beneficial insect profile: Tachinid Flies
Tachinid flies are amongst the largest families of true flies with approximately 8,000 species world wide. They are generally solitary and are about the size of a housefly, but can be quite diverse in appearance. Although the more noticeable tachnids with their big bristly abdomens look as though they should be swatted or stomped on, should actually be hallowed as a gardener’s friend!
All tachinid flies are parasitoids- organisms that, during their development, live in or on the body of a single host individual, eventually killing that individual. Tachinid flies deposit their eggs on the host or on nearby foliage where it will be eaten by the host. Once the eggs hatch, the larvae will enter the body of the host and feed on internal organs & reproductive organs for up to three weeks. Eggs can also overwinter in their hosts body.
These beneficial flies play an important role in suppressing populations of destructive timber and agricultural pests.
Common hosts include cutworms, potatoe beetles, hornworms, grasshoppers, tent caterpillars & other plant feeding insects.
Tachnid parsatoids of the gypsy moth were introduced from Europe in the early 1900s. The program was not a complete success but it helped lay the groundwork for future successful biological control programs using tachinid flies. One well known success was the introduction of tachinid in Hawaiian sugar cane fields to control the New Guinea sugarcane weevil.
Please refrain from using insecticides in & around your garden or yard, as it will likely kill beneficial insects like these flies who are a very effective control of a wide range of plant eating pests!