bluuebunny/crossref_metadata_2025 huggingface dataset:
Effects of Testosterone On Investigation of Stimulus Change By the Domestic Chick
Authors: Andrew R.J. , Clayton D.A.
Published: April 2008

Testosterone-treated chicks (T's) were more persistently disturbed than controls (C's), both by the introduction of a novel object into the home cage, and by its removal 24 hours later. This was shown, firstly, by delay in the first appearance of behaviour not directed to the novel object: the preliminaries to feeding (looking at the floor, visiting the food hopper) appeared later in T's, as did drowsiness. Secondly, behaviour was interrupted in T's by a return to investigation: in particular the first bout of feeding was markedly abbreviated and (after introduction of the object) was not followed as usual by stretching. None of these differences between T's and C's were present in undisturbed behaviour. It is probable that the development in T's of unusually protracted periods of sleep after removal of the novel object is another consequence of more prolonged disturbance in T's. Other evidence is cited suggesting that protracted sleep may be caused in this way. Increased persistence of attention, including an ability to return to a previous point of attention after a shift to a distracting stimulus, is known from other studies to be produced by testosterone in male chicks. Such an effect would explain the above findings. It is argued more speculatively that it may also underlie differences between T's and C's in the character of investigation, and not just its prolongation.
Retention and Recovery of Habituated Territorial Aggressive Behavior in the Three-Spined Stickleback (Gasterosteus Aculeat Us L.) : the Roles of Time and Nest Reconstruction
Authors: Peeke Harman V.S. , Figler Michael H. , Blankenship Nancy
Published: April 2008

Factors involved in the recovery and reinstatement of a territorial resident's aggression directed at an intruder after habituation were studied in the Three-spined Stickleback (Gasterosteus aculeatus). In the first experiment it was demonstrated that following initial habituation to the intruder, there was no recovery of response after 3-5 days, but there was virtually complete recovery after 14 days. It was further shown that if the stickleback's nest is removed and he rebuilds the nest between the first habituation session and the test, there is complete recovery following nest reconstruction. A second series of experiments shows that the recovery following nest removal and reconstruction is prevented if the fish is prevented from reconstructing the nest. It was further found in two additional sub-experiments that allowing post-habituation nest reconstruction appeared to re-set memory for the habituated stimulus such that the intruding stimulus fish appears novel to the territorial resident, thus abolishing the stimulus specific nature of such habituation.
Inter-Observer Reliability
Authors: Caro T.M. , Roper R. , Young M. , Dank G.R.
Published: April 2008

This paper examines the methods used in expressing agreement between observers both when individual occurrences and total frequencies of behaviour are considered. It discusses correlational methods of deriving inter-observer reliability and then examines the relations between these three methods. Some of the factors that affect reliability are reported. These include problems of definition such as how a behaviour may change with age and how reliability depends on which recipient of behaviour is considered. Frequency of occurrence of a behaviour pattern is discussed both in relation to itself and to other behavioural categories, as well as its effect on observer vigilance. The effect of partitioning data in different ways is also discussed. Finally the influence of different observers on inter-observer reliability is noted. Examples are taken from studies of children and kittens.
Le Comportement De "Renserrement" ("Herding Behaviour") Dans Un Groupe Captif De Macaca Fascicularis
Authors: Deputte Bertrand L.
Published: April 2008

Dans notre groupe captif de Macaca fascicularis, le comportement "Marche queue dressée", quand il est effectué par le ♂ "alpha", ne conduit à des poursuites que lorsqu'il est orienté vers une ♀. Ces poursuites se terminent généralement par des morsures du ♂ sur ia ♀. Elles sont plus fréquentes à l'égard de la ♀dominante, quelque soit la phase de son cycle reproducteur. Lorsque des modifications de la structure sociale apparaissent, expérimentalement ou spontanément, on observe une liaison quantitative entre ces poursuites et l'ensemble des comportements agonistiques dirigés par le ♂ "alpha" vers les ♀♀. Cette liaison disparaît lorsque la structure sociale du groupe se stabilise, les séquences "Marche queue dressée-Poursuite" devenant très rares. La confrontation expérimentale de 2 groupes conspécifiques augmente la fréquence de ces séquences. Celles-ci seraient donc liées aux phénomènes d'assertion de statut. Elles participeraient à la création du lien ♀ dominante- ♂ "alpha" nécessaire à l'acquisition de ce statut. Elles diffèrent en cela des comportements agonistiques "classiques", qui tendent, quant à eux à distancier 2 individus. Par leur aspect démonstratif, ces séquences dissuaderaient, les compétiteurs potentiels du ♂ "alpha". Cette séquence comportementale, dans son déroulement et par ses conséquences, s'apparente au comportement de "Herding" de plusieurs espèces de Cercopithecidae à structure sociale de type centripète.
Male Courtship Persistence in the Greenhouse Whitefly, Trialeurodes Vaporariorum Westwood (Homoptera : Aleyrodidae)
Authors: Las Allan
Published: April 2008

