某雌性海蜗牛可隐藏性别信息
文章来源:未知 文章作者:meng 发布时间:2010-09-14 03:31 字体: [ ]  进入论坛
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Sexual conflict is not only a human phenomenon. Scientists at the University of Gothenburg have shown that females of the rough periwinkle(玉黍螺) conceal1 their gender2 identity in order to avoid excessive copulation(交配,交尾) . The females of most species of snail3 excrete(排泄,分泌) a substance in their mucous4(黏液的) trails that enables males to find them more easily, since they can distinguish between trails from females and those from other males. The males follow the mucous trails laid down by females in order to find a partner for mating. However, the females of one of the species studied (Littorina saxatilis) have stopped labelling their mucous trails.

Males must search twice as long

"The consequence of this for the females is that they copulate less frequently, since the males often follow the trails of other males and must therefore spend twice as long looking for a female. This may appear strange at first sight, since we expect it to be in the females' interests to mate. But we show that copulation is costly5 for the females and that they already achieve more copulation than is required to fertilise all of their eggs", says Kerstin Johannesson, professor of marine6 ecology.

Scientists at Tjärnö have shown in a previous study that a snail may carry offspring that result from copulation with at least 20 males.

Less sex is beneficial for the females

The scientists have now been able to show that evolution has favoured those females who can conceal their gender identity. Females who can mask their trails copulate significantly less often than other females and thus have a greater chance of surviving.

"It is beneficial for males to mate as often as possible, since this is the only way in which they can influence the number of offspring they father. But it is costly for the females to mate often, and this is important for them in surviving during the period they are carrying offspring."

A situation in which individuals of different gender have conflicting interests is known as a "sexual conflict". Such conflicts can arise in various situations, and this is one of few examples of a sexual conflict in which the females attempt to conceal their gender. There are some other examples, including certain species of damselfly(豆娘) in which some of the females conceal their gender, simply by having the same colouring as the males.

The study of the remarkable7 behaviour of the rough periwinkle has been carried out by Kerstin Johannesson in collaboration8 with Sara Saltin, Iris9 Duranovic, Jon Havenhand and Per Jonsson at the Department of Marine Ecology, University of Gothenburg.



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1 conceal DpYzt     
v.隐藏,隐瞒,隐蔽
参考例句:
  • He had to conceal his identity to escape the police.为了躲避警方,他只好隐瞒身份。
  • He could hardly conceal his joy at his departure.他几乎掩饰不住临行时的喜悦。
2 gender slSyD     
n.(生理上的)性,(名词、代词等的)性
参考例句:
  • French differs from English in having gender for all nouns.法语不同于英语,所有的名词都有性。
  • Women are sometimes denied opportunities solely because of their gender.妇女有时仅仅因为性别而无法获得种种机会。
3 snail 8xcwS     
n.蜗牛
参考例句:
  • Snail is a small plant-eating creature with a soft body.蜗牛是一种软体草食动物。
  • Time moved at a snail's pace before the holidays.放假前的时间过得很慢。
4 mucous S6XzD     
adj. 黏液的,似黏液的
参考例句:
  • Healthy,skin,mucous membranes,and cilia are natural barriers to many viruses.健康的皮肤,粘膜和纤毛是许多病毒的天然屏障。
  • Seromucous glands contain both mucous and serous cells.浆粘液腺既含有粘液性细胞,又含有浆液性细胞。
5 costly 7zXxh     
adj.昂贵的,价值高的,豪华的
参考例句:
  • It must be very costly to keep up a house like this.维修这么一幢房子一定很昂贵。
  • This dictionary is very useful,only it is a bit costly.这本词典很有用,左不过贵了些。
6 marine 77Izo     
adj.海的;海生的;航海的;海事的;n.水兵
参考例句:
  • Marine creatures are those which live in the sea. 海洋生物是生存在海里的生物。
  • When the war broke out,he volunteered for the Marine Corps.战争爆发时,他自愿参加了海军陆战队。
7 remarkable 8Vbx6     
adj.显著的,异常的,非凡的,值得注意的
参考例句:
  • She has made remarkable headway in her writing skills.她在写作技巧方面有了长足进步。
  • These cars are remarkable for the quietness of their engines.这些汽车因发动机没有噪音而不同凡响。
8 collaboration bW7yD     
n.合作,协作;勾结
参考例句:
  • The two companies are working in close collaboration each other.这两家公司密切合作。
  • He was shot for collaboration with the enemy.他因通敌而被枪毙了。
9 iris Ekly8     
n.虹膜,彩虹
参考例句:
  • The opening of the iris is called the pupil.虹膜的开口处叫做瞳孔。
  • This incredible human eye,complete with retina and iris,can be found in the Maldives.又是在马尔代夫,有这样一只难以置信的眼睛,连视网膜和虹膜都刻画齐全了。
TAG标签: species gender copulation
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