七彩神仙鱼像哺乳动物般养育幼鱼
文章来源:未知 文章作者:meng 发布时间:2010-10-31 02:01 字体: [ ]  进入论坛
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Few fish are famed for their parenting skills. Most species leave their freshly hatched fry(鱼苗) to fend1 for themselves, but not discus fish(七彩神仙鱼) . Jonathan Buckley from the University of Plymouth, UK, explains that discus fish young feed on the mucus(黏液) that their parents secrete2(藏匿) over their bodies until they are big enough to forage3. 'The parental4 care that they exhibit is very unusual,' says Buckley. Intrigued5 by the fish's lifestyle, Buckley's PhD advisor6, Katherine Sloman, established a collaboration7 with Adalberto Val from the Laboratory of Ecophysiology and Molecular8 Evolution in Manaus, Brazil, and together with Buckley and Richard Maunder set up a colony of breeding discus fish to find out more about their strange behaviour. The team published their discovery, funded by the Leverhulme Trust, that discus fish parent their young like mammalian mothers on 29 October 2010 in The Journal of Experimental Biology at http://jeb.biologists.org/cgi/content/abstract/213/22/3787. Unfortunately, discus fish are notoriously difficult to bred and keep in captivity9. 'Hobbyists didn't succeed in rearing them until the 1970s,' explains Buckley. Having imported 30 adults from breeders in Malaysia, the team reproduced the breeding conditions in the Amazon during the dry season to encourage the fish to spawn10. They lowered the water level and left it for a few hours before topping the tank up with cold water, and repeated the process until the pair was ready to lay their eggs. Buckley also collected samples of the orange mucus from the fish's flanks before they spawned11 and at various stages after the eggs had hatched, and monitored the parent's behaviour as their offspring grew.

During the first 3 days after hatching, the fry remained attached to the cone12 where the parents laid their eggs, absorbing the yolk13(蛋黄,卵黄) and gaining strength until all of the fry were able to swim independently. Then they left the cone en masse(全体地,一同地) and began feeding on their parents' mucus, feeding for up to 10·min by biting at the parent's side until the parent expertly 'flicked14' the shoal(浅滩,鱼群) over to its partner to continue feeding. The parents diligently15 fed their young intensely for 2 weeks. However, 3 weeks after hatching the parents' behaviour began to change as they started swimming away from their young for brief periods. At the same time the fry began biting their parents less and investigating other food sources. By the fourth week the parents were actively16 swimming away from their brood for the majority of the time and the fry barely bit them at all.

'There are a lot of parallels between the discus fish's parental care and the parental care that we see in mammals and birds,' says Buckley. Initially17 the parents invest all of their effort in raising their current batch18 of young, but wean the offspring when their investment in the current brood might begin affecting later broods. Buckley suspects that he sees signs of the conflict often seen between mammals and their young – where parents want to wean their offspring and the offspring continue pursuing them – in the fish's chasing behaviour during the third week after hatching.

Monitoring the composition of the parents' mucus before they spawned and through to the end of their parental responsibilities, Buckley found a huge increase in the mucus's antibody and protein levels when the parents laid their eggs, similar to the changes seen in mammalian milk around the time of birth. The protein and antibody levels remained high until the third week and returned to pre-spawning19 levels during the fourth week after hatching. Buckley suspects that the sudden increase in protein levels at spawning is hormonally regulated, much like the changes in mammalian milk, and is keen to find out more about the hormones20 that regulate the fish's mucus supply as they care for their young.