The courtship behavior of whiteflies was examined, focusing particularly on the manner in which males maximized their fertilization rate by optimizing their time expenditure per female. Some males adopted a sneak male strategy in which they approached courting pairs and without preliminary courtship movements attempted copulation. The chief function of this strategy may have been to disrupt other males' courtships. 'Traditional courtship' was described and found to be sequentially invariable. However, if a female performed a maintenance activity during courtship, males had a significantly lower probability of success and had to court for a much longer time to improve their chances. Most males, including naive ones, persisted rather than abandoned these females. Persistence was seen as a strategy by which males could induce females with high sexual response thresholds to mate. Males reduced the primary cost of persistence, a lower encounter rate with other females, by integrating into their courtship strategy the way in which probability of insemination varied with courtship time invested. They neither courted for too short a time nor did they persist past the point of diminishing returns. Females appeared to assess males on the basis of courtship stamina and intensity. Recently mated females would remate only if the male performed a superior courtship in these respects. By copulating with males that performed more vigorous courtships, a female presumably improved the quality of her sperm store. This would increase her reproductive success because the resultant female offspring would receive a superior genetic complement from their haploid father, and the resultant male grandchildren would, on the average, possess the same desirable qualities that made their grandfather successful.
The Imminence of Behavioural Change and Startle Responses of Chicks
Authors: Culshaw A.D. , Broom D.M.
Published: April 2008

The responses of chicks startled near the end of a bout of feeding or preening were different from, and measurably greater than, those of chicks startled at the beginning of bouts of these activities. This result provides evidence about changes in motivational state during a bout of activity. It is proposed that causal factors, which are changing during the bout, may initiate an attentional change as the point of transition to another activity approaches. Distractibility and information-processing rate may be increased near the end of an activity because the individual can then attend to a greater variety of inputs than it could earlier in the bout. This would maximise the efficiency of the ensuing behavioural change. In order to carry out these experiments, bouts of feeding and preening were measured using a criterion based on log survivor curves for inter-event gap-lengths. The effects on the response of the time during a bout at which interruption occurs, were shown by chicks of 2, 4 and 6 days of age. The method used in these experiments, the interruption of activities at previously defined instants whilst observing behaviour in detail, affords opportunities for studying the nature of behavioural sequences and their control.
Gegendrehung Und Winkelsinn in Der Orientierung Von Lithobius Forficatus L. Teil Iii: Ergänzende Untersuchungen Zur Verrechnung Von Winkelfolgen
Authors: Walter Schäfer M.
Published: April 2008

The centipede Litkobius forficatus L. (Myriapoda) when forced to deviate from its initial course by passing through corridors containing sharp bends performs opposing (reverse) turns at the corridor's exits. The magnitudes of opposite turning responses appears to be a function of the size of the induced turns ("angle sense"). If corridors are used containing distances of 4 cm, entrance to turn and turn to exit, a relation of 1:0.7 between stimulus and response (induced turn : opposing turn) is measured for induced turn-angles up to about 120°; greater angles lead to a relative decrease in response up to a limit of 270° (Fig. 12). Increasing the distances from induced turn to choice point (corridor-exit) by an additional 4 cm (4:8 cm corridors) decreased opposite turning, resulting in the relation 1:0.49 between stimulus and response. Using corridors with two sequential turns and proportions of 4:4:4 cm demonstrates adding or subtracting mechanisms of stimulus sequences. However, due to the decreasing influence of increasing distances after an induced turn, passing through the second turn of the angle sequence can be seen as an increase of distance after the first angle, and therefore a decreasing response which must be added to the second turn (Fig. 1). An alternative addingmechanism could be a linear addition without the decreasing ("unloading") effect of distance referred to above. Sequences with left-right or right-left turns cannot be used to decide between the two possible mechanisms because both lead to identical degrees of response (Fig. 2). Experiments were performed using sequences of the same or opposed induced turns with various corridor distances. It could be demonstrated that, although decreasing effects of straight distances after turns were acting, linear additions of induced turn sequences were possible without the influence of unloading, but limited by the capacity of the neural store (Fig. 13).
Étude Ontogénétique De L'Exploration Chez Le Hamster Doré
Authors: Vauclair J.
Published: April 2008

