bluuebunny/crossref_metadata_2025_split huggingface dataset:
Copulation Behaviour of Birds
Authors: Møller A.P. , Atkin L. , Birkhead T.R. 
Published: April 2008

AbstractInter-specific variation in copulation behaviour among birds is described. The following factors explaining variation in copulation rate are examined: (i) the number of eggs which have to be fertilized (the fertilization hypothesis), (ii) the importance of the pair-bond (the social bond hypothesis), (iii) predation risk during copulation (the predation hypothesis), and (iv) cuckoldry risk (the sperm competition hypothesis). These hypotheses were investigated in preliminary analyses at the generic level using data on copulation behaviour in 131 bird species. The sperm competition hypothesis was supported by several lines of evidence: (i) frequent copulations among genera where males are not able to guard their mates (colonial birds, diurnal birds of prey, and owls), (ii) frequent copulations in polyandrous genera, (iii) copulations inside hole-nests of colonial birds but outside the hole-nests of solitarily nesting genera, and (iv) by the occurrence of forced pair copulations following extra-pair copulation in some species. The predation and social bond hypotheses were not totally dismissed, but there was no evidence that fertilization ability was limited by copulation frequency (i.e. the fertilization hypothesis).
Scramble and Contest in Feeding Competition Among Female Long-Tailed Macaques (Macaca Fascicularis)
Authors: Van Noordwijk Maria A. , Van Schaik Carel P. 
Published: April 2008

AbstractMost previous studies of feeding competition in gregarious primates compared some average or group-level characteristic over a range of group sizes. Here an attempt is made to separate the effects of within-group scramble (the "group size" effect) and of within-group contest (the "dominance" effect) on energy expenditure and food intake in female long-tailed macaques (Macaca fascicularis). Significant or consistent scramble and contest components were demonstrated for locomotion and energy expenditure, for the presence in the main party of the group, and for birth rate. The intake of fruit or animal matter was not increased in compensation, but the intake of dispersed vegetable matter probably was. It is concluded that both components of feeding competition exist in long-tailed macaques, but that contest for food is often transferred into contest for safety. A framework is proposed to relate interspecific variation in contest effects to food distribution and group cohesion.
A Phonological Analysis of Male Gibbon Singing Behavior
Authors: Mitani John C. , Marler Peter 
Published: April 2008

Abstract
Acoustic analyses and experimental field playbacks were conducted to investigate the nature and communicative significance of the phonological structure and organization of male gibbon (Hylobates agilis) songs. Males use a limited number of spectrographically discrete elements or note types to construct songs. A classification of these note types was produced initially through a visual sorting process using gross spectral and temporal features. Measurement of single acoustic variables and a digital sound program, which compared the two-dimensional cross-correlation values of note spectrograms, were employed to check the results of the qualitative sorting procedure. The sequential organization of notes composing songs was examined by tabulating the frequencies of occurrence of each note type in different positions and the transition probabilities between note types. These analyses revealed that songs are formed within a framework of rules, which define regular patterns in the placement and order of note types. To investigate whether the gibbons employ these rules in a biologically meaningful fashion, a field playback experiment was conducted comparing the responses of animals to normal and phonologically rearranged songs. Although the gibbons identify rearranged songs as conspecific territorial signals, responses to playbacks suggested that the hypothesized rules generating songs are communicatively significant; male gibbons responded in a qualitatively different fashion to normal and phonologically rearranged songs. These results are evaluated in light of other studies of animal vocal communication.
Family Planning in the Great Tit (Parus Major): Optimal Clutch Size as Integration of Parent and Offspring Fitness
Authors: Tinbergen Joost M. , Daan Serge 
Published: April 2008

AbstractFitness variations due to natural variation in the size of the first clutch and its laying date were estimated using Fisher's reproductive value for both the clutch (Vc) and the parent (Vp) in a population of great tits. In order to test the hypothesis that individual birds maximize their reproductive value by the choice of clutch size, artificial variation in brood size was introduced and the consequences in terms of reproductive value estimated. Maximal Vc, computed on the basis of natural variation in clutch size, occurred at a clutch size of 15.2, and increased slightly with laying date (Fig. 1A) Vp increased with natural variation in clutch size and decreased with date (Fig. 1B). The total reproductive value V (= Vc+Vp) was maximal at a clutch size of 15.4 (Fig. 1C), substantially higher than the population mean clutch size (9.2). The components of the reproductive value of the clutch (Vc) that were negatively affected by manipulation were the survival of the nestlings and the recruitment rate. The reproductive value of the parent (Vp) was negatively affected only through the probability of having a second clutch. Maximal Vc computed on basis of artificial variation in clutch size, occurred at a clutch size of 10.0, and also increased with date (Fig. 1D). Vp decreased with artificial variation in clutch size (Fig. 1E causing the clutch size maximising reproductive value V to shift to a value of 9.4 (Figs 1F, 3), very close to the population mean clutch size (9.2). It is concluded that the majority of great tits produces the number of eggs (9-10) that maximizes their individual fitness, even though those individual birds laying 15 eggs have the highest reproductive value in the population. The fact that birds laying very large clutches have the highest reproductive value points in the direction of a selection pressure towards larger clutches. Yet, over the last 30 years clutch sizes have not increased in the study population. This apparent contradiction is discussed. Either no genetic variation in clutch size is involved, or a complex polymorphism exists.
Instability of Harems of Feral Horses in Relation To Season and Presence of Subordinate Stallions
Authors: Franke Stevens Elizabeth 
Published: April 2008

