bluuebunny/crossref_metadata_2025_split huggingface dataset:
Directional Sexual Selection Cannot Explain Variation in Song Repertoire Size in the New World Blackbirds (Icterinae)
Authors: Irwin Rebecca E. 
Published: May 2010

AbstractHypotheses that song repertoire evolves by way of directional sexual selection for large repertoires were examined with a comparative study of the avian subfamily Icterinae (Passeriformes: Emberiznae). Song repertoire size varies between closely related icterine species, so phylogenetic effects cannot explain repertoire size variation. Overall, song repertoire is not associated with polygyny or with presence or absence of territoriality.Different associations of repertoire with mating system are observed in different icterine groups. Either the directional hypotheses do not apply to the evolution of song repertoire in the Icterinae, or different processes of directional sexual selection have occurred in different icterine groups.
Parent‐offspring Conflict during the Post‐fledging Period in the Egyptian Vulture Neophron percnopterus (Aves, Accipitridae)
Authors: Ceballos Olga , Donazar Jose A. 
Published: May 2010

AbstractEgyptian vultures were studied during their post‐fledging dependence period in northern Spain in order to detect if there were parent‐offspring and sibling tensions during the transition of young to independence. The frequency of parental feedings and the frequency of movements of the parents towards their young decreased during the post‐fledging period, especially in its final part. At the same time, the frequency of movements and of aggression by the young towards their parents increased. Aggression by adults to their young was not observed. Siblings disputed feedings, but there was no other evidence for sibling conflict. The results suggest that parent‐offspring and sibling conflict exists and that its development is broken by the departure of young on migration. Some behavioural traits of adults (maintenance of distance from young and of intensity of nest‐defence, tolerance of young during foraging trips through the home range) do not accord with parent‐offspring conflict perhaps because they are related to factors other than family tension.
Aggression among Lekking Male Fallow Deer (Dama dama): Territory Effects and Relationship with Copulatory Success
Authors: Festa‐Bianchet Marco , Apollonio Marco , Mari Franco , Rasola Giulia 
Published: May 2010

AbstractWe studied the aggressive behavior of territorial male fallow deer (Dama dama) at two leks. Daily number of escalated fights was not correlated with number of matings. A dominance index including all agonistic interactions was weakly correlated with copulatory success; the correlation was stronger when each half of the rut was considered separately. Dominance likely changed over the rut due to fatigue. We ranked lek territories by the number of copulations seen in each. Males that won fights were likely to take over the loser's territory only if it ranked higher than the one they held. Winners were more likely to fight with a third male after defeating an opponent that held a higher‐ranking territory than one from a lower‐ranking territory. Exposure to attacks by third‐party males may be a major cost of fighting. Males appear aware of the relative value of different lek territories, but the frequency of aggression was not scaled to potential fitness benefits, possibly because males seldom fought with opponents they were unlikely to beat. The outcome of interactions on the lek may not always reflect the relative dominance rank of the contestants. Females are unlikely to use the outcome of fights as a direct criterion for mate selection.
Representation of Faces in Longtailed Macaques (Macaca fascicularis)
Authors: Dittrich Winand 
Published: May 2010

AbstractThe experiments described in this study were intended to increase our knowledge about social cognition in primates. Longtailed macaques (Macaca fascicularis) had to discriminate facial drawings of different emotional expressions. A new experimental approach was used. During the experimental sessions social interactions within the group were permitted, but the learning behaviour of individual monkeys was analysed. The procedure consisted of a simultaneous discrimination between four visual patterns under continuous reinforcement. It has implications not only for simple tasks of stimulus discrimination but also for complex problems of internal representations and visual communication.The monkeys learned quickly to discriminate faces of different emotional expressions. This discrimination ability was completely invariant with variations of colour, brightness, size, and rotation. Rotated and inverted faces were recognized perfectly. A preference test for particular features resulted in a graded estimation of particular facial components. Most important for face recognition was the outline, followed by the eye region and the mouth. An asymmetry in recognition of the left and right halves of the face was found. Further tests involving jumbled faces indicated that not only the presence of distinct facial cues but the specific relation of facial features is essential in recognizing faces. The experiment generally confirms that causal mechanisms of social cognition in non‐human primates can be studied experimentally. The behavioural results are highly consistent with findings from neurophysiology and research with human subjects.
Structural Variation in the Call of the Cory's Shearwater (Calonectris diomedea, Aves, Procellariidae)
Authors: Bretagnolle Vincent , Lequette Benoit 
Published: May 2010

