Not all warning colouration signals toxicity

[The Economist December 23rd 2017]

BRIGHT colours in the natural world are often a warning. In the case of tiger snakes, blue-ringed octopuses, arrow-poison frogs, hornets and many other species, the warning is that the animal carries toxins that will sicken or kill. Thus it was that Alfred Russel Wallace, co-inventor of the theory of natural selection and an avid in- sect collector, proposed that the beautifully coloured Pachyrhynchus weevils of east- ern Asia and Australia were dangerous.

Yet, after spending hours trying to pin the weevils onto wooden boards in his col- lection and eventually having to use a drill for the chore, he suggested that the threat the beetles were warning of with their col- ours was not poison, but the presence of body armour that would be impossible for predators to chew. Now, 150 years after Wallace proposed this idea, Chung-Ping Lin and Lu-Yi Wang of the National Taiwan Normal University, in Taipei, have tested it. They show, in a paper in the Journal of Experimental Biology, that Wallace was right.

Dr. Lin knew of Wallace’s idea and was surprised, when he conducted a literature review, to discover that it had never been tested formally. He and Ms. Wang therefore collected from the wild six Pachyrhynchus weevils and 78 specimens of an insectivorous lizard called Swinhoe’s japalure. They then ran an experiment. They used the weevils to found a breeding colony. The lizards came from a place uninhabited by Pachyrhynchus weevils, so that the reptiles could have had no prior experience of such beetles.

Each lizard was kept without food in a plastic cage for three days. It was then presented with a weevil. The lizard had three minutes to attempt to eat the beetle before it was taken away again. In some cases the weevils were two months old, an age at which their armoured exoskeleton is fully developed and hardened. In others, they were newly hatched from their pupae and their exoskeletons were still soft. A spectroscopic analysis showed, however, that all were precisely the same hue.

Half of the lizards attacked the weevil soon after it was introduced into the arena. Those that attacked a two-month-old took only one bite before spitting the insect out. All weevils so rejected survived the encounter and went on to live out the remaining two months of their lives in the comfort of Dr. Lin’s laboratory. In contrast, all of the newly hatched beetles that were attacked were crushed by the lizards’ jaws and eaten. That showed the weevils did not taste noxious. Nor did any of the beetle-consuming lizards show any subsequent signs of having been poisoned.

These findings suggested that the tough carapace was the defensive mechanism that the weevils were warning of with their colours. However, the researchers theorised that the claws the insects have at the ends of their legs, which sharpen as their body armour hardens, might also force lizards to spit them out. To check, they offered lizards weevils that had had their claws removed. It made no difference. If the weevil was a two-month-old, it got spat out. If it was a juvenile, it was devoured.

Dr. Lin and Ms. Wang did also consider the possibility that mature weevils, unlike newly hatched ones, might contain or be coated by a toxic or noxious compound. To find out, they ground some up and analysed the compounds therein using mass spectrometry and gas chromatography. This revealed nothing known to be poisonous or irritating.

The upsum, then, is that Wallace seems to have been correct. But the story does not end there. Since both edible and inedible Pachyrhynchus sport the same warning patterns, the newly hatched, soft-bodied beetles are actually sailing under false col- ours. They are, in essence, mimicking their elders. Mimicry of a dangerous animal by a harmless one is a well-known phenomenon. But this is the first known case in natural history where a harmless animal bene- fits from mimicking its future self.

文章精读：

文章简介：生物学的文章是雅思阅读最常考过的主题。本篇文章进化生物学讲了象鼻虫的警戒色，建议对生物学背景知识及词汇不甚熟悉的同学好好阅读。

Evolutionary biology

Hard to swallow

Not all warning colouration signals toxicity

[The Economist December 23rd 2017]

BRIGHT colours in the natural world are often a warning. In the case of tiger snakes, blue-ringed octopuses, arrow-poison frogs, hornets and many other species, the warning is that the animal carries toxins that will sicken or kill. Thus it was that Alfred Russel Wallace, co-inventor of the theory of natural selection and an avid insect collector, proposed that the beautifully coloured Pachyrhynchus weevils of eastern Asia and Australia were dangerous.

· toxicity n.毒性

衍生词：toxic adj.有毒的 toxin n. 毒素

e.g. Experts are concerned that the toxicity of nanoparticles to human health and the environment has not been studied extensively enough.

担心纳米颗粒对人类健康的毒性，而环境没有得到广泛的研究。

· in the case of就…来说，至于

原文例句：

In the case of tiger snakes, blue-ringed octopuses, arrow-poison frogs, hornets and many other species, the warning is that the animal carries toxins that will sicken or kill.

