| Home | [11–20] << 21 22 23 24 25 26 27 28 29 30 >> [31–40] |
|
Jennings, D. J., Gammell, M. P., Carlin, C. M., & Hayden, T. J. (2004). Effect of body weight, antler length, resource value and experience on fight duration and intensity in fallow deer. Anim. Behav., 68(1), 213–221.
Abstract: We tested predictions of evolutionary game theory focusing on fight duration and intensity during contests between European fallow deer, Dama dama L. We examined the relation between contest duration and intensity and resource-holding potential (RHP; body weight and antler size), in an effort to reveal the assessment rules used by competing males. We examined other potential determinants of duration and intensity: resource value (the oestrous female) and experience of agonistic interactions. Asymmetry in body weight or antler length of contestants was not correlated with fight duration. Body weight and antler length of the fight winner or loser were also not correlated with fight duration. Neither were the body weight of the heavier or lighter animal or the antler length of the animal that had longer or shorter antlers. A measure of intensity (the jump clash) was positively related to the body weight of the losing animal and the lighter member of the dyad. These results are consistent with the hypothesis that opponents escalate contest intensity based on assessment of their own ability rather than through mutual assessment. There was no evidence that resource value is an important factor in either fight duration or intensity in this population. As the number of fights between pairs of males increased, there was a decrease in fight duration. Fights were longer when at least one member of a competing pair of males had previously experienced a victory.
|
|
Jennings, D. J., Gammell, M. P., Carlin, C. M., & Hayden, T. J. (2003). Is the parallel walk between competing male fallow deer, Dama dama, a lateral display of individual quality? Anim. Behav., 65(5), 1005–1012.
Abstract: During competitive encounters protagonists are expected to use signals of individual quality particularly if there is a risk of injury or death. Lateral presentation of body profile, by which information regarding phenotypic characteristics associated with individual quality are displayed, may represent such a strategy. During aggressive interactions, male fallow deer frequently engage in parallel walking which is assumed to represent a mutual display of quality, as mediated by exposure of the maximal profile of the body or antlers. We examined the context and role of the parallel walk during competitive encounters to investigate whether there was evidence that dyads of competing males were assessing differences in phenotypic characteristics. There was no evidence to support the hypotheses that the parallel walk is a lateral display of body size or weaponry or that its use is associated with a reduced level of escalated or risky behaviours during fighting. Total time spent fighting was not shorter when a parallel walk was present than when there was no parallel walk. The parallel walk was highly associated with fighting and it was more likely to be initiated by the subsequent loser. Furthermore, parallel walking frequently followed bouts of fighting and as such may represent a strategy that permits an animal the opportunity to decide whether to continue fighting. Parallel walking was also associated with a failure to resolve contests in favour of one animal indicating that it may be a means of withdrawing from further fighting without incurring a loss in dominance status. Copyright 2003 Published by Elsevier Science Ltd on behalf of The Association for the Study of Animal Behaviour.
|
|
Galef BG, J., & Giraldeau, L. A. (2001). Social influences on foraging in vertebrates: causal mechanisms and adaptive functions. Anim. Behav., 61(1), 3–15.
Abstract: We summarize 20 years of empirical and theoretical research on causes and functions of social influences on foraging by animals. We consider separately studies of social influence on when, where, what and how to eat. Implicit in discussion of the majority of studies is our assumption that social influences on foraging reflect a biasing of individual learning processes by social stimuli rather than action of independent social-learning mechanisms. Our review of theoretical approaches suggests that the majority of formally derived hypotheses concerning functions of social influence on foraging have not yet been tested adequately and many models are in need of further refinement. We also consider the importance to the future of the field of integrating 'top-down' and 'bottom-up' approaches to the study of social learning. Copyright 2001 The Association for the Study of Animal Behaviour.
|
|
Mottley, K., & Giraldeau, L. A. (2000). Experimental evidence that group foragers can converge on predicted producer-scrounger equilibria. Anim. Behav., 60(3), 341–350.
Abstract: When foraging together, animals are often observed to feed from food discoveries of others. The producer-scrounger (PS) game predicts how frequently this phenomenon of food parasitism should occur. The game assumes: (1) at any moment all individuals can unambiguously be categorized as either playing producer (searching for undiscovered food resources) or scrounger (searching for exploitation opportunities), and (2) the payoffs received from the scrounger tactic are negatively frequency dependent; a scrounger does better than a producer when the scrounger tactic is rare, but worse when it is common. No study to date has shown that the payoffs of producer and scrounger conform to the game's assumptions or that groups of foragers reach the predicted stable equilibrium frequency (SEF) of scrounger, whereby both tactics obtain the same payoff. The current study of three captive flocks of spice finches, Lonchura punctulata, provides the first test of the PS game using an apparatus in which both assumptions of the PS game are met. The payoffs to the scrounger, measured as feeding rate (seeds/s), were highly negatively frequency dependent on the frequency of scrounger. The feeding rate for scrounger declined linearly while the rate for producer either declined only slightly or not at all with increasing scrounger frequency. When given the opportunity to alternate between tactics, the birds changed their use of each, such that the group converged on the predicted SEF of scrounger after 5-8 days of testing. Individuals in this study, therefore, demonstrated sufficient plasticity in tactic use such that the flock foraged at the SEF of scrounger. Copyright 2000 The Association for the Study of Animal Behaviour.
|
|
Powell, F., & Banks, P. B. (2004). Do house mice modify their foraging behaviour in response to predator odours and habitat? Anim. Behav., 67(4), 753–759.