AbstractThe duet call, the principal vocalization of Cory's shearwaters, was structurally variable with different classes of call being apparent, corresponding to different individuals, sexes and populations. In playback tests, birds responded more frequently to the call of their mate than to other birds, birds of a given sex responded more frequently to playback calls of their own sex and birds of a given locality responded more frequently to birds of their own locality. We suggest some biological functions with respect to mating strategy, individual recognition, territorial behaviour, and population isolation.
Body Size Effects on the Acoustic Structure of Pigtail Macaque (Macaca nemestrina) Screams
Authors: Gouzoules Harold , Gouzoules Sarah 
Published: May 2010

AbstractScream vocalizations produced by pigtail macaques during agonistic encounters were classified according to caller body weight (small, medium, large) on the basis of six frequency‐related acoustic variables using direct discriminant analysis. Separate discriminant analyses were run for: 1. calls produced when the attack involved an opponent higher‐ranking than the victim and contact occurred, and 2. calls produced when the opponent was higher‐ranking, but no contact occurred. Screams were correctly classified as to the caller's weight class at levels significantly above those expected by chance alone. Screams given during contact aggression were classified significantly better than those given in the absence of contact. The effect of greater arousal level (fear) on the frequency range of calls may account for this difference. Macaque screams are representational signals that are important in the solicitation of agonistic aid from allies in the social group. That a relationship between body size and the frequency of screams is nonetheless evident argues for the fundamental nature of the relationship.
Strategies of Spatial Behaviour in Helix pomatia
Authors: Lind Hans 
Published: May 2010

AbstractSeasonal and lifetime spatial movements were studied in the field in a large number of marked individuals. Most snails were resident, each within a small part of the suitable habitat. Three different types of spatial movement patterns could be recognized. Characteristic of most snails were radiating movements between permanent core areas in the wood and principal feeding areas in glades, and sometimes explorations. The duration of the excursions was usually between a week and a month. Two different return strategies seem to exist in Helix, one adapted to the utilization of known habitats within the home range, and one adapted to secure site fidelity. Explorations were usually shorter than the critical homing distance and thereby the risk of disorientation was reduced. Juveniles spent much time in feeding areas maximizing growth, whereas adults in midsummer spent much time in the wood thereby probably increasing the chance of survival for next year's reproduction and of exploring new feeding areas. It seems that a rather permanent home range develops from birth on through unlearned orientation responses, exploration, topographic learning and return movements. Some individuals in the study area were extremely stationary, others used an exploratory strategy and increased their home ranges with new feeding areas. The exploratory strategy of resident snails may be an investment which pays off if the suitability of the habitat decreases. There is some evidence that different feeding places are assessed and that a home range can be partially changed according to this. Snails in one habitat of decreasing quality showed a relatively high emigration frequency. They used one of two different strategies: Exploration and gradual home range displacement, or exploration and sudden emigration over a relatively long distance. Emigrants always settled in a good snail habitat, and habitat assessment is probably part of both strategies. Non‐strategic, “accidental” emigration also occurred. No evidence of age‐dependent dispersal was found. Relevant parts of the animal migration model presented by Baker (1978) are confirmed.
Ethotypic Variation of Prey Recognition in Juvenile Anolis lineatopus (Reptilia: Iguanidae)
Authors: von Brockhusen‐Holzer Friederike , Curio Eberhard 
Published: May 2010

