More Urban Species on the porch

[urbpan]

Blue bottle fly Calliphora vicina

It was a warm Saturday--for December--and I was sitting on the porch. There haven't been many insects around, but this one huge (1cm) blue-black fly kept circling. It landed on the rail long enough for a picture. I could tell it was a carrion fly, and other clues and online observers pointed to it being a blue bottle fly. These are said to be native to Europe, but are fully cosmopolitan creatures, thriving wherever there are dead animals. The London Museum of Natural History even calls them the "urban bluebottle blowfly."

As well as cleaning up all the rotten meat that would otherwise pile up, these animals perform another service for us. Their life cycle, as it relates to corpses, is so predictable that they can be used in court to determine various facts about dead bodies, especially the important fact of how long that body has been bereft of life. Besides carrion, adult blue bottle flies may visit flowers for food, providing some important pollination work.