Entomophthora muscae is a species of pathogenic fungus in the order Entomophthorales

Entomophthorales

The Entomophthorales are an order of fungi that were previously classified in the class Zygomycetes. A new subphylum, Entomophthoromycotina, has recently been described for them.Most species of the Entomophthorales are pathogens of insects...

 which causes a fatal disease in flies

Fly

True flies are insects of the order Diptera . They possess a pair of wings on the mesothorax and a pair of halteres, derived from the hind wings, on the metathorax...

. It can cause epizootic

Epizootic

In epizoology, an epizootic is a disease that appears as new cases in a given animal population, during a given period, at a rate that substantially exceeds what is "expected" based on recent experience . Epidemic is the analogous term applied to human populations...

 outbreaks of disease in houseflies

Housefly

The housefly , Musca domestica, is a fly of the suborder Cyclorrhapha...

 and has been investigated as a potential biological control

Biological pest control

Biological control of pests in agriculture is a method of controlling pests that relies on predation, parasitism, herbivory, or other natural mechanisms...

 agent.

Life cycle

Soon after a fly dies from infection with this pathogenic fungus, large primary conidia

Conidium

Conidia, sometimes termed conidiospores, are asexual, non-motile spores of a fungus and are named after the greek word for dust, konia. They are also called mitospores due to the way they are generated through the cellular process of mitosis...

 are produced at the apex of a conidiophore which emerge from the intersegmental membranes. When the spores are mature they are forcibly ejected and may fall onto flies resting nearby. If no hosts are available for infection, a smaller secondary conidium may develop. The conidia germinate within a few hours and a germ tube begins to penetrate the insect's cuticle. Once this reaches the haemocoel, the cytoplasm

Cytoplasm

The cytoplasm is a small gel-like substance residing between the cell membrane holding all the cell's internal sub-structures , except for the nucleus. All the contents of the cells of prokaryote organisms are contained within the cytoplasm...

 flows through the tube and into the fly's haemolymph. The mycelium

Mycelium

thumb|right|Fungal myceliaMycelium is the vegetative part of a fungus, consisting of a mass of branching, thread-like hyphae. The mass of hyphae is sometimes called shiro, especially within the fairy ring fungi. Fungal colonies composed of mycelia are found in soil and on or within many other...

 of the fungus may grow into an area of the brain that controls the behaviour of the fly, forcing it to land on a surface and crawl upwards. The hyphae gradually grow through the whole of the body, digesting the guts, and the fly dies in about five to seven days. When it is critically ill, it tends to crawl to a high point, straighten its hind legs and open its wings, a behaviour that ensures that the fungal spores are dispersed as widely as possible. Some three hours later, conidiophores start to develop and a new shower of conidia is initiated.

Host range

As well as the housefly, Musca domestica

Housefly

The housefly , Musca domestica, is a fly of the suborder Cyclorrhapha...

, infection has been observed in adult flies in the families Calliphoridae, Culicidae

Mosquito

Mosquitoes are members of a family of nematocerid flies: the Culicidae . The word Mosquito is from the Spanish and Portuguese for little fly...

 Drosophilidae

Drosophilidae

Drosophilidae is a diverse, cosmopolitan family of flies, which includes fruit flies. Another family of flies called Tephritidae also includes fruit flies. The best known species of Drosophilidae is Drosophila melanogaster, within the genus Drosophila, and this species Is used extensively for...

, Muscidae

Muscidae

Muscidae are a family of flies found in the superfamily Muscoidea. The apical segment of the antennae of Muscidae are plumose, and the basal portion is smooth....

, Sarcophagidae

Flesh-fly

Flies of the Diptera family Sarcophagidae are commonly known as flesh flies. Most flesh flies breed in carrion, dung, or decaying material, but a few species lay their eggs in the open wounds of mammals; hence their common name...

, Scathophagidae

Scathophagidae

The Scathophagidae is a small family of Muscoidea which are often known as "Dung-flies" although this name is not appropriate except for a few species of the genus Scathophaga which do indeed pass their larval stages in animal dung. The name probably derives from the "Common Yellow Dung-fly", S...

, Syrphidae

Hoverfly

Hoverflies, sometimes called flower flies or syrphid flies, make up the insect family Syrphidae. As their common name suggests, they are often seen hovering or nectaring at flowers; the adults of many species feed mainly on nectar and pollen, while the larvae eat a wide range of foods...

 and Tachinidae

Tachinidae

Tachinidae is a large and rather variable family of true flies within the insect order Diptera, with more than 8,200 known species and many more to be discovered. There are over 1300 species in North America. Insects in this family are commonly called tachina flies or simply tachinids...

.

Ecology

Outbreaks of infection with Entomophthora muscae tend to occur in the spring and autumn. The fungus is found in most temperate regions and sporulation usually takes place in cool, humid conditions in areas where flies congregate and rest. In houses, the corpses of flies are frequently seen attached to windows or window frames, a place where other flies may easily become infected. In the open, they may be seen attached to the underneath of leaves, on fences and walls, in agricultural buildings and poultry houses.

Use in biological control

There are technical difficulties in controlling flies with Entomophthora muscae. The fungus is sensitive to temperature and when the air temperature is high, the prevalence of the disease decreases to very low levels. Houseflies infected with E. muscae were able to rid themselves of the infection by resting at temperatures that inhibited the growth of the fungus. Storage of the organism in a viable state is difficult and it cannot be easily cultured in the laboratory. Captive colonies need to be maintained through direct transmission from fly to fly. There is no commercially available supply of the pathogen.