Giant Tachinid Fly

Tachina grossa — the giant tachinid fly — is one of about 8,200 species in family Tachinidae (the parasitoid flies) and one of the largest European tachinid species. The species is widespread across temperate Europe. Adults are 14-20 mm body length with jet-black body, orange-yellow head and pronotum, and stiff bristly setae across the body that distinguish all Tachinidae from non-parasitoid flies. The family Tachinidae as a whole is one of the most ecologically important groups in the entire insect order Diptera. ALL TACHINID FLIES ARE PARASITOIDS — every species lays eggs on or inside other arthropods, and the larvae develop inside the host, eventually killing it. Host species include caterpillars (the most common host group, parasitized by the majority of tachinid species), beetles, true bugs, grasshoppers, spiders, and even other parasitoid wasps. The egg-laying strategies vary across tachinid species: some species lay eggs directly on the host's body surface; some lay eggs on plant leaves where the host caterpillar will eat them; some inject eggs directly into the host's body cavity using a piercing oviposition; some lay 'mobile' first-instar larvae onto plant surfaces where they actively seek out and burrow into passing host arthropods. Tachinid flies are the second-most-species-rich fly family after Muscidae and are arguably the most numerous beneficial insects in many ecosystems — providing free natural control of agricultural caterpillar and beetle pests across most of the world's farmland and forests. Significant fractions of caterpillar populations across temperate forests and croplands (often 30-60%) are killed by tachinid parasitoids each generation. The species T. grossa is a major parasitoid of large hawk-moth caterpillars (Sphingidae) and is one of the most-photographed European tachinids in macro nature photography because of the dramatic black-and-orange coloration. The family is the subject of decades of biological control research — several tachinid species have been deliberately introduced to North America and other regions as biocontrol agents against invasive moth and beetle pests.