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1.
The aim of the present study was to test sun orientation and rhythmic activity of two sandhopper populations from two Atlantic macro-tidal beaches. A population from Le Verger beach (orientated to 346°, Ille et Vilaine, Brittany, France) and a population from Damgan (orientated to 195°, Morbihan, Brittany, France), were tested on the beach under clear sky discriminating for landscape vision. For both populations locomotor activity rhythm was recorded in the laboratory. The two beaches differed for climatic features, tidal range and for human use. Both talitrid populations resulted very well orientated toward the shoreline, and both used solar position and landscape vision to orient. However the multiple regression analysis of orientation with climatic features showed a different use of local cues by the two populations and a slight influence of tidal regime (ebbing and rising tide), in spite of the supralittoral zonation of sandhoppers. In the laboratory they showed a well defined rhythmic behaviour as well as a bimodal rhythmicity, explained as a tidal one. These results are a new brick in the complex picture of orientation and rhythm studies on sandy beach invertebrates.  相似文献   
2.
The day–night cycle is one of the strongest geophysical cycles modulating species' behavioral rhythms. However, in deep-water continental margins, where light intensity decreases over depth, interspecific competition may alter behavioral responses to day–night cycles. The burrowing decapod crustacean Nephrops norvegicus is a large-size predator in benthic communities, exerting despotic territorial behavior. In this study, we analysed how the effect of light intensity cycles on decapod behavioral rhythms is reduced as one moves from shelves to slopes. In the Western Mediterranean, the predatory behavior and interspecific competition for substrate use of Nephrops increases moving from the shelf (100–110 m) to the slope (400–430 m). Vector fitting and generalized additive models were used to assess the effect of light intensity and behavioral rhythms of N. norvegicus on the temporal variation of prey decapods co-occurring in trawl tow catches carried out on the shelf and the slope during October 1999 and June 2000. The combination of diel variations in light intensity and N. norvegicus abundance influences the activity rhythms of prey decapods in a depth- and seasonal-dependent manner. Light modulation is stronger on the shelf and weaker on the slope, where Nephrops population size is greater. Although present regression analysis does not necessarily imply a direct cause–effect relationship between rhythms of predators and prey, we suggest that Nephrops alters the temporal patterning in the behavior of its prey on the slope, where light intensity is reduced. This alteration is stronger in endobenthic species than in benthopelagic species; the former rely on bottom substrate for the expression of behavioral rhythms, experiencing stronger interspecific competitions with Nephrops at time of activity.  相似文献   
3.
为探究不同光谱下许氏平鲉的消化代谢水平及外周激素节律,在5种光谱(红光、绿光、黄光、蓝光、白光,光周期12L∶12D)下,通过对许氏平鲉的血清、肠道、肝脏进行24 h (8:00,12:00,16:00,20:00,24:00)取样,结果显示:不同的光谱下许氏平鲉的消化代谢酶活性除胰蛋白酶(TRY)外均具有节律性,红光、黄光下α-淀粉酶(α-AMS)、脂肪酶(LPS)活性的峰值相位与白光组相比左移;胰蛋白酶活性无时间差异性;在绿光、黄光及红光下乳酸脱氢酶(LDH)活性的峰值相位与白光组相比发生左移,在五种光谱环境中,红、黄光影响消化酶活性峰值提前出现;丙酮酸激酶(PK)活性在绿、蓝及红光下峰值相位左移;己糖激酶(HK)的活性在绿、蓝、黄光下,其峰值相位与白光组相比发生左移,在五种光谱环境中,绿、蓝光影响代谢酶活性类峰值提前出现。许氏平鲉血清中褪黑素含量呈现昼低夜高分泌水平;皮质醇的含量表现为在白天降低,午夜显著升高至最高值后又持续降低。峰值相位的改变预示着生理节律的变动,以上结果表明不同光谱可以影响鱼类的生理代谢节律,在今后养殖过程中需要充分考虑光谱对养殖生物的生物学作用,进而制定更为合理的光照条件。  相似文献   
4.
