Sarge

Worldwide there are around 2,700 species of soldierfly, but less than fifty of them are found in the UK. It's not really clear why they're called soldierflies, because they are harmless to humans, but many of them have a metallic sheen on the thorax and abdomen, and it's been suggested that this might be said to resemble polished armour. On the other hand there are many species that aren't metallic, but instead are strongly patterned and look like large, robust hoverflies, but the soldierfly apologists simply say of these that they're so smart they look as if they're wearing uniforms. 

Hmmmm.

Whatever the reasoning, it's worth getting to know the most common soldierflies, because they tend to be strikingly handsome and make good photographic subjects. They're often quite passive too, which is helpful. This is a female Twin-spot Centurion, Sargus bipunctatus, which I spotted on the laurel hedge in the secret garden this morning, and by approaching slowly I was able to get quite close without putting her to flight.

Sargus bipunctatus flies from June till November, but I tend to find it most often in September and October. Males are about 1cm long, and are slender, with a metallic green thorax and a bronzy abdomen. Females are larger, at about 1.5cm, and more robust. The thorax is green, and the abdomen is variably red at the base and then black, with a blue iridescence. They usually rest with their wings closed, but last autumn I managed to get an open-wing shot of a female that showed the abdominal colours pretty well; it's on my Instagram if you'd like to see it. Both sexes have orange legs, and a pair of white spots on the frons, just above the antennal insertions.

Females lay their eggs on animal dung, manure, or rotting vegetation, and the larvae play a role in breaking down these wastes and helping to return them to the soil. They have also been reported - though I don't recommend that you read this if you're squeamish - performing the same service on human remains, which had laid undiscovered for a long time in a Polish park.