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Funnel-web spiders have a fearsome reputation. People bitten by these Australian arachnids suffer extreme pain,
漏斗網蜘蛛有著一個可怕的名聲。被這些澳大利亞蛛形綱動物叮咬過的人都會出現極度疼痛、
breathing problems, confusion, convulsions and dangerously high blood pressure. Left untreated, the venom can kill within hours.
呼吸困難、精神混亂、抽搐和高危血壓的癥狀。如果不進行治療，毒液可以在數小時內致命。
For years, researchers assumed this lethal effect was an evolutionary accident.
多年來，研究人員一直認為這種殺傷作用是進化的意外。
The venom, they presumed, evolved to help the spiders kill their prey— normally insects.
他們推測這些毒液的進化是為了幫助蜘蛛殺死它們的獵物——通常是昆蟲。
Killing mammals was either just collateral damage or a form of protection against possible predators.
殺死哺乳類動物要么只是一種附帶損傷，要么是一種防御潛在捕食者的形式。
Except that the venom does not, in general, kill mammals. Dogs, cats, mice, rabbits and guinea pigs all shake it off.
不過，這種毒液一般不會殺死哺乳動物。狗、貓、老鼠、兔子和豚鼠都會把它給抖掉。
It is only human beings and other primates that succumb. And there is another odd thing about it.
受到傷害的只有人類和其他靈長類動物。還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,
漏斗網蜘蛛的毒液中含有數千種成分，但delta-hexatoxins，毒液中的這種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產——在此期間，它們幾乎不進食。
Putting these various facts together has led Bryan Fry of the University of Queensland to suggest,
所有這些事實讓昆士蘭大學的Bryan Fry在發表于《Proceedings of the National Academy of Sciences》
in a paper published in the Proceedings of the National Academy of Sciences,
的一篇論文中提出了這樣的觀點，
that the role of delta-hexatoxins in funnel-web venom is not to kill prey but rather as a sophisticated form of defence—
在漏斗網蜘蛛的毒液中，delta-hexatoxins的作用不是殺死獵物，而是充當著一種復雜的防御形式——
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，它們對人類的致命性，既不是因為他們，也不是因為他們的靈長類動物祖先對蜘蛛構成了威脅。
Prey animals routinely attacked by venomous predators are under powerful pressure from natural selection.
經常被有毒捕食者襲擊的獵物都承受著來自自然選擇的巨大壓力。
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變都會擴散。這給捕食者帶來了進化壓力，
encouraging the emergence of more potent venoms, which encourages further resistance and provokes further potency.
鼓勵了更強效毒液的出現，從而進一步鼓勵其耐藥性，激發更強的效力。
And so on. Toxins directed against prey thus evolve rapidly.
等等。因此針對獵物的毒素迅速進化。
That, though, is not true for defensive venoms. Taking a single type of spider off its menu
然而，防御性毒液卻不是這樣。將一種類型的蜘蛛除名
diminishes a predator's potential to survive and reproduce only slightly.
只會略微降低捕食者生存和繁殖的潛力。
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