Cranefly  (Lipsothrix nigristigma)

Classified as Endangered in the UK.

Most people have experienced a cranefly or 'daddy long-legs' Tipula oleracea in the house at the end of the summer. Lipsothrix nigristigma resembles this much more familiar cousin, but is considerably smaller, and has a yellowish body.

This species is recorded in a number of countries throughout northern Europe, where it is generally associated with mountain regions. It is thought that this species may be the same as a crane fly (Lipsothrix nobilis) found in the alpine regions of Austria, Czechoslovakia, Germany, France and Yugoslavia. In Britain, it has only been found at a small number of sites in recent years near Telford in Shropshire.

This cranefly is associated with woodland streams where the larval stage is spent in wet and rotten fallen logs, especially those in log-jams.

It is known that adult females lay their eggs on to the surface of logs in flowing water. They seem to prefer logs with a diameter of at least 70cm, which are jammed at the edge of the stream, or which form part of a log-jam. The logs must be partially submerged, as the larvae seem to favour the wood along the water line.

With so little known about this insect, it is difficult to be certain about the reasons for its scarcity. An important factor is the need for the cranefly to have access to semi-submerged, rotten wood. If this becomes unavailable through tidying-up operations, then the number of potential breeding opportunities is reduced. It is possible that it may also require sheltered locations.

This species is listed in the UK Biodiversity Action Plans (UK BAP), and is included on English Nature's Species Recovery Programme. Ultimately, more research into the cranefly's ecology will enable more direct species and habitat management to take place, and help to achieve the UK BAP target of ten viable populations by the year 2010.

The UK Biodiversity Action Plan for this species is available at UK BAP.