bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Communicative Repertoire of Captive Bonobos (Pan Paniscus), Compared To That of Chimpanzees
Authors: De Waal Frans B.M. 
Published: April 2008

AbstractTen bonobos (Pan paniscus), housed in three separate subgroups at the San Diego Zoological Garden, were observed for 288 hours over a four-month period. The colony included one adult male, two adult females, two adolescent males, four juveniles, and one infant. Data on 5,135 sequences of social behavior were collected either as spoken accounts or as video recordings. In addition, high-quality sound recordings were obtained for spectrographic analysis. The data were subjected to a quantitative analysis of probabilities of association between 44 communicative behavior patterns and 40 different context types. The paper treats each communicative behavior pattern separately, providing a) its frequency, b) the most common inter-individual directions of performance, c) characteristic contexts, d) a description, e) a commentary on its possible functions, and 1) a comparison with the behavior of chimpanzees (Pan troglodytes). The study shows that, while the behavioral repertoires of the two Pan species are fundamentally similar, interesting differences exist in their vocal repertoires, sexual behavior, and agonistic behavior. The bonobo's voice has a higher pitch, and many of its vocalizations are structurally different from homologous chimpanzee vocalizations. The greatest difference concerns the long-distance hooting calls of the two species. The bonobo's sexual behavior is much more elaborate than the chimpanzee's, including ventro-ventral copulation, and "GG-rubbing" between adult females. Sexual forms of contact seem to serve many of the reassurance and reconciliation functions fulfilled by nongenital contact forms in the chimpanzee. Finally, the bonobo's agonistic behavior is less elaborate and appears more controlled than the chimpanzee's.
Some Determinants of the Mating System in a Population of Painted Reed Frogs (Hyperolius Marmoratus)
Authors: Telford Steven R. , Dyson Miranda L. 
Published: April 2008

AbstractHyperolius marmoratus shares its breeding site with 12 synchronously breeding species. Males call from elevated perches to attract females. Observations of captive populations suggest that males may adopt alternative mating strategies when chorus densities are high. Similar strategies were not observed in natural choruses. The operational sex ratio (OSR) was always male-biased and also highly variable. Mating was polygynous, only 25% of the male population actually mated. Females mated either once or twice. Variance in mating success was much greater among males, an obvious consequence of a skewed OSR. Female choice was probably not a causal factor because male mating success was correlated with neither size nor age. Size-based variation in the male advertisement call does exist, but females cannot exploit this potential vocal cue because of their impaired discriminatory ability in a complex sonic environment and the potential risk of mismating. Although the mating system may best be described as lek-like, with males forming organised choruses through competitive interactions, the variance in male mating success is probably a consequence of stochastic factors.
Food Competition in Brown Capuchin Monkeys (Cebus Apella): Quantitative Effects of Group Size and Tree Productivity
Authors: Janson Charles H. 
Published: April 2008

AbstractThe effects of group size and fruit availability in tree crowns on per-capita food intake was examined for wild brown capuchin monkeys living in groups of 3-12 individuals. Per-capita feeding time was nearly exactly inversely proportional to group size in small-crowned trees with little fruit, but was essentially independent of group size in large-crowned trees with abundant fruit. Despite the use of such productive trees, per-capita feeding time in the average tree visited decreased by 50% over a 4-fold range of group sizes. This cost of indirect food competition in large groups was not compensated by increased rates of ingestion, preferential use of large trees, of a higher rate of fruit tree encounter per distance travelled. Instead, foraging effort (distance travelled, number of minutes devoted to foraging, total activity minutes per day) increased at large group sizes. Estimates of total energy intake and expenditure suggest that net energy gain is constant for individuals in group sizes of 5-12. I suggest that the upper limit to group size is set by the daylength available for foraging in large groups. Aggression in food trees increased in frequency in larger groups, but the relative feeding rates of dominants and subordinates of a given rank did not appear to depend on group size. Observed decreases in per-capita food intake due to either indirect or aggressive food competition within large groups are substantially greater than the 4% gain in mean food intake that large groups achieve by displacing smaller groups from fruit trees.
Food Competition and Foraging Party Size in the Black Spider Monkey (Ateles Paniscus Chamek)
Authors: M M. 
Published: April 2008

