Flies in the Afternoon

Even when there’s not much to look at in the garden, there are always flies. Aside from the house flies, these are two of the commoner ones, the Common Greenbottle (Lucilia sericata) and the Common Flesh Fly (Sarcophaga carnaria). As the name indicates, the larvae of flesh flies mostly live on dead animals, while the green-bottle is less fussy and will also go for faeces and rotting fruit.

For both groups, identification at a species level is difficult and requires a microscope, as there are a few very similar species. However for the greenbottle this one has the right pattern of hairs on its thorax for Lucilia sericata, which is also the commonest species of greenbottle fly. Although both are flies, and their larvae feed on similar things, their lifecycles are quite different. The greenbottle lays eggs which then hatch into larvae; but the flesh fly is ovoviviparous, the eggs developing in the uterus of the female before they are deposited as larvae on a suitable food source.

#63 Common Greenbottle Fly (Lucilia sericata)

#511 Common Flesh Fly (Sarcophaga carnaria sp.)

Common Awl Robberfly (Neoitamus cyanurus, #520)

Another interesting insect in the garden - my first robberfly - a Common Awl Robberfly (Neoitamus cyanurus). This one got itself trapped in the kitchen window, but usually these insectivores should be found outside hunting flies and larger insects which they grab in mid-air and then immobilise with a venom. Sometimes also known as assassin flies or stiletto flies, these flies are strong and can often take insects as large or larger than themselves.

Common Awl Robberfly (Neoitamus cyanurus)

Common Awl Robberfly (Neoitamus cyanurus)

Three Flies

Not everyone’s favourite, but with the weather turning cold again other insects have taken a rain-check and disappeared, but the flies are still there. Flies are also an important part of the UK’s biodiversity, with over 7,000 species to be found - so plenty of scope for finding new species for my list. Such diversity does bring challenges with identification though - so it’s not easy. Going by www,naturespot.org.uk and other photos on the web the first two are closely related species of root-maggot fly. The first of them has been quite common around the garden during April, Hydrophoria lancifer (#448); while the second, with its different patterning and reddish-coloured thighs, is Hydrophoria linogrisea (#469). The third fly is a female Yellow Dung Fly (Scathophaga stercoraria, #127), much greener than its yellow coloured mate,

#448 Hydrophoria lancifer

#469 Hydrophoria linogrisea

127 Yellow Dung Fly (Scathophaga stercoraria)

Sleeping Centurion

There’s not so many new insects now the weather has cooled right down, so I was surprised to find this late-flying soldier fly, #355 Twin-Spot Centurion (Sargus bipunctatus), while pruning back some overgrown shrubs. You can’t see the two white dots by the eyes on this photo. This fly is typically seen during August-November, its larvae living in mature and rotting vegetation. It was really inactive, sitting on its leaf while I cut back branches all around it.