Locomotor behaviour in males,females and groups of Orchestia montagui (Amphipoda,Talitridae) in the supralittoral zone of Bizerte lagoon

Locomotor activity rhythm of Orchestia montagui was investigated under constant darkness in a population collected in spring from the supralittoral zone of Bizerte lagoon (northern region of Tunisia) at Menzel Jmil in spring. This rhythm was recorded in individual and groups of animal by infrared actography every 20 min by multichannel data loggers, at a constant temperature of 18 ± 0.5 °C. According to double-plotted actograms, wave forms and periodogram analysis, results revealed different locomotor pattern. However, locomotor activity rhythm of males was more stable than females. Furthermore, the mortality was statistically higher in unmixed groups than in mixed groups.     

Etude Ultrastructurale de la Sporulation de Paramarteilia orchestiae gen. n., sp. n., Parasite de l'Amphipode Orchestia gammarellus (Pallas)

RESUME. L'individualisation de 2 spores bicellulaires à partir d'un měme pansporoblaste caractérise la sporulation du parasite de l'Amphipode Orchestia gammarellus (Pallas) précédemment décrit sous le nom de Marteilia sp. Cette sporulation le distingue des espèces du měme genre parasite d'Hutres qui sont toutes caractérisées par la production de spores tricellulaires. Les conditions semblables dans lesquelles les pansporoblastes paraissent se differencier à partir d'une cellule souche dans laquelle ils poursuivent leur évolution vers la sporogenèse ainsi que divers caractères cytologiques communs, nous incitent à maintenir tous ces parasites dans une měme famille mais à placer celui de l'Amphipode dans un genre différent. Nous proposons de le nommer Paramarteilia orchestiae gen. n., sp. n.
Ces parasites ne peuvent ětre maintenus dans les Protozoaires en raison de leur évolution vers la pluricellularité et de l'individualisation de ces éléments somatiques que représentent la cellule souche primaire, les pansporoblastes et cellules sporales (à l'exception des sporoplasmes). Il semble logique de les inclure dans l'embranchement des Myxozoaires créé par Grassé pour les Myxosporidies et Actinomyxidies qui différencient également des spores pluricellulaires et des éléments somatiques. Les centrioles à 9 singlets de P. orchestiae ainsi que les cellules primaires uninucléées, quel que soit le nombre de pansporoblastes qu'elles contiennent, peuvent ětre considérés comme des caractères résiduels d'Unicellulaires.     

Ichnofossils of the Psilonichnus Ichnofacies and Their Paleoecological and Paleoenvironmental Significance in the Scottish Middle Jurassic

In the Bathonian (Middle Jurassic) Kilmaluag Formation, Great Estuarine Group, on the Isle of Skye, northwest Scotland, are ichnofossils that can be attributed to the burrowing activity of semi-terrestrial crab-like animals. The ichnofossils are preserved within supralittoral breccia-conglomerates and littoral calcareous mudstones and micrites deposited in a closed and shallow, low-salinity to freshwater coastal-lagoon setting. The dominant ichnofossil assemblage is preserved in the supralittoral rocks and comprises variable burrow types forming an ichnocoenosis and assigned to the Psilonichnus ichnofacies. These ichnofossils potentially provide the earliest known record of crab activity and their physiological adaptation to survive in a semi-terrestrial environment. Burrow characteristics include enlarged funnel-shaped apertures, unlined walls, absence of branching or biogenic reworking, inclined to vertical, U- and L-shaped forms and possible basal dwelling chamber. The ichnofossil assemblage preserved in the littoral rocks is attributed to the activity of either semi-terrestrial crabs or shrimps. Ichnofaunal characteristics reveal unique aspects of the paleoenvironments and paleoecology of the tracemaking community, including climatic conditions, substrate characteristics, the possible influence of paleowater table levels, paleoshoreline position, spatial variation in burrow morphology and possible gregarious and territorial behavior.     

Azadirachtin affects the circadian rhythm of locomotion in Leucophaea maderae

Abstract

Azadirachtin shortens the period length of the locomotor activity rhythm in the circadian rhythm of Leucophaea maderae and induces splitting of this rhythm in two components in about 40% of the animals. The phase relationship between the two components is 180°. Both shortening of period and splitting are more pronounced in animals possessing longer periods before the injection of azadirachtin.     

