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1.
Roth A 《Die Naturwissenschaften》2003,90(6):251-255
In amphibians the lateral line sense organs, i.e., mechanoreceptors (neuromasts) and electroreceptors, develop autonomously from placodal tissue, with no need for innervating nerve fibers. The present study deals with the question whether or not the mechano- and the (ampullary) electroreceptors develop in the same manner in teleosts. On the tail of larval catfish, Silurus, the first mechano- and electroreceptors appear several days after hatching in two longitudinal rows, one along the outgrowing main branch of the lateral line nerve and one along its ventral branch. Prevention of outgrowth of both nerve branches by repeated nerve sectioning, before the receptors form, shows (1) that the mechanoreceptors can develop without innervation as in amphibians, and (2) that the electroreceptors do not develop without innervation, unlike amphibian electroreceptors. These results are discussed with regard to the placodal origin and the phylogeny of the two sense organs. 相似文献
2.
Christoph J. Hellig Michaela Kerschbaumer Kristina M. Sefc Stephan Koblmüller 《Die Naturwissenschaften》2010,97(7):663-672
The morphological versatility of the pharyngeal jaw of cichlid fishes is assumed to represent a key factor facilitating their
unparalleled trophic diversification and explosive radiation. It is generally believed that the functional design of an organism
relates to its ecology, and thus, specializations to different diets are typically associated with distinct morphological
designs, especially manifested in the cichlids’ pharyngeal jaw apparatus. Thereby, the lower pharyngeal jaw (LPJ) incorporates
some of the most predictive features for distinct diet-related morphotypes. Thus, considering that piscivorous cichlids experience
an ontogenetic dietary shift from typically various kinds of invertebrates to fish, concomitant morphological changes in the
LPJ are expected. Using Lepidiolamprologus elongatus, a top predator in the shallow rocky habitat of Lake Tanganyika, as model, and applying geometric and traditional morphometric
techniques, we demonstrate an allometric change in ontogenetic LPJ shape development coinciding with the completion of the
dietary shift toward piscivory. The piscivorous LPJ morphotype is initiated in juvenile fish by increasing elongation and
narrowing of the LPJ and—when the fish reach a size of 80–90 mm standard length—further refined by the elongation of the posterior
muscular processes, which serve as insertion for the fourth musculus levator externus. The enlarged muscular processes of
the fully mature piscivorous morphotype provide for the construction of a powerful lever system, which allows the large individuals
to process large prey fish and rely on exclusive piscivory. 相似文献
3.
Jari Syväranta Julien Cucherousset Dorothée Kopp Aurélia Martino Régis Céréghino Frédéric Santoul 《Die Naturwissenschaften》2009,96(5):631-635
Many anadromous fish species, when migrating from the sea to spawn in fresh waters, can potentially be a valuable prey for
larger predatory fish, thereby efficiently linking these two ecosystems. Here, we assess the contribution of anadromous fish
to the diet of European catfish (Silurus glanis) in a large river system (Garonne, southwestern France) using stable isotope analysis and allis shad (Alosa alosa) as an example of anadromous fish. Allis shad caught in the Garonne had a very distinct marine δ13C value, over 8‰ higher after lipid extraction compared to the mean δ13C value of all other potential freshwater prey fish. The δ13C values of European catfish varied considerably between these two extremes and some individuals were clearly specializing
on freshwater prey, whereas others specialized on anadromous fish. The mean contribution of anadromous fish to the entire
European catfish population was estimated to be between 53% and 65%, depending on the fractionation factor used for δ13C. 相似文献
4.
The relative roles of the fish lateral line and inner ear for the perception of hydrodynamic stimuli are poorly investigated.
Here, we studied responsiveness to a 100 Hz vibrating sphere (dipole stimulus) of goldfish and oscars, two species that differ
in peripheral lateral line morphology, inner ear morphology, mechanical linkage between inner ear and swim bladder, and inner
ear sensitivity. We measured unconditioned dipole-evoked changes in breathing activity in still water and in the presence
of a 5-cm s−1 background flow. In still water, individuals from both species responded to sound pressure levels (SPLs) between 92 and 109 dB
SPL re 1 μPaRMS. Responsiveness was not affected by background flow or by temporary inactivation of the lateral line. The data suggest that
fish with different lateral line and inner ear morphologies have similar sensitivities to vibrating sphere stimuli and can
detect and respond to dipole sources equally well in still water and in moderate background flows. Moreover, behavioral responses
were not dependent on a functional lateral line, suggesting that in this type of experiment, the inner ear is the dominant
sense organ for the perception of hydrodynamic stimuli. 相似文献
5.