AbstractIn Ateles, individuals forage for fruit in subgroups of unstable membership. The size and composition of these foraging parties are highly variable. Data from my long-term field study of a population of black spider monkeys in Peru show a strong positive correlation between the average size of these parties and the number and size of trees currently producing fruit in the environment. This correlation appears to be driven by intragroup feeding competition, since individuals in larger parties showed substantially lowered feeding efficiencies, as measured by increased daily ranges and decreased time spent feeding. Patch size and patch density, which jointly determine fruit abundance, interact to determine foraging party size, apparently by the following mechanism. The number of spider monkeys that can feed within a particular patch is limited by the size of that patch. When patches are close together (i. e. high patch density) individuals in excess of this limit are able to feed in nearby patches and thus maintain contact with the other members of their foraging party. When patch density is low, the increased travel costs associated with such a strategy become prohibitive and foraging parties are smaller than or equal to the number of individuals able to feed within a single patch. Females that are routinely excluded from the best feeding sites may have reduced reproductive success because of their low priority of access to resources. These data provide a quantitative link between two ecological variables (resource patch size and density) and fission-fusion social organization in the spider monkey.
Feeding Competition and Patch Size in the Chimpanzee Species Pan Paniscus and Pan Troglodytes
Authors: Wrangham Richard W. , White Frances J. 
Published: April 2008

AbstractThe relative importance of feeding competition in Pan paniscus and Pan troglodytes schweinfurthii is examined in an attempt to understand the major differences in social organization of the two species. P. paniscus at Lomako is characterized by a stronger tendency for association among females than among female P. troglodytes at Gombe. Party size in P. paniscus is dependent on patch size. Feeding competition was more important in small patches than in large patches. The total amount of feeding time by a party in a patch (chimp-minutes) was a measure of patch size that was available for both chimpanzee species. P. paniscus was found to have larger party sizes and to use larger food patches than P. troglodytes. The importance of dispersed ground foods for each species of chimpanzee was compared and, although the results are not conclusive, they indicate that this type of food was equally important in the diets of both populations. Two hypotheses of the ecological basis for differences in social structure are compared in light of this evidence.
Benefits, Costs, and Determinants of Dominance in American Black Ducks
Authors: Hepp Gary R. 
Published: April 2008

AbstractBehavioural dominance was studied in captive American black ducks (Anas rubripes) during October-December 1984. Eighty ducks were marked individually, and groups of 10 ducks consisting of 5 adults (3 males and 2 females) and 5 juveniles (3 males and 2 females) were assigned to each of 8 experimental pens. Ducks in 4 pens received an ad libitum diet, and ducks in the other 4 pens were given a restricted diet. Dominance structure within pens was linear. Adults were dominant to young, and body mass had no influence on dominance rank. The effect of sex on dominance rank was age-specific. Adult males were dominant to adult females and to young black ducks of both sexes; however, dominance rank of young males did not differ from adult or young females. Paired adults were dominant to unpaired adults and to young individuals that were either paired or unpaired. Paired young black ducks were similar in dominance rank to unpaired adults and unpaired young indicating that pairing did not make these individuals more dominant. Ducks on the restricted diet gained less body mass than ducks on the ad libitum diet (HEPP, 1986), but dominant and subordinate black ducks within treatment groups experienced similar changes in body mass during the early winter. Dominant black ducks interacted more frequently and were more likely to form pair bonds than subordinates, thus higher energy costs of dominant individuals may explain the poor relationship between physical condition and dominance rank. There was a significant positive association between the dominance ranks of pair members.
Vocal Mimicry and Interspecific Aggression in Songbirds: Experiments Using White-Crowned Sparrow Imitation of Song Sparrow Song
Authors: Baptista Luis F. , Catchpole Clive K. 
Published: April 2008

Abstract
A series of playback experiments was carried out to determine whether territorial male song sparrows could discriminate between their own species song, and the same song produced by a white-crowned sparrow. In two out of three measures of response, the males did not discriminate between model and mimic song. In constrast, most males showed no response to control white-crowned sparrow song, although two individuals showed a strong interspecific response. Other examples of interspecific aggression were also detected during the experiments. The results are discussed in relation to recent studies on interspecific song learning and the competition hypothesis of vocal mimicry in songbirds.
Distance Regulation of Hand-Reared Goslings (Anser Indicus) To an Unresponsive Parent: a Study of the Short-Term Dynamics of Attachment
Authors: Lamprecht Jürg 
Published: April 2008

