bluuebunny/crossref_metadata_2025_split huggingface dataset:
Integrity of a Red Deer Stag Group During the Velvet Period, Association of Individuals and Timing of Antler Cleaning
Authors: Bartos Ludek , Perner Vaclav 
Published: April 2008

Abstract
Previous studies on a "white" red deer herd at Zehušice, Czechoslovakia showed that a stag's antler casting and cleaning dates were related to his rank in the dominance hierarchy. The relationship was less apparent with antler cleaning than with casting. It was suggested that this is a consequence of disintegration of the bachelor group during the period of antler growth. A group of 14 individually recognised stags in a 1.26 km2 enclosure were observed 77 times between March 15th and August 22nd 1983. The number of stag groups, the distribution of stags into groups and the number of solitary stags was recorded on each occasion. For each observation the "relative dominance index" (RDI, rank position within a group divided by the number of stags in the group) was calculated for each individual. Correlation coefficients between antler cleaning dates and summed RDI values were calculated. As in previous seasons, and in contrast to the period preceding antler casting, the bachelor group disintegrated during the velvet period. As antler cleaning approached the stags tended to disperse into more groups and separate from other deer. The stags associated with others of similar rank and age. There was a close association between summed RDI values for individual stags for the last two weeks of the velvet period and dates of antler cleaning. Among pairs of stags which were closest associates during this period, the higher ranking stag always cleaned earlier. It is concluded that the disintegration of the bachelor group in the period before antler cleaning may be the major factor which causes a less apparent relationship between rank and the date of antler cleaning than between rank and date of antler casting. It is suggested that these two points in the antler cycle are regulated by hormones modulated by agonistic behaviour related to rank.
Structure of the Dominance Hierarchy and Dominance Determining "Group Factors" in Melanochromis Auratus (Pisces, Cichlidae)
Authors: Nelissen Mark H.J. 
Published: April 2008

AbstractTwo questions are asked: (1) Which relation is there between the dominance hierarchy and communication? (2) Which are the dominance determining factors that are a result of group life ("group factors") and that cannot be found in pairs of animals? Melanochromis auratus, a cichlid fish from Lake Malawi, is studied under laboratory conditions as a representative model. Dominance relations in pairs of animals differ from those (between the same fishes) in groups of conspecifics. In groups M. auratus establishes and maintains a linear dominance hierarchy, of which the communicative structure is described and discussed. The number of aggressive interactions between two group members, is determined by the rank number of the actor and the reactor. Most interactions occur between rank neighbours. "Group factors" are looked for by analysing the clustering of all possible chase-interactions. Four categories of such clusterings are discussed: a preceding aggressive interaction can have an influence on high-ranked animals, the effect of such an influence is directed towards low-ranked animals. The stable hierarchy can be changed by successive circle fights. The highest-ranked group members always intervene in circle fights in order to stabilize the hierarchy, for their own benefit. This is another "group factor". An alpha animal has to spend all its energy in obtaining and maintaining its rank status. When it looses this position, it drops down the hierarchy. The benefit of the alpha place could be the reproductive succes.
Conflict and Cooperation in the Group Feeding of the Social Spider Stegodyphus Mimosarum
Authors: Ward Paul I. , Enders Margit M. 
Published: April 2008

Abstract
1. Stegodyphus mimosarum, a social spider, lives in colonies which may contain hundreds of individuals. Feeding behaviour was examined with respect to feeding group size and prey size. 2. Prey were less likely to escape and were subdued more quickly when attacked by more than one spider. 3. During capture small prey were frequently bitten directly on the body whereas large prey were almost always bitten on an appendage. 4. Pulling struggles for subdued prey occurred. They lasted longest over medium sized prey. Small prey were easier to transport to the nest than medium prey and large prey were pulled by more spiders from a single retreat. 5. Spiders which had participated in a capture initially bit preferentially on the prey's head or thorax but others which joined later to feed bit at random. 6. Feeding became less efficient as group size increased and an experiment suggests that individuals injected less poison and digestive enzymes when feeding in groups.
Categorisation of Interpulse Intervals and Stochastic Analysis of Discharge Patterns in Resting Weak-Electric Mormyrid Fish (Gnathonemus Petersii)
Authors: TEYSSÈDRE Claudine , Boudinot Michel , Minisclou Catherine 
Published: April 2008

