Photo: Gilles San Martin

What are Laboulbeniales?

Laboulbeniales are a group of fungi that live on the outside of a variety of arthropods. Unlike other fungi, they do not form hyphae nor a mycelium but instead produce multiple 3-dimensional structures called thalli, which “hang” onto their host. This is where the common name for the group comes from: beetle hangers. While some species of Laboulbeniales are only superficially attached to their host, others are more invasive; they penetrate the outside of their host with a piercing structure called a haustorium, which makes contact with the body cavity to draw nutrients. Laboulbeniales are found primarily on beetles, but also on flies, mites, harvestmen, cockroaches, and millipedes, among others. Though researchers have known about Laboulbeniales since the 19th century, they are still a poorly studied group of organisms. An average of 16 new species of Laboulbeniales are formally described every year. Thus far, 2,325 species and 146 genera of Laboulbeniales are known.¬†¬†