bluuebunny/crossref_metadata_2025 huggingface dataset:
Determinants of Dominance in Male Sticklebacks (Gasterosteus Aculeatus L.)
Authors: Bakker Th C.M. , Sevenster P.
Published: April 2008

When two males of the three-spined stickleback (Gasterosteus aculeatus L.) in reproductive condition are placed in a tank of small size, one becomes dominant over the other in a very short time. In this way a group of isolated reproductive males were tested pairwise on their capacity to become dominant. It appeared that the males could be arranged in a linear order of dominance. Their rank was to some extent correlated with their territorial aggressiveness as assessed in other tests. Their experience in previous dominance tests played a more important role. The brightness of their colouration, however, was probably the most consistent and decisive determinant of dominance. The interaction of colour and experience could be traced in the outcome of the dominance tests. The occurrence of roundabout fighting is discussed.
Clasping Behaviour in Macaca Tonkeana
Authors: Thierry Bernard
Published: April 2008

Clasping behaviour was studied in two groups of Macaca tonkeana, one being confined in a cage, the other living in a half-hectare park. Five patterns have been distinguished: grasping the hindquarters, grasping, reaching around, embracing and hugging. Clasping may occur in three contexts: greeting, aggression and sexual harassment. There seems to be no direct relationship between context and pattern of clasping. However, there is substantial variation in form and context according to age- and sex-class. Females are the individuals mostly involved in clasps, being initiators as well as receivers; adult males also initiate numerous clasps but receive few. Adult and subadult males especially use grasping the hindquarters while other age- and sex-classes more often use reaching around. Clasping in aggression is more characteristic of females than males. Several behaviours may be associated with clasping. The accompanying behaviours are more frequent in initiator than in receiver. Clasp is often followed by social grooming, mount, wrestle or another clasp. The results of this study in Macaca tonkeana may be compared with information from other studies of non-human primate species. This allows one to draw several conclusions: 1. Frequency, form and distribution of clasping vary from one species to another. There is great variation in certain species, for instance, Macaca tonkeana. 2. Several behaviours usually accompany clasping and may modulate its meaning. 3. Clasping behaviour shows many similarities to mounting behaviour. Although these two behaviours have different origins, they have acquired similar social functions. 4. Clasping plays a prominent role in control of aggression. In Macaca tonkeana, this behaviour is especially used in appeasement (an individual receiving aggression clasps its aggressor during the aggression), reconciliation (an aggressor clasps its antagonist after the aggression) and non-agonistic protection (a third individual intervenes in an agonistic interaction by clasping the aggressor). Non-agonistic protection is an interaction which was until now described only in chimpanzees.
Recognition of Conspecifics and Sex By Territorial Males of the Social Wasp Polistes Fuscatus (Hymenoptera: Vespidae)
Authors: Post David C. , Jeanne Robert L.
Published: April 2008

Territorial males of Polistes fuscatus (subspecies variatus) respond to intruders with a chain of behavior of increasing intensity as follows: (1) no reaction, (2) orient, (3) pursue, (4) grasp, and (5) either grapple (with male intruders) or attempt copulation (with females). In the laboratory test objects combining different visual, chemical, and behavioral stimuli were tethered and waved in front of perched territorial males to determine the role of each in eliciting a male response. All test objects elicited an orient response. The overall color or contrast with the background and shape of the test object had little effect on male response. The black and yellow banded coloration characteristic of conspecifics released pursuit and grasping behavior, while chemical cues in combination with the banded coloration released grasping and grappling or attempt copulation. Recognition of sex was based on chemical cues and not on the sexually dichromic coloration. From this and previous studies we conclude that the black and yellow banded coloration of conspecifics is the most important visual stimulus for long-range attraction (> 15 cm) of males, while at close-range or on contact a cuticular surface pheromone and a sex pheromone from the venom are important in the recognition of conspecifics and for discrimination between the sexes.
Measuring the Strength of Social Bonds: Experiments With Hand-Reared Goslings (Anser Indicus)
Authors: Lamprecht J.
Published: April 2008

