Effects of temperature and perch diameter on arboreal locomotion in the snake Elaphe guttata

Arboreality is widespread in multiple lineages of snakes and these habitats are important for foraging, escaping predators, and thermoregulation for many species. However, very little is known about factors influencing the arboreal locomotor abilities of snakes. Arboreal performance was assessed in a semi-arboreal snake (Elaphe guttata) using an artificial perch apparatus. Locomotor velocity, body posture, and balance was measured during movement on three perch diameters (3, 6, 10-cm) at three temperatures (10, 20, 30 degrees C). Velocities attained by E. guttata on perches are much slower than those of terrestrial lateral undulation and swimming and somewhat slower than concertina velocities recorded in other species across the same experimental temperatures. At higher temperatures, faster speeds were associated with a more elongated posture. At lower temperatures, snakes displayed a more looped body posture, but still fell more often than at higher temperatures. Our results suggest that temperature has a large influence on both balance and movement by snakes on perches. Although there were no differences in velocities resulting from perch diameter, snakes fell more often from thicker perches. This differs from arboreal velocities attained by limbed vertebrates, which decrease with decreasing perch diameter, suggesting that snakes have a size-relative advantage over limbed animals, such as lizards, when traversing a network of narrow branches. Future studies investigating arboreal locomotion among snakes that vary both phylogenetically and morphologically are needed to assess the potential benefits of limblessness in complex, three-dimensional environments.     

Spatial ecology of arboreal snakes (Hoplocephalus stephensii,Elapidae) in an eastern Australian forest

Abstract Stephens' Banded Snakes (Hoplocephalus stephensii Krefft 1869) are large (to 1 m), highly arboreal elapid snakes, restricted to mesic forested areas along the eastern coast of Australia. Radiotelemetric monitoring of 16 individuals at Whian Whian State Forest in north‐eastern New South Wales over 25 months provided the first data on spatial ecology of this threatened taxon. Two major influences on movements by Stephens' Banded Snakes were identified: the distribution of large hollow‐bearing trees, and the avoidance of conspecifics. Radiotracked snakes were sedentary inside tree hollows for extended periods (mean = 8 days) during their active season, interrupted by occasional long (mean = 124 m) nocturnal movements to another shelter tree. Snakes travelled on the ground rather than within the canopy, and thus were potentially exposed to terrestrial predators. Although the home ranges of the radiotracked snakes overlapped substantially (mean = 27%), simultaneous occupancy of ‘shared’ shelter trees was less common than expected by chance. Hence, we conclude that adult Stephens' Banded Snakes generally avoid the presence of conspecifics. Snakes used from five to 30 shelter trees and home ranges of male snakes were larger than those of females (mean = 20.2 vs 5.4 ha). The large spatial scale of these movements, and limited overlap among individuals, means that a viable population of this taxon requires a large area of contiguous forest. This requirement may explain why the species has not persisted in small forest fragments.     

Microhabitat use affects goby (Gobiidae) cue choice in spatial learning task

This study investigated whether spatial learning ability and cue use of gobies (Gobiidae) from two contrasting habitats differed in a spatial task. Gobies were collected from the spatially complex rock pools and dynamic, homogenous sandy shores. Fishes were trained to locate a shelter under the simulated threat of predation and it was determined whether they used local or extra‐maze (global) and geometric cues to do so. It was hypothesized that fishes from rock pools would outperform fishes from sandy shores in their ability to relocate shelter and the two groups would differ in their cue use. It was found that rock‐pool species learnt the location of the correct shelter much faster, made fewer errors and used a combination of all available cues to locate the shelter, while sand species relied significantly more on extra‐maze and geometric cues for orientation. The results reported here support the hypothesis that fishes living in complex habitats have enhanced capacity for spatial learning and are more likely to rely on local landmarks as directional cues than fishes living in mundane habitats where local cues such as visual landmarks are unreliable.     

Effects of vinconate on spatial learning impairments induced by medial septal lesion in rats.

We investigated the effects of vinconate, a novel vinca alkaloid, on spatial learning deficits induced by medial septal (MS) lesion in rats. MS lesion was produced by passing an anodal DC current. In vehicle-treated MS-lesioned rats impairment of spatial learning was observed, shown by a decrease in correct choices and an increase in total errors during training in a radial arm maze task. Vinconate (10 mg/kg) treatment alleviated the decrease in correct choices and the increase in total errors induced by MS lesion. Vinconate (5 and 10 mg/kg) treatment showed a tendency to reverse the decrease in choline acetyltransferase activity in the hippocampus caused by MS lesion. The present study suggests that vinconate has an anti-amnesic effect on MS lesion-induced amnesia by ameliorating the dysfunction in cholinergic (ACh) neurons.     

