鄱阳湖区稻田生境中灰鹤越冬行为的时间分配与觅食行为

2013年11月—2014年2月,采用瞬时扫描和焦点动物法研究了鄱阳湖区稻田生境中灰鹤越冬行为的时间分配、活动节律与觅食行为。结果显示,觅食(64.09%)行为所占比例最大,其次为警戒(15.97%)、飞行(8.67%)和修整(7.37%)行为。4种主要行为中,觅食行为时间分配随越冬前期(11月)、中期(12月—翌年1月)、后期(2月)逐渐增加,其余行为时间均逐渐减少。各环境因子对主要行为的影响存在显著交互效应,修整行为随各环境因子变化最为明显,日最低温度升高、日最高温度降低、日照长度增加及湿度降低都会使修整行为增加;日照长度增加和湿度降低时,觅食行为增加;日照长度增加时,警戒行为减少。环境因子对成鹤影响效果与总体相同。环境因子仅对幼鹤的觅食行为影响显著,即日照长度增加和湿度降低,幼鹤觅食行为增加。环境因子对行为的影响为非线性关系,致使其影响趋势在不同范围内有所变化。行为节律上,灰鹤昼间各时段觅食行为保持较高水平,觅食高峰出现在11:00—11:59和17:00—17:30。灰鹤觅食生境与其夜宿地分离,致其上午觅食高峰有所推后。幼鹤昼间各时段行为节律与成鹤有较大差异,且各时段觅食行为比例均高于成鹤。灰鹤越冬期在稻田生境的平均啄食频率为(32.06±0.47)次/min,平均步行频率为(6.55±0.35)步/min。啄食频率与步行频率呈极显著负相关。时段和集群类型对啄食频率的影响存在显著交互效应。稻田中食物资源的可利用性逐渐下降,灰鹤的啄食频率随时间逐渐降低,为保证越冬期间获取足够的能量供应,灰鹤采取逐渐增加步行频率和觅食时间的策略。有觅食间隔的抽样单元中,平均警戒次数为(1.37±0.04)次/单元,平均警戒持续时间为(6.02±0.37)s/单元。成鹤花费在警戒的时间多于幼鹤,家庭群中的个体警戒持续时间多于聚集群中的个体。     

Outline of a probabilistic approach to animal sociology: III

The probabilities of the emergence of the two kinds of social structure in a 3-bird flock (chain and cycle) are deduced under the assumption of certain biases acting on the social dynamics of the flock. In particular a bias against the reversal of peck order and a bias against encounters of individuals of disparate social rank are considered. Like-wise a distribution of an “inherent” fighting ability is considered which influences the outcomes of encounters. A functional relation is derived between the importance of this ability and the initial probability of a chain structure.     

QUININE HYDROCHLORIDE ACCEPTABILITY AFTER WATER DEPRIVATION IN GALLUS DOMESTICUS

The latency to peck and show the oral aversion response wasmeasured when 6 Brown Leghorn hens were presented with eitherwater or 0.005 M quinine hydrochloride (QHCl) after either 2,4 or 6 h water deprivation. The absence of any differences inthe latencies to peck at water with the 3 deprivation schedulesindicated no significant increase in the level of motivation,whereas, it was found that the latencies to peck at the quininesolution were significantly reduced with increasing deprivation.After 2 h deprivation the birds showed significantly longerlatencies than with water but after 6 h deprivation there wasno significant difference. By comparing the ratio values ofthe number of pecks followed by the oral aversion response dividedby the total number of pecks given to the QHCl solution it wasfound that there was a significant decrease in this ratio from2 to 6 h deprivation. It was suggested that the increase inacceptance of the quinine hydrochloride following deprivationmay be due to changes in ‘taste’ sensitivity.     

The peck orders of chickens: How do they develop and why are they linear?

The development of peck orders in mixed sex groups of domestic chickens was observed to determine how linearity occurred. Based on threats, head-pecks and submission, dominance relationships emerged in a virtual peck right form. Leaping by males, however, did not closely conform to dominance relationships. There were no rank reversals in 50% of male-male and 80% of female-female relationships, and only single changes occurred in most of the others. These resulted from the movements of individuals up the hierarchy rather than from any general reorganization of relationships. Reversals did not necessarily occur between rank neighbours, and stable triangles were sometimes introduced. The initial status of males and females depended upon the age at which they first showed aggression, while the final, stable status of males depended upon the age at which they were first submitted to. Sexual maturity of the males produced a number of changes, with earlier-maturing birds tending to rise in status above their later-maturing companions. Linear hierarchies therefore appear to result from birds developing at different rates.     

