bluuebunny/crossref_metadata_2025_split huggingface dataset:
Ability of Female Squirrel Monkeys (Saimiri sciureus) to Discriminate between Conspecific Urine Odours
Authors: Laska Matthias , Hudson Robyn 
Published: May 2010

AbstractIn this study, an odour‐conditioning paradigm was used to investigate the ability of captive squirrel monkeys, Saimiri sciureus, to discriminate between urine odours of conspecifics. It was found that the three test females could: 1. Readily discriminate between urine from conspecifics and other primate species; 2. Discriminate between urine from individual conspecifics, whether unfamiliar animals or members of the test animals' social group, and whether or not they were of the same sex; and 3. Not discriminate so easily between urine from genetically related conspecifics as between urine from unrelated individuals, particularly where both donors were female. The findings suggest that an individually distinct and stable factor is present in squirrel‐monkey urine, that this is more similar in genetically related than unrelated individuals, and that, in males, some additional source of individual variability exists enabling the discrimination of even close relatives. While the biological significance of these findings remains to be investigated, this study demonstrates that squirrel‐monkey urine contains a considerable amount of information of potential signal value.
Infanticide by Adult and Subadult Males in Free‐ranging Red Howler Monkeys, Alouatta seniculus, in Venezuela
Authors: Agoramoorthy Govindasamy , Rudran Rasanayagam 
Published: May 2010

AbstractAfter 15 males invaded troops of wild red howler monkeys (Alouatta seniculus) present in Venezuela during the period from Apr. 1989 to May 1991, five infant killings and eight infant disappearances occurred. Among the eight groups that were invaded, 10 infants of less than 3 mo old and three of over 5 mo old were killed either by the adult or subadult males, or disappeared. However, on the five occasions of invasion, none of the nine infants were killed. In two other groups, there were no infants present at the time of invasion. It was also noted that no infant of kin of the invading males was killed. At least six of the females that had lost their infant during such invasion subsequently copulated both with the invader as with the original resident male. In one case, a female copulated with the resident male of a neighbouring group. In the four cases of subadult males committing infanticide there was no immediate sexual access to the females. The data presented here are inconsistent with the reproductive sexual‐advantage hypothesis, but consistent with the hypothesis concerning food competition.
Honeybee Long‐distance Orientation in a Controlled Environment
Authors: Chittka Lars , Geiger Karl 
Published: May 2010

AbstractThe integration of artificial movable landmarks (tetrahedral tents of 3.46 m height) into the longdistance course control of bees was investigated in an environment that provided a minimum of natural orientation cues. Bees were trained along a row of four landmarks which were equally spaced in a setup of 300 m in length. The animals were then tested in situations where the position of the landmark line indicated a direction of the feeding site other than the (originally trained) sun‐compass direction. This discrepancy was systematically varied. We show that the sun compass is dominant over the landmarks. This preference is negligible if the deviation between the two indicated directions is small, but it increases as the angle of deviation becomes larger. In contrast, if the entire sky is overcast by clouds, more bees will follow the direction indicated by the artificial landmarks than under sunny conditions. However, as the deviation between the trained direction and the landmark direction increases, more individuals will land at the training site.
Does Polymorphism Protect? An Experiment with Human ‘Predators’
Authors: Knill Rebecca , Allen John A. 
Published: May 2010

AbstractPolymorphism in cryptic prey species may be ‘protective’, in the sense of reducing the rate of predation by visual predators. We tested this supposed function by presenting 80 schoolgirls (aged 12–13) with populations of square ‘prey’ on backgrounds displayed on computer screens. The backgrounds were composed of random distributions of small coloured squares and the prey were composed of the same small squares, the grid of the prey being parallel to (but usually imperfectly aligned with) that of the background. Different ‘morphs’ of prey were defined by the spatial distribution of the small squares, and prey of a given morph were always presented in the same orientation. Each subject was presented with a sequence of 40 screens, of which 36 were background containing a single randomly positioned prey, while four were background alone. Subjects ‘zapped’ prey with the mouse, or pressed the space bar if the screen was judged to be empty, and then moved automatically to the next screen in the sequence. Each subject received a single ‘treatment’: high or low crypsis combined with one of four levels of polymorphism (1, 2, 6 or 12 morphs). The results showed that hit (‘predation’) rate tended to be lower on populations with high crypsis and was inversely related to the number of morphs in the population. We thus conclude that polymorphism may indeed ‘protect’.
Influence of Movement by Coho Salmon (Oncorhynchus kisutch) Parr on Their Detection by Common Mergansers (Mergus merganser)
Authors: Martel Guy , Dill Lawrence M. 
Published: May 2010