AbstractMale horses (Equus caballus) defend harems of females (bands) year-round and throughout their lifetimes. A male's lifetime reproductive success depends upon the number of females in his harem. Although harems have previously been reported as remaining stable over many years, during the two years of this study 30 % of the adult females in an island population of feral horses changed harems during late winter. The seasonal differences in harem stability resulted from seasonal differences in the abundance and distribution of food. The spacing between band members was greater and the frequency of social interactions between them was lower in winter than in summer. In addition, the amount of time devoted to grazing increased in winter. These differences are attributed to the lower availability of suitable vegetation duirng winter. Harem stability did not depend on the age of females, the size of the harem, nor the age of the harem stallion, but did depend on the presence of subordinate stallions attached to the band. All of the females that changed bands left single-male bands; multi-male bands were stable throughout the study.
Routine Formation and Flexibility in Social and Non-Social Behaviour of Aggressive and Non-Aggressive Male Mice
Authors: Benus R.F. , DEN DAAS S. , Koolhaas J.M. , VAN OORTMERSSEN G.A. 
Published: April 2008

Abstract
To investigate the relationship between aggression and routine-like behaviour the response of male mice of bidirectionally selected lines for attack latency to a change in the social and non-social environment has been measured. In a non-social situation the extent of routine-like behaviour was measured in a Y-maze in which only one of the two arms gave access to the food compartments. The number of errors made in response to reversal of the arm that was blocked was taken as indicator for the degree of routine formation. Males of the short attack latency (SAL) line made significantly more errors, and hence were more routine-like in their performance, than mice of the long attack latency (LAL) line. Males of the LAL line that nevertheless had short attack latencies (i. e. aggressive LAL mice) turned out to be flexible in their behaviour; their response was similar to that of the non-aggressive LAL males. In a social situation SAL and aggressive LAL mice were used to investigate routine formation in attacking behaviour. The males were given different amounts of experience with male opponents after which their own female was introduced as opponent. The more extended the experience with male intruders was, the more SAL males subsequently attacked their female. In contrast, LAL mice appropriately changed their behaviour towards the female opponent. Thus, the attacking behaviour of SAL mice gets routine-like, whereas that of LAL males remains flexible. It is concluded that selection for attack latency generally coincides with selection for routine-like behaviour, suggesting that these two factors are influenced by many of the same genes. Regarding the fact that aggressive males of the LAL line show flexible behaviour, it may be proposed that with the phenotypic selection for attack latency there has in fact been selected for a mechanism that determines the organization (routine-like vs flexible) of behaviour.
The Development of a Behavior System: Dustbathing in the Burmese Red Junglefowl I. the Influence of the Rearing Environment On the Organization of Dustbathing
Authors: Vestergaard Klaus , Hogan Jerry A. , Kruijt Jaap P. 
Published: April 2008

Abstract
The purpose of this study was to determine the role played by functional experience in the development of the dustbathing behavior system in junglefowl. Small groups of birds were raised either in a rich environment with sand and earth, or in a poor environment with a wire mesh floor. Dustbathing and other behaviors were recorded at intervals between 2 and 9 months of age. The results showed that the form of the individual behavior patterns as well as the organization of extended bouts of dustbathing developed normally in chicks raised in a dustless environment. Further, the frequency of occurrence of dustbathing and the diurnal rhythm did not differ between groups raised in the two environments. Functional experience was necessary for the development of dust recognition, but some stimuli came to be recognized as "dust" more easily than others.
Signature Versus Perceptual Adaptations for Individual Vocal Recognition in Swallows
Authors: Loesche Patricia , Stoddard Philip K. , Higgins B.J. , Beecher Michael D. 
Published: April 2008