Allogrooming, dueting and other behaviours observed only between pair or group members are often said to reinforce or strengthen social bonds, yet the strength of these bonds was not measured independently. 'Bond strength' should reflect the stability of an attachment relationship and thus the probability of a permanent separation from the partner. The latter is a function of opportunity or external force as well as of an internal 'divorce tendency'. Only the divorcc tendency is inversely related to that motivational variable which can be called 'bond strength'. To find a behavioural measure of individual divorce tendency, the relationship of hand-reared bar-headed goslings (Anser indicus) to their human foster parents was investigated in four experiments. The following results were obtained: (1) The subjects (n = 18) significantly preferred their own, familiar foster parent (Hp) to a less familiar person (Hu). (2) This was also true when the Hu was the preferred Hp of another group of goslings, indicating that familiarity and not his suitability as a 'goose parent' is the relevant factor. (3) Alone with one person on a lawn, all goslings (n = 12) also maintained proximity when this was an Hu, indicating a bond to him also. Median distances maintained to Hp and Hu did not differ significantly, and were therefore no indicators of a gosling's preference. But the distress calling rate was significantly higher and the feeding rate significantly lower when a gosling was with an Hu than when with its Hp. (4) Distress calling rate in the presence of a stationary person was also a good indicator of a gosling's (n = 15) tendency to leave him and follow a slowly moving stranger. Approaches towards the stranger were significantly longer when the stationary person was an Hu than when it was the Hp. The amount of distress calling in the presence of an Hu was positively correlated (p<0.01) with the distance that the subjects later moved towards the stranger. The distress calling rate therefore is a good relative measure of a gosling's tendency to abandon a particular object, this tendency reflecting what we may call the strength of a bond or attachment.
Vocal Communication in Raccoons (Procyon Lotor)
Authors: Sieber Otto J.
Published: April 2008

The study describes structure, ontogeny and contexts of raccoon (Procyon lotor) vocalizations and investigates whether structure and motivation interplay in the way predicted by general motivation-structural rules (MORTON, 1977, 1982). Observations during a full reproductive cycle in a mixed group of captive raccoons indicate that they use an elaborate vocal repertoire including 13 calls (Table 1). Two calls are tonal (whistle, squeal), three noisy (snort, bark, growl); four have a mixed structure (cry, screech, gecker, grunt) and four have pulsed syllables (chitter 1, chitter 2, churr, purr). Though some calls grade into one another, the repertoire is largely discrete. Three calls are present at birth and form the nestling repertoire. The adult repertoire gradually develops through the time of weaning (Fig. 2). Several calls are characteristic for the sexual and parental phase. Most calls are associated with one or a few contexts (Table 2). Four calls are utilized by animals while distressed and have an attracting effect on others. Four calls express hostile motivation and repel other animals. Five calls are used by animals approaching another or having body contact; they serve in promoting or maintaining contact. Calls used in similar contexts show remarkable structural similarities. Distress calls are tonal or mixed, hostile calls noisy in accordance with motivation-structural rules. Contact calls deviate in being noisy and low in basic frequency. Possible reasons are discussed. A comparison of the vocalizations in other carnivores reveals that the structure-motivational pattern found in raccoons is a wide-spread phenomenon in carnivores.
Long-Range Vocal Interactions Between Groups of Gibbons (Hylobates Lar)
Authors: Raemaekers Patricia M. , Raemaekers Jeremy J.
Published: April 2008

We report on long-range duet interactions among twelve wild groups of lar gibbons (Hylobates lar) in Thailand. Statistical analysis demonstrates that groups were more likely to respond with an answering duet to a duet sung by a neighbouring group than to one sung by a non-neighbouring group in the population. A distinctive pattern of response among neighbours was to wait until a neighbouring group had finished its duet before immediately answering with a duet, resulting in avoidance of overlap between the two duets. Non-neighbours did not exhibit this pattern. The effect is shown to be due solely to neighbour status and not to the degree of mutual audibility of the duets. There was no evidence that, when duets overlapped, the first group to sing modified the length of its duet in response to the second duet, whether given by a neighbour or by a non-neighbour. In general, among those groups which responded to one another's duets, there were no identifiable leaders and followers: the order of duetting groups was random. We discuss why neighbours interact more by duet than do non-neighbours, and consider what may be the functions of avoiding overlap of duets.
Breeder-Helper Conflict in a Cichlid Fish With Broodcare Helpers: an Experimental Analysis
Authors: Taborsky Michael
Published: April 2008

This paper reports an experimental analysis of conflicting interests in the cooperatively breeding Lamprologus brichardi (Cichlidae). Helpers clearly prefer to stay in the family territory rather than leave for an aggregation of same-size young or for an unoccupied area-even when their chances of reproducing independently are superior to those in the field. Helpers usually attain independence when the breeders force them to leave the territory. Breeders' toleration of helpers depends on the stage in the reproductive cycle, the size of helpers and the need for helpers. Large, previously expelled helpers are reaccepted when competition is increased. In these circumstances breeders prefer their own former helpers to strange young. Experimental and field evidence suggests that 3 factors are ultimately important for the breeder/helper relationship: reproductive parasitism by mature helpers, eventual cannibalism on breeders' eggs and competition for shelter within the territory. A graphical model shows how the initially common interests of breeders and helpers develop divergently when helpers reach the size at which they become sexually mature and less susceptible to predation. Large helpers pay to stay. The relationship of breeders and large helpers meets the criterion of reciprocal altruism.
Responses of Lambs To Model Ewes
Authors: Shillito Walser Elizabeth , Walters E. , Hague P. , Williams T.
Published: April 2008