AbstractInter-individual similarities in the electric organ discharge activity of immobile, isolated and undisturbed mormyrid fish were investigated. Two types of analysis were performed on the discharge patterns of 10 Gnathonemus petersii: (1) The Bout Interval Criterion method was used to categorise the intervals between consecutive electric pulses; (2) an analysis of sequences of acts was performed to study the serial ordering of the interpulse intervals. Interpulse intervals were demonstrated to belong to distinct classes, having similar limits for most animals. Most fish show five classes of interpulse intervals (23 to 68 ms; 69 to 108 ms; 109 to 170 ms; 171 to 212 ms; >212 ms), to which a sixth class (<23 ms) is added in some cases. Each class contains a similar number of intervals in all individuals. Particular associations were found between the occurrences of interpulse intervals belonging to different classes. Some of these associations (for example BB and EC) are displayed by most fish, whereas others express individual differences in the patterns of discharge. The discharge of immobile, undisturbed, isolated mormyrid fish is thus shown to present many similarities among individuals. Inter-individual differences exist only in the serial ordering of the intervals, where they arc best regarded as variations around a same theme. The absence of overlapping between the two main categories of interpulse intervals (category I: 69 to 108 ms; category II: 171 to 212 ms), as well as the constancy of their baselines, suggest that two oscillating systems participate to the electromotor command. The stochastic analysis of the serial ordering of the interpulse intervals suggest in addition that these two oscillators do not function independently. Momentaneous modifications of the activity of these two oscillators would provide an economical explanation for the various changes in the types of interpulse intervals associated with behavioural state or social interactions.
Predictions From the Ranging Hypothesis for the Evolution of Long Distance Signals in Birds
Authors: Morton Eugene S. 
Published: April 2008

AbstractThe Ranging Hypothesis (RH) (MORTON, 1982) proposed a form of distance assessment (ranging) based upon perception of signal degradation using memorized signals as a yardstick to distance. The predictions of the RH include distance assessment mechanisms, DAMs; it is proposed that these have opened a new evolutionary process illustrated by the complicated songs and singing behaviour in the oscine passerines ("songbirds"). The RH identifies sources of selection favouring learning, multiple or single song types, song structural complexity not accounted for by species isolating mechanism ideas, and emphasizes the ecological basis for the evolution of long distance communication. New importance is given to the acoustic physical structure of songs. The RH encompasses and contrasts song evolution in warm climate regions with those in cold temperate climates. Three interrelated stages of long distance signal evolution are presented: detectability, threat, and disrupt. A singer/listener role dichotomy in selective pressures is described and the results discussed. Listeners developed distance assessment mechanisms (DAMs) resulting in an evolutionary arms race between listeners and singers. Singers developed methods to use DAMs to their best interest (threat and disrupt). Song learning in passerines developed in response to this arms race to enhance disruption, a situation most prevalent in cold temperate zone regions. The acoustic determinants of effective song distance are described and discussed in relation to the evolution of signal structures. Finally, the RH is discussed in relation to some previous hypotheses on song function and evolution.
Distraction, Decisions and Persistence in Runway Tests Using the Domestic Chick
Authors: Andrew R.J. , Klein R.M. 
Published: April 2008

AbstractAndrogens appear to cause reduced distractibility and increased focussing of attention in a number of species of mammals and birds. It is here shown, using runway tests, that in the domestic chick the changes in attention produced by testosterone are diverse, affecting on the one hand processes following immediately after perception, and on the other the allocation of attention between different stimuli over quite long periods of time. Examples of the first type include reduced distraction at first presentations of a conspicuous but irrelevant stimulus, increased response to change in the stimulus on which attention is focussed, and increased likelihood of fast response when a stimulus of the type which is being sought, appears in an unexpected position. All can be explained as due to an increased ability to specify stably a particular stimulus or type of stimulus as that which is being sought or on which attention is to be sustained. Longer term changes in the organisation of behaviour suggest that more than one focus of attention can be stably specified in a particular period of time. Testosterone-treated chicks will alternate attention between two very different stimuli (food and a conspicuous novel stimulus), even when one cannot be seen from the other without locomotion. It is necessary to consider the full complex of linked changes which may result from modulation of attention by hormones (or other physiological variables), in any discussion of the benefits and costs which might result.
The Influence of Group Size On Predator Scanning and Foraging Behaviour of Wedgecapped Capuchin Monkeys (Cebus Olivaceus)
Authors: De Ruiter Jan R. 
Published: April 2008

AbstractThe behaviour of two groups of wedgecapped capuchin monkeys, Cebus olivaceus, a small one (n = 8) and a large one (n = 25) was recorded. Time budgets and other aspects of behaviour depended on group size. The differences can be explained as: adjustment to predation risk and intra-group food competition. In order to evade predation, members of the small groups scan more and stay at greater heights than those of the large group. Higher food competition within the large group was reflected in the composition of its diet, in longer travel distances, and higher levels of social behaviour. In particular during the dry season, the large group exploited unattractive and risky food sources. These results support ALEXANDER'S hypothesis on the causes of group formation.
The Behavior of Aplysia Californica Cooper (Gastropoda; Opisthobranchia): I. Ethogram
Authors: Leonard Janet L. , Lukowiak Ken 
Published: April 2008

