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1.
条背萤幼虫水生适应性形态与游泳行为研究   总被引:4,自引:2,他引:2  
研究了条背萤Luciolasubstriata幼虫的形态特征及其对游泳行为的适应。形态及扫描电镜观察发现,条背萤幼虫存在二态现象。1~2龄幼虫虫体扁平,多毛。有7对呼吸鳃,分别位于腹部第1~7节。3~6龄幼虫虫体扁平呈船形,无呼吸鳃,靠气管呼吸。二者均具有扁平桨状的足、燕尾状尾节及位于尾节末端的圆柱形粘附器官。条背萤幼虫游动时身体腹面朝上,呈仰泳姿态,足向后划水。3~6龄幼虫仰泳时足共有8种摆动姿势。幼虫仰泳时足摆动1个周期所需时间为(0.611±0.16)s。腹部末端可上下左右摆动,当幼虫向前游动时,尾部上下摆动1个周期所需时间为(1.795±0.44)s。幼虫的游泳速度为(0.85±0.16)mh。仰泳中的幼虫改变方向时,头部和尾部同时向身体的一侧弯曲,当头部与尾部呈近90°时,幼虫用力将尾部伸直,此时水产生一个反作用力继续推动幼虫转向,幼虫转向的范围为0~90°。条背萤2种类型幼虫呼吸系统的不同决定着幼虫外部形态的差异及游泳行为的不同,而导致这种呼吸系统、形态及运动行为不同的原因很可能是条背萤对环境的适应性进化。  相似文献
2.
Two new species of Conchostraca (Crustacea: Branchiopoda) from Iraq   总被引:1,自引:1,他引:0  
The swimming and feeding behaviors of Mesocyclops are described from a review of the literature and personal observations. Mesocyclops exhibits considerable behavioral flexibility in response to environmental stimuli. Mesocyclops edax exhibits an increase in horizontal looping behavior at high prey densities, and performs a tight vertical looping behavior in response to the loss of captured prey. Ingestion rates by Mesocyclops are a complex function of prey density, morphology, and behavior in addition to prey size. Vertebrate predators induce a rapid escape response in Mesocyclops and may be responsible at least in part for their extensive diel vertical migrations. The complex behavioral patterns of Mesocyclops suggest that its distribution and abundance in nature will be distinctly nonrandom and influenced as much by its own behavioral responses as by other external physical factors such as water circulation patterns.  相似文献
3.
亚成体巨须裂腹鱼游泳能力及活动代谢研究   总被引:1,自引:0,他引:1  
以野生雅鲁藏布江巨须裂腹鱼(Schizothorax macropogon)为对象,通过自制的鱼类游泳实验装置,测定了4个温度(5、10、15和18℃)梯度下亚成体巨须裂腹鱼的临界游泳速度(Ucrit)及流速变化对耗氧率的影响,并通过摄像记录分析了不同游泳速度下的游泳行为。野生亚成体巨须裂腹鱼的临界游速随着温度的变化呈近似线性的递增趋势(P<0.001),4个温度下的绝对临界游速(Ucrit-a)分别为(0.88±0.07)、(1.09±0.07)、(1.24±0.15)和(1.49±0.15)m/s;若以单位时间内游过的体长倍数(BL/s)表示,相对临界游速(Ucrit-r)分别为(3.96±0.21)、(4.4±0.16)、(4.9±0.18)和(5.35±0.14)BL/s。根据不同温度及流速下耗氧率的变化情况,采用非线性拟合得到了4个温度梯度下耗氧率与游泳速度关系的幂函数模型(P<0.05)。模型表明耗氧率随游泳速度的增大而增加,且温度越高耗氧率随游泳速度的变化越显著。4个温度下的速度指数分别为2.4、2.6,2.8及3.1,表明有氧运动的效率随温度升高有所降低。在自然水温条件下(5—9℃),摆尾频率(TBF)与流速的关系呈线性正相关(P<0.001),而运动步长(Ls)的变化与流速没有显著关系,出现由高至低再升高的三个阶段。录像分析表明在流速逐渐增加的过程中,巨须裂腹鱼采用了三种不同的游泳方式,以实现降低能量消耗的目的。研究可为鱼道等过鱼设施的设计提供参考,对数量日益减少的巨须裂腹鱼保护具有较大的意义。  相似文献
4.