Rats (Rattus norvegicus) and pigeons (Columbia livia) are sensitive to the distance to food,but only rats request more food when distance increases

Three experiments investigated foraging by rats and pigeons. In Experiment 1, each response on a manipulandum delivered food to a cup, with the distance between the manipulandum and the cup varying across conditions. The number of responses made before traveling to collect and eat the food increased with distance for rats, but not for pigeons. In Experiment 2, two manipulanda were placed at different distances from a fixed food source; both pigeons and rats preferentially used the manipulandum closest to the food source. Experiment 3 was a systematic replication of Experiment 1 with pigeons. In different conditions, each peck on the left key increased the upcoming hopper duration by 0.5, 1.5 or 2.5 s. Completing a ratio requirement on the right key of 1, 4, 8, 16 or 32 pecks, depending on the condition, then produced the food hopper for a duration that depended on the number of prior left pecks. As the ratio requirement increased on the right key, pigeons responded more on the left key and earned more food. Overall, the results replicate previous research, underlining similarities and differences between these species. The results are discussed in terms of optimal foraging, reinforcer sensitivity and delay discounting.     

An instance of viewpoint consistency in pigeon object recognition

Pigeons were trained on a visual discrimination, a task using a TV monitor. Two different types of stimuli appeared as pictures on the TV screen, one was a feeder used in their home cages and the other a coffee mug. One group of the pigeons was trained to peck the screen when the feeder appeared on it, while the other group was trained to peck the screen when the mug appeared. The feeder was considered to be a `familiar object' but the mug an `unfamiliar object' for the subjects. After training, to peck the familiar object, the subjects showed generalization to unusual view pictures of the object, but they did not show such generalization after training to peck the unfamiliar object. These results suggest that view point consistency is limited to familiar objects in pigeons.     

Behavioral research in pigeons with ARENA: An Automated Remote Environmental Navigation Apparatus

Three experiments established the effectiveness of an Automated Remote Environmental Navigation Apparatus (ARENA) developed in our lab to study behavioral processes in pigeons. The technology utilizes one or more wireless modules, each capable of presenting colored lights as visual stimuli to signal reward and of detecting subject peck responses. In Experiment 1, subjects were instrumentally shaped to peck at a single ARENA module following an unsuccessful autoshaping procedure. In Experiment 2, pigeons were trained with a simultaneous discrimination procedure during which two modules were illuminated different colors; pecks to one color (S+) were reinforced while pecks to the other color (S−) were not. Pigeons learned to preferentially peck the module displaying the S+. In Experiment 3, two modules were lit the same color concurrently from a set of six colors in a conditional discrimination task. For three of the colors pecks to the module in one location (e.g., upper quadrant) were reinforced while for the remaining colors pecks at the other module (e.g., lower quadrant) were reinforced. After learning this discrimination, the color-reinforced location assignments were reversed. Pigeons successfully acquired the reversal. ARENA is an automated system for open-field studies and a more ecologically valid alternative to the touchscreen.     

Good foragers can also be good at detecting predators

The degree to which foraging and vigilance are mutually exclusive is crucial to understanding the management of the predation and starvation risk trade-off in animals. We tested whether wild-caught captive chaffinches that feed at a higher rate do so at the expense of their speed in responding to a model sparrowhawk flying nearby, and whether consistently good foragers will therefore tend to respond more slowly on average. First, we confirmed that the time taken to respond to the approaching predator depended on the rate of scanning: as head-up rate increased so chaffinches responded more quickly. However, against predictions, as peck rate increased so head-up rate increased and mean length of head-up and head-down periods decreased. Head-up rate was probably dependent on peck rate because almost every time a seed was found, a bird raised its head to handle it. Therefore chaffinches with higher peck rates responded more quickly. Individual chaffinches showed consistent durations of both their head-down and head-up periods and, therefore, individuals that were good foragers were also good detectors of predators. In relation to the broad range of species that have a similar foraging mode to chaffinches, our results have two major implications for predation/starvation risk trade-offs: (i) feeding rate can determine vigilance scanning patterns; and (ii) the best foragers can also be the best at detecting predators. We discuss how our results can be explained in mechanistic terms relating to fundamental differences in how the probabilities of detecting food rather than a predator are affected by time. In addition, our results offer a plausible explanation for the widely observed effect that vigilance continues to decline with group size even when there is no further benefit to reducing vigilance.     