First Insight into Exploration and Cognition in Wild Caught and Domesticated Sea Bass (Dicentrarchus labrax) in a Maze

European sea bass aquaculture is so recent that very little is known on the effects of the early steps of its domestication. Behavioural parameters are sensitive indicators of the domestication process since they are generally impacted as soon as the first generation. The present work compared wild-caught and domesticated sea bass juvenile swimming activity, exploration and ability to learn to discriminate between two 2-D objects associated to a simple spatial task that enabled the tested individual to visually interact with an unfamiliar congener (the reward) located behind a transparent wall at the end of one of the two arms of a maze. Ten fish from each origin were individually tested 3 times in a row during 3 days (9 trials in total). Fish were placed in a start box closed by a transparent wall located in front of two 2-D objects. Fish were filmed during 10 min after the removal of the start box wall. Different swimming variables including angular velocity, total distance travelled and velocity mean, were analyzed from videos as well as the time spent in each of 6 virtual zones including the reward zone near the congener (Cong) and the zone opposite to the reward zone (OpCong). Two learning criteria were chosen: the number of successful turns and time to reach Cong. Behavioural differences were found between domesticated and wild fish. Angular velocity was higher in wild fish while the distance travelled and the velocity mean were higher in domesticated ones. Wild and domesticated fish spent most of the time in Cong and in OpCong. No differences were seen in learning ability between wild and domesticated fish. However, our findings for learning require confirmation by further studies with larger numbers of learning sessions and experiments designed to minimise stress. This study therefore demonstrated an impact of domestication on swimming behaviour but not on spatial learning.     

Spatial-motor asymmetry in rat behavior

The experiments were carried out on rats in three different mazes: U-shape, complicated linear and 12-beam radial. Series of tests differed by succession of rats learning in the mazes and the character of reinforcement. Most of the rats manifested a spatial-motor asymmetry (SMA) in all used situations. Under all conditions SMA increased in the process of learning parallel to a decrease of the errors number or the time of the task performing. In the group of rats sequently learning in different mazes, the direction of moving changed with changes in spatial characteristics of the medium. Preliminary training of rats in conditions creating SMA, promoted its acceleration in new conditions. The conclusion is made that the rats have no physiological mechanism which rigidly fixes a single (in all conditions) direction of runs. SMA is considered as a behavioural tactics which is corrected in the process of training and which provides for an adequate behaviour.     

The social transmission of spatial information in homing pigeons

We adapted a technique to explore the social transmission of spatial information in homing pigeons Columba livia. Five demonstrator pigeons were first trained to find a food goal within an indoor arena. This arena consisted of nine lidded cups laid out within a 12x12 grid on the floor. The task was to find the goal cup and flip the lid to obtain the food hidden within. Once the demonstrators had reached criterion the experiment proper began. During stage 1 of the experiment, 10 target birds, which had not previously been trained to find the goal, were introduced to the spatial task either in isolation or paired with a demonstrator. We measured how long they took to complete the task, the number of squares crossed on the grid, and the number of incorrect lids flipped. In stage 2, the target birds were introduced to the arena a second time, by themselves, and we compared the performance of the birds in the two treatments. The pigeons that had been introduced to the task with a demonstrator in stage 1 walked further and made more incorrect choices when searching for the food goal in stage 2 than the pigeons that were introduced to the task alone. This indicates that pigeons learn a spatial, food-finding task more effectively when performing the task alone than when accompanied by a knowledgeable conspecific. We discuss possible reasons for this in the light of previous experiments. Copyright 1999 The Association for the Study of Animal Behaviour.     