Life sized models of sheep were used to determine the importance of sound and movement in eliciting orientation and approach of lambs. Dalesbred and Jacob lambs were tested at 3 weeks of age with two models, one of which appeared to be grazing while the other moved its head or bleated or both bleated and moved. Lambs were tested twice; their behaviour was recorded to note 1) time of orientation to models and approach; 2) positive or negative response; 3) approach within 2 m of the models. The Dalesbred lambs ran faster than the Jacobs towards the models, and more Dalesbreds responded positively on the second test. Both breeds responded more quickly to the vocal models than to the silent models; there was no difference in time of response to moving and non-moving models. 90% lambs approached and looked at the models on the first test, 51 % responded on the second test. All lambs that responded went up close to bleating models, but not to moving models. Movement did not increase attraction and seemed to deter close investigation, whereas vocalisation made the models most attractive to the lambs.
The Influence of Weather On Incubation Scheduling of the White-Rumped Sandpiper (Calidris Fuscicollis): a Uniparental Incubator in a Cold Environment
Authors: Cantar Ralph V. , Montgomerie Robert D.
Published: April 2008

We studied the incubation scheduling of 8 white-rumped sandpipers (Calidris fuscicollis), a species in which only the female incubates. Because the female is small and nests in the high arctic, these birds are probably under more cold stress than birds nesting in the temperate zone. We examined the individual and collective effects of several weather variables on a female's incubation behaviour to ascertain what amount of the variability within a day was directly attributable to weather conditions. Birds made an average of 25.1 off-nest trips each day, averaging 10.5 min each. This resulted in spending, on average, 82.5% of their time incubating eggs. There was a clear within-day cycle in incubation scheduling; birds made more and longer trips in the middle of the day and, as a result, spent more total time off the nest in that period. Birds adjusted their hour-by-hour schedules to weather largely by altering the number of trips made, and less so by adjusting trip length. There was a circadian rhythm in recess time/h, explaining at least 11% of the variation in recess time/h. When the circadian rhythm was controlled statistically, weather accounted for an average of 38% of the explainable variation in recess time/h. The relative importance of each weather variable on the recess time/h was (in descending order of importance): wind speed, air temperature, solar radiation, barometric pressure, and relative humidity. Weather (primarily wind speed and temperature) exerted its strongest effects early and late in the bird's active day (0400-2300 h). On cold and windy days, birds increased the time spent on their nests early and late in the day, and made more trips than usual in the middle of the day, when air temperature was highest. We suggest that the incubation scheduling of these birds conformed to the long-term predictability of the daily weather cycle by following a circadian rhythm of behaviour modified by a response to concurrent weather that would have reduced egg cooling.
Feeding Strategies of Male and Female Adult Herring Gulls (Larus Argentatus)
Authors: Greig S.A. , Coulson J.C. , Monaghan P.
Published: April 2008

This paper examines the foraging behaviour of adult male and female herring gulls at refuse tips during winter. Although the majority of herring gulls were either on the tip or nearby for much of the daylight period, an individual male or female fed at the tip for only 30 minutes per day. Three types of feeding were distinguished: (a) undisturbed primary feeding on freshly dumped refuse; (b) disturbed primary feeding where the gulls fed whilst a bulldozer was moving the refuse; and (c) secondary feeding on dispersed refuse partially covered with earth. During primary feeding the herring gulls fed at high density and the feeding flock comprised 73% adults whilst during secondary feeding they were at low density and the flock contained only 25 % adults. A comparison of disturbed and undisturbed primary feeding showed that the birds dipped for food from the air in the former but searched for food on the ground in the latter. This resulted in eight times more encounters per individual and much greater competition in undisturbed feeding. Proportionally more adult male than female herring gulls participated in undisturbed (i.e. competitive) feeding, whereas the reverse was true of disturbed feeding. These differences were greatest in the first half of the winter (i.e. October-mid-December). There were no differences in the sex-ratio of those participating in secondary feeding. During undisturbed primary feeding adult females had higher pecking and walking rates and lower encounter rates than males. Males obtained at least a fifth of their food by attacking and displacing other feeding herring gulls, three times more than females. Female herring gulls fed more often on the edge of the refuse pile where competitive interactions were less frequent but also where foraging success was lower. As the undisturbed feeding bout progressed, attack rates of males increased and their swallowing rate was sustained. In contrast, the attack rates of females decreased as did the swallowing rates. The proportion of females present also decreased, suggesting that some females were responding to the increased levels of aggression by leaving the feeding area. Refuse tips provide a variety of feeding opportunities. In a competitive feeding situation the smaller female herring gulls are disadvantaged by the dominance of males. In disturbed feeding they are able to compensate to some extent because their smaller size results in greater manoeuvrability.
Suckling and Weaning in Captive White-Tailed and Fallow Deer
Authors: Gauthier Danielle , Barrette Cyrille
Published: April 2008

