The adult flight period is from late June to early September.
In the UK there is usually only one generation per year, though in southern Europe there may be two generations per summer season, though this has not yet been verified.
Adults feed on nectar and pollen of flowers.

Like most tachinid flies, the female lays eggs on other living insect larva, the fly larvae then develop inside the living host, devouring it and eventually killing it.
Its main hosts are the large hairy Lepidopteran caterpillars, particularly the oak eggar moth (Lasiocampa quercus), the fox moth (Macrothylacia rubi) and other Lasiocampidae.
The adult flight period is from late June to early September. In the UK there is usually only one generation per year, though in southern Europe there may be two generations per summer season, though this has not yet been verified. Adults feed on nectar and pollen of flowers.
Like most tachinid flies, the female lays eggs on other living insect larva, the fly larvae then develop inside the living host, devouring it and eventually killing it. Its main hosts are the large hairy Lepidopteran caterpillars, particularly the oak eggar moth (Lasiocampa quercus), the fox moth (Macrothylacia rubi) and other Lasiocampidae.
Tachina grossa