Entomopathogenic Fungal Infections

All the flies below have been consumed alive and killed by a fungus of the genus Entomophthora. Insects are infected simply by either accidentally contacting a fungal spore or, since the spores are aerially dispersed, having one land on them. Once a spore attaches to a fly’s external skeleton, it will penetrate this hard cuticle by sending a peg down through it to reach the internal cavity. The fungus will then grow within the living fly, usually favouring the abdomen. Just before the fly dies, around 5-8 days after initial infection, it will be ‘driven’ by the fungus to assume a high position on the underside of overhanging objects with wings and legs outstretched. This is the fly’s last act before it dies. Having consumed all the internal nutrients, the fungus must now sporulate to survive and pushes masses of white conidial spores between the fly’s abdominal segments which then disperse in the wind to repeat the process.

Mid September 2011
Ulverstone

18 hours later

Mid September 2011
Ulverstone

18 hours later

Mid September 2011
Ulverstone
(right 18 hours later)

Mid September 2011
Ulverstone
(right 18 hours later)

Mid October 2011
Hobart

the next day…

References

Hajek, A. E. & Leger, R. J. S. 1994. Interactions between fungal pathogens and insect hosts. Annual Review of Entomology 39: 293-322.

Roy, H. E., Steinkraus, D.C., Eilenberg, J., Hajek, A. E. & Pell, J. K. 2006. Bizarre interactions and endgames: entomopathogenic fungi and their arthropod hosts. Annual Review of Entomology 51; 331-57.