L'activité exploratoire spontanée du Hamster doré est étudiée d'un point de vue ontogénétique 1° dans le milieu familier (cage), et 2° dans un espace nouveau ("open-field") relié topographiquement à la cage où vit l'animal. Les résultats ont montré que l'activité exploratoire dans la cage augmente fortement dès 14 jours jusqu'à 30-36 jours, alors que l'exploration dans l' "open-field" est la plus intense à 30 jours et qu'elle diminue ensuite avec l'âge, mais de manière non monotonique. L'analyse des résultats de groupes de contrôle montre que la diminution de l'exploration est indépendante de la répétition de l'exposition à la situation nouvelle. Le rôle du facteur âge, comme responsable unique des changements observés dans l'exploration est discuté par rapport aux facteurs concomitants de type maturationnel et social.
Location of Insect Hosts By the Nematode, Neoaplectana Carpocapsae, in Response To Temperature
Authors: Byers J.A. , Poinar G.O.
Published: April 2008

1. The infective stage juveniles of Neoaplectana carpocapsae, a parasitic nematode of insects, was found to aggregate at point sources heated to temperatures of only 0.3°C or less above ambient in either light or dark conditions. 2. The nematode also aggregated in response to heat conducted from a wax moth larva (about 0.3°C above ambient) in the absence of CO2 or chemical gradients. 3. The responses to heat sources (1° above ambient) occurred over a wide range of ambient temperatures. 4. The apparent response of the nematode to light is at least in part caused by effects of heat from light absorption by the agar medium and nematode. 5. The response to temperature appears to function in host location especially at close range from (within a few mm) the insect.
Influences of Motivation On Display Divergences in Three Cichlid Fish Species (Haplochromis)
Authors: Carlstead Kathy
Published: April 2008

Differences between three cichlid fish species in responsiveness to a restrained territorial intruder have been investigated while an experimenter, considered a disturbing stimulus, was sitting 2 meters in front of the tank in view of the fish. The purpose of the analyses was to determine which motivational factors control responses to intruders and disturbances between Haplochromis elegans, H. squamipinnis, and H. angustifrons. This could be done on the basis of a model for the causal organization of these responses that was developed in an earlier paper (CARLSTEAD, 1982). It was found that H. angustifrons responds significantly less to the intruder than the other two species, and this is because it responds more to the experimenter. H. squampinnis hides from the experimenter in longer bouts than the other two. It was concluded that angustifrons has a basically higher activation level of system D (refer to model, Fig. 3), a system determining the responsiveness to stimuli indicative of potential danger and controlling motor patterns for hiding responses. Elegans has a relatively higher activation level of system T for responding to territorial intruders. Squamipinnis was found to have a higher level of a general factor for reactivity to all unexpected, thus novel stimuli. Species differences in courtship display were also investigated. These displays differ little between species, but each shows one particular display more often than expected in temporal association with spawning. This display proved in each species to be the display performed more often than expected to a restrained male territorial intruder in the behavior sequence after a conflict to approach it or withdraw from it had occurred (Turning-Around). Using the model, the motivational differences between the three species described above could account for the latter differences. If only one particular motivational configuration can be assumed to be required for a display to occur in any situation, then a approach/withdrawal conflict to a male intruder and a female showing willingness to spawn must elicit the same motivational configuration. It was concluded that species divergences in the activation level of certain motivational factors are reflected in this particular momentary motivational configuration. Characteristics of each species' ecological niche in Lake George, to which they are all endemic, have been discussed with respect to the factors selecting for these motivational divergences, It was concluded that the hypothesis is supported that adaptations for features of a species' habitat may cause divergences in display behavior that are not directly selected for their signal value. This occurs through selection for optimal activation levels of motivational factors that in the behavioral organization control both responsiveness to types of environmental stimuli and motor patterns of display.
Movement Orders and Leadership in a Semi-Wild Cattle Herd
Authors: Reinhardt Viktor
Published: April 2008

Stable movement orders have been found in a semi-wild cattle herd. Orders of voluntary movements (2-4 km to and from nocturnal resting site) were correlated with each other but not with the order of foced movement (dipping). The individual average travelling positions as well as their standard deviations showed no significant dependency on age or on dominance. A tendency for old (experienced) animals to walk in the van and for young ones to make up the rear was only evidenced during forced movement. Calves travelled in the neighbourhood of their dams. It was concluded that the conservative retainment of particular movement positions is primed by matrilineal tradition. The single adult bull consistently walked in the rear group of the moving mob. It was only during encounters with strange cattle that he temporarily took the leadership and actively hindered his animals from mixing with the other herd. Each kind of herd movement was preceded by a different leader cow who regularly walked on position No. 1. During voluntary movements the herd showed a certain dependency on its leader, and it was up to her to make the decision when to start moving away from one location and which direction to choose. In cow Alma spatial leadership was traced over a period of five years. Leadership showed no strict dependency on age or dominance.
Use of Perches as Vantage Points During Foraging By Male and Female Stonechats Saxicola Torquata
Authors: Greig-Smith P.W.
Published: April 2008