至于(澳洲)虎蛇，蓝环章鱼，箭毒蛙,大黄蜂以及其他物种，(它们发出的)警告是携带的会致病或要命的毒素。

· avid adj. 热衷的, 急切的

· propose v.提出 [proposal n.提议 proposition n.议题]

原文精句：

Thus it was that Alfred Russel Wallace, co-inventor of the theory of natural selection and an avid insect collector, proposed that the beautifully coloured Pachyrhynchus weevils of eastern Asia and Australia were dangerous.

因而阿尔弗雷德·罗素·华莱士—自然选择学说的共同发明者同时又是一个昆虫的热衷收集者，提出东非以及澳大利亚漂亮多彩的Pachyrhynchus象鼻虫非常危险。

注：阿尔弗雷德·罗素·华莱士(Alfred Russel Wallace)是一位英国探险家和自然主义者，他独立提出以自然选择原理来解释物种进化现象。

Yet, after spending hours trying to pin the weevils onto wooden boards in his collection and eventually having to use a drill for the chore, he suggested that thethreat the beetles were warning of with their colours was not poison, but the presence of body armour that would be impossible for predators to chew. Now, 150 years after Wallace proposed this idea, Chung-Ping Lin and Lu-Yi Wang of the National Taiwan Normal University, in Taipei, have tested it. They show, in a paper in the Journal of Experimental Biology, that Wallace was right.

· chore n. n. 家庭杂务;日常的零星事务;讨厌的或累人的工作

· threat n.威胁

· predator n.猎食者

原文精句：

Yet, after spending hours trying to pin the weevils onto wooden boards in his collection and eventually having to use a drill for the chore, he suggested that the threat the beetles were warning of with their colours was not poison, but the presence of body armour that would be impossible for predators to chew.

[此句较长，但结构比较清楚，较多地使用定语从句the threat the beetles were warning of with their colours, 红色部分为threat的定语, 以及body armour (that would be impossible forpredators to chew)括号内为body armour的定语。]

句子翻译：然而，华莱士搜集过程中在花了数小时试图将象鼻虫固定到木板并最终不得不用钻机完成这件事之后，他认为这种用作警戒的颜色并非毒液，而昆虫盔甲却让猎食者无法吃掉它们。

Dr. Lin knew of Wallace’s idea and was surprised, when he conducted a literature review, to discover that it had never been tested formally. He and Ms. Wang therefore collected from the wild six Pachyrhynchus weevils and 78 specimens of an insectivorous lizard called Swinhoe’s japalure. They then ran an experiment. They used the weevils to found a breeding colony. The lizards came from a placeuninhabited by Pachyrhynchus weevils, so that the reptiles could have had no prior experience of such beetles.

· conduct a literature review 做文献综述/回顾

原文例句：

Dr. Lin knew of Wallace’s idea and was surprised, when he conducted a literature review, to discover that it had never been tested formally.

翻译：Dr. Lin知道华莱士的观点，当他做文献综述时很吃惊地发现(华莱士的)观点从来未被正式验证过。

· insectivorous adj.食虫的

衍生词：

insectivore 食虫动物/植物

carnivore 食肉动物

herbivore 食草动物

原文例句：He and Ms. Wang therefore collected from the wild six Pachyrhynchus weevils and 78 specimens of an insectivorous lizard called Swinhoe’s japalure.

翻译：因此他以及王女士从六种野生象鼻虫以及78种叫做台湾攀蜥食草类蜥蜴的样本进行搜集。

· run an experiment 进行/开展试验

· a breeding colony 繁殖群(落)

breed v.繁殖，育种 n.品种

colony n.殖民地，聚集地;动物栖息地，群落

colonize v.〔动植物在某地〕聚居; 将…开拓为殖民地

e.g. a dead tree that has been colonized by ants

被蚂蚁占据的一棵死树

· uninhabited v. adj. 无人居住的

inhabit v.居住

habitat 栖息地

inhabitable 可居住的

原文例句：

The lizards came from a place uninhabited by Pachyrhynchus weevils, so that the reptiles could have had no prior experience of such beetles.

翻译：这些蜥蜴(台湾攀蜥)来自没有象鼻虫居住的地方，因此这些爬行动物可能还没有对付这种的虫子的经验。

Each lizard was kept without food in a plastic cage for three days. It was then presented with a weevil. The lizard had three minutes to attempt to eat the beetle before it was taken away again. In some cases the weevils were two months old, an age at which their armoured exoskeleton is fully developed and hardened. In others, they were newly hatched from their pupae and their exoskeletons were still soft. A spectroscopic analysis showed, however, that all were precisely the same hue.

· attempt v.试图

原文例句：

The lizard had three minutes to attempt to eat the beetle before it was taken away again.

翻译：蜥蜴有三分钟时间尝试在虫子被拿走之前吃掉它。

· exoskeleton n.外骨骼

exo- 外部的

· hatch v.孵化

· pupae n.蛹

原文例句：

In others, they were newly hatched from their pupae and their exoskeletons were still soft.

