Ladybirds, fungi and alien invaders

Of all species on Earth it is the parasites that seem to receive least appreciation for their intrinsic beauty. Yet they are exquisite. I have been fascinated by parasites for many years, particularly fungal pathogens of insects. I began my exploration of these intriguing fungi through studies on an obligate parasite of aphids – Pandora neoaphidis. The intricate fungal structures of this delicate (and lethal) fungus when viewed under the microscope are simply beautiful but perhaps even more inspiring are the amazing ways in which this fungus interacts so intimately with the host aphids it infects. It can alter the behaviour of aphids in dramatic ways even affecting the communication between aphids to enhance transmission.

Harlequins on a wall

Ladybirds also play a part in the dispersal of this aphid-pathogenic fungus but they are also host to their own fungal parasites too.

"We are now hoping that people across the UK can help us unravel the mysteries of this unique parasite by contributing to a new parasite survey"

Recently Katie Murray, a PhD student based at the University of Stirling but who I have the pleasure of also supervising, found one of the most quirky groups of fungi infecting Harmonia axyridis (harlequin ladybird) in London - the Laboulbeniales. The species of fungus is called Hesperomyces virescens and has previously been studied within Adalia bipunctata (2-spot ladybird) in London. 

I met Katie, and her co-supervisor Matt Tinsley, the day after she had made her discovery. The fungus utterly captivated us all. The small yellow fruiting bodies that protrude from infected individuals are striking. The supervisory meeting was dominated by our lively and excitable speculations on the life-history of this fungi and specifically the extent of the epidemic that Katie had stumbled upon. We have so many questions and so few answers.

We are now hoping that people across the UK can help us unravel the mysteries of this unique parasite by contributing to a new parasite survey. As harlequin ladybirds move into people’s homes this winter we are encouraging them to submit photographs, count how many ladybirds they spot and how many appear to have the fungal infection. You can find out more details about Laboulbeniales fungi and take part in the parasite survey here.

Dr Helen Roy is an Ecological Entomologist, working within the Biological Records Centre at the Centre for Ecology & Hydrology. She also leads the UK Ladybird Survey.

More information about the appeal for citizen scientists to help in mapping the fungal epidemic can be found on the CEH News Centre.

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