Parental investment and parent-offspring conflict theories make specific predictions on the behavior of parents and offspring. Since milk is a direct and vital form of maternal investment in mammals, nursing behavior is very well suited to test such predictions. We provide such tests here, as well as a fine-grained quantitative description of the weaning process in two species of deer. Both in white-tailed and fallow deer, fawns of primiparas had a significantly higher suckling rate than those of multiparous mothers in the first few days of life (2.90 ± 0.70 vs 1.24 ± 0.21 suckles/h from 0 to 5 days in FD, p < 0.01; and 1.42 ± 0.22 vs 0.81 ± 0.08 suckles/h from 6 to 10 days in WTD, p < 0.01). In both species, in the first 10 days of lactation, suckling bouts initiated by the mother had a significantly longer mean duration than those initiated by the fawn. We found no inter-sex difference in the rate of suckling, mean duration of suckles, total time suckling (s/h), and proportion of suckling attempts that were successful, in fawns of both species, at any age from birth to 80 days. White-tailed deer single fawns were identical to twins for all the above parameters. Fallow deer mothers were much more aggressive toward alien fawns than white-tailed deer mothers were, and spent more time close to their fawns (less than 10 m, 38% of the time from birth to 80 days, compared to 12% for white-tailed deer). We propose that weaning starts at about 20 days of age in both species. This is the time when the mother terminates more than half of all suckling bouts, terminates more bouts than she initiates, and when suckles are shorter when she initiates compared to when it is her fawn that does.
Size Assessment and Cues: Studies of Hermit Crab Contests
Authors: Neil Susan J.
Published: April 2008

The agonistic behaviour of pairs of hermit crabs (Pagurus bernhardus) was observed in the laboratory. It was found that relative size was a reliable predictor of the outcome of a contest only when the crabs differed by at least 100% in weight. However, weight differences of 10 to 30% could be sufficient to cause differences in behaviour. It was concluded from this that whereas crabs can accurately assess small differences in weight, these differences may not be sufficient to reliably determine the outcome of contests. Other factors affecting RHP are relevant at intermediate size differences. Two possible cues for size assessment were tested: the size of the major cheliped and the size of the opponent's shell. The presence and size of the major cheliped were found to have a strong effect on contest initiation and outcome, and therefore this is likely to be a cue used in RHP assessment. The major cheliped was also found to play an important part in defensive behaviour, crabs lacking this appendage being less successful in defending their shells from attack. However, the apparent size of the opponent's shell did not seem to affect the initiation or outcome of contests. Thus it seems that crabs assess their opponents independently of the shells they occupy. It is concluded that large size differences are sufficient to decide contests. For smaller size differences other factors of RHP are important, and can override size differences. There is no evidence indicating that the defending crab can assess the quality of its oppo- nent's shell and make contest decisions based on this evidence. These data do not support the negotiation hypothesis.
Experiments On the Relationship Between the Hen and Chick (Gallus Gallus): the Role of the Auditory Mode in Recognition and the Effects of Maternal Separation
Authors: Kent J.P.
Published: April 2008

