Some rather dramatic dead white spiders recently began to appear, often still suspended in their webs, in the catacomb beneath the Anglican Chapel of Kensal Green Cemetery, to the fascination of guides and visitors on the Friends of Kensal Green Cemetery's regular Sunday tours. They appear to have succumbed to some sort of fungal infection (and much of the catacomb is certainly damp and dark), but we would like to know more. Can anyone please advise specifically what causes this, or suggest why this phenomenon should (apparently) suddenly appear in a 175-year-old building?
These spiders have succumbed to an entomopathogenic fungus, which is a fungus that infects insects and slowly but surely kills them. That said, spiders of course are not insects, but I do not think that the fungus is as specific as that and will hit spiders as well. For a while at least some spiders may well be alive with fungus sprouting from them, but these will not be long for this world. Once the fungus is there the spores produced rapidly infect other spiders and the ghostly furry white corpses sinisterly hang in the air. The sudden appearance is likely to be because this fungus is fairly recently introduced to this catacomb and possibly by another infected insect that has used the space to hibernate.
Thank you very much indeed for your prompt and informative explanation! With your permission, we'll include this in our members' magazine, and the environmental report as well. It's also extremely useful to know that they might just still be moving; that would be quite alarming to see, without warning.