Science and technology

　　科学技术

　　Animal behaviour

　　动物行为

　　Drip-feeding

　　滴定进食

　　Ecology raids the techniques of chemistry

　　生态学里应用上了化学技术。

　　Time to change restaurant

　　该换家馆子了。

　　BIOLOGISTS are sometimes accused of physics envy―and there is truth in this accusation .

　　生物学家们常常被认为非常嫉妒研究物理学的人。

　　The essential fuzziness of biological systems can never be captured by the precise, mathematically based experiments of something like the Large Hadron Collider.

　　他们永远不可能通过像大型强子加速碰撞那样精确、量化的实验来揭示生物学里的一些关键性的奥秘。

　　Between physics and biology on the spectrum of fuzziness, though, lies chemistry.

　　但是在这种奥秘的“两极”―物理学和生物学之间还有化学。

　　And a group of researchers led by Carolyn Nersesian of the University of Sydney has just borrowed one of chemistry’s most elegant techniques, titration, to answer a pressing ecological question: how do animals choose where to feed?

　　最近由悉尼大学的卡洛琳?涅尔谢相带领的一组研究人员借用化学里一种非常精妙的技术―滴定法来解决一个迫待回答的问题：动物们如何选择觅食场所。

　　Titration, to remind those who dozed through their chemistry lessons, is a way of working out the concentration of a substance in a solution.

　　滴定法是一种计算溶质在溶液中的浓度的方法。

　　A reagent of known concentration is dripped into the unknown solution in the presence of an appropriate indicator molecule.

　　在某种特定的指示分子的参与下，将一种已知浓度的溶液滴到未知溶液中。

　　When the tipping point comes, and all of the unknown reagent has reacted, the solution changes colour.

　　当滴定终点到来时，所有的未知溶液全都完成了化学反应，溶液的颜色就会发生变化。

　　The unknown concentration can then be calculated from the amount of known reagent used.

　　然后未知溶液的浓度就可以通过被消耗掉的已知溶液的体积计算出来。

　　In Dr Nersesian’s titration the litmus was a species called the brushtail possum. The two reagents were predators and poisons.

　　涅尔谢相博士的滴定实验中的“石蕊指示剂”是一种叫帚尾袋貂的动物。那两种溶液是“猎食者”和“有毒物”。

　　In the wild, possums feed mainly on eucalyptus trees.

　　在野生环境下，袋貂主要以桉树叶为食。

　　Feeding in trees this way also keeps them safe from ground-based predators, such as foxes.

　　生活在树上也能让它们安全地远离地面上的那些猎食者―例如狐狸。

　　They frequently have to shift from tree to tree in search of non-poisonous leaves, though, because a tree that is being browsed starts manufacturing toxins.

　　但是他们还得经常从一棵树上换到另一棵树上去寻找那些没有毒的叶子。因为一颗树如果被它们吃久了就会自动分泌毒素。

　　Dr Nersesian reasoned that there is probably a measurable point at which a plant becomes so toxic that possums prefer to take their chances with the predators on the ground―and she realised this was a perfect opportunity to do an ecological titration.

　　涅尔谢相博士认为可能当植物中的毒素达到一个量值的时候，袋貂会选择冒着被猎食的风险，然后她就意识到这是一个应用生态滴定法绝好的机会。

　　As she reports in the Journal of Animal Ecology, she attempted to imitate the distinction between trees and ground by giving eight possums the opportunity to feed in either of two enclosures.

　　她发表在动物生态学报上报告中写道：她通过给8只袋貂两种桉树来选择觅食来模拟树上和地面的区别。