Sunday, 27 September 2020

Entomopathogenic Fungi'ed Fluffy Flies





Spring in Canberra this year has had an abundance of wet weather and variably cool mornings. Conditions which are ideal for a pathogenic fungus which infects a range of insects, but is particularly noticeable to us humans when it affects flies. Entomophthora is also sometimes known as the puppeteer fungus and causes infected flies to have distended abdomens, with spread legs, and outstretched, often forward-pointing, wings.

Entomophthora comes from the Greek roots entomo (entomo), meaning insect, and   jqora (phthora), meaning deterioration/damage/destruction/decay – so a very apt construction. It belongs to a group (Phylum) of fungi called Zygomycota, and is very far removed from the various fungi, such as mushrooms, bracket fungi, and even yeast, that we are more familiar with.

The reason for the name puppeteer fungus is the concept that some of these fungi effectively hijack the insect’s brain, turning them into ‘zombies’ with behaviours that enhance the further success of the fungal infection.

Entomophthora fungus is not uncommon, provided the right conditions prevail, but infected flies, apart from being small, tend to cling to the undersides of leaves or are otherwise unobvious and not noticed by the vast majority of people. I found a dozen or so infected and very dead flies early one dewy morning in mid-September when I was inspecting our nectarine tree to see how much fruit set there might be this year. Later, I found more on a range of other plants, including azaleas and on the undersides of the leaves of the olive tree. These provided opportunities for what I think are some beautiful, if rather gruesome, photos.

Several links to further information are provided at the end of this post.