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Attack of the cannibal wolf spiders

13 May 2020 | News Roundup

If you liked Attack of the Giant Leeches or the Killer Tomatoes, or Plan 9 from Outer Space, you’ll love this one. Due to (what else?) climate change, the Arctic is threatened with a plague of overgrown cannibal wolf spiders. Move over, giant atomic ants from Them. Here comes an even more loathsome swarm. But don’t count on the fabled balance of nature to  kick in because climate change only ever means bad things. Even if the Arctic warms up to a level at which the fabled balance of nature does just fine everywhere else.

It’s probably not necessary to explain why being overrun with cannibal wolf spiders would be bad even if you’d rather they were eating one another than, say, you. But in case you’re not an arachnologist, here are a few handy facts about wolf spiders. First, no yucky webs. They are solitary hunters who stalk prey or lurk in ambush. They are also robust, agile, camouflaged, have very good eyesight and can hunt with their egg sac “attached to the spinnerets at the end of the abdomen”.

In case the name had you worried, they are not as big as wolves. And a good thing too. They seem typically to be 10-35 mm not counting their disgusting hairy segmented legs, and have eight disgusting eyes in three rows.

No, sorry, not disgusting. Beautiful. Nature is beautiful. Although if you look at a picture of a wolf spider you will very likely conclude that it is ugly even by the standards of spiders. Just saying. (Specifically, just saying “ugh.” A face only a mother with a sac bound to her spinnerets could love.)

Wherever one comes down on the “Who’s the fairest” issue, the study presents the following nightmare scenario: As the Arctic warms, wolf spiders get bigger and have more babies because, well, warmth is favourable to life. But since all effects of climate change are bad, the result won’t be more food for wolf spiders as well.

If you’re wondering what wolf spiders eat beyond one another, it’s not sheep spiders, it’s bugs. Crickets, ants, other spiders, even the odd small lizard or frog. So why won’t there be more, juicier (ugh) versions of this banquet on legs? Because, says the lead study author, “Space and resources on the tundra are finite.”

Space limited on the tundra? Have the authors ever looked at a map? And as the tundra warms it presumably gets less tundra-like, so resources ought to expand considerably. Space is even more limited in a rainforest but there seem to be lots of bugs. Including ones a wolf spider would regard as tastier than another wolf spider, and easier to eat.

But back to everything being bad. It also turns out that as spiders flourish and breed, “competition among them increases” (who saw that coming?) in turn “triggering higher rates of cannibalism and reducing the number of young spiders that survive to adulthood”. Which is apparently good as a general rule, in a disgusting kind of way, because it regulates population. Except because of climate change, it’s bad even when it’s good.

According to Phys.org, “The results of this study suggest that cannibalism does regulate wolf spider populations in the wild by reducing juvenile survival. However, in the long term, frequent cannibalization may not be advantageous for individuals, or spider populations.”

The discovery that being cannibalized is bad for individuals may not justify a research grant. Nor that it might reduce the population. But the legitimate point here is that eating your own kind isn’t a great idea even nutritionally. However, as so often, if a species gets so numerous that it has trouble finding food, its numbers fall again in complex boom and bust cycles favoured by people illustrating chaos theory by talking about rabbits.

It happens in the Arctic, it happens outside the Arctic, and it happens with wolf spiders outside the Arctic. So not much to see here. Though there is one more disgusting detail we should mention in case you were considering a trip to the Arctic when the lockdown ends.

Wolf spiders are so common in the Arctic that in the aggregate they outweigh actual wolves. Disgusting.

One comment on “Attack of the cannibal wolf spiders”

  1. Cartoon in Playboy decades ago. 2 female hippos in foreground. Single male in background. One goil to the udder goil. 'You know, he's almost toooooooooo handsome. Beauty is in the eye........etc.

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