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:
Reports from 1990 to 2016 suggest a much more northerly black widow range than reports from 1960 to 1989.
Since 2012, individual black widows have started turning up in regions of the Canadian provinces of Ontario and southern Quebec where they'd never before been reported.
Across all 46 years studied, both spider species were more likely to turn up during warm weather than cold weather.
The period from 1990 to 2016 has also been much warmer than the period from 1960 to 1989, as the Earth has consistently warmed in recent decades.
Black widows are particularly able to move into new areas as the world warms, the researchers wrote in the study, because these spiders are "habitat and prey generalist[s]."
In other words, the dangerous critters can comfortably live in a whole range of sufficiently warm environments and eat whatever prey happens to already be there. Plus, the researchers noted, black widows tend to lay lots of eggs at once. So, once the first black widow arrives in a new spot, many more will likely soon appear.
Black widows might also be more capable of moving north, the researchers wrote, because unlike black purse-web spiders, they're perfectly happy nesting in human dwellings — which can allow them to ride out cold winters.
The researchers noted that even in areas where black widows are present, the odds of getting bitten by one are low. But a black widow bite is sufficiently dangerous, they wrote, that the threat is worth taking seriously.
For that reason, they called for a focused citizen-science project to track the creatures and document their potential northern migration. Black widows make particularly good candidates for data from citizen researchers, the study's authors wrote, because the bulbous, inky females with red spots on their bellies are so readily identifiable and unusual-looking.
To learn more about spiders and how to get rid of them safe, contact EHS Pest.
It was just another day at the office for employees at a New Hampshire town hall on Tuesday until an unusual visitor dropped in from the ceiling to hang out for a spell.
Mary Jo McCullough, the town clerk and tax collector in Newton, New Hampshire, shared a video of the rodent hanging — head first — out of a ceiling tile in the town hall’s drop ceiling.
Shrieks and laughter can be heard as the women in the office urge for a bucket to be placed underneath the dangling mouse.
“It’s coming out!” one woman yells.
The mouse appears to slowly slip through until it is just holding on by its back legs. Then, as if it realized its gone too far, it starts to reach back with its front legs to the hole.
Only to plunge into the waiting waste basket.
“We didn’t know, was it dead? Was it alive? Is it a mouse? Is it a rat? Is it a mole?” McCullough told the New Hampshire Union Leader of when the rodent’s head was first spotted poking out of the tile.
Her deputy, Cheryl Sanders, told the newspaper that at one point she tried banging on the ceiling with a broom to make the mouse fall out, but it didn’t work.
Once the mouse was in the trash can, the bin was taken outside, tipped over, and the mouse scurried out with the encouragement of a broom, according to the Union Leader.
“Never a dull day at Town Hall,” McCullough wrote on Facebook of the incident.
To properly get rid of mouse and rats, contact EHS Pest.
For the first time in 50 years, a new tick species has arrived in the United States — one that in its Asian home range carries fearsome diseases.
The Asian long-horned tick, Haemaphysalis longicornis, is spreading rapidly along the Eastern Seaboard. It has been found in seven states and in the heavily populated suburbs of New York City.
At the moment, public health experts say they are concerned, but not alarmed.
Although domestic American ticks are a growing menace and transmit a dozen pathogens, no long-horned ticks here have yet been found with any human diseases. In Asia, however, the species carries a virus that kills 15 percent of its victims.
For now, the new arrivals are considered a greater threat to livestock.
Known in Australia as bush ticks and in New Zealand as cattle ticks, long-horned ticks can multiply rapidly and suck so much blood from a young animal that it dies. The ticks bloat up like fat raisins until their tiny legs are barely able to support them.
After a blood meal, females can lay hundreds of fertile eggs without mating.
“One tick can crank out females in fairly large numbers,” said Thomas Yuill, a retired pathobiologist at the University of Wisconsin, Madison, who was one of the first to raise alarms about the invaders.
The first long-horned tick was found last summer in western New Jersey. This summer they were collected in public parks and a golf course in Bergen, Essex and Middlesex counties in New Jersey, and in wooded and grassy areas of New York’s Westchester County.
They were reported in Pennsylvania for the first time last week, and have been sighted in Arkansas, North Carolina, Virginia and West Virginia.
They were found feeding on horses, dogs, deer, a calf, a sheep and an opossum. They do bite humans, but it is not clear how often.