AbstractA common reaction in juvenile salmonids that detect predators is to decrease activity. To test whether there is a survival advantage to reduced movement under such circumstances, juvenile coho salmon (Oncorhynchus kisutch) were placed with common mergansers (Mergus merganser) under laboratory conditions that precluded crypsis. Mergansers were more likely to attack fish that moved than fish that remained stationary, and the relation between the lag time for detection by the birds and fish movement rate is best described as inversely exponential. The lag time for detection was not correlated with fish size. The risk of detection of prey by visual predators should be determined by both predator and prey behaviour, but our results suggest that in this case prey behaviour is more important. In the field, territorial coho juveniles do feed more and grow faster than other, non‐territorial fish. They also spend a smaller proportion of their time moving. The present experiment suggests that territorial coho may also suffer less mortality than non‐territorial fish, which would lower their ratio of mortality risk to growth rate.
Males Choose Larger Females as Mates in the Salamander Desmognathus santeetlah
Authors: Verrell Paul A. 
Published: May 2010

AbstractIntrinsic constraints resulting in temporally‐limited mating capacity may select for ‘prudence’ in the allocation of sexual resources by male salamanders. Prudence in the form of male mate choice was examined in a dusky salamander, Desmognathus santeetlah (Plethodontidae). Males mated with small and larger females at similar rates when presented sequentially with potential partners differing in snout‐vent length. However, males were more likely to mate with larger females when presented simultaneously with two potential partners that differed in snout‐vent length by at least 4 mm. The greater mating success of larger females was due to male mate choice for more fecund partners. Behavioural observations of trios composed of one male and two females revealed that males experienced ample opportunities for partner assessment that were uninfluenced by direct interactions between females. Male choice for larger females may confer an advantage on choosy males because female fecundity is positively correlated with body size in D. santeetlah: larger females carry more eggs available for fertilization. The occurrence and value of male mate choice in natural populations, where males compete for partners and females mate multiple times, remain to be determined.
Satellite Male Groups in Horseshoe Crabs, Limulus polyphemus
Authors: Brockmann H. Jane 
Published: May 2010

AbstractHorseshoe crabs arrive on the beach in pairs and spawn in the high intertidal during the springtime, new and full moon high tides. Unattached males also come to the beach, crowd around the nesting couples and compete with attached males for fertilizations. Satellite males form large groups around some couples while ignoring others, resulting in a nonrandom distribution that cannot be explained by local environmental conditions or habitat selection. In experimental manipulations, pairs that had satellites regained them after they had been removed whereas pairs with no satellites continued nesting alone, which means that satellites were not simply accumulating around the pairs that had been on the beach the longest. Manipulations also revealed that satellites were not just copying the behaviour of other males. Based on the evidence from observations and experiments, the most likely explanation for the nonrandom distribution of satellite males among nesting pairs is that unattached males are preferentially attracted to some females over others. Females with many satellites were larger and in better condition, but did not lay more eggs, than females with few or no satellites.
Evidence for Territorial Behavior in a Burrowing Wolf Spider
Authors: Marshall Samuel D. 
Published: May 2010

AbstractEvidence is presented for territorial behavior in a burrowing wolf spider, Geolycosa xera archboldi McCrone (Araneae, Lycosidae). These spiders live in burrows in the scrub habitats of central Florida, USA. Mean nearest‐neighbor distances repeatedly approximate 30 cm. The constancy of this mean indicates that social spacing may be occurring. A test for perceptual range showed that G. xera can respond to potential prey at distances greater than 30 cm, indicating that the 30‐cm nearest‐neighbor distance does not represent a distance within which larger neighboring burrow‐holders treat smaller neighboring conspecifics as food. Dyadic encounters in field enclosures showed that the distance at which neighbors would not be tolerated was within the observed mean nearest‐neighbor distance. In these experimental tests for territorial behavior, smaller dyad members lost burrows significantly more often than larger dyad members.
Influence of Parasitism on Shoal Choice in the Banded Killifish (Fundulus diaphanus, Teleostei, Cyprinodontidae)
Authors: Krause Jens , Godin Jean‐Guy J. 
Published: May 2010

AbstractBanded killifish, Fundulus diaphanus, were presented individually with a choice of ‘shoaling’ with either of two conspecific stimulus shoals, one consisting of fish with externally visible black spots (indicating the presence of a parasitic trematode worm, Crassiphiala bulboglossa), the other consisting of fish without such spots. Both parasitized and unparasitized test fish significantly preferred to shoal with unparasitized stimulus shoals over parasitized ones. The relative preference of unparasitized killifish for unparasitized shoals increased with increasing degree of parasite load in parasitized stimulus fish. However, no significant preference by unparasitized fish for unparasitized shoals was observed if unparasitized shoals were presented versus mixed shoals consisting of parasitized and unparasitized fish. We conclude that killifish preferred unparasitized shoals over parasitized shoals only if all fish in the respective stimulus shoals were phenotypically uniform (either with or without black spots). A final experiment showed that killifish used black spots as an indicator of parasite presence to make their shoal choice. The significance of these results for the formation of parasite‐assorted shoals is discussed.
Social Status and Resistance to Disease in House Mice (Mus musculus): Status‐related Modulation of Hormonal Responses in Relation to Immunity Costs in Different Social and Physical Environments
Authors: Barnard C. J. , Behnke J. M. , Sewell J. 
Published: May 2010

