Yellow Dung Flies

October 19th 2015

Scathophaga stercoraria or the Yellow Dung Fly is one of the most familiar (but probably ignored!) flies in many parts of Assynt, particularly where large mammals are present. As its common name suggests, it is generally found on the faeces of larger mammals such as cows, sheep, deer and horses. It visits the dung to breed.

S. stercoraria play a vital role in the animal kingdom as their activities are necessary in the natural break down of the dung. They have an average lifespan of one to two months and the larger males are bright orange-yellow in colour while the females are a duller green-brown.

The main prey of the adults is smaller insects, mostly other flies but they also consume some nectar and dung for additional energy. Females will spend most of their time looking for food in surrounding vegetation and will visit the dung only to mate and deposit their eggs. The males however spend most of their time on the dung pats waiting for visiting females. During this time the males feed on other dung visiting insects.

S. stercoraria themselves are an important food source for several species of birds and they also fall prey to other insects.

These photographs were taken near Stoerhead Lighthouse on 18 October 2015 and show mating pairs on cow pats.

Mating Yellow Dung Fly Scathophaga stercoraria on cow dung Raffin. Photo D. Haines
Mating Yellow Dung Fly Scathophaga stercoraria on cow dung. Photo D. Haines
Mating Yellow Dung Fly Scathophaga stercoraria on cow dung. Photo D. Haines
Mating Yellow Dung Fly Scathophaga stercoraria on cow dung. Photo D. Haines

Report a Sighting

Recent Sightings

Golden Plover

15 birds near Clachtoll Broch (AS) (29/03)

Greylag Goose

32 geese on croft at Clachtoll (AS) (29/03)

Little Grebe

Pair on loch Sgeireach, Stoer (AS) (29/03)

Skylark

17 on Clachtoll croft (AS) (29/03)

Greenshank

two birds heard calling, Oldany estuary (DAH). Our first 2020 record. In 2019 the first record was 24th March and 2018 was 28th March. (29/03)

Shelduck

pair of birds, Lochan na Leobaig, Culkein Drumbeg (DAH) (29/03)

Eider

two pairs, Lochan na Leobaig, Culkein Drumbeg (DAH) (29/03)

Pink-footed Goose

c100 heading north over Stoer (Bill and Val Badger) (28/03)

Map