2012年3~5月,采用直接瞬时扫描法和间接监控器摄像相结合的方式,对北京市野生动物救护中心顺义饲养繁育基地的一对秃鹫的繁殖行为的时间分配和活动规律进行了研究,结果显示:秃鹫在警戒、理羽、吃食、交配、孵化等行为存在着明显的节律性,警戒、理羽行为在行为比例中较高,警戒行为占绝对优势。取食行为多发生在上午的中间阶段,孵化行为不间断、并且轮流孵化幼鸟。孵化期内雌、雄个体的行为差异不大,秃鹫发情期各种行为所占的比例存在着一定的性别差异。  相似文献   
5.
本文在室内无潮汐因子作用条件下对采集于青岛太平湾基岩海岸潮间带的短滨螺进行观察,发现其具有和潮汐同步的排卵和运动节律性。30d后,仍能观察到排卵的潮汐节律性。1a后,短滨螺不呈现排卵的潮汐节律性。  相似文献   
6.
NR1D1和NR1D2转录因子属于核受体转录因子家族,二者通过调控靶基因表达参与众多生物学过程,尤其在昼夜节律调节中发挥重要作用。本研究通过分析NR1D1和NR1D2的蛋白质分子特征以及在冷胁迫下珍珠龙胆石斑鱼(Epinephelus fuscoguttatus ♀ × Epinephelus lanceolatus ♂)的基因调控关系以及它们所参与的通路,揭示它们在鱼类低温环境中的功能作用。生物信息学比较分析显示〖STBX〗NR1D1和NR1D2〖ST〗基因序列均有23个开放阅读框,编码的蛋白质均属于不稳定的亲水性蛋白质。NR1D1和NR1D2蛋白质均含有ZF C4类锌脂蛋白结构域和Hormone_Recep核激素受体的配体结合域,主要配体为含铁原卟啉IX。这两种蛋白主要在细胞核中发挥调控基因表达的作用,且与昼夜节律通路的多个关键基因有直接作用关系。结果表明,在冷胁迫下NR1D1和NR1D2作为转录因子可通过调控靶基因的表达,参与昼夜节律调节并促进糖脂代谢、线粒体氧化等过程,为珍珠龙胆石斑鱼提供必要的能量,有助于增强其耐寒性。  相似文献   
7.
The regulation and expression of biological rhythms with respect to sex and ontogeny in deep-water benthic decapod crustaceans constitutes an exciting field in marine biology that is far from understood. Liocarcinus depurator , Munida intermedia and Munida tenuimana are ecologically key crustacean decapod species of the Atlantic and Mediterranean shelves and slopes, and their activity rhythms in the field are poorly known. Our aim was to measure the behavioural rhythms of these species, while at the same time defining their type of displacement ( i.e. endobenthic, nektobenthic or benthopelagic). Whether gender and ontogeny modulate the rhythmic behaviour of these decapods is unknown, and we sought to clarify this issue. A temporally scheduled series of trawl hauls and light intensity measures was performed on the western Mediterranean shelf (100–110 m depth) and slope (400–430 m), close to the autumn equinox and the summer solstice. The sex and the size of animals in the catches were analysed. Catch patterns were evaluated through waveform and periodogram analyses. Liocarcinus depurator was captured at night on the shelf, whereas on the slope, animals displayed peaks both in the middle of the day and night. Size-related differences (but no gender differences) were found in its rhythmic behaviour, possibly due to intra-specific competition ( e.g. fighting) between juveniles and adults. Munida intermedia were weakly diurnal in October and both diurnal and nocturnal in June. Munida tenuimana presented no discernible rhythmicity in October, but was nocturnal in June. Both species showed no evident sex or size modulation of their behaviour. Data were interpreted assuming that all tested species present an endobenthic behaviour ( i.e. animals emerge from the substrate during the active phase of their behavioural cycle).  相似文献   
8.