Selective stimulus control in discrimination of lateral mirror images by pigeons

Four monocularly and two binocularly viewing pigeons were trained to peck a key when it displayed one stimulus (S+) but not to peck when it displayed another stimulus (S−). S+ and S− were a lateral mirror-image pair of two-coloured stimuli. When tested for transfer with the untrained eye open, two of the monocular birds pecked more during S− than S+, the other two continuing to favour S+. During generalization tests on the wavelength dimension all monocular birds pecked much more often during one S+ colour than during the other. The colour controlling pecking was that displayed on the side of the key facing the open eye during S+ presentations. Both binocular birds developed asymmetrical responses to the key, one favouring the left, the other the right side of the key. Generalization tests on the wavelength dimension showed selective control by the colour displayed on the favoured side of the key during S+ presentations. The results are interpreted as supporting the view that pigeons learn to discriminate lateral mirror images by developing asymmetrical observing responses that convert the left-right difference between the mirror images into a difference more easily discriminable.     

Reproduction of the blacktip sawtail catshark,Galeus sauteri,in the waters off northeastern Taiwan

The reproductive biology of blacktip sawtail catsharks,Galeus sauteri, in northeastern Taiwan waters was investigated. Male catsharks possessed paired testes producing spermatozoa, which were then stored in the epididymides all year round. No spermatophores were observed in the lower ductus deferens. Only the right ovary was functional in females, oogonia being formed in the ovarian cortex and then developing into mature ova. Ova exceeding 17 mm in diameter were ovulated. Pregnant individuals contained one eggcase only, in each side of the uterus. No hatched embryos were observed in such eggcases. The size at which 50% of blacktip sawtail catshark specimens were mature was 410–420 mm and 350–360 mm for females and males, respectively. The species does not have a well-defined reproductive season.     

Comparison of two kinds of functional asymmetry in the roach <Emphasis Type="Italic">Rutilus rutilus</Emphasis> (Teleostei: Cyprinidae)

In the higher vertebrates, asymmetries of different functions of individual are poorly connected with each other. At present it is unknown whether this poor link is a secondary phenomenon or it is characteristic of different kinds of functional asymmetry already at early stages of vertebrate evolution. In connection with this problem, in the roach Rutilus rutilus was studied asymmetry of two behavioral reactions—movements in an annular corridor and of the C-shape body bending at a sudden action of electrical stimulus. Different individuals prefer a certain direction of movement in the corridor (to the right or to the left). Comparison of these two kinds of asymmetries in the same individuals has shown the absence of significant association between asymmetry of different reactions. The obtained data indicate that already in the lower vertebrates, different kinds of functional asymmetry are controlled by different mechanisms and are poorly associated with each other.     

Reflection of Anxiety in the Characteristics of Evoked EEG Potentials in 10- to 11-Year-Old Children

We studied the peculiarities of the amplitude/time parameters of evoked EEG potentials (EPs) and event-related potentials (ERPs) in 10- to 11-year-old children characterized by low and high anxiety levels. The latter levels were estimated using the scale of the manifest anxiety test of Prikhozhan and projective techniques (“House–Tree–Person,” HTP, and the Lüscher color test). For children with a high anxiety level, the amplitudes of the following EP components and ERPs were lower than those in low-anxiety children of the same age: P1 (predominantly in the occipital region of the left hemisphere), P2 (in the right occipital region), and Р300 wave (in different loci of both hemispheres). In high-anxiety children, we also more frequently observed increased amplitudes of the N2 component in the left parietal and right occipital regions. High-anxiety individuals were characterized by longer latencies of component P1 (mostly in the right frontal and left central regions) and, at the same time, shorter latencies of component N1 (in the parietal and occipital regions of the left hemisphere and also in the right temporal region). Thus, we found that the amplitude/time characteristics of a few EP components and ERPs in children with high anxiety levels differ statistically significantly from the parameters of corresponding EPs/ERPs in individuals of the same age but with low anxiety levels.     