Abstract
Field experiments have shown that parents in the colonially-nesting cliff swallow (Hirundo pyrrhonota) discriminate between their offspring and unrelated young whereas parents in the closely-related but noncolonial barn swallow (H. rustica) do not, and that discrimination is based on the chick begging call. In a laboratory experiment, we trained three cliff swallows, two barn swallows and a European starling (Sturnus vulgaris) to discriminate among chick begging calls of the two swallow species. All birds discriminated more easily among the calls of different cliff swallows than among the calls of different barn swallows, suggesting that cliff swallow calls are more individually distinctive, and may be adapted for a signature function. Moreover, cliff swallows discriminated among both cliff swallow and barn swallow calls faster than did the other birds, which is consistent with a perceptual adaptation for conspecific calls that incidentally facilitates the discrimination of similarly-structured heterospecific calls.
Reactions of Four Passerine Species To Threats of Predation and Cowbird Parasitism: Enemy Recognition or Generalized Responses?
Authors: Neudorf Diane L. , Sealy Spencer G. 
Published: April 2008

Abstract
Four host species of the parasitic brown-headed cowbird (Molothrus ater) were exposed to taxidermic mounts of a female cowbird, fox sparrow (Passerella iliaca), and common grackle (Quiscalus quiscula) at their nests during their egg-laying or nestling stage. Red-winged blackbirds (Agelaius phoeniceus), a species that accepts cowbird eggs laid in their nests, responded more aggressively to cowbird models early in their nesting cycle, indicating that they recognized the unique threat the cowbird posed. Gray catbirds (Dumetella carolinensis), northern orioles (Icterus galbula), and cedar waxwings (Bombycilla cedrorum) can remove cowbird eggs from their nests and for the most part they responded similarly to cowbird models and the "nonthreatening control," i.e. a fox sparrow. Cedar waxwings were nonaggressive to all the models and may rely on concealment to protect their nests from enemies. Removal of cowbird eggs by puncture ejection is more risky than grasp ejection. Despite this, orioles and waxwings (puncture ejectors) were not significantly more aggressive to cowbird models at egg laying than catbirds (grasp ejectors). Responses of the three rejector species toward the cowbird model did not change over the nesting cycle, indicating further that they do not recognize cowbirds as a unique threat. Rejector species may not recognize cowbirds because they have little experience with them. With the exception of waxwings, all of the hosts recognized the grackle as an enemy and increased their levels of defence from the laying to nestling stages. Three of the host-species did not simply respond in a generalized manner to any intruder at their nests but indeed recognized specific enemies. Considerable interspecific variability exists amongst the four species in defensive behaviours, which may reflect their different nesting habitats.
The Ontogeny of Food-Storing and Retrieval in Marsh Tits
Authors: Clayton N.S. 
Published: April 2008

AbstractMarsh tits, Parus palustris, store food and rely on an accurate spatial memory to retrieve their caches. This study considers the ontogeny of storing and the spatial memory involved in retrieving these caches in juvenile hand-raised marsh tits. Preliminary work showed that these birds began storing and retrieving their caches around the time of feeding independence, suggesting that juveniles do not need to learn from adults. However, storing gradually improved over the first few trials, in terms of the appropriateness of items stored, the efficiency of choosing suitable storage sites and the rate of storing seeds. To answer the question of whether the behavioural improvement is a function of age, experience or both, the retrieval performance of two groups of birds were compared. During the first eight trials (24 days) after nutritional independence from the parents, the two groups were exposed to two different kinds of experience: experienced birds were provided with seeds which they could store and retrieve two hours later, whereas the naive birds were exposed only to the storage sites but they could not store. In the following eight trials, both groups were allowed to store and retrieve their caches. If the improvement was merely a consequence of age (maturation) no difference should be found between the two groups on trial 9. In contrast, if improvement was purely a function of experience then the pattern of improvement in the naive group should follow that of the experienced group, but showing an eight-trial time lag. The results suggested a pattern intermediate between these extremes, indicating that either the development of food-storing was a function of both age and experience or that other differences between the two groups, such as differences in motivation to store and/or experience at handling seeds, were important. In contrast, retrieval performance was better than expected by chance on the first trial it occurred and showed little, if any, improvement.
Female Resistance and Precopulatory Guarding in the Isopod Idotea Baltica (Pallas)
Authors: Jormalainen Veijo , Merilaita Sami 
Published: April 2008