Positive impact of levetiracetam on emotional learning and memory in naive mice

AimsThe effect of an antiepileptic drug on cognitive function is of primary importance with respect to the patient's quality of life. Levetiracetam (LEV) is a novel antiepileptic drug used to treat epilepsy, but its effects on spatial and emotional learning and memory are not yet well understood. The goal of our study was to establish the effects of LEV (17 and 54 mg/kg, intraperitoneally (IP)) on spatial memory retrieval in the Morris water maze test and on acquisition and memory formation in the passive avoidance (PA) test in naive mice.Main methodsThe subjects were adult male BALB/c mice. Spatial learning and memory was established with the Morris water maze (MWM) test. The ‘time spent in escape platforms quadrant’ and the ‘distance to platform’ analyses were measured using a video tracking system to determine spatial memory function. Emotional learning and memory were determined with a one-trial, step-through passive avoidance test.Key findingsIn the MWM test, LEV (17 and 54 mg/kg) neither affected the time spent in the target quadrant nor altered the distance to platform. Moreover, LEV had no effect on swim speed. In the PA task, LEV (17 and 54 mg/kg) significantly prolonged retention latency.SignificanceOur results indicate that LEV did not alter spatial memory retrieval in the MWM test, but it did show some ameliorating effects on acquisition and memory formation in the PA test in naive mice.     

Attenuation of NF-κβ mediated apoptotic signaling by tocotrienol ameliorates cognitive deficits in rats postnatally exposed to ethanol

Ethanol-induced damage in the developing brain may result in cognitive impairment including deficits on neuropsychological tests of learning, memory and executive function, yet the underlying mechanisms remain elusive. In the present study we investigated the protective effect of tocotrienol against cognitive deficit, neuroinflammation and neuronal apoptosis in rat pups postnatally exposed to ethanol. Pups were administered ethanol (5g/kg, 12% v/v) by intragastric intubation on postnatal days 7, 8 and 9. Ethanol-exposed pups showed significant memory impairment in Morris water maze task as evident from increase in escape latency and total distance travelled to reach the hidden platform. Time spent in target quadrant, % total distance traversed in target quadrant and frequency of appearance in target quadrant was also significantly decreased in ethanol exposed pups in probe trial. Poor memory retention was exhibited by ethanol-exposed pups in elevated plus maze test also. Impaired cognition was associated with significantly enhanced acetylcholinesterase activity, increased neuroinflammation (oxidative-nitrosative stress, TNF-α, IL-1β and TGF-β1) and neuronal apoptosis (NF-κβ and Caspase-3) in different brain regions of ethanol-exposed pups. Co-administration with tocotrienol significantly ameliorated all the behavioral, biochemical and molecular alterations in the different brain regions of ethanol exposed pups. The current study thus demonstrates the possible involvement of NF-κβ mediated apoptotic signaling in cognitive deficits associated with postnatal ethanol exposure in rats and points to the potential of tocotrienol in the prevention of cognitive deficits in children with fetal alcohol spectrum disorders (FASDs).     

Arena behaviour of ewes selected for superior mothering ability differs from that of unselected ewes

As part of a study searching for criteria for the genetic improvement of maternal ability, behavioural parameters were measured in ewes from two flocks, one selected for maternal ability (Fertility Flock), the other unselected (Random Flock). Behaviour was measured in an open-field test prior to mating in 1990 and in an arena test prior to mating in 1990 and 1991, and prior to lambing in 1991.The open-field test consisted of placing the ewes in an enclosed field measuring 16 m × 16 m for a period of 5 min. The field was divided into 16 squares each measuring 4 m × 4 m. The following measures were made: number of squares entered, whether or not the ewe bleated, urinated or defaecated and the number of bleats.The arena test consisted of placing the ewes in an enclosed arena measuring 3 m × 13 m; at one end of the arena there was a pen of sheep, in front of which sat a person. The floor of the arena was marked into 39 squares each measuring 1 m × 1 m. The test lasted 10 min and the following parameters were derived by recording the square in which the animal was located every 15 s; minimum and maximum distance from the person, mean distance from the person and distance travelled. The number of bleats was also recorded for each ewe, as well as whether or not she bleated, urinated or defaecated.There were no differences between the two flocks in any of the parameters measured in the open-field test. However, on all three occasions, there were differences between the two flocks in the total distance travelled and the number of bleats. The coefficients of repeatability of these two parameters, as measured by the intra-class coefficient of correlation, were 0.48 and 0.57 respectively.The results indicate that the arena test measures differences in the behaviour of ewes that differ in maternal ability and may therefore be of use in identifying ewes of superior mothering ability.     

