Caterpillar Hunter

Tachina fera

On recent rambles through the garden, we've been struck by the number of these big flies (measuring 12-15 mm, or a bit more than half an inch) we've seen buzzing around the place. They're Tachina fera (no common name that I know of), one of the more than 600 species assigned to the worldwide genus Tachina. The brick-red edges to the abdomen are distinctive, as are the buffy bases to the wings. And the red legs and yellow facial hairs are unusual among Britain's flies. According to Collins Complete British Insects, they fly from April to September. They're said to prefer damp habitats, so I'm not quite sure what they're doing in our distinctly dry garden. Like most Tachina species, this one parasitizes caterpillars — though considering how few butterflies and moths we've seen so far this spring, they must be having a hard time finding any to parasitize at the moment!