Abstract: Predator odours and habitat structure are thought to influence the behaviour of small mammalian prey, which use them as cues to reduce risks of predation. We tested this general hypothesis for house mice, Mus domesticus, by manipulating fox odour density via addition of fox scats and habitat via patchy mowing of vegetation, for populations in 15 x 15-m field enclosures. Using giving-up densities (GUDs), the density of food remaining when an animal quits harvesting a patch, we measured foraging behaviours in response to these treatments. Mice consistently avoided open areas, leaving GUDs two to four times greater in these areas than in densely vegetated patches. However, mouse GUDs did not change in response to the addition of fox scats, even immediately after fresh scats were added. There was no interaction between fox odour and habitat use. We then tested whether habituation to fox odours had occurred, by comparing the individual responses to scats of eight mice born into enclosures with fox scats to those of eight mice born into scat-free enclosures and five wild mice. In smaller enclosures, GUDs of trays with scats did not differ from GUDs of trays without scats for any treatment. We conclude that exposure to high levels of fox odours did not alter the foraging behaviour of mice, but that mice did reduce foraging in areas where habitat was removed, perceiving predation risk to be greater in these areas than controls. We suggest further that studies using the `scat-at-trap' technique, which have shown avoidance of predator odours by mice and other small mammals, may overestimate the general avoidance of predator odours by free-living prey, which must forage with a constant background of predator odours.
|
|
Wolff, P. R., & Powell, A. J. (1984). Urine patterns in mice: An analysis of male/female counter-marking. Anim. Behav., 32(4), 1185–1191.
Abstract: Counter-marking in mice, Mus musculus was investigated by analysing urine deposition on filter paper marked asymmetrically with urine of the opposite sex. Intact males deposited large numbers of urine spots with a marked angular bias towards previously marked quadrants. More spots were deposited on proestrous and ovariectomized donor urine patterns, their distribution being more centrifugal on oestrous urine and more centripetal in quadrants containing a large female urine spot in a central position. In contrast, castrated male mice deposited very few spots with no angular bias. Female urine patterns showed angular bias in response to intact, but not castrated male donor urine, a larger number of spots being produced by oestrous females. Thus the pattern of deposition offers scope for two-way communication of information about reproductive potential.
|
|
Powell, A. J., & Wolff, P. R. (1982). Sex differences in mouse urination patterns. Anim. Behav., 30(4), 1207–1211.
Abstract: When tested in circular open fields male and female mice (Mus musculus) produced strongly centrifugal urination patterns, which showed a clear `edge-dependency' in all the field sizes used. However, striking sex differences in the pattern of deposition were shown in terms of both the number and distribution of the urine spots. Male mice produce large numbers of spots which are regularly dispersed, while females produce relatively fewer spots with a more clumped distribution. It is suggested that a hitherto unsuspected level of intersexual communication may explain these differences.
|
|
Powell, R. A. (1979). The dog: Its domestication and behavior : By . New York: Garland STPM Press (1978). 296 pp. $24.50. Anim. Behav., 27(Part 1), 318–1211.
|
|
Powell, G. V. N. (1974). Experimental analysis of the social value of flocking by starlings (Sturnus vulgaris) in relation to predation and foraging. Anim. Behav., 22(2), 501–505.
Abstract: In groups of ten, indidual starlings, Sturnus vulgaris, spent significantly less time in surveillance than did individuals in smaller groups and responded more quickly than single birds to a flying model hawk. Captive starlings in flocks reduce their individual surveillance efforts, but their combined efforts still enable them to be more effective than single birds in the detection of predators. Foraging behaviour of flocks was observed by placing single starlings with groups of tricoloured blackbirds, Agelaius tricolor; the starlings reduced the time they devoted to surveillance at the same rate as if they were with other starlings.
|
|
Reader, S. M., & Laland, K. N. (2000). Diffusion of foraging innovations in the guppy. Anim. Behav., 60(2), 175–180.
Abstract: The way in which novel learned behaviour patterns spread through animal populations remains poorly understood, despite extensive field research and the recognition that such processes play an important role in the behavioural development, social interactions and evolution of many animal species. We conducted a series of controlled diffusions of foraging information in replicate experimental populations of the guppy, Poecilia reticulata. We presented novel foraging tasks over 15 trials to mixed-sex groups, made up of food-deprived and nonfood-deprived adults (experiment 1) or small, young fish and old, large adults (experiment 2). In these diffusions, knowledge of a route to a feeder could spread through the group by subjects learning from others, discovering the route for themselves, or, most likely, by some combination of these social and asocial learning processes. We found a striking sex difference, with novel foraging information spreading at a significantly faster rate through subgroups of females than of males. Females both discovered the goal and learned the route more quickly than males. Food-deprived individuals were faster at completing the tasks over the 15 trials than nonfood-deprived guppies, and there was a significant interaction between sex and size, with a sex difference in adults but not young individuals. There was also an interaction between sex and hunger level, with food deprivation having a stronger effect on male than female performance. We suggest that information may diffuse in a similar nonrandom or 'directed' manner through many natural populations of animals. Copyright 2000 The Association for the Study of Animal Behaviour.
|