AbstractAmong prey‐naive Anolis lineatopus from Jamaica, individuals reject ants most commonly, crickets less commonly, and waxmoth larvae almost never. This study investigates the individual differences in the mechanism underlying prey perception in two of many ethotypes found, i.e., cricket‐rejectors and cricket‐acceptors. In one experiment artificially coloured live waxmoth larvae, crickets and ants were presented, in another experiment crickets and waxmoth larvae were moved passively with different speeds. Ethotypes differ in their evaluation of the interaction of prey key stimuli. Cricket‐rejectors and cricket‐acceptors differ in their responses to both crickets and waxmoth larvae that were either unicoloured yellow or black, but not in their responses to two types of ants of either colouration. Both ethotypes also differ in their preferences for artificially moved crickets and waxmoth larvae as a function of the interaction of prey type and velocity.In all but two prey items there is interaction in the perceptual pathways concerned. The first presentation in ontogeny of an ant inhibits attack on a cricket presented the next day. Some results suggest that ethotypes differ but gradually in their evaluation of stimuli presented, with cricket‐rejectors having a higher threshold for attack. However, other results suggest that cricket‐rejectors evaluate certain prey in a way qualitatively different from that of acceptors. At present there is little evidence for an understanding of the ethotypic differences of prey selection at a neural level, probably because neuroethologists have failed to look at individual differences of prey recognition; this failure is discussed in some detail.
Variations of Predatory Tactics of a Water Bug during Development
Authors: Cloarec Ann 
Published: May 2010

AbstractAt all developmental stages, Diplonychus indicus Venk. & Rao (Heteroptera: Belostomatidae) bugs make predatory attempts and catch prey both from ambush and while foraging actively. The distribution of predatory movements between these two foraging modes does not vary significantly during development, although a bug generally performs more predatory attempts from ambush than during active search. Both modes were subdivided and six different predatory movement types were recorded. These different predatory types are not all performed at the same frequency at all developmental stages. The proportion of predatory attempts including a preliminary lunge decreases with age whereas the proportion of simple predatory attempts (strike) increases with age. There is a significant effect of developmental stage and of predatory mode on capture success. General capture success rate increases with age and success rates vary with predatory type. Capture success of predatory attempts made while swimming is always lower than capture success of simple predatory attempts (strike). These rates do not vary during development. On the contrary, success rates for the predatory types dive and lunge increase with developmental stage. For some predatory categories, capture success varies with predator‐prey distance. The data then suggest that the bugs are undershooting.
Defining Natural Categories in Acoustic Signals: Comparison of Three Methods Applied to ‘Chick‐a‐dee’ Call Notes
Authors: Nowicki Stephen , Nelson Douglas A. 
Published: May 2010

AbstractIdentifying units of behavior is a universal problem in ethology. Here we compare three different techniques for identifying natural categories among notes in the chick‐a‐dee call of the black‐capped chickadee (Parus atricapillus). The combinatorial nature of ‘chick‐a‐dee’ calls, in which different note combinations are presumed to convey different messages, makes a problem of note classification especially relevant. The three techniques we used were (1) multidimensional scaling of inter‐note similarities derived from two‐dimensional cross‐correlation of digital spectrograms, 2) visual sorting of notes by human observers, and 3) k‐means cluster analysis based on a principal components analysis of 14 measured acoustic features. The three methods yielded generally concordant results, with closest agreement between the multidimensional scaling and visual classifications. We discuss possible mechanisms of information coding and perception, and the significance of these for the chick‐a‐dee call system. The techniques we employed provide powerful, complementary tools for the analysis of variation in acoustic communication signals.
A Quantitative Analysis of the Sounds of Hector's Dolphin
Authors: Dawson Stephen M. , Thorpe C. William 
Published: May 2010

