Wednesday, November 9, 2016

Anthropomorphizing Spiders for the Championship Round

If you can see human characteristics in a spider then you're ready for an article in which spiders explored the world more diligently and with greater success than any who followed and they did it eight million years before Magellan.  (Scientific American:  Seafaring Spiders Made It around the World—in 8 Million Years)

Get ready for the spider conquistadors of the ancient world since conquest was their purpose and they were so good at it even on an international scale.

Until now it was not known whether an ancestral population of this species had arisen in ancient supercontinent Gondwanaland and then moved away from one another when it split—or if the spiders evolved on a single continent and then scattered across the oceans.  To solve this mystery, scientists collected 45 specimens of Amaurobioides in South Africa, Australia, Tasmania, New Zealand and Chile.  They then analyzed the spiders’ genetic information, reconstructed their evolutionary family tree and explored their movement around the world.
- Scientific American

So there's the question of just how those spiders spread all over the world if they didn't get free rides when Gondwanaland split apart in the first place.

“In this case, thanks to genetic analysis, we could determine the age of the species in each area. It was not a single event, but several waves of spiders, enough to establish a viable population.”  Spiders are incredibly diverse, and many kinds are innate explorers and conquerors. For example, they are often among the first species to show up on volcanic islands emerging from the oceans.

- Scientific American

That's getting a tad poetic with spiders being 'innate explorers and conquerers' but ok.

Amaurobioides spiders are small—between one and 1.5 centimeters in length—and in coastal areas they tend to build tiny cells within rocks, so their homes are not flooded when the water rises.  Whereas there are species that travel long distances pushed by the wind, researchers suspect Amaurobioides crossed vast stretches of water floating on matter ranging from algae remains to logs. “They can survive for months without food,” says arachnologist Robert Raven of Queensland Museum in Australia, co-author on this research, which was published in PLoS ONE. And these minuscule explorers did not need an engine or sails—they had the ACC and prevailing winds flowing from west to east in their patient and silent conquest.

- Scientific American

Now we're definitely getting poetic but it's still incredible that the spiders do this.  The part about them being innate explorers implies some internal drive but maybe they just wind up on some type of drifting junk and they survive because they live that long anyway.

Being any kind of an explorer needs quite a bit of intelligence since, quite apart from anything else, what kind of idiot spider thinks it will find food on the water.  How much of a spider mind is necessary to conceive the idea the water is a path to somewhere else when it seems obviously counterintuitive.

It seems there must be more genetic triggers firing off for this behavior since, much as I so dearly love spiders, believing they have any conception of embarking on any kind of journey just doesn't, erm, float all that well.

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