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.