Environmental enrichment alters the behavioral profile of ratsnakes (Elaphe)

This study investigated the effects of environmentally enriched and standard laboratory housing conditions on behavioral performance in 16 subadult ratsnakes (Elaphe obsoleta) using a split-clutch design. In a problem-solving task, snakes housed in enriched environments (EC) exhibited shorter latencies to the goal hole as compared to snakes housed in standard conditions (SC). In an open field task, EC snakes tended to habituate more quickly than SC snakes with repeated testing. A feeding task did not reveal any significant differences between EC and SC snakes. A discriminant function analysis correctly assigned all snakes to their appropriate housing treatment groups, based on the responses in each of the behavioral tasks. This suggests that each group had a distinct behavioral profile; that is, EC snakes were more behaviorally adaptive than SC snakes. This study demonstrated that housing conditions can affect the behavior of captive snakes and produce improvements in behavior similar to those seen in mammalian enrichment studies.     

Experimental Validation of Sex Differences in Spatial Behavior Patterns of Free‐Ranging Snakes: Implications for Social Interactions

Social interactions often play a significant role in determining patterns of spatial use. Although snakes are generally thought of as asocial, recent spatial dispersion studies suggest that the spatial ecology of snakes may be more strongly influenced by social interactions than previously thought. We investigated the spatial behavior patterns of a western cottonmouth (Agkistrodon piscivorus) population in east Texas by uniquely combining radio‐telemetry studies on free‐ranging snakes with experimental arena trials with captive individuals from the same population. Observations from the radio‐telemetry study on free‐ranging A. piscivorus indicated that females were more gregarious than males. In the follow‐up study, spatial dispersion data from captive snakes maintained in experimental field arenas yielded similar results to spatial behavior patterns of free‐ranging individuals. When compared to random experimental controls, these data suggest that observed spatial behavior patterns are related to mechanisms associated with both active avoidance among males and conspecific attraction among females. In addition to uniquely combining both free‐ranging and captive observations, this is the first snake study to demonstrate sex differences with both of these divergent (attraction and avoidance) spatial patterns within a single population. Thus, similar to other vertebrate groups, a growing body of literature suggests that social interactions in snakes should be strongly considered in interpretations of spatial ecology and behavior.     

跑台运动促进幼龄大鼠学习能力

为了探讨跑台运动对幼龄大鼠学习能力的影响,实验采用5周龄Sprague-Dawley大鼠,随机分为安静对照组和跑台运动组,其中跑台运动组大鼠以低强度进行为期一周的跑台运动;然后使用Morris水迷宫,对两组大鼠的定位航行和空间探索能力进行分析。在定位航行实验中,运动组大鼠寻找到平台的潜伏期明显短于对照组（P〈0．05）;并且随着训练次数的增加,运动组大鼠的游泳速度明显高于对照组（P〈0．01）;另外,运动轨迹的弯曲度表明运动组大鼠还表现出了较强的寻找平台的动机以及对平台位置较为准确的空间定位能力。在空间探索实验中,两组大鼠的游泳速度并没有明显差异,从大鼠在各象限内穿越平台相应位置的次数来看,运动组大鼠在D象限穿越的次数高于对照组,但无统计学差异（P〉0．05）。上述结果提示,低强度的跑台运动在短时间内便可以明显提高幼龄大鼠的学习能力。     

Hippocampal Lesions Impair Rapid Learning of a Continuous Spatial Alternation Task

The hippocampus is essential for the formation of memories for events, but the specific features of hippocampal neural activity that support memory formation are not yet understood. The ideal experiment to explore this issue would be to monitor changes in hippocampal neural coding throughout the entire learning process, as subjects acquire and use new episodic memories to guide behavior. Unfortunately, it is not clear whether established hippocampally-dependent learning paradigms are suitable for this kind of experiment. The goal of this study was to determine whether learning of the W-track continuous alternation task depends on the hippocampal formation. We tested six rats with NMDA lesions of the hippocampal formation and four sham-operated controls. Compared to controls, rats with hippocampal lesions made a significantly higher proportion of errors and took significantly longer to reach learning criterion. The effect of hippocampal lesion was not due to a deficit in locomotion or motivation, because rats with hippocampal lesions ran well on a linear track for food reward. Rats with hippocampal lesions also exhibited a pattern of perseverative errors during early task experience suggestive of an inability to suppress behaviors learned during pretraining on a linear track. Our findings establish the W-track continuous alternation task as a hippocampally-dependent learning paradigm which may be useful for identifying changes in the neural representation of spatial sequences and reward contingencies as rats learn and apply new task rules.     

