Winter gnats

With the winter being generally mild, there have been small swarms of winter gnats Trichocera sp. in the garden throughout, with their larvae probably feeding on the rotting leaves that we've piled up to make leaf mould.

Lately these long-legged little flies have gravitated towards the last few crab apples that are still hanging on the tree, gently rotting in the spring sunshine.

It's a convenient site for mating. When a female strays into the dancing swarms of males she's quickly captured ..... and so begins the next generation of winter gnats. The male is on the right. 

Dancing fly

These tiny flies that seem to be laying eggs in the water-filled shell and decaying remains of a garden snail (one at 11 o'clock on the shell rim, the other at 5 o'clock just inside the shell) are Sepsis fulgens. They are about 5mm. long and are said to be ant mimics - their black shiny bodies certainly give that appearance, although I've never come across any evidence for the functional significance of this similarity.

They've emerged in large numbers in our garden during the recent spell of hot, humid weather. In this image you can see the two white halteres just behind the wings, which show that these are true flies (dipterans) and not winged ants, which are hymenopterans with two pairs of wings.

Sepsis has very distinctive behaviour, scuttling over leaves, dancing and waving its wings at other flies.

The similarity with an ant is particularly striking in this side view.

Eye-to-eye with a fly

I haven't managed to identify the species that this fly belongs to yet, but it does have beautiful eyes.......

Transformers

Drone fly larvae, commonly known as rat-railed maggots, possess one of the most amazing pieces of equipment found in any insect larva. They live in waterlogged soil or shallow water around the margin of ponds, where the water level can rise and fall all the time - especially in a wet summer like the one we are enduring now. 

The long tail is the insect equivalent of a submarine snorkel, with muscles that allow it to shorten or elongate so that the tip of the tube is always level with the water surface.

At this stage in their life cycle they may not be high on aesthetic appeal but when they metamorphose they transform ........... 

...............into one of these 

A life that starts in stagnant mud becomes a drone fly, hovering in a sunbeam on a sunny afternoon.

Daggers Drawn

This ungainly looking fly with a long, straight proboscis is Empis tessellata, seen here feeding on hogweed nectar. That isn't its only reason for lurking on hogweed umbels though - it's a predator of other small flies that are attracted to the flowers.

Individual hogweed flowers secrete nectar from the surface of the ovary, from which a pair of styles with stigmas at their tips arise. The nectar is a very convenient energy source for small insects. By providing small amounts of nectar on numerous flowers, the plant ensures that the pollinator must wander all over the surface of the umbel to collect it, accidentally pollinating stigmas of many flowers in the process.

Empidid flies are sometimes known as dagger flies, on account of those long piercing mouthparts. This is the largest British species.