在其他情况下，它们(象鼻虫)刚刚从蛹中孵化出来，外骨骼还很柔软。

· spectroscopic adj. 光谱学的

spectro-光谱

Half of the lizards attacked the weevil soon after it was introduced into the arena. Those that attacked a two-month-old took only one bite before spitting the insectout. All weevils so rejected survived the encounter and went on to live out the remaining two months of their lives in the comfort of Dr. Lin’s laboratory. In contrast, all of the newly hatched beetles that were attacked were crushed by the lizards’ jaws and eaten. That showed the weevils did not taste noxious. Nor did any of the beetle-consuming lizards show any subsequent signs of having been poisoned.

· spit sth. out

原文例句：

Those that attacked a two-month-old took only one bite before spitting the insect out.

翻译：那些攻击两个月大甲虫的蜥蜴只咬了一口就把它们吐了出来。

· in the comfort of 舒适地

· crush v.压碎，弄碎

原文例句：

In contrast, all of the newly hatched beetles that were attacked were crushed by the lizards’ jaws and eaten.

翻译：与此相反，所有被(蜥蜴)攻击刚孵化的甲虫都被蜥蜴咬碎吃掉了。

· noxious adj.有毒的

innocuous adj.无毒的

· subsequent adj.随后的

sequent adj.连续的

sequence n.顺序

原文例句：

Nor did any of the beetle-consuming lizards show any subsequent signs of having been poisoned.

翻译：这些食虫蜥蜴随后也没有中毒的迹象。

These findings suggested that the tough carapace was the defensive mechanism that the weevils were warning of with their colours. However, the researchers theorised that the claws the insects have at the ends of their legs, which sharpen as their body armour hardens, might also force lizards to spit them out. To check, they offered lizards weevils that had had their claws removed. It made no difference. If the weevil was a two-month-old, it got spat out. If it was ajuvenile, it was devoured.

· tough adj.坚固的，坚强的，艰苦的

· defensive mechanism 防御机制

原文例句：

These findings suggested that the tough carapace was the defensive mechanism that the weevils were warning of with their colours.

翻译：这些发现表明坚硬的外壳是象鼻虫的防御机制—它们用颜色来警告(猎食者)。

· theorise v.理论化，创立理论

· sharpen v.变锋利

原文精句：

However, the researchers theorised that the claws the insects have at the ends of their legs, which sharpen as their body armour hardens, might also force lizards to spit them out.

然而，研究人员的理论是昆虫腿末端的爪--随着身体盔甲变硬而锋利--可能也会迫使蜥蜴将它们吐出来。

· juvenile n.幼年;未成年人 adj. [鸟或动物]幼小的; 未成年的

Dr. Lin and Ms. Wang did also consider the possibility that mature weevils, unlike newly hatched ones, might contain or be coated by a toxic or noxious compound.To find out, they ground some up and analysed the compounds therein using massspectrometry and gas chromatography. This revealed nothing known to be poisonous or irritating.

· compound n.化合物

原文精句：

Dr. Lin and Ms. Wang did also consider the possibility that mature weevils, unlike newly hatched ones, might contain or be coated by a toxic or noxious compound.

翻译：林博士和王女士确实也考虑了一种可能性，即不像新孵化的幼虫，成年象鼻虫可能会含有或者被覆盖着有毒物质。

· spectrometry n.光谱测定

· chromatography色谱法

chromo- 颜色

· irritating adj.刺激性的;令人恼火的

The upsum, then, is that Wallace seems to have been correct. But the story does not end there. Since both edible and inedible Pachyrhynchus sport the same warning patterns, the newly hatched, soft-bodied beetles are actually sailing under false colours. They are, in essence, mimicking their elders. Mimicry of a dangerous animal by a harmless one is a well-known phenomenon. But this is the first known case in natural history where a harmless animal benefits from mimicking its future self.

· upsum n.结论

· sport v.炫耀，展示

· sail under false colours 冒充(衍生意思为欺世盗名，挂羊头卖狗肉)

原文精句：

Since both edible and inedible Pachyrhynchus sport the same warning patterns, the newly hatched, soft-bodied beetles are actually sailing under false colours.

翻译：由于可食用的和不可食用的Pachyrhynchus象鼻虫都是同样一个警戒色，新孵化出来的身体柔软的甲虫们实际上是在冒充(成虫)。

· in essence 本质上

· mimic v.模仿

· mimicry n.模拟，拟态

· benefit from 从…获益

原文例句：

But this is the first known case in natural history where a harmless animal benefits from mimicking its future self.

但这是自然史中所知的无毒的动物从模仿未来自己样子获益的例。

本文作者简介：

王少娟

上海新航道雅思主讲，上海外国语大学教育技术学硕士。对综合英语的阅读教学有深入的研究，教授了数百名学生均取得了优异的英语成绩。讲解细致、逻辑清晰、课堂活跃，丰富的教学经验能帮助学生在学习中和练习中能够更有效的提高英语能力。