评论
打印
Funnel-web spiders have a fearsome reputation. People bitten by these Australian arachnids suffer extreme pain,
漏斗网蜘蛛有着一个可怕的名声。被这些澳大利亚蛛形纲动物叮咬过的人都会出现极度疼痛、
breathing problems, confusion, convulsions and dangerously high blood pressure. Left untreated, the venom can kill within hours.
呼吸困难、精神混乱、抽搐和高危血压的症状。如果不进行治疗，毒液可以在数小时内致命。
For years, researchers assumed this lethal effect was an evolutionary accident.
多年来，研究人员一直认为这种杀伤作用是进化的意外。
The venom, they presumed, evolved to help the spiders kill their prey— normally insects.
他们推测这些毒液的进化是为了帮助蜘蛛杀死它们的猎物——通常是昆虫。
Killing mammals was either just collateral damage or a form of protection against possible predators.
杀死哺乳类动物要么只是一种附带损伤，要么是一种防御潜在捕食者的形式。
Except that the venom does not, in general, kill mammals. Dogs, cats, mice, rabbits and guinea pigs all shake it off.
不过，这种毒液一般不会杀死哺乳动物。狗、猫、老鼠、兔子和豚鼠都会把它给抖掉。
It is only human beings and other primates that succumb. And there is another odd thing about it.
受到伤害的只有人类和其他灵长类动物。还有另一件奇怪的事情。
Funnel-web-spider venom has thousands of components, but delta-hexatoxins, the specific molecules within it that kill people,
漏斗网蜘蛛的毒液中含有数千种成分，但delta-hexatoxins，毒液中的这种致人死亡的特殊分子
are produced in particularly large quantities by sexually mature males during the breeding season—a time when they are barely feeding at all.
由在繁殖期性成熟的雄性蜘蛛大量生产——在此期间，它们几乎不进食。
Putting these various facts together has led Bryan Fry of the University of Queensland to suggest,
所有这些事实让昆士兰大学的Bryan Fry在发表于《Proceedings of the National Academy of Sciences》
in a paper published in the Proceedings of the National Academy of Sciences,
的一篇论文中提出了这样的观点，
that the role of delta-hexatoxins in funnel-web venom is not to kill prey but rather as a sophisticated form of defence—
在漏斗网蜘蛛的毒液中，delta-hexatoxins的作用不是杀死猎物，而是充当着一种复杂的防御形式——
and that, paradoxically, its deadliness to humans is because neither they nor their primate ancestors were, until recently, a threat to the spiders.
奇怪的是，它们对人类的致命性，既不是因为他们，也不是因为他们的灵长类动物祖先对蜘蛛构成了威胁。
Prey animals routinely attacked by venomous predators are under powerful pressure from natural selection.
经常被有毒捕食者袭击的猎物都承受着来自自然选择的巨大压力。
Any mutation which confers resistance to the venom will spread. This puts evolutionary pressure back onto the predator,
任何能抵抗毒液的突变都会扩散。这给捕食者带来了进化压力，
encouraging the emergence of more potent venoms, which encourages further resistance and provokes further potency.
鼓励了更强效毒液的出现，从而进一步鼓励其耐药性，激发更强的效力。
And so on. Toxins directed against prey thus evolve rapidly.
等等。因此针对猎物的毒素迅速进化。
That, though, is not true for defensive venoms. Taking a single type of spider off its menu
然而，防御性毒液却不是这样。将一种类型的蜘蛛除名
diminishes a predator's potential to survive and reproduce only slightly.
只会略微降低捕食者生存和繁殖的潜力。
译文由可可原创，仅供学习交流使用，未经许可请勿转载。
