18 Mimicry by Female Insects only

But there is yet another series of phenomena¹ connected with this subject, which considerably² strengthens the view here adopted, while it seems quite incompatible³ with either of the other hypotheses; namely, the relation of protective colouring and mimicry⁴ to the sexual differences of animals. It will be clear to every one that if two animals, which as regards “external conditions” and “hereditary descent,” are exactly alike, yet differ remarkably⁵ in colouration, one resembling a protected species and the other not, the resemblance that exists in one only can hardly be imputed⁷ to the influence of external conditions or as the effect of heredity. And if, further, it can be proved that the one requires protection more than the other, and that in several cases it is that one which mimics⁸ the protected species, while the one that least requires protection never does so, it will afford very strong corroborative⁹ evidence that there is a real connexion between the necessity for protection and the phenomenon of mimicry. Now the sexes of insects offer us a test of the nature here indicated, and appear to furnish one of the most conclusive¹⁰ arguments in favour of the theory that the phenomena termed “mimicry” are produced by natural selection.

The comparative importance of the sexes varies much in different classes of animals. In the higher vertebrates, where the number of young produced at a birth is small and the same individuals breed many years in succession, the preservation¹¹ of both sexes is almost equally important. In all the numerous cases in which the male protects the female and her offspring, or helps to supply them with food, his importance in the economy of nature is proportionately increased, though it is never perhaps quite equal to that of the female. In insects the case is very different; they pair but once in their lives, and the prolonged existence of the male is in most cases quite unnecessary for the continuance of the race. The female, however, must continue to exist long enough to deposit her eggs in a place adapted for the development and growth of the progeny¹². Hence there is a wide difference in the need for protection in the two sexes; and we should, therefore, expect to find that in some cases the special protection given to the female was in the male less in amount or altogether wanting. The facts entirely¹³ confirm this expectation. In the spectre insects (Phasmid?) it is often the females alone that so strikingly resemble leaves, while the males show only a rude approximation. The male Diadema misippus is a very handsome and conspicuous¹⁴ butterfly, without a sign of protective or imitative colouring, while the female is entirely unlike her partner, and is one of the most wonderful cases of mimicry on record, resembling most accurately¹⁵ the common Danais chrysippus, in whose company it is often found. So in several species of South American Pieris, the males are white and black, of a similar type of colouring to our own “cabbage” butterflies, while the females are rich yellow and buff, spotted¹⁶ and marked so as exactly to resemble species of Heliconid? with which they associate in the forest. In the Malay archipelago is found a Diadema which had always been considered a male insect on account of its glossy¹⁷ metallic-blue tints¹⁸, while its companion of sober brown was looked upon as the female. I discovered, however, that the reverse is the case, and that the rich and glossy colours of the female are imitative and protective, since they cause her exactly to resemble the common Euploea midamus of the same regions, a species which has been already mentioned in this essay as mimicked¹⁹ by another butterfly, Papilio paradoxa. I have since named this interesting species Diadema anomala (see the Transactions of the Entomological Society, 1869, p. 285). In this case, and in that of Diadema misippus, there is no difference in the habits of the two sexes, which fly in similar localities; so that the influence of “external conditions” cannot be invoked²⁰ here as it has been in the case of the South American Pieris pyrrha and allies, where the white males frequent open sunny places, while the Heliconia-like females haunt the shades of the forest.

We may impute⁶ to the same general cause (the greater need of protection for the female, owing to her weaker flight, greater exposure to attack, and supreme²¹ importance)— the fact of the colours of female insects being so very generally duller and less conspicuous than those of the other sex. And that it is chiefly due to this cause rather than to what Mr. Darwin terms “sexual selection” appears to be shown by the otherwise inexplicable²² fact, that in the groups which have a protection of any kind independent of concealment²³, sexual differences of colour are either quite wanting or slightly developed. The Heliconid? and Danaid?, protected by a disagreeable flavour, have the females as bright and conspicuous as the males, and very rarely differing at all from them. The stinging Hymenoptera have the two sexes equally well coloured. The Carabid?, the Coccinellid?, Chrysomelid?, and the Telephori have both sexes equally conspicuous, and seldom differing in colours. The brilliant Curculios, which are protected by their hardness, are brilliant in both sexes. Lastly, the glittering Cetoniad? and Buprestid?, which seem to be protected by their hard and polished coats, their rapid motions, and peculiar²⁴ habits, present few sexual differences of colour, while sexual selection has often manifested itself by structural²⁵ differences, such as horns, spines²⁶, or other processes.

