Oct 18, 2012


by Lorraine Julien

Photo: Northern Black Widow Spider (Latrodectus Variolus).

With frost on the pumpkins and leaves falling from the trees, you just know that spooky Hallowe’en is just around the corner! I tried to think of the creepiest subject for this column and the Northern Black Widow Spider (properly known as Latrodectus variolus) came instantly to mind. Over the past few years, there have been a few sightings of this southern Ontario native. In some rare cases, this insect has even bitten a few unlucky people.

The main thing to remember is that the Northern Black Widow is very rarely encountered. Many entomologists have never seen one of these spiders in the wild in Ontario, so your chance of seeing one is remote (hopefully!).

The Northern Black Widow is a very timid and shy spider that quietly goes about its business spinning its webs and hiding in dark, damp places in the hope of catching its prey. Favourite locations are around wood piles, garbage piles, storage sheds, veggie gardens, old tree stumps and under rocks or logs where they can wait for their favourite food: flies, mosquitoes, beetles and grasshoppers. The only risk of being bitten is if you happen to disturb them. The one to watch out for is the female; the male does not bite.

Both predators and prey get tangled in the funnel-shaped web. When this happens, the spider wraps more silk around the unlucky victim and paralyzes it with venom. The spider then drags the bundle home to enjoy the feast.

If you happen to be bitten, clean the wound thoroughly with soap and water and apply an ice pack to slow down the venom. Ibuprofen will help alleviate the pain. You should seek medical attention at the nearest hospital as medicine to counteract Black Widow Spider venom (anti-venom) is available in Canada. If possible, photograph or collect the spider.

A Black Widow’s venom is said to be 15 times stronger than that of a rattlesnake, but the tiny amount of venom a spider injects with one bite is rarely fatal for humans. Bite symptoms at the site include redness, swelling, and itching. In 30-60 minutes, pain will start in muscle groups, cramps and abdominal pain. Pain and cramping are worse between 2-3 hours and may last up to 36 hours or longer. Other symptoms include perspiration, nausea, fatigue, shock and coma. It’s important to remember that most people (99% of those who are bitten) suffer no serious injury or death. Small children, the elderly, or those with compromised immune systems are most at risk.

The finger-nailed size female is shiny black with a large abdomen and a red or yellowish marking on the underside of her belly - if you should get so close! The abdomen markings are two red triangles whose tips don’t quite touch (almost like an hourglass). The male Black Widow is actually dark brown, half the size of the female, doesn’t bite and doesn’t have venom. In fact, the poor fellow is usually eaten by the female after she’s mated with him.

Black Widows may become more common as our winters get milder and our summers hotter. They cannot survive in really cold weather. Probably more of these spiders have been spotted this year because of the mild winter we experienced last year. Although the Northern Black Widow is slightly smaller and not quite as venomous as its more famous cousin, the Southern Black Widow (Latrodectus maclans), you definitely do not want to fool around with it.

The bottom line is that while you may want to keep an eye out for this kind of spider, there is no reason to fear them as they are still quite rare, very reclusive and it’s extremely unlikely that you’d be bitten. There is no reason to spray or kill every spider you see because it is not necessary.

Happy Hallowe’en, everyone!

Please feel free to report any observations to Lorraine Julien at This email address is being protected from spambots. You need JavaScript enabled to view it.  or Steve Blight at This email address is being protected from spambots. You need JavaScript enabled to view it.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

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