In a series of 6 experimental studies, the means by which a chick recognises its mother, and the reversibility of filial attachments were examined using bantam hens and their chicks. In a simultaneous discrimination test it was determined that the chick could discriminate between own and alien hens by means of the hens' cluck vocalizations, on the 4th and 8th days post hatching, (Experiment 1). The chicks could make this discrimination more efficiently when live hens were presented (Experiment 2). On separating the hen and chicks for 4 h on the 4th day, the chicks could no longer discriminate between own and an alien live hen (Experiment 3) while they would accept an alien hen, (Experiment 4). These findings suggest that maternal-filial bonds may be reversed with little difficulty. Thus Experiment 5 was designed to examine the stability of these later maternal filial bonds. Chicks spent the first 3 days post hatching, with the hen who incubated the eggs. Then they spent 3 days with an alien hen, after which 3 days isolation followed. It was found that chicks could discriminate in favour of their own hen after the first period of exposure, and in favour of the alien hen after the second period of exposure. Following 3 days isolation they showed no preference for either hen. Experiment 6 was essentially a replication of Experiment 5, but included a control for familiarity. Only one test took place after the 3 days isolation. The chicks were presented with the 1st 2nd and an unfamiliar alien hen. The chicks did not discriminate in favour of any particular hen. It is concluded that after 4 h or 3 days isolation, the chicks did not discriminate between the hens presented, yet they remained responsive to hens.
Evaluating Sex Differences in Aggressiveness in Cattle, Bison and Rhesus Monkeys
Authors: Reinhardt Viktor , Reinhardt Catherine , Reinhardt Annie
Published: April 2008

The assumption has often been made that aggressiveness is predominantly a masculine characteristic (e.g. COLLIAS, 1944; MOYER, 1974; SCOTT, 1975; BOUISSOU, 1983a, b). Many investigators simply accept the idea that males are more aggressive than females. Based on generally applicable operational terms, the validity of the "notion of universal male aggressiveness" (JOHNSON, 1972) has been tested in three different mammalian species. The study was done under nonexperimental conditions by scoring partner-directed aggressions (potentially injurious actions) among members of three undisturbed, heterogeneous groups of Bos taurus, Bison bison and Macaca mulatta. The expression of aggression was regulated by the number of subordinate partners (animals who, without being the target of aggression, consistently withdrew), with high-ranking individuals having more opportunities to display aggressions than low-ranking individuals. Hence, it was self-evident that, whenever the two sexes differed in dominance status (number of subordinates), they also differed in terms of aggression rate (total number of aggressions shown per unit time). The average number of aggressions directed by dominant animals against individual subordinate partners (aggression index: REINHARDT & REINHARDT, 1975) did not exhibit a significant sex difference in any of the three species studied (Bos taurus: xf= 1.8 vs xm = 1.8; Bison bison: xf= 6.9 vs xm = 6.6 ; Macaca mulatta: xf= 4.1 vs xm = 2.9). This was not only true in general but was also consistently confirmed when comparing the sexes within different age classes (adults and juveniles). From this it was inferred that the two sexes were equally aggressive in the general day-to-day situation of dominance reinforcement in all three species. The data thus did not support the general belief that mammalian males are more aggressive than females.
Queen Regulation of Worker Foraging in Paper Wasps: a Social Feedback Control System (Polistes Fuscatus, Hymenoptera: Vespidae)
Authors: Reeve Hudson K. , Gamboa George J.
Published: April 2008

We examined the queen's role in regulation of worker foraging in small field colonies of the primitively eusocial wasp, Polistes fuscatus (29 colonies; 148 h observation). Queen removal results in a significant reduction in worker departure rate. The placement of a cooled, inactive queen into her queenless nest produces a significantly greater reduction in worker departure rate than does queen removal, and the resumption of activity by an inactive queen causes a significant increase in worker departure rate. Removal or cooling of a single worker does not produce similar effects on worker foraging, suggesting that the queen is the central regulator of worker foraging in small P. fuscatus colonies. We present evidence that: (1) the queen's control of worker foraging is mediated primarily by her influence on worker nest activity, (2) queen aggression may be important in stimulating departures by workers with low tendencies to leave the nest (i.e., dominant workers), and (3) the magnitude of the queen's stimulatory influence on worker foraging is directly related to the number of workers on the nest. We integrate these results with evidence from our other studies of polistine colony dynamics in a feedback control model of the social regulation of foraging.
Defence as Parental Care in Tawny Owls (Strix Aluco)
Authors: Wallin Kjell
Published: April 2008

Parental defence was studied during the breeding season with individually marked tawny owls (Strix aluco). Attacking tawny owls pose a serious threat to an intruder because of their dangerous talons. As predicted by theory, parental defence was positively correlated with offspring age and brood size. Pairs with equal numbers of offspring but with different initial clutch sizes showed equal defence levels. The level of defence is therefore determined more by expected gain in number of offspring produced than by cumulative investment. Pairs breeding early in the season defended more strongly than those breeding later on. This was partly explained by a seasonal decrease in brood size, but the trend also persisted within each brood size. One possible explanation is that the probability of breeding failure increase as the breeding season progresses, making a risky defence less worthwhile for late-breeding pairs. The level of defence was positively correlated with the female's body mass. Defence behaviour did not change significantly with female age. Females in pairs that defended their offspring had a lower probability of breeding the following season than did females in non-defending pairs. Individual females changed their defence behaviour between years in relation to their seasonal start of breeding, suggesting that parental defence is a plastic behaviour.
Dominance and Its Fitness Consequences in American Bison Cows
Authors: Rutberg Allen T.
Published: April 2008

