Spiders, unfortunately, act all too human

Can a biologist's research shed any light on what's happening in Washington?

As our politicians in Washington stopped devouring each other for just a few days, I decided to reach out to an expert.

A man who studies extinction, and is wise in the ways of aggressive and docile species that eat meat.

Jonathan Pruitt, biologist, is an assistant professor of behavioral ecology at the University of Pittsburgh. He doesn't study politicians, per se.

He studies eight-legged creatures, some poisonous, with hair on their backs and mouths that open sideways:


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Spiders.

There are about 42,000 species of spiders. Of that number, only 25 species are social, meaning spiders that raise young in colonies and work together.

His radical experiment in these "social spiders" should be immediately funded, even in these days of the sequester.

"I basically give each spider a little personality test and then see how they do in different psychological challenges," he said Wednesday in a telephone interview from his laboratory, which, naturally, contains spiders. "And these spiders make a society — they make a giant colony together where they operate a division of labor."

In Pruitt's experiment, he took a particular spider species, the cobweb weaver spiders, related to black widow spiders, and paired them off.

He put the dociles with the dociles and the aggressives with the aggressives. He also put together a group of dociles and aggressives.

Then he studied them for seven years. He watched them live and interact and breed. He observed how they grabbed helpless creatures and ate them, just like humans.

It turned out that the docile (let's call them "good") spiders quickly created large productive colonies with many little spider kids. And the aggressive spiders (the "bad" spiders) had fewer spider children and smaller colonies. The medium spiders (let's call them "kinda like people") with aggressive and nonaggressive traits, had medium-sized colonies.

What Pruitt found was that at the most productive colonies, other spiders showed up, to hang out, uninvited. He didn't use the scientific term "hang out." He used the term "infiltrate."

"They're social parasites," he explained of the infiltrators, who were attracted to the spider colony by pheromones. They stole food, and attacked and fed on the colonists.

The passive or "good" spiders were so gentle that their colonies were overrun and destroyed by infiltrators. And the aggressive or "bad" spiders never got much going, but at least they survived.

Meanwhile, the "kinda like people" spider colony — with aggressive and nonaggressive traits — was able to survive extinction.

So it takes all kinds?

"It's kind of a feel-good method at the end. It sounds like a children's book, but your intuition is probably right. It takes all kinds," Dr. Pruitt said. "If we have too many aggressives, then the group has too much infighting and frequently they miss out on important resources.

"If you have too many dociles, yeah, everybody gets along, everything is going along amicably until you have a serious challenge in front of you, Some foreign species or some foreign entity."

Eureka, I thought, and told an editor, who made a face and asked, in the manner of most Americans:

 

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