四川卧龙国家级自然保护区三种高山同域鸡形目鸟类的时空生态位比较

高海拔山区气候条件恶劣, 资源匮乏, 探究同域分布的近缘物种如何利用有限的资源以实现稳定共存, 对于了解高山生态系统生物多样性格局的形成和维持机制具有重要意义。鸡形目鸟类飞行能力弱, 属于典型的地栖物种, 生态位空间相对狭窄, 可能面临更高的种间竞争压力。本研究旨在比较几种同域分布的鸡形目鸟类的时空生态位, 为了解高山生态系统同域物种的共存机制提供新的研究案例。2020年4-9月, 研究人员在四川卧龙国家级自然保护区海拔3,300-4,200 m的高山区域进行了野外调查, 通过样线法和样方法对鸡形目鸟类群落优势物种绿尾虹雉(Lophophorus lhuysii)、雉鹑(Tetraophasis obscurus)和雪鹑(Lerwa lerwa)繁殖期的微生境进行调查, 使用红外相机对其活动节律进行监测, 并运用核密度估计法从微生境利用和日活动节律两个生态维度进行了种间生态位比较。结果显示, 雪鹑在微生境利用和日活动节律上均与其他两个物种存在显著差异。绿尾虹雉与雉鹑在微生境的利用上具有相似偏好; 但绿尾虹雉的早活动高峰晚于雉鹑, 晚活动高峰早于雉鹑, 表现出显著的种间日活动节律差异; 然而, 整合两个维度后, 绿尾虹雉和雉鹑的整体生态位仍然高度重叠, 没有显著分化。本研究表明高山鸡形目物种间的生态位分化体现于多个不同的生态维度, 并且不同物种之间的分化方式有所差异。在空间和时间生态位上的显著分化使雪鹑与同域物种间的竞争压力相对较小, 有利于其实现稳定共存。而绿尾虹雉与雉鹑的整体生态位高度重叠, 建议进一步对其食性开展研究, 探讨营养生态位上的潜在种间分化。     

Residual circadian rhythmicity after bilateral lamina-medulla removal or optic stalk transection in the cricket, Gryllus bimaculatus

Bilateral optic stalk severance or lamina-medulla region removal were carried out in 47 adult male crickets Gryllus bimaculatus DeGeer. Effects of the operations on circadian locomotor activity were investigated under 12 h light: 12 h dark and at a constant temperature of 26°C. In the pre-operative days, 39 of the animals showed a typical nocturnal activity rhythm (normal rhythm), but the remaining 8 exhibited an atypical rhythm which is diurnal rather than nocturnal (abnormal rhythm). The operations eventually caused an arrhythmicity in all animals, suggesting that the crucial part of the central nervous system controlling the cricket circadian activity is located in the lamina-medulla region. However, in some of the post-operative crickets, the rhythm did not immediately disappear but persisted for a while: the diurnal increase of activity was observed up to 2 weeks in all 8 abnormal- and 4 normal-rhythm animals. In addition, 8 out of 39 normal-rhythm animals showed a single well-defined post-operative peak which occurred approximately in phase with the nocturnal peak prior to surgery. These results are discussed in relation to a possibility of involvement of the oscillatory structure outside the optic lobes.     

Effects of dark-light step transitions on circadian locomotor activity rhythms of the hagfish,Eptatretus burgeri

Captive hagfish,Eptatretus burgeri, were subjected to step transitions from continuous dark (DD) to continuous light (LL) and their locomotor activity patterns recorded. Free-running activity rhythms occurred in both the DD and LL regimes. The timing of the transition influenced the circadian period (τ), the relationship between the period response (δτ, or τ{inLL}–τ{inDD}, change in the circadian period) and the former being represented by a cosine curve δτ became most positive and most negative when hagfish underwent a DD-LL transition shortly before the beginning of the duration of activity (α) and shortly after the end of such, respectively. The phase response (δ-phase, change in the relative timing of the activity phase) was characterized by a delay in the activity phase after the DD-LL transition, although its magnitude bore no relation to the timing of the transition.     

Circadian Locomotor Activity in Freshwater Decapods: An Ecological Approach

Circadian rhythms of locomotor activity shown by freshwater decapods display different patterns among crayfish, Procambarus, and crabs, when exposed to artificial light-dark cycles. Crayfish are mainly nocturnal while a crepuscular activity is observed in crabs of the genus Pseudothelphusa. In constant darkness, free running rhythms are displayed in unimodal or bimodal patterns by crayfish Procambarus; however, Pseudothelphusa continues to show bimodal rhythms. The many studies using locomotor activity indicate that the rhythm in freshwater crabs is circadian in nature, but that a multioscillatory system may be controlling the overt rhythm. In the present study, the implications of different locomotor activity patterns are analyzed in selected freshwater decapods with regard to the interactions between light and the organisms. Crabs and crayfish are commonly found in similar habitats, often sharing the same environment; however, different patterns of locomotor activity as well as different sensitivities of the bouts of activity with regard to entrainment by light, indicate that distinct temporal niches may exist that result in temporal exclusion or low competition.     