AbstractAplysia californica has been extremely popular with neurophysiologists interested in understanding the neural basis of behavior. The major drawback to neuroethological work on this species has been the lack of information on its behavior. We present the first ethogram of this species and a model of the physiological organization of drives (motivational systems) in Aplysia. The ethogram of A. californica contains 45 action patterns, most of which involve relatively subtle movements or postures of the head. Some of these action patterns have been studied physiologically and we summarize that information. The action patterns are superimposable and an individual may perform several action paterns simultaneously. A. californica has five distinct "drives" or motivational systems: feeding, escape, reproduction as a male, reproduction as a female and spawning. The sequence of events involved in escape behavior in response to attack by Navanax (a natural predator) or other mechanical stimuli to the rear is described. Each "drive" activates a particular sequence of action patterns, and certain "drives" are superimposable. Aplysia can copulate as a female while copulating as a male, feeding, or laying eggs. On the other hand, escape is incompatible with female sexual behavior. The available physiological evidence suggests that neuropeptides may play an important role in the organization of drives and their interactions. We present a model which combines the available physiological and behavioral data with the classical ethological drive hypothesis to produce a testable model of the physiological organization of motivation in Aplysia.
The Criteria Determining the Selection of Mussels Mytilus Edulis By Oystercatchers Haematopus Ostralegus
Authors: Sutherland William J. , Ens Bruno J. 
Published: April 2008

AbstractVentral hammering oystercatchers tend to specialise upon attacking either the right or left valve of mussels. Both in the field and in captivity they initially select medium sized mussels. Selection against small mussels can be understood from the low profitability of small mussels, but large mussels are very profitable. The hammering oystercatchers select thin shelled mussels even though capable of opening ones with thicker shells. Once the preferred prey are depleted, they take thicker and larger mussels. Indirect evidence suggests that within a size class the profitability of thick-shelled mussels is lower. Stabbing birds open larger and thicker mussels than do hammering birds. When feeding on boiled mussels size taken is larger than when feeding on live mussels.
Variation in Mate Guarding Intensity By Male Purple Martins
Authors: Morton Eugene S. 
Published: April 2008

AbstractThe frequency with which individual male purple martins (Hirundinidae: Progne subis) guard their mates during forays to gather nest material varies from 0 to 100%. During such forays, guarding males accompany their mates continuously from the time a female leaves the nest site until she returns to the nest site with nest material. Non-guarding males do not accompany females on these collecting forays. Unguarded females are subject to forced extrapair copulation attempts on almost all of their forays to collect nest material. Because this suggested that non-guarding males may have a lowered assurance of paternity relative to guarding males, I asked if mate guarding frequency is directly related to parental care. However, male parental effort, as assessed by feeding rates, was not related to mate guarding intensity. Mate guarding intensity may vary widely among individual male martins since nest site defense may preclude guarding in some and superiority in sperm competition by means other than exclusive access to females may reduce their chances of being cuckolded.
Diet, Foraging Patterns, and Resource Defense in a Mixed Species Troop of Saguinus Mystax and Saguinus Fuscicollis in Amazonian Peru
Authors: Garber Paul A. 
Published: April 2008

AbstractIn the Amazon Basin of northeastern Peru, moustached (Saguinus mystax) and saddle-back (S. fuscicollis) tamarins form stable mixed species assemblages in which groups of each species feed, forage, rest, travel and cooperatively defend a territory throughout the entire year. Data presented indicate that despite extreme overlap in feeding and ranging behavior, a change in troop size did not have a significant affect on dietary preferences, activity budgets, day range, foraging effort, and the number and length of daily feeding bouts of either resident species. The larger troop, however, was more successful at defending major feeding trees than the smaller troop. Unsuccessful resource defense resulted in a decrease in time spent feeding and foraging, and an increase in the distance traveled to the next major feeding site. It is proposed that within-troop feeding competition is generally not a critical factor in the feeding ecology of this mixed species tamarin troop. Rather, the formation of such a troop enables each resident species to more effectively exploit and defend a set of productive feeding trees.
Food Competition Among Individuals in a Free-Ranging Chimpanzee Community in Kibale Forest, Uganda
Authors: Isabirye-Basuta Gilbert 
Published: April 2008

