科学美国人60秒:Social Spider Groups Need Bold and Shy Members

What has eight legs, eight eyes, and lives together with thousands of others like it? Arachnophobia sufferers do not want to hear the answer—which is, spiders that live in large social groups.
什么东西有八条腿，八只眼睛，并与成千上万的其他类似物种居住在一起？蜘蛛恐惧症患者绝不希望听到的答案——这就是生活在庞大社会群体中的蜘蛛。

It's pretty rare to find such group-living spiders. Of the 45,000 spider species we know about, only about 25 are social. These species weave massive webs and dwell in colonies of dozens, hundreds or even thousands of individual spiders.
找到群居生活的蜘蛛是很罕见的。在我们所了解的45000种蜘蛛物种中，只有25种蜘蛛是群居生活。这些蜘蛛可以编织出巨大的网，数十只、数百只甚至数千只蜘蛛群体居住。

"When we want to count the spiders inside the colony, what we do is, somebody rips apart the colony, basically, with their hands. We call it 'making it rain,' and then dozens or hundreds of spiders basically shower down on little silken lines like little parachuters." University of California Santa Barbara arachnologist Jonathan Pruitt.
“如果我们想要计算群居地内的蜘蛛数量，我们要做的是有人要用手撕破它们的群居地。我们称之为“下雨”，然后数十或数百只蜘蛛从细绸线上纷纷降落下来，像小伞兵一样。”圣塔芭芭拉加州大学蜘蛛学家乔纳森·普瑞特说道。

He and his students study social spiders in South Africa's Kalahari Desert.After counting and weighing hundreds of African social spiders, Pruitt and his team gave each spider a personality assessment—some are bold, others shy. They wanted to understand how the personality composition of a colony influences its interactions with predators, and how the colony behaved over time.
他和他的学生们在南非卡拉哈里沙漠研究群居蜘蛛。在对数百只群居蜘蛛计数及称量之后，普瑞特和他的团队给每只蜘蛛进行个性评估——有些是大胆的，其他是害羞的。他们想了解群体的个性成分是如何影响与捕食者交互的，以及随着时间的推移，这个群体如何表现。

So the researchers combined their spiders into artificial groupings. Some of the experimental colonies were composed only of bold spiders, others of shy ones, and some had the two personality types in equal proportion. Then the researchers introduced predators to the party.
因此，研究人员对他们的蜘蛛进行人工分组。一些实验群体只由大胆的蜘蛛组成，另一实验群体由害羞及拥有双重个性的蜘蛛组成，数量上等比例。然后研究人员向群体引进捕食者。

"The most voracious predator that they deal with is this pugnacious ant, Anoplolepis steingroveri, which is this horrible ant. If you dropped one of these social spiders onto the ground, it's identified in seconds. And so these ants rip it apart and then drag it over to their colony."
它们需要应对的最贪婪的捕食者是这只好斗的蚂蚁，捷蚁，就是这只可怕的蚂蚁。如果你将其中一只群体蜘蛛扔到地面上，在数秒之内它就会被识别，然后这些蚂蚁会将它撕碎，拖到它们的群居地。

Turned out that the mixed-personality colonies were best able to learn from the repeated threat of ant raids, and build defensive nests to ward off attackers. Both the all-bold and all-shy colonies were less able to get it together enough to create their defensive structures, presumably because of too many—or not enough—leaders. The results are in the journal Animal Behaviour. [Colin M. Wright, Carl N. Keiser, & Jonathan N. Pruitt. Colony personality composition alters colony-level plasticity and magnitude of defensive behaviour in a social spider.]
结果证明，拥有混合个性的群体最有能力从反复的蚂蚁袭击威胁中吸取教训并建立防御巢，以抵御攻击。大胆的蜘蛛群体与害羞的蜘蛛群体都不太善于建造自己的防御建筑。大概是因为有太多或没有足够的领导者。该项研究结果发表在《动物行为》杂志上。

"The cool thing about social spiders is we know that they have these personality differences, and we know that societies are organized along these individual differences in behavior—actually very similar to the way that human societies are organized in a lot of ways."
关于群体蜘蛛最好玩儿的地方是我们知道它们在个性上存在差异，根据这些在行为上的个体差异可以组建群体，这在很多方面非常类似于人类社会的组建方式。

—Jason G. Goldman
Jason G. Goldman报道。