Champion Species: Yellow May dun

Heptagenia sulphurea

Did you Know?

The Yellow May can be found in unpolluted rivers and streams with gravel and vegetation to support their lifecycle. Itis sensitive to pollution and is an indicator of good water quality. It is a favoured food of brown trout. They are easily identified from the yellow body and transparent lacy wings and two long tails. The flies hatch from May to July, often emerging from mid-morning but on bright sunny days most flies hatch at dusk. They can appear to glow bright yellow when the sun hits them.  

champion species badge of a yellow may dun fly

Fun Fact:

The duns are an unmistakable sulphur yellow in colour. Its body is about 10 mm long, and the fly has two tails.

Fishing-flies are made to look like mayflies as they are the favourite food for another of our champion species, Brown Trout!

Identification:

Yellow May Dun, are, as their name suggests vibrant yellow in colour, and they have broad, lace-like, clear wings, very short antennae and up to three, very long, fine tail bristles.

Web link:

I-naturalist