TEN GREEN BOTTLES

You may not be delighted to behold Greenbottles (Lucilia sericata) jostling on a dead rodent, but it's a good job somebody clears dead animals away.  They lay their eggs in the corpse and the larvae (maggots) eat it up.

Unfortunately I was unable to capture the attractive metallic green colour on their bodies.  

Photo: Simon Bennett, on naturespot website

This colour helps them select mates.  As they fly, sunlight reflects from their carapace through their wings in a series of flashes - one flash per wing beat. Younger flies will make better mates and because they flap faster they flash faster, which makes them more attractive to the opposite sex.  This is different from most insects who use a sense of smell to locate and select mates.