4 misconceptions about the black widow spider

http://www.cbsnews.com/news/4-misconceptions-about-the-black-widow-spider/

By Elizabeth Palermo Livescience.com June 1, 2015

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1. They don't want to go home with you

Believe it or not, black widow spiders don't want to live inside your bag of grapes. If you happen to find one of these critters in your grocery bag, you can bet the arachnid got there by accident, said Catherine Scott, an arachnologist at Simon Fraser University in British Columbia, Canada. [Creepy, Crawly & Incredible: Photos of Spiders]

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2. They rarely bite humans

Despite their ferocious-sounding name, black widows are not aggressive creatures, said Scott, adding that a better word to describe these spiders is "shy."

"They have no reason to bite us unless they're threatened," Scott said. "We pose a much greater threat to them than they do to us."

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In fact, you really have to pinch a western black widow to get it to sink its teeth in, said Scott, who referenced a recent study that found that this species of spider is most likely to bite when it's pinched along the entire length of its body (something that might happen if it is attacked by a predator or sat upon by an unsuspecting human).

In most cases, poking the spider repeatedly with a finger wasn't enough to get the arachnid to bite, the researchers found. Instead, the prodded black widows in the study often ran away, played dead or flicked a few strands of silk at their attackers.

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3. When they do bite, they don't usually kill

Black widows eat insects, as well as other arachnids, that they catch in their webs. The spiders' venomous bites can kill a mosquito, fly, caterpillar or even a grasshopper. However, their venom isn't meant to kill you. While these spiders' bites can cause fatalities in humans, they rarely do, according to the National Institutes of Health, which states that fatalities from black widow bites typically occur among young children, the elderly and those who are extremely ill.

"Yes, black widows are venomous, but they pose very little danger to humans," Scott said. "The majority of bites that do occur are not serious. People either recover with no intervention at all, or they go to the hospital and are treated and then are fine."

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In fact, not all bites from a black widow spider result in envenomation. These spiders can choose when to inject venom into their perceived attackers, and how much to inject. The same study that found black widows tend to reserve bites for extreme threats also found that black widows' bites are usually venomous only when the spiders feel their lives are in imminent danger. If the threat is less severe, the black widow may deliver what's known as a dry, or nonvenomous, bite, the researchers found.

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4. They're actually kind of awesome

Once you get over your fear of black widows, you can finally stop to appreciate how cool these arachnids really are. Scott said the thing that interests her most about this spider is its complex system of communication.

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And despite what her name suggests, the female black widow doesn't always dispose of her mate after copulation, Scott explained. While some species of widow spider (particularly the Australian redback spider) always consume their sex partners, the western black widow that recently made headlines rarely engages in such cannibalistic activities, said Scott.