Takashi A. Inoue Kiyoshi Asaoka Kazuaki Seta Daisuke Imaeda Mamiko Ozaki 《Die Naturwissenschaften》2009,96(3):355-363
The feeding behavior in nectar-feeding insects is triggered by a sugar-receptor response in contact chemosensilla. The contact
chemosensilla are distributed not only on tarsi and the outside of the proboscis but also on the inside of the food canal
in Lepidoptera. Although the chemosensilla inside the food canal are assumed to detect sweet taste during the passage of nectar
through the food canal, their electrophysiological function has received little attention. In the nectar-feeding Asian swallowtail
butterfly, Papilio xuthus (Lepidoptera: Papilionidae), we found 15- to 30-μm-long sensilla neatly lined up along the inside galea wall, which forms
the food canal in the proboscis. The receptor neurons of these sensilla responded to sucrose. We hypothesized that starch
and sucrose compete with each other for a taste receptor site on the sensilla. When we added starch and sucrose to the food-canal
sensilla, the electrophysiological responses of food-canal sensilla were inhibited in parallel with the food-sucking behavior
of the butterflies. These results suggest that the food-canal sensilla are involved in the behavioral control of nectar-sucking
in this butterfly species. 相似文献
6.
During reproductive migration the electroreceptive African sharptooth catfish, Clarias gariepinus (Siluriformes), preys mainly on a weakly electric fish, the bulldog Marcusenius macrolepidotus (Mormyridae; Merron 1993). This is puzzling because the electric organ discharges of known Marcusenius species are pulses of a duration (<1 ms) too short for being detected by the catfishes' low-frequency electroreceptive system
(optimum sensitivity, 10–30 Hz; Peters and Bretschneider 1981). On the recent discovery that M. macrolepidotus males emit discharges lasting approximately ten times longer than those of females (Kramer 1997a) we determined behavioral
thresholds for discharges of both sexes, using synthetic playbacks of field-recorded discharges. C. gariepinus detected M. macrolepidotus male discharges down to a field gradient of 103 μVpeak-peak/cm and up to a distance of 1.5 m at natural field conditions. In contrast, thresholds for female discharges were not reached
with our setup, and we presume the bulldogs eaten by catfish are predominantly male.
Received: 7 October 1998 / Accepted in revised form: 29 December 1998 相似文献
7.
采用GC/MS技术对典型血吸虫病疫区不同水期采集的1种软体生物和5种鱼体肌肉进行分析.实验发现3类二氯苯和六氯苯(HCB)为优势污染物.ΣCBs在软体生物肌肉中几何均值(以脂肪质量计,下同)为11 947 ng·g-1;在鱼体肌肉中范围为1 851~8 159 ng·g-1,鱼体ΣCBs最高浓度出现在鲶鱼体内,最低浓度出现在鲫鱼体内;实验结果与国内外相关文献报道值比较,显示该区域软体生物体内HCB含量与其他区域相当;鱼体肌肉中HCB含量则处于较高污染水平.癌症风险评价结果表明因软体生物和鱼类摄入HCB而带来的风险分别为1.49×10-7和3.73~21.1×10-7,说明研究区域水生生物中因HCB污染引起的癌症风险处于可接受水平. 相似文献
8.
原油作为主要能源之一对现代社会的重要作用不言而喻,但其所带来的污染危害同样不容忽视.通过自制的有机玻璃水槽,建立模型模拟自然地层的非均质性,模拟了原油在沿海土-水系统中的运移过程,探讨了局部非渗透性透镜体、底部隔水层、土壤初始含水率、土壤质地、岩性突变界面对原油在砂土中运移速度和路径的影响.结果表明,局部非渗透性透镜体和底部隔水层对原油的运移具有阻碍作用,会改变其运动速度和路径.在一定范围内,土壤初始含水率越高,原油的侧向运移速率和垂向运移速率越大(模拟成层性土层中原油垂向运移速率随含水率增大,由0.43 cm·min~(-1)增大到1.00 cm·min~(-1),在低含水率区域原油侧向运移速率分别为0.08 cm·min~(-1)(粗-细界面)和0.10 cm·min~(-1)(细-粗界面),而在含水率较高的区域则为0.14 cm·min~(-1)),而过高的含水率又会阻碍原油的运移.土壤孔隙越大,垂向运移越快,侧向运移越慢,反之,垂向运移越慢,侧向运移越快(模拟成层性土层中,原油在粗砂中的垂向平均运移速率为0.54 cm·min~(-1),而在细砂中仅为0.33 cm·min~(-1),自然泄漏时原油在粗砂中的最大扩散范围为9.10 cm,在细砂中为12.50 cm).原油在土壤中运移遇到岩性突变界面时,会产生聚集效应,在聚集处产生侧向运移,试验中在粗-细界面扩散宽度为6.70 cm,在细-粗界面扩散宽度为29.00 cm. 相似文献
9.
