When a BBC documentary crew entered an abandoned gunpowder storeroom in Northern Ireland, they had no idea of the miniature horror movie they would encounter. The ‘Winterwatch’ team, who presumably looked up, and froze in shock, saw a spider.

Scary enough for some, but that wasn’t what freaked them out (they are nature documentarians after all!) It was the fact that the deceased spider was embedded in a coral-like shroud. The cave-dwelling arachnid, the orb-weaving Metellina merianae, was barely recognizable as the reclusive species they knew.

A Scary New Species Named After Sir David Attenborough

The grizzly corpse was sent to mycologist Harry Evans and his team at the Centre for Agriculture and Bioscience International. Extra specimens found in other caves, including Whitefather’s Cave in the Republic of Ireland, helped the team to identify the fungus as a new species. It has been named Gibellula attenboroughii after Sir David, and despite the fact he has over 50 organism species named after him, we’re zagotovo that this must be his favourite. 😉

In each afflicted specimen the fungi was fused with a carcass of either M. merianae or a similar orb-building cave spider, the European Meta menardi. One of the fascinating (and unnerving) elements of the discovery was that it appears the fungus had caused the spiders to act in unnatural ways, uncharacteristic to their species. Despite both types of the spiders being ‘sit-and-wait predators’ (meaning that they hide themselves near their webs and watch for prey), each specimen infected was found out in the open, on the exposed cave ceiling. 

‘Infected spider in situ, on cave ceiling, showing early infection with immature synnemata on compact, white subiculum,’ (via Fungal Systematics and Evolution)

A Cousin of the Cordyceps?

If any of this sounds familiar to the mycology-minded out there, then you are correct. Popular medicinal mushroom, the Ophiocordyceps (commonly known as cordyceps), exerts a similar control over the carpenter ants it parasitically inhabits. It is thought that dopamine plays a role in the takeover. 

“The fact that Gibellula-infected spiders are found in prominent positions on the roof or ceiling of their subterranean habitats indicates a behavioral change, possibly manipulated by the fungus,” so zapisali avtorji.

“The sporulating cadavers would be exposed to the air currents circulating through the caves promoting the release and subsequent dispersal of the dry spores through the system.”

Basically, the poor, dried-out spider becomes a distribution system for the spores of the fungi so it can reproduce.

A wasp infected by parasitic cordyceps (prek Wikimedia Commons)

A Shape-Shifting Spider Slayer

Additionally, it appears that this fungus is incredibly adaptable. Despite looking very different, both the gunpowder room and cave specimens are all one species. For example, in the gunpowder store (which was underground) the total absence of air movement could explain why the spores stuck in column-like forms to the fungal surface, and the lack of light in the space could have resulted in the loss of pigment. 

Evan’s team suspects that the variety of forms this species exhibits could be due to the different environmental conditions it finds itself growing in. 

In comparison, “Within the cave system, especially in the threshold zone favored by Metellina merianae, there would be both diffuse light and air currents to dislodge and disperse the [spores] resulting in a decreased incidence of long chains or blocks of spores,” the team writes.


Gibellula attenboroughii A. On cave ceiling, Tullybelcoo Ground Bridge,
County Fermanagh, Northern Ireland. B. Whitefathers’ Caves, County Cavan,
Republic of Ireland. C. On moss, Lake Vyrnwy, Powys, Wales (image: D. McNeil).
Scale bars: A, B = 1.5 mm; C = 1 mm. (via Fungal Systematics and Evolution)

The Answer to Unsolved Mushroom Mysteries

The spooky discovery has led scientists to suspect that the same fungus could be the answer to the mysterious infections of M. merianae spiders found in Wales. Usually living in the entrances of rock fissures or similar man-made crevices around a (cave-free) lakeside, it seems the spiders moved from these safe nooks and crannies to overhanging sphagnum moss, again, an unnatural behaviour for the species. Could they too have become spore puppets for the same fungus?

Blowing the dust off the herbarium  archives, the team found illustrations and other records of similar fungi that could also be Gibellula. The authors speculated;

“There is a hidden diversity in the British Isles and that many more species of Gibellula remain to be discovered,”

As we know, unlike humans, fungi tend to flourish in the darkest, dankest, dampest corners of the world. Who knows what other unknown mushroom mysteries lurk in the places we’d rather not tread? Watch this space… če si upate.

The research was published by Fungal Systematics and Evolution.