Alder Fly - Sialis lutaria


The Alder Fly is black with greyish-brown wings with black veins. There are other very similar species and expert confirmation of identification is recommended.

Where the image has not received expert verification, which is necessary to be certain of accuracy in this species, it is highlighted with a red box. For that reason it is only claimed as likely to be this species


Photo ID?

It can be found near ponds and streams with silted bottoms and an abundance of weed or plant detritus. Despite its name, it has no association with Alder trees, other than being found on foliage beside water, which is where Alder is usually found.

When to see it

Adults can be seen resting on emergent vegetation around the pond, mainly in May and June, often in large numbers.

Life History

It lays its eggs in large batches of 200 or more on plants or other objects at the water's edge. The larvae are aquatic, living amongst mud and detritus and preying on smaller insects.

UK Status

Very common and widespread in Britain.

VC55 Status

Common in Leicestershire and Rutland.

Leicestershire & Rutland Map

UK Map