Monday, July 10, 2006

Greenbottle lifestyle

click photo to enlarge
"Time flies like an arrow, fruit flies like a banana", Groucho Marx (1890-1977), US comedian

Greenbottles (Lucilia caesar) are engaging little chaps. An iridescent green blow-fly 8-15mm long, they are never happier than when they are laying eggs on the putrid flesh of a dead sheep or a road-kill rabbit. Unless that is they are watching their larval offspring chewing their way through the festering open sore of a cow or goat. As a break from these engrossing pastimes they spend many happy hours feeding on piles of steaming dung! Oh, and now and then they drink nectar from lovely flowers like this white marguerite (Chrysanthemum frutescens).

But it's not all highlife eating and drinking for the greenbottle! Oh no, some of the more adventurous larvae go around inflicting asthma and rhinoconjunctivitis on humans who sell them as fish bait. And they really love the outdoor life, rarely venturing into houses, happy in whatever weather their home countries in Europe and Asia can throw at them. They can even be seen on walls enjoying the sunshine in the depths of winter! Life for the greenbottle seems to consist of pleasure upon pleasure. And, though we may turn up our noses in disgust at such a lifestyle, it is in fact a benefit to us all. The French naturalist, Jean-Henri Fabre (1823-1915) , speaking of the offspring of the greenbottle observed, "... the maggot is a power in this world. To give back to life with all speed, the remains of that which has lived, it macerates and condenses corpses, distilling them into an essence wherewith the earth, the plant's foster mother, may be nourished and enriched."

I think this is the first insect photograph that I've posted - they're not something I usually shoot. It was the metallic green of the this particular fly that caused me to photograph it before the bees that were also around these marguerites. I used a hand-held macro lens at 200 ISO, a high shutter speed, and consequently a relatively shallow depth of field, and stayed sufficiently far back to include the radiating petals which lead towards the greenbottle as it probed for nectar in the centre of the flower. Post processing included lightening the fly to reveal more detail.
photograph & text (c) T. Boughen