People should use the same precautions they do against domestic ticks, experts said, such as using repellents and checking for ticks after walking through woods or tall grass.
The ear of a sheep in New Jersey covered with long-horned ticks. This infestation was the first confirmed appearance of the new tick species in the U.S.CreditTadhgh Rainey
Tadhgh Rainey, an entomologist at the public health department of Hunterdon County, N.J., found the first long-horned ticks in the country last August, when a woman who had been shearing her pet Icelandic sheep came to his department with ticks on her hands and wrists.
“I thought she’d have a few,” Mr. Rainey said in an interview. “But she was covered in them, easily over 1,000 on her pants alone.”
Most were young nymphs about the size of dust specks. “She had a change of clothes in her car, so we put her clothes in the freezer to kill them,” Mr. Rainey recalled.
The ticks didn’t match any North American pests, and initially he could not identify them. The woman’s 12-year-old sheep was penned alone and had never traveled, so where they came from remained a mystery.
A month later the woman called again to see if he had figured out what they were, and Mr. Rainey drove out to see the animal for himself. “A minute after we entered the paddock, even before I touched the sheep, I was covered in ticks,” he said.
The sheep was weak from blood loss, so he gave the owner some insecticidal livestock wash. The grass around the paddock was later cut and the area sprayed in an effort to eliminate the outbreak.
Andrea Egizi, an entomologist at Rutgers University, finally identified the longhorns by DNA analysis. Her lab has now tested more than 100 specimens found in New York and New Jersey.
Thus far, Dr. Egizi said, none have any of the pathogens causing the six diseases she screens for: Lyme disease, relapsing fever, babesiosis, anaplasmosis and two varieties of erlichiosis.
The Centers for Disease Control and Prevention lab in Fort Collins, Colo., has screened about 100 long-horned ticks for three dangerous viruses — Powassan, Heartland and Bourbon — and all came up negative, said Ben Beard, the agency’s deputy director of vector-borne diseases.
The lab now has 10 live long-horned ticks and is feeding them to create a colony, Dr. Beard said. That will take about a year, and then researchers can determine whether they can transmit Rocky Mountain spotted fever and other diseases.
In East Asia, long-horned ticks do carry pathogens related to Lyme and others found in North America. But the biggest threat is a phlebovirus that causes S.F.T.S., for severe fever with thrombocytopenia syndrome. (Thrombocytopenia means abnormally low levels of platelets, which help the blood clot; a severe drop triggers internal bleeding and organ failure.)
The syndrome has an overall fatality rate of about 15 percent, said Terry A. Klein, an entomologist working with the American military in South Korea. But S.F.T.S. is more lethal to people aged 60 or older, killing half of them.
However, the syndrome is not found in Australia or New Zealand, earlier stops for the long-horned ticks as they spread from Asia. In those countries, they cause babesiosis and theileriosis in cattle but are mostly “of nuisance value” to humans, said Dr. David Thomson, a veterinarian in Queensland, Australia.
It’s not clear that the S.F.T.S. virus, which is related to the Heartland virus found in a number of American states, could get established in this country, because its transmission cycle is unknown — it may need more than one host.
(Although West Nile virus, for example, is transmitted to humans by mosquitoes, they first get it from birds, because humans do not build up enough of the virus to pass on.)
It’s not known when or how long-horned ticks reached the United States, nor why the species is spreading so fast now.
They bite birds, but Mr. Rainey said he suspected they originally arrived on a large animal. As far back as 1960, he said, the ticks were found on a horse held in quarantine.
One collected in 2013, Dr. Beard said, was misidentified until recently as a rabbit tick, which is also in the Haemaphysalis genus.
In theory, just one female could have produced all the long-horned ticks spreading in the country through asexual reproduction. But Dr. Egizi said she has found three mitochondrial DNA lineages, meaning at least three females arrived.
Although experts said having a new invader is unsettling, they worry more about deer ticks, lone star ticks and other established species whose ranges are growing as winters get warmer.
Cases of the illnesses they transmit — everything from Lyme disease to alpha-gal syndrome, an allergy to red meat — are rapidly increasing. Even in Asia, only about 1 percent of long-horned ticks have the S.F.T.S. virus; in parts of this country, 25 percent of deer ticks carry Lyme disease.
“The jury’s still out on how big a threat this is,” Dr. Beard said. “But we think it’s a very important question to address.”
To find out how to control ticks, contact EHS Pest.
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