (8–12 mm) long, varying by the size and species of the host. The adult is a fly with a black and yellowish or white prothorax (first segment behind the head), a mostly orange abdomen, and dark wings. The hind legs have a prominent fringe of featherlike bristles that can be seen here. Because of this feature Trichopoda species are sometimes called feather-legged flies.

Eggs occur glued on the body of true bugs (Heteroptera). They are gray to white, oval, and about 1/50 inch (0.5 mm) long. The cream-colored or whitish larvae are maggotlike with distinct segments and dark, hooklike mouthparts. The puparium is dark red and oblong.

Life Cycle

Trichopoda pennipes develops through four life stages: egg, larva, pupa, and adult. Where winters are cold T. pennipes overwinters as a larva in its overwintering host. In late spring or early summer the parasitoid pupates and emerges from its host as an adult fly and the host is killed.

Adults seek flowers where they consume nectar. The adult female seeks large nymphs or adults of relatively large species of true bug and lays 1 to several eggs on the host. An adult female lays about 100 eggs during her lifespan which can be several weeks if nectar is available for nutrition.

The larvae hatch within a few days after eggs are laid. They chew downward through their egg shell and into the bug's body. If more than one egg was laid on a host and multiple larvae bored into the bug, the tachinid larvae fight each other and generally only one survives to maturity within each bug.

After developing through three increasingly larger instars and killing its host, the mature larva (prepupa) exits its host and drops or walks to the ground where it pupates in litter or topsoil.

Trichopoda pennipes can feed and develop throughout the year in locations with mild winters if its hosts are available. If the location experiences cold winters, T. pennipes overwinters inside hosts. Trichopoda pennipes has several generations per year.

Habitat

Trichopoda pennipes can occur in gardens, landscapes, tree and field crops, and in wildlands wherever its host bug species occur.

To improve biological control

Control ants because they attack natural enemies of various pests.
Grow flowering insectary plants, such as alyssum that provides adult natural enemies with nectar and pollen as food.
Reduce dustiness that disrupts the activities of natural enemies (e.g., irrigate overhead or periodically hose off small plants).
Avoid the application of broad-spectrum, persistent insecticides for all pests because they are toxic to natural enemies.

See Protecting Natural Enemies and Pollinators and Relative Toxicities of Pesticides Used in Cucurbits to Natural Enemies and Honey Bees for more information.

Species

At least 3 Trichopoda species occur in California: T. indivisa, T. pennipes, and T. subdivisa. Trichopoda pennipes parasitizes over 30 species of true bugs in the families Coreidae, Largidae, Pentatomidae, and Scutelleridae. Economically important hosts of T. pennipes include harlequin bug, leaffooted bugs, redshouldered stink bug, southern green stink bug, and squash bug. For a more complete list of the bug species T. pennipes is known to parasitize see Taxonomic and Host Catalogue of the Tachinidae of America North of Mexico.