Dead Flies 

Kiwicare was recently asked to identify some flies in a photo. The flies looked rather strange; with housefly-like head and thorax (chest) but a pale cream abdomen with dark stripes. The look of the flies was unfamiliar and checks of databases of flies and identification keys did not bare any successful identifications.

The sender was asked what situation the flies were found in. When the reply was that the "flies were dead but looked alive because they were standing up on a bed and others were attached to a clothesline" that the 'penny dropped'. The flies are 'zombie flies'.

Zombie flies are flies (in this case house flies) affected by a fungus that slowly kills the flies. The flies often attach themselves to the foliage of plants or other surfaces as the fungus spreads throughout the body. The fungus eventually engulfs the fly inside and the abdomen expands so that the white fungal hypha break out between the segments of the fly's abdomen. The flies are unable to move and die stuck in position giving the appearance of still being alive.

Such fungi are more prevalent in wet and damp conditions and can affect a variety of insects including ants and other flies.

Watch out for those zombie flies.

David Brittain
Kiwicare