Caerau Nature & the rest of the world: Tachind flies

As we have had 7" of rain in the last 2 days [not pleasant while driving back and forth to Gatwick (400miles)], there is no way to go out and look for hoverflies. When I'm out looking I always come across other families such as butterflies, bees, beetles etc. But one of the other fly families I usually see are Tachinidae flies known simply as Tachinids. There are 172 species on the family list I have found out, but many need to be caught and examined under magnification to determine the species. Conversely they also have some of the largest and most recognisable flies out there including Britain's biggest fly. I've managed to photograph ten of these species but know very little about their biology. So I decided to do a bit of reading on this family. What I learnt was pretty interesting. Tachinids are parasitiod flies rather than parasite flies, which means they lay their eggs in the host larva species and eat them alive, while parasite flies usually leave the host live. Most Tachinid species are specialist feeders on specific hosts within the butterfly, moths, beetle and bugs families. Identifying Tachinids is not easy as there are very closely related families in the fly group. Generally Tachinids have bristles on the body and have large squamae (fleshy flaps underneath the base of the wings), but the only true way to tell them from other close related families is that they have an enlarged sub-scutellum. This appears as a large fleshy bulge underneath the end of the scutellum when viewed from the side. Below are the ten Tachinids I have photographed with brief explanations on numbers seen, flight periods and hosts.

***** Paul Parsons and Paul Tabor have photographed other species of Tachinids that I have yet to see or photograph. *****

Dexiosoma caninum - 26 Jun - 2 Oct (11 records). Host - Common Cockchafer Bug.

Eriothrix rufomaculata - 21 Jul (1 record). Host - crambid grass moths especially Chrysoteuchia culmella.

Gonia picea - 27 Mar (1 record). Host - Noctuid moths especially Antler Moth and Square Spot Rustic.

Lophosia fasciata - 22 Aug - 30 Aug (5 records). Host - Shieldbugs especially Hawthorn Shieldbug.

Nowickia ferox - 04 Aug - 07 Sep (4 records). Host - Dark Arches Moth.

Phasia hemiptera - 26 Jun - 26 Aug (17 records). Host - Forest Bug in spring and Green Shieldbug in autumn.

Tachina fera - 06 Jun - 22 Sep (14 records). Host - Noctuid moths especially Broom, Dun-bar and Pine Beauty. This species is slightly different to other parasitiods because the adult lays its eggs on the foodplant of these moths and the larva wait for the unsuspecting moth larva to feed and then they eat their way in and when finished pupate.