Warmer weather equals more spiders

A Golden baboon spider. Picture: www.exxaro.com

A Golden baboon spider. Picture: www.exxaro.com

Published Apr 8, 2015

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Washington – One major downside of global warming? Spiders. So many spiders. Previous studies have suggested that warmer weather may mean more spiders overall (and bigger ones, at that) and may make poisonous species more common as more and more regions fit their temperature preferences.

But apparently we have to worry about them getting fast and clumsy, too.

Is a fast and clumsy spider better than a slow, methodical spider? Unclear. Both sound terrible.

In a recent study published in the Journal of Experimental Biology, researchers tested how temperature changes a spider’s ability to move. It’s a good question: Spiders rely on fluid to move their limbs.

Instead of using muscles like we do, their bodies control the ebb and flow of fluid to fill up and move different limb portions. It would make sense for that fluid – and by extension, their movements – to change based on the temperature.

Sure enough, when the researchers tracked the movements of spiders at different temperatures they found that the cold made them sluggish. At 59 degrees Fahrenheit, the spiders moved no faster than 20cm a second. At the top temperature of 104 degrees, they nearly tripled that speed.

But the spiders weren’t taking bigger steps – just more of them. They went all the way from four steps a second to as many as 10. And that made them clumsier. Their joints weren’t as coordinated as they were at lower temperatures. This is probably because the fluid that controls their limb movement can’t keep up with the high speeds that come with high temperatures.

It’s unclear whether this change is enough to really hurt the toasty spiders. But the researchers suggest that it may be why the arachnids they studied – Texas Brown tarantulas – come out to hunt for food in the cool evening instead of soaking up the sun.

Washington Post-Bloomberg

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