The behaviour of individual stonechats (Saxicola torquata) foraging in heathland habitats was studied, to reveal possible influences of the height of the perches used as vantage points on feeding efficiency. Feeding rates, methods of prey capture, time spent on perches, and perching heights were quantified for male and female birds in a pre-breeding, and breeding periods; in addition, the integration of foraging with pre-breeding male song behaviour was examined. Rates of prey capture were highly variable, showing no clear seasonal trends or sex differences. Perching heights averaged 1.0 m in spring, and 1.6 m in summer, and although sex differences were small, males tended to perch higher, and closer to the top of the vegetation, in spring. Comparison with randomly encountered perches showed that birds selected higher perches than the average available. Of three principal prey-capture techniques, only diving to the ground was used in spring, but flycatching, and snatching prey off foliage, were also employed in summer. The change correlated with the appearance of new prey types on the foliage of birch and bracken. Visits to perches were short, averaging 25 s, and showed no clear sex or seasonal differences, but tended to be longer on higher perches, up to 2 min. These data were combined to assess the profitabilty for foraging of different perching heights. For feeding by diving to the ground, the lowest heights provided the greatest capture rates, but for flycatching and snatching, very high perches were more successful. The birds' observed preferences for perches in spring corresponded to those allowing the highest chance of capture per visit, rather than per unit time. In summer, there was no correspondence. Birds departed from perches when their prospects of capture were still high, and thus the lengths of unsuccessful visits cannot be regarded as 'giving-up' times. In spring, the frequencies of foraging attempts and song-phrases were inversely related in short observation periods, and incompatibility of the activities was suggested by the different heights chosen (averaging 0.9 m for foraging, 1.8 m for singing). The lack of differences in the spring foraging behaviour of males and females (who do not sing) suggests that males separated their foraging and singing into discrete bouts. This was apparently accomplished by tactical allocation of time in stable conditions, rather than relegation of singing to times when foraging conditions were poor.
Importance of Female's Precopulatory Behaviour for the Primary Initiation of Male's Copulatory Behaviour in the Laboratory Rat
Authors: Madlafousek J. , Hlinák Z.
Published: April 2008

Precopulatory and copulatory behaviour of adult (90-100 days old) Wistar male laboratory rats in their first encounter with a female was observed. Four levels of female sexual behaviour, characterized by lordosis, presenting, hopping and darting, were used as the experimental variable. A male was considered to have exhibited precopulatory behaviour if he performed at least three specific activities toward the female, such as anogenital exploration, touching the flanks, climbing over, pursuing. The performance of three intromittory copulations, the first of which had to occur within 10 minutes, was used as a criterion of the initiation of copulatory behaviour. In Experiment 1 it was found that not all the males who exhibit precopulatory behaviour also initiate copulations. With increasing level of sexual behaviour of the female the percentage of males exhibiting precopulatory behaviour hardly changes, but the probability that a male will initiate copulations substantially increases. Whereas no male imtiates copulations with a lordotic (passively receptive) female, a darting female provokes copulations in about 90% of the males. Experiment 2 showed that different breeding conditions, additional testosterone and cadmium intoxication did not influence the established dependence of the male's sexual behaviour on sexual behaviour of the female. Multiple repeated exposures of the males to a presenting female (Experiment 3) led to an increase in the percentage of males
Contests for Space in Breeding Cichlasoma Meeki: the Use of Increased Apparent Size Displays
Authors: Neil Susan J.
Published: April 2008

1. The conditions under which firemouth cichlids (Cichlasoma meeki) employed a branchiostegal display (erection of the gill membranes) were investigated to test four predictions concerning Increased Apparent Size (IAS) displays, in which the apparent size of an animal increases without an increase in Resource Holding Potential (RHP). Since size correlates with RHP for many species, IAS displays are assumed to increase an animal's apparent RHP. If contests are settled on the basis of differences in perceived RHP values, animals exhibiting falsely high values of RHP may avoid escalated contests and thus acquire resources at less cost. 2. The branchiostegal display could be performed alone or simultaneously with any other agonistic behaviour. It accompanied non-contact behaviour acts more commonly than contact acts, but accompanied no type of act more than one third of the times that act was performed. 3. It was performed primarily towards paired intruders, and those equal to or larger in size than the resident. 4. It was performed more often towards larger heterospecifics than towards larger conspecifics, and rarely towards smaller fish of any species. 5. The display often accompanied the first act of a contest, and this probability was greatest for contests with larger pairs of conspecifics. 6. The function of the display seems most likely to be a combination of an IAS display and a signal of a low probability of attack.
The Significance of a Hovering Display At Nests of the Long-Tailed Tit Aegithalos Caudatus
Authors: Greig-Smith Peter W.
Published: April 2008

