Ecologists are calling for Kiwis to report sightings of one of the world’s most invasive spiders with a “potentially sinister bite” known to cause serious infections.
The noble false widow spider — named for its resemblance to the notorious black widow — had its first confirmed sighting in Porirua November last year.
Watch spider expert explain the threat on TVNZ+
Massey University evolutionary ecologist Steven Trewick told Breakfast more confirmed sightings were needed to understand just how widespread they were in Aotearoa.
He said while small, they could be identified by their spherical bulbous bodies and long thin legs — similar to black widow and native Katipo spiders which the noble false widow was related to.
“That might be the kind of spider that freaks spiderphobes out the most,” Trewick said.
The spider appeared to thrive in urban environments, particularly around gardens and outdoor furniture.
They were also fast runners, although Trewick said they were more likely to be running away than aggressively towards people.
“If they are accidentally cornered or you lean on one, that is where you might get a bite.”
The noble false widow was originally from the Canary Islands and Madeira, with it also becoming well established in the UK, Europe and North America.
In an arachnophobe’s worse nightmare scenario, some UK schools have been forced to temporarily close in recent years due to infestations.
So far in New Zealand, the spider has been found in Wellington, Christchurch, Nelson, Northland and Waikato.
However, Trewick believed they were likely to be much more widespread, hence his call for sightings.
“It’s up to the people to get their phones out when they spot a spider in the backyard, take a picture of it and post it to iNaturalist.org.”
Spider’s bite
Trewick detailed the potential outcome for humans bitten by a false widow spider.
“Although considered less dangerous than black widows, the venom of Steatoda nobilis (noble false widow) contains similar toxins.”
He said of particular concern was its venom’s association with antibiotic-resistant bacteria.
“Infections resulting from bites don’t always respond to treatment, and that’s a significant medical concern.”
Mild symptoms included swelling, redness and pain; however, some cases had been linked to more serious symptoms such as tissue necrosis, nausea, hypotension, impaired mobility and secondary bacterial infections that might be resistant to standard antibiotics.
