[Image: James van den Broek, Shutterstock]
Until Mark Wong recently flipped over a rock in Tallaganda State Forest in New South Wales, Australia, it had been just another day of looking at spiders. Then, the ecologist spotted the burrow of Atrax sutherlandi, a funnel-web spider. “I began poking at it with a stick, and I was amazed at what came rushing out at me. The first thing that caught my eye was the red fang,” says Wong.
Normally, A. sutherlandi has a glossy black back and fang, as well as a deep-brown or plum underbelly. The spider that sprung from the burrow, however, had a blood-red belly and fang.
Wong knew immediately that he had made an once-in-a-lifetime discovery. “I had never seen a funnel-web spider with those colors before"—and it turns out no one else had, either, says Wong, a National Geographic Young Explorer and Ph.D. student at the Australian National University in Canberra.
The red-fanged funnel-web spider poses, ready to strike. [Photograph by Mark Wong, The Australian National University]
It's very common for individual animals, even spiders, to have different colours, says Amber Beavis, a spider expert and senior researcher at the Regional Australia Institute, an independent think tank in Canberra.
"There’s more variation than you might think,” Beavis says. But the red-fanged spider struck her as a particularly unusual find. “I spent five years in this area looking for spiders, and I didn’t see anything like it.”
A careful search of the area also didn’t yield any other spiders with similar colouring, says Wong. He brought the oddly coloured spider back to the lab, but it died.
He's not sure what gave this particular spider its scarlet hue, but it's likely some sort of genetic mutation.
The colour is also probably not for communicating with other funnel-web spiders, he says. Not only do A. sutherlandi mostly live in complete darkness, they're solitary and have notoriously poor eyesight.
Funnel-webs, which reach about two five centimetres in length, spend most of their lives in underground burrows, with males emerging only to look for mates.
The arachnids line their burrows with silk that vibrates when prey is at the entrance. Then, the spiders spring into action, just like Wong experienced firsthand.
Funnel-webs are also well known in Australia for their venom: Bites from the closely related Sydney funnel-web spiders (A. robustus) used to kill several people every year until scientists developed an effective anti-venom. A. sutherlandi are also venomous, although have killed far fewer people due to their remote habitats.
A normally coloured female funnel-web spider (left) next to the oddly red specimen. [Photograph by Mark Wong, The Australian National University]
Although the red-fanged arachnid isn't new to science, it's still special, Beavis adds.
"When we see these one-off examples that look different from every other members of their species, it gets people to look at spiders a bit differently,” Beavis says.
“Spiders have a bit of an image problem. Lots of folks find them scary," she says.
Even Beavis. When she first started her Ph.D. research, “I was trying to do my work and one of them would move, and I would squeal. It was pretty undignified,” Beavis said.
Now, however, she has learned to love spiders—both as predators of many pest species and, like the red-fanged oddity, as simply beautiful creatures.