Breeding long-tailed tits were studied to determine the significance of a hovering display performed by birds bringing food to nestlings. Its contexts implied that it represents communication to other adults, rather than to nestlings, or predators. Three-quarters of nests with young were attended by one or two 'helpers' as well as the parents, and all birds made hover displays. Feeding visits to the nest tended to be synchronous. This pattern was related to the hover display, which if performed by the second of two birds visiting the nest together caused them to return more quickly, and more often synchronously than if there was no display. Two functional aspects of this effect were tested. It did not serve to accelerate food delivery to nestlings after they had been deprived, nor did it minimise the presence of adults near nests that were most vulnerable to predation. The importance of the display may lie in its promotion of communal foraging by the adults.
Function of Manx Shearwater Calls in Mate Attraction
Authors: Storey A.E.
Published: April 2008

Playback experiments were used to study the role of vocalization in mate attraction by Manx shearwaters, a nocturnal seabird. Pre-breeding birds were exposed to test calls of male and female shearwaters calling from the range of normal locations: above the colony as in a flyover call, on the ground in the colony, or from within the nesting burrow. Both female and male test calls increased the frequency of male calling but only male calls increased the frequency of female calling. These findings suggest that male calls 1) facilitated competing responses from other males that are attempting to attract females to their burrows and 2) stimulated calling in available females that require more directional information to find the advertising male. Male calling location, inside or outside the burrow, probably reflected a compromise between being audible to females and being susceptible to predation. Because the call was more widely broadcast, male test calls played from outside the burrow caused more females to land in the colony than the same call played from inside the burrow. However in a simultaneous choice test between a burrow and an outside male test call, males calling from inside did not lose females to the adjacent outside male. Thus calling from inside the burrow in an area where another male is calling outside maximized female attraction while minimizing risk of predation. The male call played from inside the burrow attracted as many females as a pair call from inside but the response of females to the pair was less sustained, indicating that duetting pairs-inhibited the response of unpaired females. Male and female calls emanating from above the colony suppressed the rate of female flyover calls suggesting that during this test condition other birds stopped calling in an attempt to orient to the source of the test call.
Alternative Mating Strategies in the Mongolian Gerbil
Authors: Agren Greta
Published: April 2008

1. In previous enclosure studies female Mongolian gerbils were found to trespass into strange territories on oestrous days and mate with the neighbouring males, although they lived in stable territorial pairs or family-groups (ÅGREN, 1976, 1983, 1984). The females mated with their social partners as well. 2. A comparable 'unfaithful' behaviour in females in oestrous was observed in a laboratory choice-test (ÅGREN & MEYERSON, 1977). 3. A mating-preference for non-siblings has been demonstrated in enclosure as well as laboratory studies (ÅGREN, 1981, 1983). 4. In the present enclosure studies four females of one family consistently trespassed in oestrous, while three females in a second family did not. Only these latter females mated within their own social group, i.e. the two daughters incestuously. 5. When two females and three males of each of these same families were placed into a new enclosure only cross family pairs formed. 6. In a laboratory experiment 12 out of 18 pairliving females gave birth to, and raised their litter, sired by a strange male, when replaced into the cage of the familiar male the day following oestrous. The cage mate was prevented from copulations by a wire-mesh during 10 days following the insemination by the strange male. These results indicate that an 'unfaithful' female may be reproductively successful. 7. The observations of the unfaithful behaviour in the females are suggestive of an alternative mating strategy to monogamy in females beneficial under high population densities. This strategy would result in avoidance of inbreeding, low migration costs, and increased chances for winter-survival.
Some Observations of the Caravaning Behavior in the Musk Shrew (Suncus Murinus)
Authors: Tsuji Keiichiro , Ishikawa Tomohiko
Published: April 2008

Observations of caravaning were made on the domesticated musk shrew (Suncus murinus) with particular reference to its developmental aspects. In a rearing box (Experiment I), caravaning appeared from 10 to 22 days of age, peaking at 16 days. In the open-field test (Experiment II), it occurred over a range from 5 to 22 days, with its peak at around 13 days. Its formation patterns also changed with age of days; five patterns were identified in this situation. Another type of test (encounter test; Experiment III) showed a sensitive period similar to that obtained in Experiment II. Caravaning peaked at a period shifting from the mother-initiative stage to the young-initiative stage in the mother-offspring relation. Inanimated model released caravaning, as was expected (Experiment IV). It occurred for the same period, peaking at the same age of days, although on closer examination it was found that the smaller peak obtained in Experiment II disappeared. The findings of the present study suggest that caravaning plays an important role in the mother-offspring relation of this species. Developmental changes in caravaning seem to reflect the maturation process of sensory functions. Possibilities of releasers in caravan formation were discussed by referring to histological and electrophysiological investigations.
The Suckling Behaviour of Domestic Pigs in a Semi-Natural Environment
Authors: Newberry Ruth C. , Wood-Gush David G.M.
Published: April 2008

