Hesperomyces

Hesperomyces is a very small parasitic fungus that attaches to the outside of ladybirds. They are part of a group of fungi called the Laboulbeniales, all of which attach themselves to arthropods. Unlike most fungi, Laboulbeniales don’t form a thread-like mycelium. Hesperomyces looks like a small, yellow-green, banana-shaped structure dangling from the ladybird. These structures, called thalli, are filled with spores, which shoot from their tip when the fungus is disturbed, like when the ladybirds are mating. The spores then land on a new host, and grow a new thallus there. It’s possible to see Hesperomyces with the naked eye. It is also easy to spot when taking zoomed-in photographs. However, loupe may help see the smaller immature thalli. You can find them on a large variety of ladybirds.

You can learn more on the genus from our booklet.

While parasitic fungi on insects are very common, they are understudied and tend to go unnoticed by entomologists – who usually don’t look at fungi – and mycologists – who usually don’t collect insects. Many species are still undescribed and it’s often unclear in which habitats they thrive in. Hesperomyces is one such understudied taxa.

Probably the most common Hesperomyces species is Hesperomyces harmoniae, which parasites Harmonia axyridis, the harlequin ladybird. The harlequin ladybird is an invasive species originally from Eastern Asia which outcompetes local ladybirds, and is now very common around Europe – as also probably is its fungal parasite!

Reporting your findings on Hesperomyces can enhance our understanding of the host-parasite interactions and the dynamics of invasive species. 

Hesperomyces species can be found anywhere where there are ladybirds. While Hesperomyces can be found year-round where suitable hosts are present, it is most common in spring, shortly after ladybirds emerge from hibernation. Harlequin ladybirds can easily be collected from broad-leaved trees and shrubs using hand, net, or beating sheets. In winter, they often seek shelter indoors, particularly around windowsills, ceilings, and attics. They are also attracted to light and can frequently be found in light traps used for moths.

Long thought to be a few fungal species which infected all kinds of ladybirds, DNA research has shown that Hesperomyces is likely to include many different species which are very specific to their hosts.

For more information about Hesperomyces, how to identify their host and how to collect them check out the attached booklet.