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Science and Technology Animal behaviour Sexual appetite
科技 動物行為 欲壑難填
Being a male spider is even more dangerous than previously thought
雄性蜘蛛遭遇的險境遠遠超乎人們之前的想象
FOR male spiders, the equivalent of a post-coital cigarette is not a sensible option.
對于雄性蜘蛛而言，交配過后悠閑地吸上一口美煙可不是什么明智的選擇。
Making straight for the door is much wiser, since he who hangs around risks being eaten by his consort.
拍拍屁股直接走人才是更為聰明的做法，因為自己隨時可能成為性伴侶的口食。
In this context, the females of Leucauge argyra, a Central American species, are particularly fiendish.
中美洲有種雌性長角銀腹蛛，其兇殘至極的個性就是上述情況的最好體現。
They seem to have subverted a male trick that is intended to ensure paternity rights, and turned it into a trap.
她們似乎在顛覆雄性蜘蛛欲掌父權而慣用的伎倆并將這種伎倆變成溫柔的陷阱。
Many animals—not just spiders—make plugs of mucus to seal the female's orifice after mating.
包括蜘蛛在內的許多動物都會制作一種封堵粘液，以便交配之后將雌性伴侶的生殖管道封閉。
Normally such plugs are secreted by the male, to stymie subsequent suitors.
通常情況下，這種粘液由雄性分泌，以此阻斷其它狂蜂浪碟的追求欲念。
In spiders, though, the female sometimes assists the process.
但就蜘蛛而言，雌性蜘蛛有時也會協助這個過程。
At first sight, that is odd.
乍看上去，這是種奇怪的現象。
It is always in a male's interest to try to stop a female mating again.
試圖阻止雌性蜘蛛再次交配通常是對雄性蜘蛛有利的事情。
Contrariwise, that female might come across a better male and thus wish to be rid of the first lot of sperm. (Female spiders can do this because they store sperm for a period of days or weeks before they use it to fertilise their eggs.)
但反過來看，雌性蜘蛛也可能會遇到更好的雄性伴侶，因此就會打算拋棄前夫的精液（雌性蜘蛛之所以能這樣做是因為她們能將精液存留數日或幾周的時間，然后決定是否用其對卵子受精）。
After studying this phenomenon for several years, Anita Aisenberg of the Clemente Estable Institute of Biological Research in Uruguay has concluded that females are able to assess a male's quality during mating and that they assist plug formation only when a mate passes muster and they thus wish to give his sperm priority.
烏拉圭Clemente Estable生物研究所的Anita Aisenberg對此現象潛心研究幾年后得出結論，雌性蜘蛛在交配過程中能夠評估雄性蜘蛛的質素，只有被雌性蜘蛛認可了的雄性蜘蛛才可能協助他封堵自己的生殖管道并優先采用其精液受孕。
Which makes sense.
這種解釋是有道理的。
In a paper just published in Naturwissenschaften, though, Dr Aisenberg and her colleague Gilbert Barrantes at the University of Costa Rica report that female Leucauge argyra go further: they create plugs all by themselves.
但Aisenberg博士與她的哥斯達黎加大學同事Gilbert Barrantes在《自然科學》雜志上新發表的論文指出："長角銀腹"雌性蜘蛛還有一手更絕妙的高招：她們能自行分泌封堵粘液。
And that really is odd.
這就真的讓人覺得奇怪了。
Because plugging is in a male's interest, he should never leave it just to the female.
因為封堵行為是對雄性蜘蛛有利的事情，他怎么會將這種特權拱手讓給雌性蜘蛛單獨完成呢？
Except that in this case the plug turns out to be very much not in a male's interest.
除非有這種情況出現，即封堵行為會對雄性蜘蛛有非常不利的影響。
In fact, it can kill him.
事實上，這種讓權造就了雄性蜘蛛的死亡。
Spider sex is unusual in that males transfer their sperm to the female on small limbs called pedipalps.
蜘蛛的交配方式與眾不同，雄性蜘蛛利用稱做"須肢"的小肢干將精液輸送給雌性蜘蛛。
They use these to pick their sperm up from their genitals and insert it into the female's sexual orifice, rather than copulating directly.
雄性蜘蛛先用"須肢"將精液從生殖器中取出再將其插入到雌性蜘蛛的性器官內，而不是采用直接交配方式。
Dr Aisenberg and Dr Barrantes observed the process 17 times in pairs of Leucauge argyra.
isenberg博士和Barrantes博士觀察了17對長角銀腹蛛的交配過程。
On the 14 occasions a sexual plug was made, the female produced it without assistance from the male.
A在14例交配過程中，雌性蜘蛛在未借助雄性蜘蛛幫助的情況下自己了分泌封閉粘液。
On ten of these occasions the male's pedipalps then seemed to get stuck while he was transferring the sperm (which is rarely the case in other species of spider), and he had great difficulty freeing
這14例交配中出現10例雄性蜘蛛在輸送精液時，"須肢"似乎被卡在了雌性蜘蛛的性器官內（此情況在其它種類蜘蛛身上極少發生），使他難以掙脫。
In two of those ten instances, he was eaten as a result.
10例中有2例以雄性蜘蛛被吃掉而告終。
The two researchers conclude, therefore, that what was once a mechanism which allowed females to discriminate between males has evolved into a way of trapping them so that they can be consumed at leisure.
因此兩位研究人員得出結論，雌性蜘蛛過去用來判別雄性蜘蛛質素的機制已經演化成"誘騙"他們的手段，并從容地吃掉被誘騙的雄性蜘蛛。
Whether only high-quality males, whose sperm the female also wishes to keep, are affected is not yet clear—though eating such males may bring the bonus of denying their sperm to rivals.
是否只有高質素的雄性蜘蛛（雌性蜘蛛愿意留存它們的精液）才會受到影響，目前尚沒有定論—但是雌性蜘蛛吃掉她們的伴侶可以防止這些雄性蜘蛛將精液輸送到她們的情敵手中。
Whatever the details, for male Leucauge argyra this behaviour gives a new meaning to the term "unsafe sex".
無論事情的來龍去脈如何，對于雄性長角銀腹蛛而言，這種行為都給"危險性交"賦予了新的含義。
