Summits disease

The most striking of hoverfly enemies is the entomophagous (insect eating) fungus - Entomophthora muscae. It attacks a wide range of Diptera, with Melanostoma (scalare - this species) being particulary open to attack. The fungus enters via the digest tract and expands until it can be seen forcing itself between the abdominal plates. Before the fly dies the fungus somehow makes the fly crawl to a high point, straighten its legs and open its wings, giving the fungal spores the best chance of dispersal. This action by the fly is known as "Summits disease". The above photos were taken by Paul Parsons on the weekend in the Llynfi valley and shows the fungus's actions perfectly.