The Strength of Species Recognition in Captive Female Zebra Finches (Taeniopygia guttata): A Comparison Across Estrildid Heterospecifics

Conspecific recognition is essential for sexually reproducing species. Captive zebra finches ( Taeniopygia guttata ) are a model system in which the behavioural, ontogenetic and neurobiological bases of own-species (conspecific) recognition have been studied in detail. To assess the potential role of phylogeographic effects on species recognition, we examined the spatial preferences of unmated captive-bred female zebra finches between unfamiliar captive males of conspecific and estrildid heterospecific male stimuli. In accordance with prior studies using domesticated Bengalese finches ( Lonchura striata vars. domestica ), we found significant spatial and behavioural preference for conspecific males by female zebra finches, irrespective of heterospecific male phylogeographic origin mating status, or individual behaviour. This result has ramifications for the interpretation of social and mate preferences in this model species as it implies a consistency of species discrimination by captive female zebra finches.     

基于防灾目标的城市公园空间结构及合理性评价——邻域法在长春市的应用

防灾公园作为重要的空间要素之一,是城市应急避难场所建设的主要形式.基于防灾目标,运用邻域法对长春市公园布局合理性进行评价.结果表明:研究区防灾公园的空间分布不均衡,西北部密集、东南部稀疏,呈现出同一等级防灾公园集中分布、不同等级防灾公园分散分布的空间格局.防灾公园避难有效性较低.50%以上公园人均避难面积不足,近40%公园可达性超过最长避难时间.不同等级防灾公园的避难有效性存在显著差异,中心防灾公园最高、固定防灾公园次之、紧急防灾公园最差.针对长春市防灾公园布局不合理情况提出以下主要建议:不同等级防灾公园可采用镶嵌式的空间布局模式;公园设置标准应与人口分布趋势相对应;加强紧急防灾公园建设.     

Proteomic analyses of songbird (Zebra finch; Taeniopygia guttata) retina

Proteomic analyses of male songbird (Zebra finch; Taeniopygia guttata; ZF) retina were performed resulting in identification of 129 proteins. Comparison of T. guttata retinal proteome with that of chicken found proteins detected in both retinas. Immunohistochemical analyses of T. guttata retinal sections and Western analyses of total retinal protein extract were performed confirming presence of select bona fide retinal proteins. Results demonstrate the utility of one-dimensional gel fractionation for mass spectrometry and will be useful for future proteomic comparison of songbird retina and brain tissues in different behavioral and pharmacological studies.     

水迷宫实验中不同性别树鼩学习记忆能力的比较

目的研究雌雄树鼩空间学习和记忆能力的差异。方法随机选择自繁F1代树鼩20只（雄11只,雌9只）,在相同条件下进行8 d的水迷宫实验,包括前7 d的定位航行实验和第8天的空间探索实验。结果定位航行实验中雌雄逃避潜伏期、游泳总路程差异无显著性（P〉0.05）,但不同时间水平差异有显著性（P〈0.05）;平均游泳速度雌雄差异无显著性（P〉0.05）。空间探索实验中目标象限游泳时间和总时间之比、目标象限游泳路程和总路程之比雌雄差异无显著性（P〉0.05）;穿越目标象限次数和搜索策略雌雄差异有显著性（P〈0.05）。结论水迷宫实验中树鼩在空间学习能力上雌雄无差异,但在空间探索实验中雄性的表现优于雌性。     

Tail loss, body condition and swimming performances in tiger snakes, Notechis ater occidentalis

In limbless tetrapods such as snakes, propulsive forces are generated by lateral undulations of the body and of the tail. In a large population of tiger snakes from Western Australia, tail loss was extremely common (58% of the individuals) and often very severe (more than two-thirds of the tail was missing in 14% of the cases, and in some instances, the tail was totally lost). Tail loss was not however correlated with body size, mass or body condition of wild individuals, and hence did not influence their abilities to acquire resources. These large venomous snakes exhibit marked aquatic habits. Locomotor tests in controlled conditions revealed that tail loss had a significant negative influence on burst swimming performances. However, no effect was found on routine swimming speed and total distance travelled over 5 min. These results suggest that a long and slender tail, although important for maximal speed, is not necessarily relevant for the locomotor abilities required for successful hunting. Tail-damaged individuals outnumbered intact snakes, suggesting that tail loss did not severely compromise survival. Overall, in this species, a slight deterioration of maximal speed due to severe tail loss probably has a low (undetectable) ecological impact, at least for adults.