AbstractWe developed an automatic, computer‐based system in which digital signal processing techniques were used to measure 31 variables from digitized Hector's dolphin (Cephalorhynchus hectori) sounds. Principal component analyses of these data were used to investigate the relationships between sounds. Hector's dolphins make only a very few types of pulsed “clicks”, most of which are centred around 125 kHz. None of these had an average frequency of less than 82 kHz, and the only audible sounds were made up of high‐frequency clicks repeated at such high rates that the repetition rate was audible to us as a tonal “cry” or “squeal”. In comparison to signal levels recorded from other cetaceans, all the Hector's dolphin signals were low‐level; the maximum received sound pressure level was 163 dB (re 1μPa).
Provisioning and Food Sharing by Lactating Spotted Hyenas, Crocuta crocuta (Mammalia: Hyaenidae)
Authors: Holekamp Kay E. , Smale Laura 
Published: May 2010

AbstractIn contrast to most other carnivores, spotted hyenas (Crocuta crocuta) do not regularly carry food back to their dens for provisioning of dependent young. Kruuk (1976) and Mills (1989) hypothesized that high levels of competition for provisioned food at the communal dens utilized by spotted hyenas may have selected against provisioning behavior in this species. We observed lactating female spotted hyenas carry food from ungulate kills to their dependent cubs at the den 18 times, and share food with their dependent cubs at kills 33 times. We used these data to test the Kruuk/Mills hypothesis by assessing effects of feeding competition on provisioning behavior. Provisioning rates were low, and were correlated with social rank. Provisioning attempts were often unsuccessful. Females dominant to the provisioner, with cubs also residing at the communal den, were the most effective competitors for provisioned food. Attempts to share food with cubs at kills were more successful than were attempts to provision cubs at the den. Our data thus support the Kruuk/Mills hypothesis.
Probing, Assessment, and Management during Interactions between Ground Squirrels and Rattlesnakes
Authors: Rowe Matthew P. , Owings Donald H. 
Published: May 2010

AbstractThe predator‐prey relationship between California ground squirrels (Spermophilus beecheyi) and northern Pacific rattlesnakes (Crotalus viridis) is a useful system for exploring conflict and assessment. Rattlesnakes are major predators of ground squirrel pups, but pose a less significant threat to adult squirrels. Adults approach, harass, and even attack rattlesnakes in defense of their pups.Two factors that may influence risk to both squirrel and snake during encounters are the size and body temperature of the rattlesnake. We used high‐speed video to analyze the strikes of rattlesnakes of various sizes tested at different body temperatures. Results indicate that warmer snakes are more dangerous because they strike with higher velocity, greater accuracy, and less hesitation. Similarly, larger snakes are more dangerous because they can strike farther and at higher speeds, and keep their fangs embedded longer. Thus, ground squirrels would benefit from extracting information about a rattlesnake's size and temperature.The converse of our results is that cooler, smaller rattlesnakes may be more vulnerable. These snakes could mitigate their risk by avoiding dangerous adversaries and minimizing cues that divulge their weaknesses. Such tactics might explain the active probing that squirrels direct at rattlesnakes, which may function to overcome a snake's resistance to disclosing its vulnerability.
Coupling Delayed Breeding with Short‐distance Dispersal in Cooperatively Breeding Birds
Authors: Zack Steve 
Published: May 2010

AbstractShort‐distance dispersal in cooperatively breeding birds is demonstrated and a new model describes how it could be causally related to delayed breeding. Nonbreeders are hypothesized to wait for specific, adjacent territories of high quality. Strong, predictable differences in territory quality select for extended natal philopatry in comparison with species whose young disperse upon maturity. A nonbreeder's ability to discriminate territory quality, and competitive advantages of age and proximity in obtaining nearby breeding positions, are necessary conditions of this model. Direct benefits to both males (potential for inheritance of a breeding position on the natal territory) and females (priority to nearby territories of high quality) result from philopatry. This model differs from most others by emphasizing potential direct benefits of delayed dispersal, rather than assuming constraints, such as habitat saturation. Short‐distance dispersal is widespread in other bird and mammal social systems characterized by natal philopatry and delayed breeding, suggesting a general application of this model.
Quantitative Analysis of the Ontogeny of Play Behaviour in Canid Hybrids
Authors: Willkomm Silke 
Published: May 2010

