Of the world’s 43,000 known varieties of spiders, an overwhelming majority are peevish loners: spinning webs, slinging lassos, liquefying prey and attacking trespassers, each spider unto its own.
But about 25 arachnid species have swapped the hermit’s hair shirt for a more sociable and cooperative strategy, in which dozens or hundreds of spiders pool their powers to exploit resources that would elude a solo player.
“It’s very satisfying to me that the most maligned of organisms may have something to tell us about who we are,” said Jonathan N. Pruitt, a biologist at the University of Pittsburgh who studies social spiders.
The new work on social spiders is part of the expanding field of animal personality research, which seeks to delineate, quantify and understand the many stylistic differences that have been identified in a vast array of species, including monkeys, minks, bighorn sheep, dumpling squid, zebra finches and spotted hyenas.
Animals have been shown to differ, sometimes hugely, on traits like shyness, boldness, aggressiveness and neophobia, or fear of the new. Among the big questions in the field are where those differences come from, and why they exist.
Reporting recently in The Proceedings of the Royal Society B, Dr. Pruitt and Kate L. Laskowski, of the Leibniz Institute of Freshwater Ecology and Inland Fisheries in Berlin, have determined that character-building in social spiders is a communal affair. While they quickly display the first glimmerings of a basic predisposition — a relative tendency toward shyness or boldness, tetchiness or docility — that personality is then powerfully influenced by the other spiders in the group.
In laboratory experiments, the researchers showed that spiders exposed to the same group day after day developed stronger and more distinctive personalities than those that were shifted from one set of spiders to the next. Moreover, the spiders in a stable social setting grew ever less like one another over time.
In other words, far from fostering behavioral conformity, a predictable social life accentuated each spider’s quirks and personal style, rather as the characters in a sitcom — the Goth girl, the huckster, the lovable buffoon — rise ever more to type with every passing laugh-tracked week.
Thursday, May 29, 2014
The more stable the environment the more differentiated the individual
Interesting not so much as confirmed truth but as a model of thinking. The Lives of Sociable Spiders by Natalie Angier.