Abstract
In a laboratory experiment in I. baltica the precopulatory guarding was preceded by a period of struggles between the sexes as males continuously tried to initiate the precopulatory guarding and females resisted their guarding attempts. This struggling lasted for a few days, during which the females escaped from the males on the average 1.3 times per hour. While the females resisted, the males usually responded by kicking back. Once the precopula started, on the average 43 h before the completion of the female parturial ecdysis, the female resistance stopped. If the guarding male was replaced by another male, the female accepted the new male without resistance or resisted only weakly. Larger males were able to perform longer precopulas, and furthermore, when males were hunger stressed they performed shorter precopulas than control males. The female resistance and the existence of struggles imply a conflict between the sexes over whether or not to start the precopulatory phase. This conflict may occur either because of different optimum precopula duration of the sexes or because of the unwillingness of the females to pair with whatever male. By resisting, females may, at least to some extent, control the duration of the guarding, and the resistance may lead to selection among male candidates. Thus the female resistance, although for so far largely neglected, may have potential importance in the mate choice and sexual selection of aquatic crustaceans with precopulatory guarding.
Mating Tactics in the Tropical Millipede Alloporus Uncinatus (Diplopoda: Spirostreptidae)
Authors: Telford Steven R. , Dangerfield J. Mark 
Published: April 2008

AbstractField and laboratory observations of mating behaviour in a population of the tropical millipede Alloporus uncinatus were carried out over one breeding season. Males obtained mates through random encounters and by forming triplet associations with copula pairs. The occurrence of triplet associations in the field was coincident with a highly male biased operational sex ratio. Mate acquisition by males was apparently stochastic and direct physical competition did not occur. In laboratory experiments mating was size-selective probably as a consequence of female choice. We consider the possibility that sperm competition has contributed to the evolution of the mating system in this species.
Hunting Decisions in Wild Chimpanzees
Authors: Stanford Craig B. , Wallis Janette , Mpongo Eslom , Goodall Jane 
Published: April 2008

AbstractWhile field studies of wild chimpanzees have investigated the proximate determinants of hunting success, little attention has been paid to the decision to hunt. We present evidence from Gombe National Park, Tanzania, showing that the social factors that most strongly influence the decision to hunt red colobus monkeys are the presence of female chimpanzees with anogenital sexual swellings in the foraging party, the number of adult and adolescent males in the party, and the total size of the foraging party. Of these, the presence of one or more swollen females was the best predictor of a decision to undertake hunts of red colobus groups at all but the smalles chimpanzee foraging party size. Two likely explanations for this pattern are discussed. First, swollen females may be a primary influence on male grouping patterns, which in turn promotes hunting. Second, this finding, together with previous research showing that male chimpanzees preferentially give meat to estrous females, suggests that male chimpanzee hunting performance may be under sexual selection. While nutritional and ecological factors may influence chimpanzee hunting patterns at times, chimpanzees appear to hunt red colobus at least partially to obtain meat for use as a social and reproductive tool.
Jumping Spiders Make Predatory Detours Requiring Movement Away From Prey
Authors: Tarsitano M.S. , Jackson R.R. 
Published: April 2008

AbstractThe terms "reversed-route detours" and "forward-route detours" are introduced to distinguish between detours that require moving away from a goal and those that do not. We provide the first evidence under controlled laboratory conditions that salticids can perform reversed-route detours. Two species were tested: 1) Portia fimbriata, a web-invading salticid from Queensland, Australia, that normally preys on web-building spiders; 2) Trite planiceps, an insectivorous cursorial salticid from New Zealand. Although both of these species completed reversed-route detours, Trite planiceps was much more dependent on prey movement than Portia fimbriata. Interspecific differences appear to be related to the different predatory styles of these two salticids.
Philopatry and Affiliation Among Red Colobus
Authors: Starin E.D. 
Published: April 2008

AbstractTemminck's red colobus (Procolobus badius temminckii) living in the Abuko Nature Reserve, The Gambia, have more prominent female-female bonds and less prominent male-male bonds than has been described in most other female-transfer, male-resident groups. This may be due to a number of factors such as female peer-group transfer, the small number of groups available to a transferee, the lack of sexual dimorphism, and the presence and importance of females in initiating and defending the social integrity of the social unit. It is clear from this that the presence of female-transfer, male-residence patterns is not always enough to automatically predict strong male-male bonds. Other factors must also be considered.
Social Relationships of Male Bonnet Macaques: Male Bonding in a Matrilineal Society
Authors: Silk Joan B. 
Published: April 2008

AbstractAffiliative and cooperative relationships are not common among mammalian males. This may be partly the result of sexual selection which favors competitive and agonistic interactions among mature males, and partly the result of the fact that female mammals are generally philopatric. This means that adult males usually live among unrelated and unfamiliar individuals. Bonnet macaques (Macaca radiata) represent one of several exceptions to this general pattern. Adult males in this species frequently sit together, groom, huddle, greet, and support one another. The nature of social relationships among males are related to their participation in coalitions as males tend to support the males with whom they associate and interact affilatively, and intervene against the males with whom they generally exchange greetings and aggression.