普通齿蛉幼虫的游泳行为(英文)   总被引:1,自引:0,他引:1       下载免费PDF全文
为了探究广翅目昆虫幼虫在水中的游泳能力, 以丰富其水生习性的行为学资料, 选取中国特有种普通齿蛉Neoneuromus ignobilis幼虫为研究对象, 通过室内试验对其游泳的姿势、 刺激因素、 不同龄期游泳能力及在外界刺激下的游泳行为进行了观察和测定。结果表明: 普通齿蛉幼虫有垂直、 平行、 仰面和侧面等4种游泳姿势, 出现的频率分别为89.08%, 5.49%, 4.40%和0.61%。游泳时身体呈不同程度的“S”形, 利用头部和尾部方向的改变实现虫体的上升、 下沉和游泳姿势的改变。普通齿蛉幼虫利用身体的摆动游泳, 游泳时3对足以固定的姿势靠紧身体。不同龄期的幼虫游泳能力差异很大, 6龄幼虫的游泳能力远强于2龄和末龄幼虫。在游泳时, 普通齿蛉幼虫还具有比较复杂和独特的防御行为, 如其腹部末端会喷射出化学物质。据此认为, 普通齿蛉拥有较强的游泳能力, 有助于其逃生和防御。  相似文献
5.
To investigate the role of helmet formation in defense against predation, laboratory experiments were used to analyze the effects of morphological changes in Daphnia on susceptibility to Chaoborus predation. Behavioral observations of Chaoborus preying on helmeted and non-helmeted Daphnia suggest pre-contact advantages for helmeted prey but post-contact advantages for non-helmeted prey. Helmeted Daphnia are better at evading capture by Chaoborus but may also be more easily handled by the predator. Swimming behavior of the prey, which is influenced by the presence of a tailspine, may affect Chaoborus strike distance. These results re-emphasize the potential hydromechanical importance of body shape changes in defense against predation.  相似文献
6.
A laboratory method is presented for studying zooplankton swimming behaviors such as phototaxis and photokinesis. The method attempts to standardize laboratory conditions and to minimize the effects of several phenomena which modify zooplankton behavior. The role of angular light distribution in zooplankton behavior is discussed, and an apparatus which simulates a natural underwater light environment is described. The procedure minimizes the fluctuations in zooplankton swimming speed and vertical distribution that are caused by large light stimuli, noise, food deprivation, endogenous rhythms, and other factors. The experimental animals were viewed remotely with the aid of a light amplifier and video camera. A mathematical equation and computer program for calculating three-dimensional swimming speeds of zooplankton from video recordings are described in detail.  相似文献
7.
正鱼类在摄食、迁徙、逃避敌害时均需采用游泳行为,鱼类游泳行为对鱼类的生存发挥重要作用[1]。鱼类游泳行为受到国内外学者广泛关注,如Wang,et al.研究了中华鲟(Acipenser sinensis)产卵群体的洄游游泳速度[2],Yuuki,et al.记录了中华鲟个体在三峡库区的游泳速度[3],Zhuang,et al.分析了几种鲟鱼在个体发育过程中的游泳行为特征[4],田凯等测算了瓦氏黄颡鱼的游泳速度[5],石小涛等指出游泳行为在通过水流障碍中的重要性[6]。在工程应用中,  相似文献
8.