1. Dominance relations among adult female American bison (Bison bison) were studied between June 1980 and August 1982 at the National Bison Range, Moiese, Montana, and Yellowstone National Park, Wyoming, U.S.A. 2. Contested interactions, or "battles", between cows were rare at both sites. Only one of 362 observed interactions among known Bison Range cows was contested, and only four such interactions were observed during the entire study. 3. Among Bison Range cows, reversals of dominance status within dyads occurred at an extrapolated rate of once every 7.5 dyad-years. 4. Success in aggressive encounters between Bison Range cows was strongly, positively correlated with age, but uncorrelated with body weight or horn damage. Hence, dominance appears to be poorly correlated with fighting ability. Instead, dominance may be determined by cost-benefit asymmetries; older cows may have less to lose from aggression than younger cows. 5. The cow dominance "hierarchy" at the Bison Range does not show a higher degree of linearity than expected given the age-dominance correlation. 6. At neither Yellowstone nor the Bison Range was there evidence of aggressive inhibition of female reproduction, or of harassment of calves by dominant cows. 7. In a variety of environments, a cow that received aggression during foraging suffered a reduction in the proportion of foraging time she spent cropping. Since aggression frequencies varied considerably between habitats, however, the influence of dominance on cropping times also varied between habitats. 8. Aggression frequencies were highest in habitats where forage was sparse and heterogeneous in quality. Accordingly, aggression was most frequent, and probably had the strongest effects on feeding efficiency, in habitats where there was significant travel time between suitable grazing patches.
Response of the Newly Born Clun Forest Lamb To Maternal Vocalisations
Authors: Vince Margaret A.
Published: April 2008

Forty Clun Forest lambs were removed from their dams immediately after lambing and were tested singly for 30 minutes in a circular arena under one of four conditions: (1) with no stimulation, (2) in the presence of recorded low frequency, low amplitude "rumble"-type vocalisations of the kind made by the ewe from just before lambing and in caring for her lamb, (3) in the presence of a large, rectangular, white, moving object, or (4) in the presence of the same white object and of the recorded "rumbles". The results showed that righting movements were reduced and standing delayed in the lambs which heard "rumbles", whether or not they were in the presence of the moving object. For two other indices of response there was no effect of rumbles but behaviour varied with the presence or absence of the moving object: there were fewer ear movements in lambs presented with the model, as compared with those without and there was more tail-wagging in the presence of the model, than without it. Results are discussed in terms of the dam as a composite stimulus for her lamb.
Recognition of the Sow's Voice By Neonatal Piglets
Authors: SHILLITO WALSER Elizabeth E.
Published: April 2008

Piglets were tested for recognition of their sow's voice at 1, 2 & 6 days of age. Each piglet was tested individually by playing one minute of recorded grunts from its own sow and one minute of recordings from an alien sow, compared with a one minute period alone with no sound. The vocalizations of the piglets were recorded and analysed. Some piglets responded to their own sow's voice by making rapid 'quacking' grunts which differed in tone from the 'closed mouth grunts' made alone; some piglets responded by orientation and movements towards the sound. At one day old 29% piglets responded vocally exclusively to their own sow and 52 % responded when movement was included as a sign of recognition. 27 % piglets responded to both own and alien sow voices. At 2 days the response had become exclusive to their own sow's voice and 87 % piglets responded (57 % vocally). At 6 days 81 % piglets responded positively to their own sow's voice (62% vocally). The number of grunts increased in each minute of the tests with 1 and 2 day old piglets regardless of treatment, but at 6 days old, the piglets grunted more to their own sow's voice than to an alien.
Development of Predatory Behaviour in the Southern Grasshopper Mouse (Onychomys Torridus)
Authors: Langley William M.
Published: April 2008