AbstractThis study investigated the ways in which young goslings contribute to the proximity between parent and offspring in geese. It sought to detect the rules governing excursions of hand-reared goslings (Anser indicus) from a stationary and non-responding human 'parent' on a large lawn. Distance to the parent and behaviours (distress calling, feeding and others) were monitored during 149 30-min-sessions of 28 goslings (7-19 days old), most of which were accompanied in some sessions by a sibling. Of two additional experiments, one demonstrated the positive effect of sibling group size on maximum distance from the parent, the other showed that distress calling induced by forced separation from the (human) parent was reduced by the presence of siblings. Excursion analysis revealed that the probability of returning to the parent was independent of time and distance. This allowed rejection of some earlier models of excursion control. Only sudden disturbances in the environment (occurring at random with respect to the start of an excursion), forced separation from the parent, and-similarly-the parent's walking away were found to elicit approach to the parent. The speed of leaving the parent was also independent of time and distance. Thus distance was not limited by an increasing locomotor tendency to return. But rate of distress calling increased with distance. Two causes for the goslings' departures were identified: 1) parental non-signalling (by the "mute" parent), which aroused a tendency "to go home", and 2) hunger combined with the tendency to forage in a fixed direction. Return probability, speed of leaving and distress call rate at any given distance were lower when a gosling was accompanied by a sibling, apparently because the social feedback received from the sibling compensated for the parent's non-signalling. In spite of behavioural tendencies which lead a gosling to potentially unlimited distances from its parents, it will not normally get lost, as it returns whenever alarmed or when the parents walk away, and because goose parents tend to join a gosling distress calling at a distance.
Condition Changes and Choice of Social Environment in African Buffalo Bulls
Authors: Prins H.H.T. 
Published: April 2008

Abstract1. The social behaviour of the African buffalo (Syncerus caffer) was studied between 1981 and 1985 in Lake Manyara National Park, northern Tanzania. Emphasis is placed on the relationships between adult bulls (i.e. older than 7 yrs). 2. These bulls were transient members of the buffalo population of the study area. At any time ± 150 adult bulls were in the area. During the study period 240 individual bulls were recognized, and the number of the 'bull pool' during this period was estimated to be 630. 3. Every few weeks, the bulls switched between the herd state and bachelor state, and wandered from herd to herd, presumably in search of oestrus cows. 4. They did not form stable associations, and when bachelor, they preferentially associated in temporary groups of 3 to 5 bulls. 5. Adult bulls engaged in sparring and showed dominance interactions very rarely. In a dyadic encounter, dominance interactions were only observed between bulls of the same body condition. Encounters involving individuals in different condition resulted in dominance being established without interaction. Fighting is extremely rare and likely to be lethal to both opponents. 6. The switching between both social environments was related to condition loss in the mixed herd and to condition gain in the bachelor state. This resulted in a 'rotating dominance hierarchy'. The bachelor phase is an essential part of the breeding cycle of an adult bull. 7. The necessity of a bachelor phase to recoup body condition may well be a general feature in mammalian species with long breeding seasons.
Optimistic and Pessimistic Fruit Flies: Evaluating Fitness Consequences of Estimation Errors
Authors: Roitberg Bernard D. 
Published: April 2008

AbstractI began with an observation that there exists consistent variation among fruit-parasitic female flies (Rhagoletis pomonella) with regard to search time allocation. In essence, populations appear to be composed of flies that are "optimistic" and "pessimistic" about their chances of locating other higher quality patches. I posed the question "how can such variation be maintaned over time?". To answer this question I developed stochastic, dynamic, state-variable model that considered patch emigration decisions by individuals as a function of: (1) current patch quality, (2) average patch quality, (3) density of patches, (4) time of day, and, (5) egg load. The model was then altered to allow for optimistic and pessimistic estimates of patch availability. The optimal behaviour for such flies was then solved. Results obtained showed that optimists move more often within trees and pessimists move more frequently among trees. Further, calculation of daily reproductive output showed that both optimists and pessimists performed nearly as well as flies with errorless estimates of patch availability so long as over and under-estimates were moderate. This is because of the interaction between egg limitation, host availability and time limitation. When patch estimate errors were large (e.g. 90%), however, pessimists performed less well than optimists. These results allowed me to derive fitness curves for optimists and pessimists. These curves were then used to predict the distribution of search allocation by flies in the field. Predictions as to the shape of the distribution were consistent with field data (i.e. optimists are over-represented in samples).
Family Planning in the Kestrel (Falco Tinnunculus): the Proximate Control of Covariation of Laying Date and Clutch Size
Authors: Meijer Theo , Daan Serge , Hall Michael 
Published: April 2008

Abstract
The time in spring when a male kestrel rapidly increases his daily hunting time and his hunting yield, and thereby the amount of food delivered to the female, determines the date when she lays the first egg. Food experiments in free-living and captive kestrels gave a significant advance in laying date. Clutch size, which decreases with progressive laying date, did not change independent of date in response to food manipulation. These effects are in agreement with most other feeding experiments. Photoperiod experiments in kestrels advanced the reproductive cycle in constant long days, and a similar seasonal decline in clutch size was found. It seems that there is an internally preprogrammed decrease in clutch size within an annual "reproductive window". A proximate control model for the seasonal decline of clutch size is proposed, modified from an earlier model by HAFTORN (1985). This incorporates an increasing tendency to incubate the first eggs with progression of the season, an egg contact-incubation positive feedback loop, and the resorption of further follicles in the ovary when the laying female incubates 50% of the time. This follicle resorption fixes the clutch size ca. four days before the last egg is laid. the 50% incubation level is reached earlier in late females and consequently resorption starts earlier and the resulting clutch is smaller than in early females. Experiments in kestrels with removal and addition of eggs, in combination with measurements of incubation behaviour are discussed in relation to the model. Plasma prolactin data of female kestrels show that this hormone is a serious candidate for a physiological component relaying time of year in our model for clutch size regulation.
Dod, Sex, Time, and Effort in a Small Mammal: Energy Allocation Strategies for Survival and Reproduction
Authors: Perrigo Glenn 
Published: April 2008