Predatory behaviour of common kestrels (Falco tinnunculus) in the wild

The predatory behaviour of eight wild adult common kestrels (Falco tinnunculus) was recorded during predatory tests carried out in the wild under controlled conditions. Those birds were offered one laboratory mouse each, which was restrained on a base, thereby simulating natural predation. The predatory sequence was recorded directly, but also video-taped. The sequence was rather homogeneous among the kestrels, with most kestrels starting the attack glide from a perch, then capturing the prey at high speed. The mouse was grabbed directly, upon landing; in one instance, however, it disentangled from the bird’s foot and was captured after a few seconds. The target was usually grabbed at the shoulders or neck, or at the trunk. Soon after capture the kestrel flew to a distant perch, where it usually stroked the prey with one single peck, before starting ingestion, which began about 1 min time after prey grasping. Our results are the first to show the possibility of maintaining standardized conditions to study the predatory behaviour of birds of prey. As they are very similar to those obtained in previous tests carried out in captivity using rehabilitated kestrels, our results also confirm earlier ones showing that the kestrel’s predatory behaviour is rather stereotyped—i.e. performed with limited variation—and that it can be studied reliably even in captivity.     

The importance of qualitative inventory sampling using electric fishing and nets in a large,tropical river (Brazil)

Qualitative fish sampling (single catch) using three methods (electric fishing, gillnets, seine nets) was assessed at three sites in the Ivai River (Paraná State, Brazil) to check their usefulness for quick inventory investigations. Electric fishing at a constant effort (15 min per each) was considered to be the best sampling technique. Taxon richness was calculated as the expected number of species using a rarefraction technique. Samples of 300–325 individuals, and 6–10 repetitions in neighbouring segments were sufficient. Even though electric fishing was conducted with the same effort in similar segments at each site there were many differences in species abundance. This suggests that the estimated fish specimen number obtained with constant effort is of limited validity on one sampling occasion and may be best considered as an ‘index of density’ only. The differences may partially be caused by the segments being located along the right and left bank of the large river (problem of different habitats). Qualitative and quantitative differences between electric fishing, gill-netting and seine-netting samples were very high at a high significance level. Nevertheless, as 22.4% taxa were caught only by gill or seine nets, these gears were important for complementing the species list. This revised version was published online in July 2006 with corrections to the Cover Date.     

Mathematical biological of social behavior: II

A group of individuals is considered in which each individual has tendencies to exhibit one or another of two mutually exclusive behaviors. Neurobiophysically this may be described in terms of Landahl's reciprocally inhibited parallel reaction chains. The spontaneous excitations ε₁ and ε₂ at the central connections of each chain are a measure of the “natural” tendency of the individual toward one or the other of the two behaviors. According to equations derived by H. D. Landahl, the probability of one or the other behavior is determined by the difference ε₁ − ε₂. A population of individuals is considered in which ε₁ − ε₂ is distributed in some continuous way, and therefore in which the probability of a given behavior is distributed continuously between 0 and 1. The effect of other individuals exhibiting a given behavior is to increase the corresponding ε of the individual. Thus behavior of others affects the probability for a given behavior of each individual. It is shown that the equations describing the behavior of the population on the basis of this neurobiophysical picture reduce in the first approximation to the differential equations which were postulated by the author in his previous work on social behavior.     

Most susceptible stage of rice panicle development to Oebalus pugnax (Hemiptera: Pentatomidae)

Oebalus pugnax (F.) (Hemiptera: Pentatomidae) damage to rice, Orya savita L., reduces rough and head rice yields, and grain quality. O. pugnax feeds on developing kernels, introducing pathogenic fungi and causing a discoloration of the grain known as "peck." The objective of this study was to determine the stage of rice panicle development most susceptible to O. pugnax attack. During 2005 and 2006, in greenhouse and field experiments, rice plants were caged at the boot stage and then infested with adult or nymphal O. pugnax. Plants were infested during one of three stages of panicle development: heading, milk, or soft dough. Insects were allowed to feed on the plants for the duration of each stage and then killed. After maturation, panicles were harvested, and grain was hulled and milled. Grain weight, percentage of pecky grain, and percentage of whole grain after milling were recorded. No differences were found in the weight of rough, brown, or milled rice infested with O. pugnax during different stages of panicle development. Number of filled grains per cage was not affected by O. pugnax, and number of empty grains per cage was affected in two of four experiments. Higher percentage of peck was found in grain from panicles infested during dough and milk than in grain from panicles infested during heading. Adult O. pugnax caused higher percentage of peck than nymphs in all stages of panicle development. An inverse relationship was found between percentage of peck and percentage of whole grain weight only in one of the experiments.     