AbstractThe question how far the ontogeny of social behaviour shows similarities and to what extent it is genetically determined is investigated for 3 F2 canid hybrids of one litter by the example of contact play behaviour. It is known that jackals, especially the golden jackal (Canis aureus L.) display a number of differences in social behaviour and a very early ontogeny compared with the wolf (C. lupus L.) and the domesticated dog (C. I. forma familiaris). In this study behaviours were classified by timing the duration of single events from video records. The analysis bases on the duration of special patterns of behaviour and not, as is usually done, on single observations. Readiness to play is of special importance. It is measured by the number of plays initiated and behaviour during play. Whereas individual duration of play of these 3 F2 hybrids is greatly influenced by exogene factors, the maximum readiness to play, occurring over a marked time interval, seems endogenously determined. The different inborn development of readiness to play leads to very different frequencies of partner combinations during the various phases of development. Animals with much play initiative more often take part in contact play of their own accord. This establishes the order of frequencies of the playmates chosen. The frequency of successfully triggering contact play and the duration of the individual play initiative turn out to be a suitable measure of the — otherwise hardly recordable — genetically determined readiness to play.
Environmental Influences on Infanticide in Columbian Ground Squirrels
Authors: Dobson F. Stephen 
Published: May 2010

AbstractInfanticide of preweaned and weanling juvenile Columbian ground squirrels (Spermophilus columbianus) has been previously reported, but its prevalence in most populations is poorly known. I examined evidence of infanticide in a six‐year study of four populations in southwestern Alberta, two of which received an experimental supplementation of food for two years. Evidence of infanticide of weanling ground squirrels was uncommon, except for one population and year (previously supplemented population at 1580 m elevation in 1984) in which 9 dead young were found, suggesting an increased rate of infanticide. The rate of total loss of pre‐weaned litters also increased at 1580 m in 1984. At higher elevation sites (2100 m), however, no evidence of infanticide was found under experimental or unmanipulated conditions. One factor that might have influenced the rate of infanticide of weanlings was their degree of development when they first emerged from natal burrows. A review of studies of 11 populations of Columbian ground squirrels suggested that under natural conditions, infanticide may have differed among environments. Differences in density among populations appeared to have little influence on the rate of infanticide, but elevation was significantly negatively associated with infanticide.
Invasion of the Nest of Polistes dominulus by the Social Parasite Sulcopolistes sulcifer (Hymenoptera, Vespidae)1
Authors: Turillazzi S. , Cervo R. , Cavallari I. 
Published: May 2010

AbstractThe main characteristics of invasion of a Polistes dominulus Christ colony by a female of Sulcopolistes sulcifer Zimmermann can be summarized as follows: the parasite is usually attacked by Polistes while still approaching the nest. The parasite fights all opponents on the ground, both foundresses and workers, some of which can be very aggressive even off the nest. Others succumb to the parasite immediately on the very first encounter. Sulcopolistes' strategy is to fight one adversary at a time and then return rapidly to the nest. In this way it is easier for her to defeat the hosts one after another, and to usurp nests with a high number of workers. While fighting on the ground the parasite never used its sting, but tried to bite the legs off its victims. The alpha foundress is the one which attacks the parasite most aggressively, which in turn is particularly aggressive towards her. Beta females on bigynic and gamma females on trigynic foundations are less aggressive than their nestmates of higher hierarchical status. After nest conquest, dominance activity of the parasite increases, and she offers drops of liquid to nest occupants during encounters. When not interacting with the hosts, Sulcopolistes performs an intense nest inspection and carefully strokes the nest surface and internal parts of some cells with her abdominal sterna.