蚤蝇的昼夜活动节律及睡眠行为研究

蚤蝇是重要的法医昆虫,同时是实验室中遗传、发育和生物测定等研究的重要对象。然而,蚤蝇的昼夜活动节律和睡眠行为及其在脑部的神经网络目前还不清晰。本文通过捕获本地蚤蝇并对其进行分子鉴定,研究了蚤蝇的昼夜活动节律和睡眠行为,同时表征了蚤蝇脑部核心钟神经元和多巴胺神经元。结果表明:蚤蝇在12h光照∶12h黑暗(12L∶12D)条件下不存在对开灯前或关灯前的活动预期,其双峰活动模式是对开关灯的光反应行为。在全黑暗(DD)条件下蚤蝇内源活动周期接近24h。黑腹果蝇神经肽PDF抗体免疫显示蚤蝇脑部核心钟神经元4~5个,不像黑腹果蝇一样存在明显的神经轴突。在睡眠行为上,蚤蝇雄虫和雌虫在整体活动强度、睡眠节律模式、总睡眠上均没有明显差异。相反,雄虫总睡眠次数和晚上睡眠次数低于雌虫,而总睡眠持续时间、晚上睡眠持续时间、总入睡时间和晚上入睡时间高于雌虫。此外,影响睡眠的重要多巴胺神经元在蚤蝇脑部的分布与黑腹果蝇类似。     

Description of a new species from Laguna Chichancanab,Yucatan, Mexico: <Emphasis Type="Italic">Cyprinodon suavium</Emphasis> (Pisces: Cyprinodontidae)

Cyprinodon suavium is a new species that belongs to the endemic species flock from Laguna Chichancanab, Yucatan, Mexico, which is proposed to have evolved by sympatric speciation in the lake during the last 8000years. C. suaviumis distinguished from all other known Cyprinodon species by a flattened and concave inter- and postorbital skull roof and a terminal mouth with distinctive thickened lips. The short gut length and dietary items found in the gut indicate that C. suavium is one of the carnivorous members of the flock.     

Assessment of Anxiety Level and Mental Health Status in Spouses and Children of Day-Working and Shift-Working Men

The present study was aimed at assessing the effects of the unusual schedules of shift-working men on anxiety and mental health of their spouses and children. The anxiety and mental health of 396 subjects that include 133 spouses and 263 children of day-working and shift-working men were monitored by employing specific inventory. Anxiety scales (trait, state and free-floating) and mental health inventory were administrated to each subject. Results indicate that the average levels of free-floating anxiety for the spouses and children of shift-working men were found to be significantly higher in comparison with that of their counterparts sampled in the family of day workers. This was also true when data were segregated with respect of gender and compared. Except in female children of shift workers all other groups of children had statistically significantly higher level of state anxiety as compared with that of their respective mothers. The results of this study further reveal that the spouses of shift-working men exhibited lower mental health rating as compared with the spouses of day-working men. Furthermore, a significant negative relationship was noticed between anxiety and mental health in all cases excepting in spouses of shift-working men for state anxiety. Although the findings of the present study could be attributed to the irregular routine of shift workers, it appears mandatory to carryout further intensive studies to draw convincing conclusions.     

Different behavior of body temperature and total locomotor activity daily rhythms during light/dark cycle in stabled Oryctolagus cuniculus

In order to investigate the potential causal link between the rhythm of activity and body temperature, we simultaneously recorded rectal temperature and total locomotor activity in five clinically healthy female rabbits (blue Vienna breed), 12 week old and mean body weight 2.7 ± 0.3. Animals were housed in individual cages (90?×?50?×?35 cm) under natural 12/12 light/dark cycle. Total locomotor activity was monitored for 15 days by an activity data logger. On day 1, 5, 10, and 15 rectal temperature was recorded every 2 h for a 24-h period. Application of single cosinor method showed a nocturnal daily rhythm of rectal temperature with a range of oscillation of about 1 °C, acrophase after dusk and low robustness value. The daily rhythm of locomotor activity showed its acrophase in the middle of the scotophase and a high robustness value. This information improves the knowledge available on the circadian biology of rabbits useful in the evaluation of physiology of this species.     