AbstractThe relationship between food energy and work effort (foraging) is crucial to small mammals such as the house mouse (Mus domesticus). Energy allocation processes were studied by using a special caging system in which animals were required to work for 45 mg food pellets by running on an activity wheel. Two experimental themes were investigated: 1) When weaning female mice were forced to work harder for less food, their highest energy allocation priority was to maintain fat reserves; body growth was next in importance while achieving puberty had the lowest prority of all. The relative insensitivity of fat deposition to high foraging costs suggests a strategy for survival whereby dispersing animals maintain emergency fat reserves at the expense of growth and fertility. In male mice, however, reproductive development is independent from body growth. Both sexes employed fundamentally different energy allocation strategies during peripubertal development. Some of these sex differences were gonad-dependent, while others were not. The time spent foraging while exposed to cold ambient temperature is also critical during peripubertal development, and this relationship probably determines whether or not house mice will breed continuously or seasonally in feral habitats. 2) Deer mice (Pemmyscus maniculatus) and house mice were challenged to produce litters at increasingly greater work requirements. Deer mice supported heavier litters and produced more pups at weaning than house mice, mainly because deer mice were more efficient at food use. With regard to circadian organisation, deer mice accomplished almost all of their locomotor tasks during darkness while house mice exhibited day-to-day flexibility in locomotor activity, especially during lactation. Deer mice attempted to wean five or six pups, regardless of how severe the feeding conditions; however, pups became progressively stunted as females worked harder and obtained less food. In contrast, house mice had more pups at birth than deer mice, but females killed and cannibalized offspring throughout the first 12 days of lactation. Most surviving house mouse pups thus attained similar body weights at weaning. These divergent energy allocation patterns may reflect strategies arising from opportunism (house mice) versus seasonality (deer mice).
Copying the Mate Choice of Others? Observations On Female Black Grouse
Authors: HÖGLUND Jacob , Alatalo Rauno V. , Lundberg Arne 
Published: April 2008

Abstract
It has been suggested that the non-random mating often observed in lekking species is a consequence of either male-male competition or active female mate choice. Here we show that the highly skewed mating distributions observed in a black grouse lek in three years were indeed different from random expectations. We suggest that females copying the mate choice of others enhance this skew. Observations in favour of copying are: females pay multiple visits to the lek during several days; females arrive and move in bands which makes it possible to observe the visits to male territories and matings of other females; in the main lek in the study area, males often mated in sequence indicating that by being visited by many females and by mating the attractiveness of males increased. However, this last effect was only evident in one of the years of the study, and only on the largest lek which had exceptionally many female visits this year. In leks with a smaller number of visiting females, copying, even if present, is difficult to detect without experiments since almost all females tend to copulate with the top-male.
Territoriality in a Terrestrial Salamander: the Influence of Resource Quality and Body Size
Authors: Mathis Alicia 
Published: April 2008

AbstractIntraspecific interference competition associated with territoriality has been documented in laboratory studies of the red-backed salamander, Plethodon cinereus. I used laboratory and field experiments to study the effect of resource quality and body size on such competition. In an experiment in southwestern Virginia, cover objects (e.g., logs) from which the resident salamanders were removed were invaded significantly more often than cover objects from which the resident salamander was not removed. These data provide the first direct test of territoriality for a salamander in a natural habitat. Newly invading salamanders were significantly smaller than the original territorial residents. Therefore, large body size is an advantage in territorial encounters. Because cover objects are important resources for terrestrial salamanders, characteristics of the cover object may contribute to territory quality. In an experiment conducted during warm summer weather at the Virginia site, soil temperatures under large cover objects were significantly cooler than those under small cover objects or under the leaf litter. Large cover objects may therefore benefit the salamanders by providing a buffer zone between the salamander and extreme environmental temperatures on the forest floor. In both laboratory and field experiments, when salamanders were offered a choice between large and small cover objects, both large and small salamanders exhibited a significant preference for large cover objects. Also I censused cover objects in a natural mixed hardwood forest habitat during courting and noncourting seasons and, for both seasons, I found a significant positive correlation between the body size of the salamander and the size of the cover object that it occupied. I conclude that, in this natural forest habitat, there is intraspecific competition for high quality cover objects and larger individuals are more successful competitors than smaller individuals.