Black Widow Spiders Bring Their Venom to Canada As Planet Warms

By Rafi Letzter, Staff Writer | August 13, 2018 07:21am ET

Venomous black widow spiders now range farther north than scientists expected, into an area including the most-inhabited parts of Canada. And there's good reason to suggest that warming temperatures are driving the fatal biters north.

That's one conclusion of a new study, published online Wednesday (Aug. 8) in the journal PLOS One. The researchers in this study were trying to identify the geographical ranges of animals using citizen science and other spotty data sources. They focused on two spider species: the northern black widow (Latrodectus variolus) and the black purse-web spider (Sphodros niger). The scientists found that data taken between 1990 and 2016 showed a black widow range extending 58 miles (94 kilometers) farther north than the northernmost observation from the period between 1960 and 1989. They suggested that black widows might already range another 30 miles (50 km) north to the Montreal area, though none have yet been reported in that region. [Creepy, Crawly & Incredible: Photos of Spiders]

The team could not conclusively demonstrate that climate change has pushed the spiders north. But a number of their findings strongly suggest that's the case, the wrote:

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Spider cannibalism

Male Spiders Let Mates Eat Them for Kids' Sake

The unkind act of butchering and eating your mate after sex, typified by the female black-widow spider and praying mantis, may make for healthier babies, new research suggests.

The researchers found that a male orb-web spider makes the ultimate evolutionary sacrifice: giving his life for the health of his offspring.

Sexual cannibalism is the act of one partner eating the other after sex. In the orb-web spider Argiope bruennichi, the female tries to grab and wrap up the male at the onset of mating so she can snack on him during sex. In the lab, only about 30 percent of the males survive their first mating, but by letting the female gnaw on them, the males prolong the sex act, making it more likely they will inseminate their partner.

Of these survivors, half go on to find a second mate, while the others try again for the same female. Due to the male's anatomy, two copulations is the limit. (When you are facing a life without sex, is it really worth it to go on?)

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Black widows found in Bristol re-homed

A pair of black widow spiders found in a classic car have found a new home at Bristol Zoo.


The infamously deadly spiders were found nesting in a 1964 Ford Falcon which was imported into Britain last January, but were only discovered when restoration began a week ago.

Mechanics at the Bicester-based Damax found one in the fuel tank and another behind the dashboard.

They identified the spiders online before putting them in a lunchbox and trying to find a home for them.

Garage manager Robin Ward said he was not scared of spiders, but nevertheless was shocked when he discovered the pair were black widows.

"We brought the car over in January and it had been stored in a garage until last week when our mechanic started getting it ready to work on.

"We found the first spider tucked under the fuel tank and carefully put it in a plastic container and looked on the internet to try and identify it.

"We continued stripping the car with a great deal of caution, and couldn't believe it when we found a second spider under the dashboard," he said.

He added: "We would have never found either of the spiders had we not completely stripped the car but we've finished it now and are 100% certain that there are no more."

Bristol Zoo says the find came at just the right time as their resident black widow had recently died of old age.

Mark Bushell, assistant curator of invertebrates, said they were not as deadly as people thought, but "could still do some quite serious harm and their bite would certainly cause health problems".

One of the spiders will go on display in a replica outside toilet in the "Bug World" section of the zoo. The other will be kept off show.

The spiders, native to the US, are rarely fatal but can cause cramps and fever. Only the females are venomous, and are known for eating their male companions after mating.


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Deadly black widow spiders found in Barton-upon-Humber

Four black widow spiders were found by workers in North Lincolnshire after hitching a ride in a consignment of jet engines from the US.

The venomous visitors dropped out of the engines close to an engineer at TC Power in Barton-upon-Humber.

Managing director Stuart Elliott said they had to stop work as soon as the spiders were discovered.

The firm has put the spiders in a glass container and are planning to rehome them with local spider experts.

"One of our engineers was actually underneath the engine," said Mr Elliott.

"One of his colleagues had noticed that a black spider had appeared out of the bottom of the engine frame and was reared up on his back legs. So we pulled everybody off the engines at that point."

Staff identified the spider on the internet by the distinctive red hour glass marking on its abdomen.

The Black Widow is one of the world's most venomous spiders. It is native to North and Central America.

Fed with flies
Their name derives from the belief that the females eat the male after mating, something naturalists say rarely happens in the wild.

The females are twice the size of the male and possess a powerful venom designed to kill much larger prey.

Craig Gledhill from the Jungle Zoo in Cleethorpes was approached by the firm for advice on dealing with the spiders.

He said that a bite could prove fatal for some people.

"A healthy human, although it would be a very serious incident if they were to be bitten, if they received quite quick medical treatment they most likely would survive.

"If the individual bitten was elderly or a small child or anybody with a heart or respiratory problem, then they would be in great danger from the neurotoxic venom."

The animals are currently housed in a glass container and are being fed with flies by the workers. The company plans to give them to local zoos and other spider specialists.