The temporal patterns of feeding activity of Lipophrys pholis and Coryphoblennius galerita were studied by snorkelling dives during high-waters. The feeding activity was especially intense during the rising-tide when compared to the ebbing-tide. The relative abundances of C. galerita and small L. pholis observed on rock-walls were higher during the rising- and high-tide. However, L. pholis larger than 7–8 cm showed higher relative abundance on rock-walls during the ebbing phase, apparently because they move up and down with the tide, and many individuals were in their downward movements as the tide ebbs. It is hypothesized that the asymmetry in feeding pattern observed in both species reflects a trade off between two conflicting needs, maximizing feeding time and reaching their low-tide shelters in time, avoiding the risk of getting stranded in unsuitable locations.  相似文献   
9.
辽西义县盆地内近东西走向的马神庙-刀把地-三百垄-金刚山一带为义县组标准地层剖面出露地,义县组建阶标准地层剖面枣茨山金刚山层为一套古湖盆相沉积组合。野外详细的沉积学和地层学研究将金刚山层自下而上划分为湖缘碎屑浊流相、浅水湖坪相和半深湖相3个沉积亚相。金刚山层下部湖缘碎屑浊流相包括3个粗-细粒序递变沉积韵律。粗粒岩石单元为灰绿色含长石岩屑凝灰质砂砾岩、杂色砾岩、灰白色含砾凝灰岩;细粒岩石单元由灰白色含砾凝灰岩、灰绿色致密凝灰岩、质纯膨润土组成。韵律沉积底部粗粒岩石单元为浊流头部沉积产物,其中常形成弥散式正粒序递变层理,细粒岩石单元为浊流体部、尾部逐渐稀释的沉积结果,其中常发育水平层理。中部浅水湖坪相沉积由5个膨润土化粉砂岩(质纯膨润土或页岩)-泥灰岩(含方解石细脉灰岩)沉积韵律构成。每一湖坪相的碳酸盐岩与下伏火山灰质沉积厚度之比值变化范围为:0.11~0.47,指示湖盆围缘经历了多期次湖坪沉积时间间隔相等的地质规律。金刚山层上部半深湖相沉积为灰白色纸片状页岩-粉砂质页岩组合。金刚山层下部湖缘火山碎屑浊流沉积指示火山喷发物质近源性、火山喷发多期作用的地质演化规律。中部湖坪相的5个膨润土化粉砂岩(质纯膨润土或页岩)-泥灰岩(含方解石细脉灰岩)沉积韵律指示古湖盆水体至少经历了5期变浅过程,在区域性干旱气候影响下,形成湖坪相泥灰岩沉积。湖盆中心相对深水沉积区接受大量细粒悬浮质沉积,形成静水半深湖相沉积。  相似文献   
10.
Diel changes in vertical distribution and gut pigment contents of Acartia clausi andPseudodiaptomus hessei were studied during several 24-h time series performed between 1993 and 1997 in four sites of the Ebrié Lagoon (Côte d'Ivoire). The sites differed by their morphology and their hydrological structure and by the vertical distribution of chlorophyll biomass. Both species showed classical diel vertical migrations (DVM). Copepodites and adult stages of P. hessei were almost benthic during the day and evenly distributed through the water column at night. The amplitude of DVM of A. clausi increased from copepodites I–III to adults. Copepodites and adults of A. clausi increased significantly their gut fluorescence at night, whereas those of P. hessei showed no clear diel feeding rhythm (DFR). These results suggest that A. clausi feed mostly at night on phytoplanktonic particles and P. hessei feed mostly on benthic algal particles during the day and on sestonic particles at night. No relationship was observed between DFR and DVM because both patterns occurred when food was either vertically homogeneous or vertically stratified. The daily average gut fluorescence of A. clausi increased with ambient chlorophyll concentration until around 12–15 μg l−1, whereas no relationship was found for P. hessei. The implication of these patterns on the adaptation capacities and the behaviour of the two species are discussed. The DVM of P. hessei should explain its rarity in the estuarine area. The comparison of our results with previous ones suggests an evolution of A. clausi DFR between 1981–1982 and 1996–1997, in relation to an intensification of eutrophication.  相似文献   
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