The suckling behaviour of domestic pigs living in a socially and ecologically rich outdoor environment was examined in order to obtain a baseline for comparison with behaviour in more restricted and barren environments. It was found that the piglets' growth rates were not consistently influenced by their suckling location along the udder, and that the concept of dominance at the udder was not justified. Crowding at the udder was probably an important factor prompting piglets to seek milk and solid food elsewhere, and two piglets switched from suckling from their own mother to suckling from another sow. True communal suckling was not exhibited. Piglets were responsible for locating their preferred teat and defending it from others. Sows did not attempt to prevent familiar piglets from other litters from suckling from them, although they sometimes terminated a suckling bout when disturbed by fights at the udder. Synchronization of suckling between litters was common. Suckling bouts did not always result in milk let-down, indicating that this is not a phenomenon exclusive to intensive housing systems. Weaning occurred naturally between 60 and 100 days after birth, and its timing varied both within and between litters but was not closely linked to the amount of aggression received from the sow.
Reaction To Novel Objects in a Troop of Guinea Baboons: Approach and Manipulation
Authors: Joubert A. , Vauclair J.
Published: April 2008

A troop of Guinea baboons living in an enclosure was exposed every day and for twelve consecutive days to a new object. The new object and the object(s) of the previous day(s) were presented simultaneously in the compound. The troop as a whole demonstrated excellent abilities to rapidly react to the new objects: 11 out of 12 new objects were discovered within a maximum of 3 min of their first presentation and were furthermore the first to be approached. An analysis conducted on data from age and sex subgroups showed the preponderant part played by juveniles and by some adult males in the discovery process and subsequent contacts with objects. The results are discussed within the conceptual frame of "cognitive mapping". In addition, the extent to which social factors (e.g. dominance) and perceptual and cognitive factors might determine the differential role of subgroups in the exploration and manipulation of objects is examined.
The Hidden Costs of Sociality: Intra-Group Variation in Feeding Strategies in Sumatran Long-Tailed Macaques (Macaca Fascicularis)
Authors: VAN NOORDWIJK Maria A. , VAN SCHAIK Carel P.
Published: April 2008

Groups of long-tailed macaques (Macaca fascicularis) are often fissioned into a large main party and one or more small parties. We studied the size and composition of the main party in relation to fruit supply and the ecology of the various age-sex categories in order to establish the cause of this fissioning. The size of the main party varied not only because the size of available fruit trees varied but also because the various age-sex categories were so different in their feeding strategies that they sometimes went separate ways. Our observations suggest that body size and sex profoundly affected food requirements and the risks attached to leaving the main party. We concluded that adult females left the main party mainly to escape from feeding competition and attempted to reduce travel time when they had infants so as to minimise the costs of carrying infants. Males, by contrast, left above all because of their different food requirements; subadult males left to eat more fruit than the others, adult males mainly to eat bigger fruit than the others. This intra-group variation in feeding strategies constitutes a usually hidden cost to sociality.
The Significance of Antiphonal Vocalisation By the Spring Peeper, Pseudacris Crucifer (Amphibia, Anura)
Authors: Forester Don C. , Harrison W. Keith
Published: April 2008

1. Male spring peepers respond to acoustic interference from an encroaching conspecific with a graded behavioral sequence: they increase their call repetition rate, they emit one or more encounter calls, they entrain their calls to those of the intruder. 2. Once entrained, males continue to call synchronously for extended periods. 3. The time interval between the end of the leader's call and the beginning of the follower's call (the intraduet interval) is consistent, and is maintained despite changes in the duration or repetition rate of the leader's call. 4. Our data corroborate earlier investigators who concluded that the follower is stimulated by the onset of the leader's call, but is inhibited from calling until a fixed time interval after the leader has ceased calling. 5. Controlled discrimination tests reveal no differential mating success by the leader or the follower within a simulated duet. 6. Females exhibited a significant preference for a duet over a soloing male. 7. Although test females were able distinguish between the simultaneous broadcast of two phase-locked call sequences differing only in frequency, they did so in the absence of alternative, uncovered calls. 8. We conclude that antiphonal vocalisation functions primarily to reduce the potential for broadcast interference during the initial phase of female phonotaxis.
Influences of Prior Agonistic Experiences On Aggression Measures in the Male Swordtail (Xiphophorus Helleri)
Authors: Franck Dierk , Ribowski Alexander
Published: April 2008