Animal lifespans range from a few days to many decades, and this life history diversity is especially pronounced in ants.
Queens can live for decades. Males, in contrast, are often assumed to act as ephemeral sperm delivery vessels that die after
a brief mating flight—a view developed from studies of lekking species in temperate habitats. In a tropical ant assemblage,
we found that males can live days to months outside the nest, a trait hypothesized to be associated with female calling, another
common mating system. We combined feeding experiments with respirometry to show that lifespan can be enhanced over 3 months
by feeding outside the nest. In one focal female calling species, Ectatomma ruidum, feeding enhanced male lifespan, but not sperm content. Extended lifespans outside the nest suggest stronger than expected
selection on premating traits of male ants, although the ways these traits shape male mating success remain poorly understood. 相似文献
10.
The queenless ant Pristomyrmex punctatus (Hymenoptera: Myrmicinae) has a unique society that differs from those of other typical ants. This species does not have
a queen, and the workers lay eggs and produce their clones parthenogenetically. However, a colony of these ants does not always
comprise members derived from a single clonal line. In this study, we examined whether P. punctatus changes its “assembling behavior” based on colony genetic structure. We prepared two subcolonies—a larger one comprising
200 individuals and a smaller one comprising 100 individuals; these subcolonies were established from a single stock colony.
We investigated whether these subcolonies assemble into a single nest. The genetically monomorphic subcolonies (single clonal
line) always fused into a single nest; however, the genetically polymorphic subcolonies (multiple clonal lines) did not tend
to form a single colony. The present study is the first to demonstrate that the colony genetic structure significantly affects
social viscosity in social insects. 相似文献
11.
David M. Cooley Christopher S. Galik Thomas P. Holmes Carolyn Kousky Roger M. Cooke 《Mitigation and Adaptation Strategies for Global Change》2012,17(1):17-24
Although forest carbon offsets can play an important role in the implementation of comprehensive climate policy, they also
face an inherent risk of reversal. If such risks are positively correlated across projects, it can affect the integrity of
larger project portfolios and potentially the entire offsets program. Here, we discuss three types of risks that could affect
forest offsets—fat tails, micro-correlation, and tail dependence—and provide examples of how they could present themselves
in a forest offset context. Given these potential dependencies, we suggest several new risk management approaches that take
into account dependencies in reversal risk across projects and which could help guard the climate integrity of an offsets
program. We also argue that data collection be included as an integral part of any offsets program so that disturbance-related
dependencies may be identified and managed as early and to the greatest extent possible. 相似文献
12.
In an attempt to better understand the mechanism underlying lateral collision avoidance in flying insects, we trained honeybees
(Apis mellifera) to fly through a large (95-cm wide) flight tunnel. We found that, depending on the entrance and feeder positions, honeybees
would either center along the corridor midline or fly along one wall. Bees kept following one wall even when a major (150-cm
long) part of the opposite wall was removed. These findings cannot be accounted for by the “optic flow balance” hypothesis
that has been put forward to explain the typical bees’ “centering response” observed in narrower corridors. Both centering
and wall-following behaviors are well accounted for, however, by a control scheme called the lateral optic flow regulator, i.e., a feedback system that strives to maintain the unilateral optic flow constant. The power of this control scheme is
that it would allow the bee to guide itself visually in a corridor without having to measure its speed or distance from the
walls. 相似文献
13.