Light and dark rations and the photic entrainment of circadian locomotor activity patterns in the South American Silver Catfish (Rhamdia quelen,Quoy & Gaimard, 1824)

The aim of this study was to evaluate the daily rhythm of locomotor activity in Rhamdia quelen (R. quelen). A total of 30 fish were enrolled in the study and were equally divided in 10 groups and maintained in 100 liters tanks. The locomotor activity was measured in fish maintained under the LD 12:12 photoperiod regime; thereafter, the LD cycle was reversed to DL in order to study the resynchronization and to explore the endogenous pacemaker. Subsequently, the fish were subjected to constant conditions of light to test whether or not locomotor rhythms are regulated by the endogenous circadian clock. The effect of increasing light length and intensity was studied on daily rhythm of locomotor activity of fish. Our results showed that the R. quelen is a strictly diurnal species, the rhythm of locomotory activity resynchronized quickly after inverting the LD cycle and persist under free course LL, suggesting a circadian origin. The light showed a significant masking effect often blocking the expression of the biological rhythm. The strictly diurnal behavior is controlled directly by the photoperiod and maintained even under very dim light (30 lux).     

Circadian Rhythms of Plasma Concentrations of Na+ and K+ and Their Urinary Excretion in Normal and Diabetic Rats

The effects of streptozotocin induced diabetes (50 mg/Kg) on the circadian rhythms in the excretion of sodium and potassium as well as their plasma concentration rhythms were investigated. Control (C) and diabetic (D) rats were studied during a light-dark (12h:12h) cycle and fed ad libitum. Statistically significant circadian rhythms were found for sodium and potassium excretion in C rats. The orthophases of both rhythms occurred in the dark phase, the potassium one occurring before that of sodium. In D rats there is increased excretion of both sodium and potassium with the rhythmicity maintained for sodium excretion only, which has an earlier orthophase than in the C rats. Plasma sodium and potassium concentrations showed a statistically significant circadian pattern in C rats, with orthophase in the light phase. This rhythmicity only appears in plasma potassium concentration for D rats, with orthophase at the end of the dark phase. The results in diabetic rats may suggest that the glomerular filtration rate (GFR) and/or tubular reabsorption rhythms are still contributing to the sodium excretory rhythm, and that the loss of the circadian rhythm in sodium plasma concentration has no influence on the sodium excretion rhythm. Nevertheless, the loss of the potassium excretion rhythm may suggest a disruption of the variations in the secretory process, as this excretion seems to be independent of the plasma potassium concentration rhythm, which is not lost in D rats.     

Meal size and feeding management strategies influence the daily rhythm of total locomotor activity in horses (Equus caballus)

Keeping and management of horses can induce changes to instinctive and innate behavioural patterns. We investigated the effect of five different management conditions in five groups of horses. All groups were housed in individual boxes under natural environmental and lighting conditions. They were fed three times a day (07:00, 12:30 and 20:00) and had free access to water. Group A was fed with 8 kg/capo/die of hay divided in the three meals. Group B was fed with 8 kg/capo/die of an unifeed divided in the three meals. Group C was fed with unifeed at 07:00 and 12:30 and with hay at 20:00. They were kept in wood-bedded boxes. Groups D and E were fed with unifeed at 07:00 and 12:30, respectively, and in the other, two meals received hay. They were kept in straw-bedded boxes. Our results showed a daily rhythm of total locomotor activity in all groups, influenced by management conditions. Group A engaged in meal patterns similar to those seen in grazing animals. Groups B and C showed the highest MESOR values due to a high searching behaviour. Group C showed a nocturnal acrophase contrary to the other groups. Groups D and E showed a total locomotor activity pattern similar to that observed in Group A probably due to an increase in straw-bedding consuming. The reduction of fibre in diet has an impact on physiology and behaviour of horses. The valuation of diet and in bedding provided to horses kept in box is useful to guarantee the maintenance of the physiological daily rhythm of total locomotor activity.     

Effects of lithium salts on the behaviour and the orcadian system of Mesocricetus auratus W.

Abstract

LiCl (195 μg/g body weight and day) reduces water uptake in Syrian hamsters by 40%. Sleep duration is increased from 50% per day to 60% per day. Other behavioural items are hardly influenced. Shortening and lengthening of the circadian period was induced by Li⁺ in individual hamsters, but the mean period of the population was not changed. The upper limit of entrainment is increased by Li⁺.