The influences of prior agonistic experience on the aggressive behaviour of swordtail males were studied in standardized aggression tests. In the "standard-opponent" test the test subject fights against a much smaller opponent behind a transparent partition, whereas in the mirror test it attacks its own mirror image. Both tests are appropriate to measure mean biting rates in an adequate sample of individuals. If reproducible estimates of the aggressiveness of single individuals are needed, the mirror test is the most appropriate method, for it gives correlation coefficients up to 0.96 between a first and a second measurement. When fish had been involved in a series of escalating activities without final decision of the encounters, in subsequent mirror tests their biting frequencies were elevated for at least 24 h after the last fight. Winning a rank order fight led to an increase and losing to a decrease in biting frequency 24 h later. By contrast, after social settlement in a long-term stabilized social hierarchy the relation is totally reversed: Dominant males showed much lower biting frequencies than subordinate males in the mirror test. The hypothesis is proposed that even under natural conditions high ranking males tend to use their energy potential in a more economic way than low ranking males. The existence of rank-dependent fighting strategies could be due to differences in risk: The fighting activities of dominant males are extremely risky because they can lose their high social status, which inevitably would lead to a lowered genetic fitness, whereas the aggressive actions of subordinate males are not very risky because their social status is low anyway.
Family Planning in the Kestrel (Falco Tinnunculus): the Ultimate Control of Covariation of Laying Date and Clutch Size
Authors: Daan Serge , Dijkstra Cor , Tinbergen Joost M.
Published: April 2008

The theory that individual birds maximize their fitness by the two major decisions in reproduction concerning date (when to start laying eggs) and clutch size (when to stop laying eggs) is empirically approached in the Kestrel by quantifying Fisher's Reproductive Value for both the clutch (Vc = c. Vo/2) and the parents (Vp). The reproductive value of an egg (Vo) was found to decrease monotonically with laying date (d) due to significant associations with d of the components So (probability for an egg to survive till fledging), S1 (probability to survive from fledging till age 1), S2 (survival age 1 till age 2), and P1 (probability of breeding at age 1). Vp declined negligibly with laying date, although there were significant associations between d (laying date) and N (probability of the nest to produce at least one fledging), Pr (probability of a repeat clutch following nest failure), and La (probability of local survival of the parents following breeding). In experiments where brood size at day 10 after hatching was increased or reduced, Vc increasing experimental brood size, while Vp simultaneously decreased. Total reproductive value (V = Vc + Vp) remained unaffected by the experiments. This result suggests that a rather broad range of clutch sizes maximizes total reproductive value, as far as detectable by the data. While the yield of kestrel hunting, and hence the number of young raisable with constant parental effort (and constant Vp), increased with the spring increase in vole population density, reproductive value of the clutches decreased. For any particular food situation (hunting yield) this leads to a unique combination of clutch size and laying date maximizing V. This could be worked out by calculating fitness contours for all combinations and for different yields (Fig. 12). The optimal solutions are on a declining slope, with smaller clutches associated with later dates. 59.4% of all clutches observed obeyed the maximization criteria. Furthermore, there was a reasonable, unbiased association between predicted laying dates and clutch sizes based on individual male hunting yields and observed dates and clutches as laid by the females. Qualitatively, any method predicts a seasonal decrease in the optimal clutch size when the environment improves while reproductive value declines with progressive date. Preliminary results from an experimental approach to test the assumption of a causal effect of date on Vo, using the release of juvenile kestrels reared in captivity under artificial light schedules, are presented.
Death in the Distance: Mortality Risk as Information for Foraging Ants
Authors: Nonacs Peter
Published: April 2008

Ant foragers are known to communicate food presence in distant patches, but do they also communicate information about distant mortality risk? Recruitment to a food source in a laboratory Lasius pallitarsis colony depended upon whether the initial returning foragers had encountered mortality risk (a larger Formica subnuda) and the quality of the food they found. When food quality was high, risk appeared to not affect recruitment; when quality was low, risk inhibited foraging. In a second experiment, L. pallitarsis colonies had access to food of several qualities through a divided trail, which forced foragers to take different routes to and from the food patch. Danger was either entirely absent, present only on the way to the patch, present only on the way from the patch, or along both routes. When food quality was poor colonies recruited to food when risk was absent, but risk anywhere significantly reduced the level of foraging. This included the situation where only returning foragers could encounter danger, which strongly suggests that their behaviour was a critical factor in whether nestmates would continue foraging. When food quality was moderate, only treatments with risk on the way to the food significantly inhibited foraging. When food quality was good, colonies continued to forage at a high rate, irrespective of presence or location or risk. In total, L. pallitarsis foragers appear to communicate and use information about both food and mortality risk in deciding whether to exploit patches.
Long Ultrasonic Calls in Male Rats Following Mating, Defeat and Aversive Stimulation: Frequency Modulation and Bout Structure
Authors: Van Der Poel Augustinus M. , Miczek Klaus A.
Published: April 2008