为了解小浪底水库汞的赋存状况,采用冷原子荧光光谱法测定了小浪底水库水体、表层沉积物、沉积物间隙水以及鱼类肌肉样品中的总汞,采用乙基化衍生-气相色谱-原子荧光法测定了上述样品中的甲基汞,进而分析了小浪底水库鱼体中汞的富集状况.结果表明,小浪底水库水体中丰、枯水期总汞浓度分别为0.71~1.42 ng·L-1和0.90~2.49 ng·L-1,均符合国家地表水环境质量标准(GB 3838-2002)一类水汞浓度标准限值,水样中未检出甲基汞.丰、枯水期沉积物中总汞浓度分别为51.74~90.42 ng·g-1和95.66~172.52 ng·g-1,甲基汞浓度分别为0.09~0.26 ng·g-1和0.18~0.39 ng·g-1,甲基汞浓度较低,这可能与水体底层溶解氧浓度较高以及沉积物中有机碳浓度较低有关.丰、枯水期沉积物间隙水总汞浓度分别为4.27~9.49 ng·L-1和5.46~41.04 ng·L-1,甲基汞浓度分别为0.09~0.99 ng·L-1和0.07~1.01 ng·L-1,间隙水中总汞和甲基汞浓度明显高于上覆水体,与水体间存在汞浓度梯度,可能存在从沉积物间隙水向水体中的扩散.鱼体肌肉总汞浓度在43.47~304.98 ng·g-1之间,甲基汞浓度为10.77~265.23 ng·g-1,甲基汞低于食品安全国家标准规定的污染物限量(GB 2762-2012)(非肉食性鱼500 ng·g-1和肉食性鱼1 000 ng·g-1).水库鱼体总汞的生物富集系数分别为鳙鱼1.3×105,梭鱼9.3×104,鲫鱼4.7×104,白条5.0×104,黄颡鱼1.7×105,弓鱼3.9×104. 相似文献
14.
为评价水污染对鱼类毒性影响和制订图们江渔业水质标准,于1977年8—11月和1979年6—7月在室内进行废水对鱼类急性和亚急性毒性试验,在野外进行鱼类胚胎和幼鱼的现场监测。同时,对鱼类区系分布、渔业资源和鱼体残毒分别作了调查和测定。 结果表明:上游铁矿废水破坏鱼类产卵场,减少鱼类食料生物种群;中游纸浆废水影响鱼类存活和回游;下游化工废水使鱼有异味,影响食用。 纸浆废水是主要污染源之一,对马苏大麻哈幼鱼96hr半致死浓度为5.6—11%。亚急性毒性以血液指标最为敏感,阈反应值为0.32%。引起鱼回避反应和对鳃组织产生危害的阈值为1%。 据此,提出保护图们江主要经济鱼类存活,生长和产卵回游的水质标准为:pH6.5—8.5:COD20mg/l;BOD55mg/l,冰封期3mg/l;DO>6mg/l(24hr内和16hr以上),≮4mg/l(任何时候);悬浮固体10mg/l;木质素2mg/l;酚0.005mg/l;氰化物0.02mg/l;砷0.1mg/l;铬1.0mg/l。 相似文献
15.
In holometabolous insects, pupation site selection behaviour has large consequences for survival. Here, we investigated the
combined effects of temperature and parasitism by the parasitoid Asobara tabida on larval pupation behaviour in two of its main Drosophila sp. hosts differing in their climate origin. We found that larvae of Drosophila melanogaster—a species with a (sub)tropical origin—placed at 25°C pupated higher in rearing jars than those placed at 15°C. The opposite
pattern was observed for Drosophila subobscura larvae—a species from temperate regions—which pupated lower, i.e. on or near the substrate at 25°C, than those placed at
15°C. When placed at 25°C, parasitized larvae of both species pupated closer to the substrate than unparasitized ones. Moreover,
the Drosophila larvae that had been exposed and probably stung by A. tabida, but were not parasitized, pupated lower than the control unparasitized larvae. These results provide new insights of host
behaviour manipulation by A. tabida larvae. 相似文献
16.
本文运用Piper三线图、Gibbs图、饱和指数和离子比例关系等方法分析新疆叶尔羌河流域地表水水化学特征及其控制因素,对流域地表水资源合理开发利用具有重要意义.结果表明,地表水pH范围为7.40~8.33,均值为7.92,整体呈弱碱性.河水、渠水和水库水的溶解性总固体(TDS)均值呈现依次递增的趋势,其中河水的TDS均值为429.24 mg·L-1,高于世界河流的平均值(115 mg·L-1).河水的水化学类型主要为HCO3·SO4-Ca·Na和SO4·HCO3·Cl-Ca·Na·Mg型.渠水的水化学类型主要为HCO3·SO4·Cl-Ca·Na型.水库水的水化学类型主要为SO4·Cl-Na·Ca型.叶尔羌河沿程河水TDS呈连续增加趋势,提孜那甫河沿程河水TDS呈连续波动变化,而主要离子的变化趋势较为复杂.地表水体离子主要受岩石风化、蒸发结晶和阳离子交换作用影响,其中岩石风化作用过程中以石膏和岩盐的溶解为主.此外,人类活动对下游地表水水化学组分具有重要影响. 相似文献
17.
18.
