As It Happens

Scientists discover rare fungus that infects and takes over the bodies of spiders

Mycologist João Araújo is one of a team of scientists who believe they discovered a new parasitic fungus that infects a species of spiders and takes over their bodies. 

Newly discovered fungus is purple and mummifies trapdoor spiders

Close-up of what looks like a whitish mushroom-like structure going underground
A newly discovered parasitic fungus after it invaded the burrow of a trapdoor spider, mummifying it. (João Araújo)

With recent attention around the HBO drama The Last of Us and its infectious fungus that turns people into zombies, the timing of a recent discovery in the Brazilian rainforest perhaps couldn't have been better. 

Mycologist João Araújo is one of a team of scientists who believe they have discovered a new parasitic fungus that infects a species of spiders and takes over their bodies. 

"It was amazing," Araújo told As It Happens host Nil Köksal. 

Araújo and his colleagues were doing research as part of a collaboration between England's Royal Botanic Gardens, Kew; the New York Botanical Garden; and the Rio de Janeiro Botanical Garden.

He and his colleagues were walking in the rainforests north of Rio de Janeiro — actually, crawling on the forest floor "to see the low level fungi" — when he came across something that looked like a mushroom stalk emerging from a hole. 

"It was purple," he said. 

The purple hue was very unusual, said Araújo, who is the assistant curator of mycology at the New York Botanical Garden. He was quite certain they had stumbled on something previously unknown. 

The fungus was cylindrical — it looked like the stalk of a mushroom without the cap — and was also quite "robust" according to Araújo, measuring about 10 centimetres in length. It was a cordycep, a fungus which typically attack a host species, such as an insect, by using mycelium to invade and eventually replace the host tissue. 

A purple coloured stalk
Mycologist João Araújo, who discovered the fungus, says its purple colour is unusual. (João Araújo)

Araújo said what they discovered the fungus was doing with trapdoor spiders in the Brazilian rainforest was even more interesting than the zombies in The Last of Us — though he admits as someone who has worked in the field for 13 years, he may be a bit biased. 

"I live these fungi everyday," he said, "so I think they're amazing." He points to fungi's ability to adapt and develop new ways to invade a new host. 

"The true biology and evolution and diversity — and the strategies that they use to infect the different hosts, from ants or flying wasps to burrow spiders... I think the whole story is beautiful."

Hopes new interest in fungi translates into more research

Trapdoor spiders build burrows in the ground with a little door made from their silk. They rarely come out and instead capture their prey by quickly opening the door and grabbing an insect as it passes by.

Araújo says the newly discovered fungus — which doesn't have a name yet — was managing to throw its spores into the burrow of the spider, entrapping and, eventually, mummifying it. 

"We are not sure yet how their life cycle works because this is a very, very new discovery," he said, but added that he does know the fungus prevents other pathogens, such as other fungi or bacteria, from getting to the spider.

"Imagine how many other soil micro-organisms are trying to penetrate and to consume this spider," he said. "So the fungus mummifies the spider in order to keep it protected."

Araújo is hoping that the newfound pop culture interest in fungi translates into more research. He says the long-neglected field of mycology could hold the key to dealing with new pathogens that destroy forests or crops — or potentially even cancers.

"We can use fungi to tackle this these problems, but we need basic research," he said.

"We need foundational, taxonomic, systematic and evolutionary studies of these fungi. We need to understand them first before trying to to use them for something." 

Interview produced by Devin Nguyen.