AbstractCompetition for fruit within chimpanzee foraging parties was investigated by testing the hypotheses that food patch size was a limiting factor to foraging party size and to foraging efficiency while chimpanzees were foraging in Pseudospondias microcarpa trees for fruit. Large food patches (as measured by phenological score or the product of diameter at breast height and phenological score) supported significantly larger parties than did smaller food patches. In addition, foraging efficiency was apparently higher for small parties than for large ones, although the difference was marginally statistically significant. Per-capita feeding time for individuals in small parties was significantly higher than for those in large parties when chimpanzees had access to both Pseudospondias and Uvariopsis congensis fruit trees. Per-capita feeding time was not significantly correlated with food patch size. When Uvariopsis fruit trees became exhausted in mid-August, some chimpanzees apparently avoided severe competition for fruit by leaving the C.C. area, where they had been feeding on both Uvariopsis and Pseudospondias fruit. Social factors did not significantly affect foraging party size nor per-capita feeding time.
Demography and Group Structure in Wedgecapped Capuchin Monkeys, Cebus Olivaceus
Authors: Robinson John G. 
Published: April 2008

AbstractThe extent to which population demography determines the age and sex composition of primate groups was examined using data from a population of wedge-capped capuchin monkeys Cebus olivaceus in central Venezuela. Demographic parameters were derived from censuses of individually recognized, aged, and sexed individuals living in nine groups over a ten year period. Animals were aged by extrapolation from census data. Animals of both sexes were classed as infants during their first year, and juveniles until they reached six years of age. Females reach sexual maturity at this time, while males were classed as subadults until they reached full adult size at age 12. Adulthood lasts at least 30 years in females, at least 24 years in males. Age-sex class specific mortality and fecundity rates generated a life table which indicated that the population was increasing (r = 0.087) between 1977 and 1986. The age and sex composition of the nine groups was described annually. On average, non-adults made up 60% of a group, with this percentage increasing with group size. There were more females than males in all groups in all years. The strong female-biased adult sex ratio (1:4.4) was a consequence of a biased birth sex ratio (1:1.9), higher female than male survivorship especially between the ages of 3 and 7 when males were dispersing, and a pronounced sexual bimaturism. The stable age distribution derived from the life table successfully predicted the observed average distribution of age-sex categories in groups. This suggests that the group structure of Cebus olivaceus groups is not a consequence of intragroup social interactions, but results from demographic parameters.
Reproductive Behaviour of Southern Sea Lions
Authors: Campagna Claudio , Le Boeuf Burney J. 
Published: April 2008

AbstractThe reproductive behaviour of individually marked southern sea lions, Otaria byronia, was studied from 1981 to 1986, at Punta Norte, Peninsula Valdés, Argentina. Males defended territories along the high water mark early in the breeding season but switched to female defence as they were joined by females. Males defended females from neighbours and intruders, and forcefully held pre-oestrous females near them. Males defended territories and females against neighbours and intruders with threat displays and by fighting. Males never strayed far from females. The frequency of aggressive interactions among males was positively correlated with the number of females in oestrus. A mean of 2.8 females was associated with each male in the central breeding area at peak season, with some males being associated with 8-16 females for a few hours. Ninety four percent of the males that held a territory for five or more days copulated. Copulations were not observed away from territories in the central breeding area. Mating success was positively correlated with tenure on territory. The first males to arrive had the longest tenures and achieved the most copulations. Mean tenure on territory was 24 days (range = 15-57 days). The mean number of observed copulations per marked adult male was 3.87 ± 3.31. Variance among breeding males was low; the most successful male achieved only 7% of the copulations observed. Females gave birth a mean of 3.3 days after arrival, copulated once six days later and then went to sea to feed 7.6 days after parturition. Thereafter, females alternated periods of feeding at sea (X = 2.8 days) with periods of nursing their pups (X = 2.3 days). Males sequester pre-oestrous females. This mating strategy leads to differences in behaviour between Otaria and males of other sea lion species. These differences are evident in harem size, time away from females (as manifested by brief and infrequent fighting), the high percentage of males breeding, and the low variance in mating success among breeding males.
Song Tutor Choice in Zebra Finches and Bengalese Finches: the Relative Importance of Visual and Vocal Cues
Authors: Clay-Ton N.S. 
Published: April 2008

AbstractThis paper examined the relative importance of visual and vocal cues for song tutor choice. In the first study zebra finches, Taeniopygia guttata, and Bengalese finches, Lonchura striata, were housed with two song tutors at independence, a zebra finch singing Bengalese finch song and a Bengalese finch singing zebra finch song. All the males tended to learn from the conspecific song tutor, irrespective of whether they had been raised by a pair of conspecifics, the female alone or cross-fostered to a pair of the other species. In the second study zebra finches were housed at independence with two conspecific song tutors, one with a normal song and one which sang Bengalese finch song elements. There was no tendency to learn zebra finch elements which suggests that species-specific elements are not important for song tutor choice in zebra finches. Other vocal differences between the tutors such as length of the song phrase and species-specific call notes might bias learning in favour of the conspecific. Visual differences between the two species, both in appearance and behaviour, seem to be important. Parental cues before independence appear to be relatively uninfluential. However, siblings may be important, both the species and number per clutch: this is a factor which has been overlooked in previous studies of song learning.