Reaction times identify a Pavlovian component in a two-choice discrimination

Six pigeons discriminated on discrete trials between two colors. In Experiment 1, two luminous spots were both either blue or green and the reinforced responses were “peck left” for blue and “peck right” for green. In Experiment 2, the hue of a center spot controlled subsequent choice pecks to left or right. In both experiments response bias was manipulated in two ways. During stimulus frequency (“SF”) sessions correct responses brought food on 40% of trials; in “imbalanced” blocks of sessions one hue appeared on 80% of trials and the other on 20%. During reinforcement probability (“RNF”) sessions the hues appeared equally often, but in imbalanced blocks the hues signaled different reinforcement probabilities, either 64% or 16%. In “balanced” control blocks the hues appeared equally often and were both reinforced at 40%. The experiments gave similar results. When bias was computed from choice percentages the imbalanced conditions yielded substantial response bias, and the amount of bias was about the same under RNF and SF treatments. However, reaction times (RTs) gave a different outcome. RNF imbalance slowed responses directed at the less reinforced stimulus, but SF imbalance had little RT effect (Experiment 1) or no effect (Experiment 2). These results suggest that choice was controlled by an instrumental stimulus-response-reinforcement association, whereas RTs were controlled by a Pavlovian stimulus-reinforcement association.     

Morphological asymmetry and behavioral laterality in the crayfish, Procambarus clarkii

Lateral asymmetry is found widely among vertebrates, but is scarcely observed in invertebrates. Here, morphological asymmetry and behavioral laterality of a wild crayfish, Procambarus clarkii, was investigated. The carapace morphology of crayfish showed left–right differences; in some, the right side of the carapace was larger than the left side, while in others, the left side was larger. A bimodal distribution in the direction of escape behaviors induced by a tactile stimulus was also observed. Experimental crayfish were definitively divided into two groups: individuals that frequently jumped leftward (right type) and those that jumped rightward (left type). Moreover, carapace asymmetry and lateralized escape responses were significantly correlated. These results suggest that crayfish exhibit left–right dimorphism in natural populations. The ecological advantages and maintenance mechanisms underlying these behaviors are also discussed.     

Two-trait selection response with marker-based assortative mating

 Marker-based assortative mating (MAM) – the mating of individuals that have similar genotypes at random marker loci – can increase selection response for a single trait by 3–8% over random mating (RM). Genetic gain is usually desired for multiple traits rather than for a single trait. My objectives in this study were to (1) compare MAM, phenotypic assortative mating (PAM), and RM of selected individuals for improving two traits and (2) determine when MAM will be most useful for improving two traits. I simulated 20 generations of selecting 32 out of 200 individuals in an F₂ population. The individuals were selected based on an index (SI) of two traits and were intermated by MAM, PAM, or RM. I studied eight genetic models that differed in three contrasts: (1) weight, number of quantitative trait loci (QTL), and heritability (h ²) for each trait; (2) linkage of QTL for each trait; and (3) trait means of the inbred parents of the F₂. For SI and the two component traits, MAM increased short-term selection response by 5–8% in six out of the eight genetic models. The MAM procedure was least effective in two genetic models, wherein the QTL for one trait were unlinked to the QTL for the other trait and the parents of the F₂ had divergent means for each trait. The loss of QTL heterozygosity was much greater with MAM than with PAM or RM. Consequently, the advantage of MAM over RM dissipated after 5–7 generations. Differences were small between selection responses with PAM and RM. The MAM procedure can enhance short-term selection response for two traits when selection is not stringent, h ² is low, and the means of the parents of the F₂ are equal for each trait. Received: 10 June 1998 / Accepted: 5 August 1998     

A probabilistic model of the spatial patterning of pecking in birds : Pilot study with young chicks

The pecking behaviour of young chicks ($\text{Gallus gallus}$) is studied in a situation involving several equivalent targets (mealworms). The question is raised whether the successive pecks are randomly distributed or whether they follow a systematic order based on the spatial arrangement of the targets. Data collected with one-week-old chicks indicate that pecking is compatible with a probabilistic model where the probability to peck at a given place is inversely proportional to the energy used for this particular peck. Pecking by chicks is interpreted as a functional compromise between random sampling and optimal exploitation of the environment.