Monday, 25 April 2011
Swarms of bibio marci (St Mark’s fly)
I was out cycling around a few of the lanes today and I couldn't help notice the swarms of 2 centimetre jet black dangly legged insects flying and hovering around everywhere. At first I somewhat bizarrely thought they were flying upside down, because the legs looked almost as big as their bodies.
As I adjusted my speed a few landed on me so I could look at them more closely. There seemed to be two types. A longer thinner one and a more 'fly-shaped' one about the size of a two-pence piece. Both distinctly bigger than any housefly but not something I recognised particularly in what amounted to Everglades-mosquito-like density in a far from swampy English setting.
Back at base I tried Google and after a few false starts in horse-fly territory (I'd have known that) I eventually stumbled onto the Bibio Marci. And the description went on to say that they are particularly prevalent on St Mark's Day, which is also the origin of their name.
I knew that it was St George's Day a couple of days ago, but had no idea when St Mark's day occurs...
Why, today, as it happens.
I suspect I've correctly identified this insect phenomenon.