1 phenomena   

n.现象

参考例句：

• Ade couldn't relate the phenomena with any theory he knew.艾德无法用他所知道的任何理论来解释这种现象。
• The object of these experiments was to find the connection,if any,between the two phenomena.这些实验的目的就是探索这两种现象之间的联系，如果存在着任何联系的话。

2 considerably   

adv.极大地；相当大地；在很大程度上

参考例句：

• The economic situation has changed considerably.经济形势已发生了相当大的变化。
• The gap has narrowed considerably.分歧大大缩小了。

3 incompatible   

adj.不相容的，不协调的，不相配的

参考例句：

• His plan is incompatible with my intent.他的计划与我的意图不相符。
• Speed and safety are not necessarily incompatible.速度和安全未必不相容。

4 mimicry   

n.（生物）拟态，模仿

参考例句：

• One of his few strengths was his skill at mimicry.他为数不多的强项之一就是善于模仿。
• Language learning usually necessitates conscious mimicry.一般地说，学习语言就要进行有意识的摹仿。

5 remarkably   

ad.不同寻常地，相当地

参考例句：

• I thought she was remarkably restrained in the circumstances. 我认为她在那种情况下非常克制。
• He made a remarkably swift recovery. 他康复得相当快。

6 impute   

v.归咎于

参考例句：

• I impute his failure to laziness.我把他的失败归咎于他的懒惰。
• It is grossly unfair to impute blame to the United Nations.把责任归咎于联合国极其不公。

7 imputed   

v.把（错误等）归咎于( impute的过去式和过去分词 )

参考例句：

• They imputed the accident to the driver's carelessness. 他们把这次车祸归咎于司机的疏忽。 来自《现代英汉综合大词典》
• He imputed the failure of his marriage to his wife's shortcomings. 他把婚姻的失败归咎于妻子的缺点。 来自辞典例句

8 mimics   

n.模仿名人言行的娱乐演员，滑稽剧演员( mimic的名词复数 )；善于模仿的人或物v.（尤指为了逗乐而）模仿( mimic的第三人称单数 )；酷似

参考例句：

• Methods:Models were generate by CT scan,Mimics software and Abaqus software. 方法：采用CT扫描，Mimics软件和Abaqus软件的CAD进行三维有限元模型的创建。 来自互联网
• Relaxing the mind and body mimics the effect that some blood-pressure pills would have. 放松身心会产生某些降压药才能产生的效果。 来自辞典例句

9 corroborative   

adj.确证（性）的，确凿的

参考例句：

• Is there any corroborative evidence for this theory? 是否有进一步说明问题的论据来支持这个理论？
• They convicted the wrong man on the basis of a signed confession with no corroborative evidence. 凭一张有签名的认罪书而没有确凿的佐证，他们就错误地判了那人有罪。 来自《简明英汉词典》

10 conclusive   

adj.最后的，结论的；确凿的，消除怀疑的

参考例句：

• They produced some fairly conclusive evidence.他们提供了一些相当确凿的证据。
• Franklin did not believe that the French tests were conclusive.富兰克林不相信这个法国人的实验是结论性的。

11 preservation   

n.保护，维护，保存，保留，保持

参考例句：

• The police are responsible for the preservation of law and order.警察负责维持法律与秩序。
• The picture is in an excellent state of preservation.这幅画保存得极为完好。