Glycogen is a vital energy substrate for anaerobic organisms, and the size of glycogen stores can be a limiting factor for
anoxia tolerance of animals. To this end, glycogen stores in 12 different tissues of the crucian carp (Carassius carassius L.), an anoxia-tolerant fish species, were examined. Glycogen content of different tissues was 2–10 times higher in winter
(0.68–18.20% of tissue wet weight) than in summer (0.12–4.23%). In scale, bone and brain glycogen stores were strongly dependent
on body mass (range between 0.6 and 785 g), small fish having significantly more glycogen than large fish (p < 0.05). In fin and skin, size dependence was evident in winter, but not in summer, while in other tissues (ventricle, atrium,
intestine, liver, muscle, and spleen), no size dependence was found. The liver was much bigger in small than large fish (p < 0.001), and there was a prominent enlargement of the liver in winter irrespective of fish size. As a consequence, the whole
body glycogen reserves, measured as a sum of glycogen from different tissues, varied from 6.1% of the body mass in the 1-g
fish to 2.0% in the 800-g fish. Since anaerobic metabolic rate scales down with body size, the whole body glycogen reserves
could provide energy for approximately 79 and 88 days of anoxia in small and large fish, respectively. There was, however,
a drastic difference in tissue distribution of glycogen between large and small fish: in the small fish, the liver was the
major glycogen store (68% of the stores), while in the large fish, the white myotomal muscle was the principal deposit of
glycogen (57%). Since muscle glycogen is considered to be unavailable for blood glucose regulation, its usefulness in anoxia
tolerance of the large crucian carp might be limited, although not excluded. Therefore, mobilization of muscle glycogen under
anoxia needs to be rigorously tested. 相似文献
19.
通过多阶段暴露试验评价嘧菌酯对斑马鱼的急性毒性与发育毒性 总被引:1,自引:0,他引:1
嘧菌酯作为最畅销的甲氧丙烯酸酯类杀菌剂,是防治水稻病害的常用农药,其对水生生态环境的负面效应值得重视.为研究嘧菌酯对水生生物的危害,进行多阶段(成鱼、仔鱼、胚胎)斑马鱼毒性试验,分析了嘧菌酯对鱼类的急性毒性,同时,通过6 d胚胎发育试验,研究了嘧菌酯对鱼类早期发育阶段的影响.结果表明,斑马鱼3个生命阶段对嘧菌酯的敏感性(以96 h-LC50(致死中浓度)表示)顺序为:仔鱼(0.39 mg·L~(-1))胚胎(0.61 mg·L~(-1))成鱼(1.37 mg·L~(-1)).6 d胚胎发育试验结果发现,嘧菌酯可诱导斑马鱼胚胎出现一系列不良症状,包括孵化率下降、心率异常、生长抑制和心包水肿等.0.25 mg·L~(-1)的嘧菌酯可显著促进斑马鱼胚胎自主运动和心率,并能明显抑制孵化仔鱼的体长.0.6 mg·L~(-1)及更高浓度的嘧菌酯可明显抑制斑马鱼胚胎眼睛、体节、尾部和心脏的发育.研究显示,嘧菌酯对斑马鱼多个生命阶段均具有一定毒性,但对早期生命阶段毒性更强,因此,其对鱼类早期生命阶段的影响值得重视. 相似文献
20.
三江平原水田灌溉-排水过程中铁形态变化及输出贡献 总被引:4,自引:1,他引:4
采集三江平原农田灌溉地下水、稻田积水、渠系排水、土壤侧渗水,并采用切向超滤技术分离水体中不同形态铁,分析在灌溉排水及地下侧渗水中铁的迁移特征,并估算水田排水中铁的输出贡献.结果表明,在灌溉排水过程中,铁主要以低分子量形态和酸性不稳定形态迁移,地下水中Fe2+含量占可溶态铁的80.45%;地下水抽取到稻田后Fe2+含量显著降低,络合态铁含量升高,稻田积水中络合态铁占可溶态铁的75.50%;稻田积水排入渠系后,络合态铁中不稳定弱配位铁含量降低13.58%,其他铁形态变化不大.稻田积水通过地下侧渗进入渠系,随侧渗水体深度加深,Fe2+含量升高,络合态和胶体态铁含量降低,地下侧渗水向渠系水主要提供络合态和胶体态铁.三江平原湿地水田化改变了水体中铁的输出形态,同时,排水过程中铁的输出也对河流形成补给,水田灌溉排水过程可溶态铁的输出通量约为390kg.a-.1km-2,输出系数为0.186,灌溉-排水过程中残留在稻田土壤中铁的量约为1460kg.a-.1km-2,残留在排水渠系土壤中铁的量约为250kg.a-.1km-2,这对三江平原水土环境产生了深远影响. 相似文献