When animals are under stress, glucocorticoids commonly inhibit adult neurogenesis by acting through glucocorticoid receptors (GRs). However, in some cases, conditions that elevate glucocorticoids promote adult neurogenesis, and the role of glucocorticoid receptors in these circumstances is not well understood. We examined the involvement of GRs in social enhancement of brain cell addition and aggressive signaling in electric fish, Apteronotus leptorhynchus. In this species, long-term social interaction simultaneously elevates plasma cortisol, enhances brain cell addition and increases production of aggressive electrocommunication signals (“chirps”). We implanted isolated and paired fish with capsules containing nothing (controls) or the GR antagonist, RU486, recorded chirp production and locomotion for 7 d, and measured the density of newborn cells in the periventricular zone. Compared to isolated controls, paired controls showed elevated chirping in two phases: much higher chirp rates in the first 5 h and moderately higher nocturnal rates thereafter. Treating paired fish with RU486 reduced chirp rates in both phases to those of isolated fish, demonstrating that GR activation is crucial for socially induced chirping. Neither RU486 nor social interaction affected locomotion. RU486 treatment to paired fish had a partial effect on cell addition: paired RU486 fish had less cell addition than paired control fish but more than isolated fish. This suggests that cortisol activation of GRs contributes to social enhancement of cell addition but works in parallel with another GR-independent mechanism. RU486 also reduced cell addition in isolated fish, indicating that GRs participate in the regulation of cell addition even when cortisol levels are low.  相似文献
9.
Ultraviolet radiation (UVR, 280-400 nm) is known to be lethal to several aquatic species; however, more subtle, ‘sublethal’ effects of UVR have recently received more attention. Larvae of the crab Cyrtograpsus altimanus are a transient component of the plankton community in the Atlantic northern Patagonia (Argentina) and thus they may be exposed to solar UVR in both open and coastal waters. The aim of this study was to determine if previous sublethal UVR exposure on larvae of C. altimanus affects development, body size and motility. Larvae which were pre-exposed to UVR had a delay/absence of molting from Zoea I to Zoea II, coupled to arrested body growth, but showed enhanced swimming behavior. In contrast, the control group (i.e., exposed only to visible light) molted from Zoea I to Zoea II after 6-9 days, with a significant increase in body size, and did not change their motility. Since hatching of this species occurs in summer (i.e., season with highest UVR levels) our results suggest that, by significantly affecting development, growth and motility, natural UVR may influence the plankton-benthos coupling in coastal waters.  相似文献
10.
The permanent eastward current at the Straits of Gibraltar may trap small Atlantic loggerhead sea turtles (Caretta caretta) inside the western Mediterranean until their swimming and diving skills improve enough to allow them counter-current swimming abilities through the current. A captivity experiment with twelve loggerhead sea turtles (straight carapace length or SCL range: 25.3-48.0 cm) revealed that the average critical velocity of this species within the considered length range was 0.38 ± 0.16 m s− 1 or 1.01 ± 0.24 bl s− 1. As a consequence, loggerhead sea turtles are predicted to require a minimum SCL of 36.0 cm to swim counter-current through the Straits of Gibraltar, where the water velocity ranges 0.31-0.37 m s− 1. Genetic analysis of 105 specimens using one mitochondrial marker and seven microsatellites, as well as the recapture of three tagged individuals, support this conclusion; all Mediterranean individuals found in the Atlantic side of the Straits were not smaller than 36.0 cm SCL and the average length (47.3 cm SCL) was significantly higher than that of the Mediterranean turtles in the Mediterranean side of the Straits (31.6 cm SCL). Furthermore, the average length of the turtles of any origin moving from the Mediterranean to the Atlantic was much larger than 36.0 cm (SCL: 54.5 cm SCL), which may indicate the intervention of a different, yet unidentified mechanism restricting east-westward movement. The Algerian current, running along northern Africa, may at least partially explain the delayed departure of loggerhead sea turtles from the Mediterranean Sea to the Atlantic Ocean, as it would force the eastward drift of loggerheads occupying the southwestern Mediterranean. Exchange through the Straits is asymmetrical, and Atlantic turtles are found to enter the Mediterranean at a length of about 20.5 cm. However, once in the Mediterranean they would be retained there for up to 7.9 years, due to the surface circulation pattern. This increases the time span at which turtles are exposed to a high mortality rate, caused by fishing.  相似文献
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