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.

Wildlife on Walls 11: Fairy foxglove, Erinus alpinus

This attractive little plant growing on the walls of Stanhope Castle in Weardale is fairy foxglove Erinus alpinus, a native of Central and Southern Europe that was first recorded on this spot in 1934. 

How and when it reached our shores is uncertain. Gordon Graham, in his Flora and Vegetation of County Durham (1988) quotes the following theory from W.J.Weston's The County of Durham, published in 1914;

"Round Edmondbyers the rare little pink flowers, a curious survival from the Roman occupation, may reward diligent search.It is supposed that the plant, which is found nowhere but in the neighbourhood of the camps was brought into the country by the Spanish legionaries"

For more wildlife on walls, click here.

BBC Radio 4 Guide to Garden Wildlife

At 9.30am. on Monday 8th. July Brett Westwood and I are presenting the first of a new five-part series called A Guide to Garden Wildlife, produced by Sarah Blunt at the BBC Natural History Unit.

The home page for the series can be accessed by clicking here.

The series also has its own dedicated blog, accessed by clicking here.