Ultrasonic calls by rats may represent affective expressions and serve communicative functions. The temporal patterning and frequency modulation of the long, 21-30 kHz ultrasonic calls were studied in 7 male rats. Following ejaculation, defeat and aversive stimulation large samples of consecutive long calls were recorded and analyzed off-line using a spectrum analyzer. The analysis was limited to long calls because other types of calls were relatively rare under the circumstances of this study and the emitter could be determined by a typical breathing pattern with reasonable certainty only for long calls. Log survivor analysis of the intervals between calls revealed that rats emit 95 % of long calls in bouts of less than 6 calls. Except for the higher bout rate after defeat, there were no significant differences between tests in call duration, percent time spent vocalizing, bout duration and intervals between bouts. However, there were significant differences between individuals across tests in call duration, number of calls per bout and bout rate. The pattern and capacity to breathe are likely important limiting factors for several temporal characteristics of rat ultrasounds, in particular maximal call duration and range of interval duration within a bout. Post-ejaculatory calls were often strongly modulated in frequency (i.e. pitch) in the medial and terminal segments. These segments of calls emitted after defeat or aversive stimulation were essentially monotonous. We propose that rats emit at least 2 types of long ultrasonic calls-one monotonous, the other modulated-each reflecting a different affective state of the animal. The modulated type may reflect a state of behavioral inhibition such as initiated by ejaculation whereas the monotonous type may reflect a state of intense fear induced by an actual physical threat in situations where escape is blocked. Both types may serve a "desist-contact" function.
Organization of Fighting in the Polychaete Nereis Virens (Sars) and the Effects of Residency and Orientation
Authors: Miron G. , Desrosiers G. , Retier C.
Published: April 2008

Intraspecific encounters of the polychaete Nereis virens (Sars) were studied within artificial burrows in order to describe behavioural interactions that occur during the defence of the burrow. This work exploited the relationship between variability in contest outcomes and fighting behavioural sequences as a function of different types of encounters. In addition, the effects of resident orientation, duration of resident occupancy (acclimatization) and initial distance of the intruder anterior end from the resident (head or tail) were all included. The eviction frequency was significantly greater in the presence of acclimated individuals. Acclimatization reduced chances of cohabitation between two individuals within the same burrow. However, the importance of the acclimatization was greater in head to head ("H-H") encounters as opposed to head to tail("H-T") encounters. Encounters within a 15 cm distance separating each individuals showed that intruders were expelled in all "H-H" cases (100%) in contrast to 32% in "H-T" encounters. No significant difference was noticed between "H-H" and "H-T" encounters where the initial distance was greater than 15 cm. Fights were settled, on average, in 10 minutes with acclimated individuals in contrast to less than 2 minutes with non-acclimated worms. Behavioural sequences, for agonistic encounters, were more complex in residents than for intruders. Complexity in patterns was also greater for non-acclimated worms.
Information Statistical Analysis and the Frequential Method of Data Collecting: Description and Illustration of a New Model in the Study of Animal Behaviour
Authors: Ellenbroek B.A. , Hoeks B. , Cools A.R.
Published: April 2008

In the past information statistical analyses have been used for the description of the temporal organization of behaviour. In general, these analyses are based upon data collected with the sequential method. This method is known to limit the general applicability of information statistical analyses. In the present report a new model, based upon data collected with the frequential method, is presented. In this model too it is assumed that animals behave according to a MARKOV process. In the present model, however, the assumption of a MARKOV process implies that information (entropy) of a certain behaviour is a function of time, and not a function of "order in time". The key-advantage of this analysis is that it can be assessed to data collected during relatively short lasting observation sessions; using a computerized time recording system with a resolution of 0.1 s, for instance, a 60 min. session provides 36000 sampling points, viz. sufficient data for filling completely a transition matrix. This, in turn, implies that the analysis allows the calculation of the maximum error of the entropy (information) using a purely analytical method. Due to the ideal combination of a high sampling frequency and a relatively short collecting time, this analysis can be used to describe the individual relationships within social group structures in great detail. In the present report the applicability of this analysis is illustrated by assessing it to a single set of data collected in a study o spontaneously occurring changes in a group of 4 Java monkeys (Macaca fascicularis). the analysis deals with data collected in 17 sessions, one hour each, and recorded on separate days. the new analysis provided a detailed and quantitative description of dynamic changes, which could not be detected with the classical frequency analysis. The new analysis also provided a new dimension to the description of dynamic changes which were detected with the frequency analysis.