点击收听单词发音收听单词发音  

1 fend N78yA     
v.照料(自己),(自己)谋生,挡开,避开
参考例句:
  • I've had to fend for myself since I was 14.我从十四岁时起就不得不照料自己。
  • He raised his arm up to fend branches from his eyes.他举手将树枝从他眼前挡开。
2 secrete hDezG     
vt.分泌;隐匿,使隐秘
参考例句:
  • The pores of your body secrete sweat.身上的毛孔分泌汗液。
  • Squirrels secrete a supply of nuts for winter.松鼠为准备过冬而藏坚果。
3 forage QgyzP     
n.(牛马的)饲料,粮草;v.搜寻,翻寻
参考例句:
  • They were forced to forage for clothing and fuel.他们不得不去寻找衣服和燃料。
  • Now the nutritive value of the forage is reduced.此时牧草的营养价值也下降了。
4 parental FL2xv     
adj.父母的;父的;母的
参考例句:
  • He encourages parental involvement in the running of school.他鼓励学生家长参与学校的管理。
  • Children always revolt against parental disciplines.孩子们总是反抗父母的管束。
5 intrigued 7acc2a75074482e2b408c60187e27c73     
adj.好奇的,被迷住了的v.搞阴谋诡计(intrigue的过去式);激起…的兴趣或好奇心;“intrigue”的过去式和过去分词
参考例句:
  • You've really intrigued me—tell me more! 你说的真有意思—再给我讲一些吧!
  • He was intrigued by her story. 他被她的故事迷住了。
6 advisor JKByk     
n.顾问,指导老师,劝告者
参考例句:
  • They employed me as an advisor.他们聘请我当顾问。
  • The professor is engaged as a technical advisor.这位教授被聘请为技术顾问。
7 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。
8 molecular mE9xh     
adj.分子的;克分子的
参考例句:
  • The research will provide direct insight into molecular mechanisms.这项研究将使人能够直接地了解分子的机理。
  • For the pressure to become zero, molecular bombardment must cease.当压强趋近于零时,分子的碰撞就停止了。
9 captivity qrJzv     
n.囚禁;被俘;束缚
参考例句:
  • A zoo is a place where live animals are kept in captivity for the public to see.动物园是圈养动物以供公众观看的场所。
  • He was held in captivity for three years.他被囚禁叁年。
10 spawn qFUzL     
n.卵,产物,后代,结果;vt.产卵,种菌丝于,产生,造成;vi.产卵,大量生产
参考例句:
  • The fish were madly pushing their way upstream to spawn.鱼群为产卵而疯狂地向上游挤进。
  • These fish will lay spawn in about one month from now.这些鱼大约一个月内会产卵。
11 spawned f3659a6561090f869f5f32f7da4b950e     
(鱼、蛙等)大量产(卵)( spawn的过去式和过去分词 ); 大量生产
参考例句:
  • The band's album spawned a string of hit singles. 这支乐队的专辑繁衍出一连串走红的单曲唱片。
  • The computer industry has spawned a lot of new companies. 由于电脑工业的发展,许多新公司纷纷成立。
12 cone lYJyi     
n.圆锥体,圆锥形东西,球果
参考例句:
  • Saw-dust piled up in a great cone.锯屑堆积如山。
  • The police have sectioned off part of the road with traffic cone.警察用锥形路标把部分路面分隔开来。
13 yolk BVTzt     
n.蛋黄,卵黄
参考例句:
  • This dish would be more delicious with some yolk powder.加点蛋黄粉,这道菜就会更好吃。
  • Egg yolk serves as the emulsifying agent in salad dressing.在色拉调味时,蛋黄能作为乳化剂。
14 flicked 7c535fef6da8b8c191b1d1548e9e790a     
(尤指用手指或手快速地)轻击( flick的过去式和过去分词 ); (用…)轻挥; (快速地)按开关; 向…笑了一下(或瞥了一眼等)
参考例句:
  • She flicked the dust off her collar. 她轻轻弹掉了衣领上的灰尘。
  • I idly picked up a magazine and flicked through it. 我漫不经心地拿起一本杂志翻看着。
15 diligently gueze5     
ad.industriously;carefully
参考例句:
  • He applied himself diligently to learning French. 他孜孜不倦地学法语。
  • He had studied diligently at college. 他在大学里勤奋学习。
16 actively lzezni     
adv.积极地,勤奋地
参考例句:
  • During this period all the students were actively participating.在这节课中所有的学生都积极参加。
  • We are actively intervening to settle a quarrel.我们正在积极调解争执。
17 initially 273xZ     
adv.最初,开始
参考例句:
  • The ban was initially opposed by the US.这一禁令首先遭到美国的反对。
  • Feathers initially developed from insect scales.羽毛最初由昆虫的翅瓣演化而来。
18 batch HQgyz     
n.一批(组,群);一批生产量
参考例句:
  • The first batch of cakes was burnt.第一炉蛋糕烤焦了。
  • I have a batch of letters to answer.我有一批信要回复。
19 spawning e223115a66b2213a16c438abb9a400cb     
产卵
参考例句:
  • Encounter sites have a small chance of spawning a "Commander" NPC. 遭遇战地区有很小的几率遇到NPC指挥官。
  • Instantly revives your Champion at your Spawning Pool, 9 minute cooldown. 立即在出生地复活你的英雄,冷却时间9分钟。
20 hormones hormones     
n. 荷尔蒙,激素 名词hormone的复数形式
参考例句:
  • This hormone interacts closely with other hormones in the body. 这种荷尔蒙与体內其他荷尔蒙紧密地相互作用。
  • The adrenals produce a large per cent of a man's sex hormones. 肾上腺分泌人体的大部分性激素。
TAG标签: water fish parents
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