A few common or garden flies

12th August 2014 - Topsham

I know they can be a nuisance, I know some of them spread diseases and I'll admit many have rather unsavoury lifestyles but take a close look at a fly and tell me they're not amazing. I've been pottering about the garden with my macro lens and, as usual, it's been mostly flies. Conditions haven't been perfect but occasionally the sun goes in (photos of shiny insects in bright sun look dreadful) and the wind drops (with exposure times of 1/5 second you don't want the subject moving at all). Here's a few mostly common species, all named using the appropriate identification keys.

Lucilia sericata Calliphoridae - 12/8/2014 Topsham

This is a common greenbottle (also known as the sheep blowfly) Lucilia sericata. Identified by the pale basicosta (that whitish nubbin at the base of the wing) and, as it's a male, by the widely separated eyes (Erzinçlioglu 1996). There are seven British species of Lucilia and this is one of only two which are safely named from a photo, for the rest you're going to need a male specimen and a microscope.

Eristalis tenax Syrphidae - 12/8/2014 Topsham

Here's a very common hoverfly Eristalis tenax, also known as a drone fly as it's a honey bee mimic - even down to the fake pollen baskets on it back legs. Identification is pretty straightforward based on the broad black stripe down the face and vertical bands on the eyes (Stubbs & Falk 2002).

Scathophaga stercoraria Scathophagidae - 12/8/2014 Topsham

Another easily recognised species, this is the common yellow dung fly Scathophaga stercoraria, safely told from the other nine British Scathophaga spp. by the conspicuously black antennae (Ball 2007).

Nemorilla floralis Tachinidae -12/8/2014 Topsham

This one, a parasite fly or Tachinid, is rather less straightforward to identify. It does show the general appearance of the family - strongly kinked medial wing vein, 'delta wing' posture and it's strikingly bristly; another useful pointer is the slow purposeful hunting flight when searching for a host (in this case caterpillars) in which to lay its eggs. I've photographed this species a few times in the garden over recent years, identified using Belshaw 1993 and confirmed by the experts at diptera.info.

References

Ball, S.G. 2007; Key to the British Scathophagidae (Diptera), Version 3.1
Belshaw, R. 1993. Tachinid flies. Diptera: Tachinidae. Handbooks for the identification of British Insects. Royal Entomological Society of London 10, Part 4a(i).
Erzinçlioglu, Z. 1996; Blowflies. Naturalists' Handbooks 23. The Richmond Publishing Co.
Stubbs, A.E. & Falk, S.J. 2002. British Hoverflies. British Entomological and Natural History Society.

Getting distracted again

13th-15th August - Topsham

The days are long and so are the gaps between posts. I could make excuses about pressures of work but the truth is I've been taking a bit of a break. There doesn't seem to be much happening bird-wise locally (maybe I'm not looking hard enough) so I find my attention wandering. As a five minute break from my desk, I like to take a walk down the garden with my macro lens/tripod set-up. There's nearly always something of interest. So, at the risk of disappointing those expecting photos of gulls, sketches of birds or even an update on my Tubenose work, here are some more insect photos. All taken in my back garden in the last few days - the technical details (if anyone's interested) are: Nikon D200, Sigma 180mm macro, Uniloc tripod and Manfrotto ball head, no flash, just long exposure, mirror lock-up, cable release and wait for the wind to drop.

First here's a bug, Deraeocoris ruber, family Miridae. I've photographed this species a few times and it varies a lot in colour; this is a paler individual, some are quite blackish - mostly males according to Southwood & Leston (1959). Both adults and young are predators of aphids and other small insects.

The next two shots show a Hoverfly, a Eumerus sp. There are four British species (Stubbs and Falk, 2002; Ball and Morris, 2013); it's not E.sabulonum as that has a reddish base to the abdomen, also I think E.ornatus can be ruled out as the ocellar triangle is not far forward enough. This leaves E.funeralis, which has a distinct bare patch on the underside of the hind femur, and E.strigatus, which doesn't. I suspect this is strigatus but can't be certain with these views.

Now for some flies with somewhat less savoury lifestyles, Tachinids, all identified, with varying degrees of confidence using Belshaw (1993) and Tschorsnig and Herting (1994). First we have Voria ruralis, I see this in some numbers locally in late summer - when I look. It parasitises moth larvae, mostly Plusiinae - Silver Y, Burnished Brass and Dark Spectacle are mentioned.

The next two photos show another fairly common Tachinid,  Eriothrix rufomaculata. The reddish patches on the sides of the abdomen (just visible through the wing) are typical, though not diagnostic, this was keyed using Belshaw (1993). This also appears to parasitise moth larvae, although it's usual host is surprisingly unknown given that it's so common.

This last fly is a new one for me, using Belshaw it keyed out as Gastrolepta anthracina, I checked reliably identified photos (e.g. Diptera.info) and, a little surprisingly, they seem to match. I'll put it down as a probable and check with those who know. This doesn't seem to be a common species - though it's hard to tell with such an under recorded group - and mainly found in coastal southern England; the host species appear to be beetles.

References

 

Belshaw, R. 1993. Tachinid flies. Diptera: Tachinidae. Handbooks for the identification of British Insects. Royal Entomological Society of London 10, Part 4a(i).
Southwood, T.R.E. & Leston, D. 1959, Land and Water Bugs of The British Isles. Warne, London.
Tschorsnig, H.P. and B. Herting. 1994. Die Raupenfliegen (Diptera: Tachinidae) Mitteleuropas: Bestimmungstabellen und Angaben zur Verbreitung und Ökologie der einzelnen Arten. Stutt. Beitr. Naturk. (A) 506, 170 pp.