12 progeny   

n.后代，子孙；结果

参考例句：

• His numerous progeny are scattered all over the country.他为数众多的后代散布在全国各地。
• He was surrounded by his numerous progeny.众多的子孙簇拥着他。

13 entirely   

ad.全部地，完整地；完全地，彻底地

参考例句：

• The fire was entirely caused by their neglect of duty. 那场火灾完全是由于他们失职而引起的。
• His life was entirely given up to the educational work. 他的一生统统献给了教育工作。

14 conspicuous   

adj.明眼的，惹人注目的；炫耀的，摆阔气的

参考例句：

• It is conspicuous that smoking is harmful to health.很明显，抽烟对健康有害。
• Its colouring makes it highly conspicuous.它的色彩使它非常惹人注目。

15 accurately   

adv.准确地，精确地

参考例句：

• It is hard to hit the ball accurately.准确地击中球很难。
• Now scientists can forecast the weather accurately.现在科学家们能准确地预报天气。

16 spotted   

adj.有斑点的，斑纹的，弄污了的

参考例句：

• The milkman selected the spotted cows,from among a herd of two hundred.牛奶商从一群200头牛中选出有斑点的牛。
• Sam's shop stocks short spotted socks.山姆的商店屯积了有斑点的短袜。

17 glossy   

adj.平滑的；有光泽的

参考例句：

• I like these glossy spots.我喜欢这些闪闪发光的花点。
• She had glossy black hair.她长着乌黑发亮的头发。

18 tints   

色彩( tint的名词复数 )； 带白的颜色； （淡色）染发剂； 痕迹

参考例句：

• leaves with red and gold autumn tints 金秋时节略呈红黄色的树叶
• The whole countryside glowed with autumn tints. 乡间处处呈现出灿烂的秋色。

19 mimicked   

v.（尤指为了逗乐而）模仿( mimic的过去式和过去分词 )；酷似

参考例句：

• He mimicked her upper-class accent. 他模仿她那上流社会的腔调。 来自辞典例句
• The boy mimicked his father's voice and set everyone off laughing. 男孩模仿他父亲的嗓音，使大家都大笑起来。 来自辞典例句

20 invoked   

v.援引( invoke的过去式和过去分词 )；行使（权利等）；祈求救助；恳求

参考例句：

• It is unlikely that libel laws will be invoked. 不大可能诉诸诽谤法。
• She had invoked the law in her own defence. 她援引法律为自己辩护。 来自《简明英汉词典》

21 supreme   

adj.极度的，最重要的；至高的，最高的

参考例句：

• It was the supreme moment in his life.那是他一生中最重要的时刻。
• He handed up the indictment to the supreme court.他把起诉书送交最高法院。

22 inexplicable   

adj.无法解释的，难理解的

参考例句：

• It is now inexplicable how that development was misinterpreted.当时对这一事态发展的错误理解究竟是怎么产生的，现在已经无法说清楚了。
• There are many things which are inexplicable by science.有很多事科学还无法解释。

23 concealment   

n.隐藏, 掩盖，隐瞒

参考例句：

• the concealment of crime 对罪行的隐瞒
• Stay in concealment until the danger has passed. 把自己藏起来，待危险过去后再出来。

24 peculiar   

adj.古怪的，异常的；特殊的，特有的

参考例句：

• He walks in a peculiar fashion.他走路的样子很奇特。
• He looked at me with a very peculiar expression.他用一种很奇怪的表情看着我。

25 structural   

adj.构造的，组织的，建筑（用）的

参考例句：

• The storm caused no structural damage.风暴没有造成建筑结构方面的破坏。
• The North American continent is made up of three great structural entities.北美大陆是由三个构造单元组成的。

26 spines   

n.脊柱( spine的名词复数 )；脊椎；（动植物的）刺；书脊

参考例句：

• Porcupines use their spines to protect themselves. 豪猪用身上的刺毛来自卫。
• The cactus has spines. 仙人掌有刺。 来自《现代英汉综合大词典》