This study described the effects that maturation and experience had on the development of cricket-catching behaviour in the southern grasshopper mouse. The responses of eight groups of mice of different ages or backgrounds were compared. Mice from the field exhibited the most proficient searches, pursuits, and kills and committed fewer errors than the lab-reared mice. Of the groups of lab-reared mice, the 20-day-old mice were the least and the 70-day-old the most proficient attackers. Maturation primarily affected the mouse's first attack response. Mice younger than 23 days of age were more reluctant to attack a cricket the first time than older lab-reared mice. These maturational changes appeared related to when weaning normally occurs in grasshopper mice. Experience contributed to the development of attack proficiency in three ways: decrease in reluctance to attack, improved killing technique and recognition of a cricket as prey sooner during an encounter. Compared with hamsters, grasshopper mice exhibit a nearly complete functional attack response the first time and require much less experience from repeated trials to become proficient insect captors. The early and rapid development of a proficient attack response may be related to the grasshopper mouse's carnivorous life style.
Habitat, Group Size, and the Behaviour of White-Tailed Deer
Authors: Lagory Kirk E.
Published: April 2008

The behaviour of white-tailed deer on Ossabaw Island, Georgia was examined in three habitats which differed in cover density and forage abundance. Forest had relatively dense cover but low forage availability; wooded pasture had relatively dense cover and abundant forage; open pasture had no woody cover but abundant forage. Deer groups were small in both the forest and the wooded pasture relative to groups in the open pasture. Group size in the open pasture did not vary with seasonal changes in forage supply. Groups were small in open pasture during the autumn rut when food was abundant, but were relatively large at other times of year, even during the winter when forage abundance was comparable to that in the forest. Deer in the open pasture spent more time feeding, less time moving, and less time alert than did deer in the forest. Deer in the wooded pasture were intermediate between deer in the other two habitats for percent time feeding, more similar to deer in the open pasture for percent time moving, and more like deer in the forest for percent time alert. Differences in alert behaviour suggest that deer in dense vegetation (e.g. forest and wooded pasture) were more wary than deer in open areas. In all habitats, deer in larger groups (four or more deer) spent more time feeding and less time alert than deer in smaller groups. More aggressive interactions were seen in the open pasture; more nonaggressive interactions were seen in the forest. The rate of aggressive interaction was not clearly related to group size. Temporal variation in nearest-neighbor distance within groups was greater in the forest than in the open pasture, possibly due to loss of contact between deer under conditions of restricted visibility. Although these data suggest that cover density rather than forage characteristics was related to deer group size, no support was given for the hypothesis that this relationship was a consequence of different anti-predator strategies. Groups may have been smaller in dense vegetation because deer had difficulty maintaining contact with other group members when visibility was restricted.
Factors Affecting the Structure of Song and the Singing Behaviour of Some Northern European Passerine Birds
Authors: Sorjonen Jorma
Published: April 2008

In this study the effects of bird size, genus, habitat, song community and geographical distribution on song structure and singing behaviour of some passcrine species in northern Europe were simultaneously studied. Most species tend to improve their long distance song propagation in their specific habitat and song community. Song propagation correlates strongest with the use of low-pitched elements but not all birds are able to use these because of size limitation. In forest habitats whistles and modulated elements were used to improve song propagation. In open habitats high-pitched elements as well as repeated and trilled syllables were often used for better propagation of acoustic information. In song communities with a great number of species, the birds reduce song interference by other singers, by singing short songs and using modulated elements and long intersong pauses. When the birds greatly profit from effective long distance song propagation, like in northern areas with only short time for pair formation, the birds can segregate in singing time by using the light nights for singing. In these communities with low numbers of species the birds have been freed from song interference and have long songs and short intersong pauses and they can increase in this way their singing rate. The effect of song community on song length, intersong pause and the use of modulated elements in the song is stronger than that of habitat. The effect of the song community increases towards the north.
The Dynamics of Snake Harassment By Black-Tailed Prairie Dogs
Authors: Loughry W.J.
Published: April 2008

Differential participation by particular classes of individuals is likely to influence how we assess the functional significance of harassing. I examined encounters between black-tailed prairie dogs (Cynomys ludovicianus) and snakes in both natural and experimentally-induced encounters and found substantial differences in how various age/sex classes of prairie dogs deal with snakes. Specifically, males spent more time close to snakes and in actively confronting these potential predators than did either females or pups. Fathers were not closer to snakes than were non-fathers, but fathers spent more time actively engaged in dealing with the snakes. Mothers and non-mothers did not differ markedly in how they dealt with snakes. Encounters with snakes occurred before and after the pups' first emergence from their natal burrows, but pup emergence did not alter the basic differences between males and females and fathers and non-fathers. Pup emergence did coincide with changes in the behavior of these classes, fathers barked less after pup emergence, and all classes with the exception of mothers were less positively oriented to snakes after pup emergence. However, the significance of these changes was not apparent. These results require that the functional significance of snake harassment by prairie dogs take into account this male bias in snake-directed behavior. Males are hypothesized to be less vulnerable to snakes than are pups and to have more at stake reproductively than do females. Fathers have more at stake reproductively than do non-fathers (although non-fathers may still be protecting mates) and thus should spend more time confronting and harassing snakes. This interpretation is founded on an understanding of the relationship between potential predator and potential prey and I conclude with a discussion of the appropriate description of this relationship.
Persistence in Foraging: When Do Bullfinches Abandon Unprofitable Seeds?
Authors: Greig-Smith Peter W.
Published: April 2008

