How a mushroom turns cave spiders into zombies

Scientists from the UK and Denmark, led by Dr Harry Evans (Emeritus Fellow, CABI), have identified a previously unknown fungus that 'zombifies' cave spiders in Ireland. The findings are published in the journal Fungal Systematics and Evolution.

The unusual fungus was first found on a spider while filming the BBC TV programme Winterwatch in Northern Ireland. DNA and morphological analysis later confirmed the new species, which was named Gibellula attenboroughii - in honour of the famous naturalist and broadcaster Sir David Attenborough. The fungus is hosted by a cave spider of the species Metellina merianae, as well as its "relative" Meta menardi. Both live in caves, and often attached to ceilings or walls, where they found and the parasitic fungus itself.

Scientists note that when infected, these spiders change their characteristic behaviour, leave their usual habitat (webs and webs) and die in open places inaccessible to other predators. This pattern is reminiscent of "zombie ants" from Brazilian rainforests that fall victim to fungi of the genus Ophiocordyceps. When "zombifying" insects, these pathogens are able to secrete metabolites (e.g. dopamine) that provoke a change in host behaviour for the sake of better spore dissemination.

In addition to current findings in Northern Ireland and the Republic of Ireland, the researchers examined historical herbarium data and references in the scientific literature. It turned out that the genus Gibellula occurs much more widely throughout the British Isles than had been thought, and in some areas - such as Norfolk and Wales - whole outbreaks of disease have been recorded among localised spider populations.

The new work highlights the need for further research, as specific substances produced by fungi of the genus Gibellula may not only alter spider behaviour, but also affect spider population dynamics. Studying the unique evolutionary "co-operation" between parasites and hosts will provide a better understanding of how such pathogens adapt to narrow ecological niches and what mechanisms underlie their effects on the victim organism.

Journal publication reference: H.C. Evans et al, "The araneopathogenic genus Gibellula (Cordycipitaceae: Hypocreales) in the British Isles, including a new zombie species on orb-weaving cave spiders (Metainae: Tetragnathidae)", Fungal Systematics and Evolution (2025). DOI: 10.3114/fuse.2025.15.07