Captive bullfinches (Pyrrhula pyrrhula) were studied in order to find out if and why they abandon fruits after lengthy unsuccessful attempts to crack open the husks. For three kinds of fruits, the probability of husks cracking remained constant throughout handling. Bullfinches feeding on ash and sunflower fruits dropped many, failing to retrieve most of those that dropped in the first 12 seconds after picking up (thus identified as 'rejected'), but only 20% of those dropped later ('abandoned'). The incidence of abandoning fruits was higher in samples taken from ash trees with less variably-sized fruits, and when sunflower fruits of a particular size were presented alone, rather than in a mixture of other sizes. Both results support the idea that unsuccessful handling provides information allowing birds to revise their estimates of fruits' profitability. However, abandonment did not occur after a consistent period, as predicted. Rejection of fruits during the first few seconds of handling was a more important food selection mechanism than either visual assessment before handling, or later abandonment.
Courtship of Drosophila Melanogaster in Large Observation Chambers: the Influence of Female Reproductive State
Authors: Ewing A.W. , Ewing L.S.
Published: April 2008

1. Mixed sex groups of D. melanogaster were observed in large observation chambers in which food was available. The ratio of mated to virgin females was 3:1. 2. Fertilised females spent more time feeding than virgins and virgin flies spent more time in locomotor activity. 3. Most courtship behaviour took place on the food and consequently mated females received more courtships. 4. To test whether fertilised females were excluding virgin females from the food, groups of females without males were observed. The groups were composed either of virgin, or of a mixture of virgin and mated females. The results showed that even in the absence of fertilised females virgins fed less and were more active. There was no evidence that mated females excluded the virgins. 5. The adaptive significance of the observations is discussed in relation to dispersal from the site of eclosion, oviposition and remating.
The Communicative Repertoire of Captive Bonobos (Pan Paniscus), Compared To That of Chimpanzees
Authors: De Waal Frans B.M.
Published: April 2008

Ten 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

Hyperolius 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.
Group Responses To Specially Skilled Individuals in a Macaca Fascicularis Group
Authors: Stammbach Eduard
Published: April 2008

The aim of this study was to investigate the capability of monkeys to assess special characteristics in conspecifics. In a first phase I ascertained that all members of a colony of longtailed macaques (Macaca fascicularis) were able to attain food by manipulating a one lever apparatus, thus introducing the "tradition" of lever pulling. Then, experiments were carried out on subgroups of the colony where only one of the lower ranking subgroup members was trained to succeed in a more complex task where three levers had to be pulled in a correct sequence. Eight specialists were established in sequence. These specialists became food producers for themselves and for the other group members. Each trial of a specialist's series was carried out in two phases. In the first, the food phase, the food dispensing apparatus was active and responses of other subgroup members to the food producing specialist were observed. In the second, the social phase, the apparatus remained inactive and observations focused on social interactions of the subgroup. As expected, primarily high ranking subgroup members attempted to participate in the food rewards gained by the specialist. It is shown that high ranking animals began to hold back their initial chasing of the specialist from the food site in course of the trials and were soon tolerated to sit near the subordinate food producer. Furthermore, some of the non-specialists began to follow or even to pass the specialist when he was approaching the apparatus to manipulate the levers. These non-specialists thus indicated that they were able to anticipate later actions. In seven out of 55 specialist-non-specialist relationships all predicted changes in social interactions occurred. In the majority of the dyads in which a change in social affiliation was registered an increase of grooming or spatial proximity was positively correlated with the amount of benefit gained from the specialist. In the social phase of the trials the non-specialists gave more grooming to the food producers and maintained spatial proximity even in this second phase. To conclude: At least some of the group members became aware of the skills of the specialists and adapted their behaviour accordingly as if to maximize benefits from their skills. Previous studies had already suggested that monkeys know about social position, social relationships and kinship of group members. This study adds a new aspect of knowledge, namely knowledge on capabilities and skills of others. Differential knowledge allows monkeys to select partners optimally according to their skills and social position.