AbstractUnrelated and previously unfamiliar male mice were maintained in groups of six tor different periods and at different ambient temperatures. High‐ and low‐ranking males differed in hormone‐related resistance to a subsequent experimental infection with the blood protozoan Babesia microti and there were rank differences in the apparent modulation of immunodepressive hormones relative to an individual's internal, social and physical environment. Resistance to B. microti was influenced by serum concentrations of corticosterone and testosterone. Associations between aggressiveness and measures of immunocompetence and resistance were related to corticosterone concentration, but only among low rankers. Effects of testosterone on resistance were confined to high rankers but were not associated with aggressiveness, although high rankers maintained greater aggressiveness than low rankers in all experimental treatments. The effects of group duration and temperature on resistance can be interpreted in terms of changing hormone and antibody levels in relation to metabolic stress. The results emphasize the importance of interactions between underlying physiological changes in relationships between behaviour, immune function and disease.
Synergism Between Stress Responses Induced by Biting Flies and Predator Odours
Authors: Kavaliers Martin , Colwell Douglas D. 
Published: May 2010

AbstractWe have previously shown that endogenous opioid systems (i.e. endorphins, enkephalins) are involved in the mediation of the behavioural and physiological effects of biting‐fly exposure. Opioid mediated reductions in pain sensitivity, or, more appropriately, nociceptive sensitivity (latency of a foot‐lifting response to a 50°C thermal surface), are evident in laboratory mice,Mus musculus domesticus, exposed to biting flies. Similar opioid‐mediated reductions in pain sensitivity (opioid analgesia) are also seen after exposure to a variety of other natural stressors such as the threat of predation. Here, we demonstrate that brief (30‐min) exposure of male mice to stable flies,Stomoxys calcitrans, significantly and synergistically augments either the concurrent or subsequent (60 min after fly exposure) analgesic effects induced by exposure to a predator (cat odour). These results demonstrate that the analgesic, and probably other opioid mediated behavioural and physiological stress responses induced by exposure to a relatively low number of biting flies, are markedly increased by the presence of another natural aversive stimulus. In addition, they show that biting‐fly exposure significantly exacerbates the effects of a subsequent stressful stimulus. These findings raise a possible mechanism whereby exposure to a low number of biting flies, which by themselves may not appear to have a great impact, can have marked behavioural and physiological consequences.
Homing Behaviour in Polyergus rufescens Latr. (Hymenoptera, Formicidae)
Authors: Grasso Donato Antonio , Ugolini Alberto , le Moli Francesco 
Published: May 2010

AbstractHoming mechanisms of the European slave‐making ant Polyergus rufescens Latr. are investigated by field experiments. The analysis of the behaviour and paths of both homing scouts and raiders after passive displacement showed that: i. Scouts probably home by using a path integration system based on celestial cues; and ii. Displaced raiders do not seem to adopt such a vectorial orientation mechanism. Moreover, we found that passively displaced scouts exhibit a systematic search strategy for the nest after a rectilinear path. By contrast, raiders perform a similar search pattern just after release. Similarities between Cataglyphis and Polyergus homing behaviour are discussed.
Reproductive Hierarchies Among Workers of the Slave‐making Ant, Chalepoxenus muellerianus
Authors: Heinze Jürgen 
Published: May 2010

AbstractIn queenright colonies of the slave‐making ant, Chalepoxenus muellerianus, workers formed dominance hierarchies through ritualized food begging and antennation bouts, but did not lay eggs. Within a few hours of the experimental removal of the queen, the frequency of dominance displays increased drastically and the interactions became considerably more violent. During the observation period, the dominant workers almost incessantly attacked subordinate slave‐makers and slaves by antennation and biting. The aggression rate decreased after approximately 3–4 wk. Within a single colony, several high‐ranking workers were observed laying eggs, although typically only one or a few top‐ranking individuals became fully fertile Directly after eclosion, young workers engaged in aggressive interactions with other young workers and high‐ranking old workers, but did not dominate the top‐ranking egg‐layers. Callows achieved ranks immediately below the top‐ranking worker.
Who is Responsible for Fission in a Free‐ranging Troop of Baboons?
Authors: Ron Tamar 
Published: May 2010

AbstractThe study troop of chacma baboons (Papio cynocephalus ursinus) at Mkuzi Game Reserve, Zululand, South‐Africa, comprised of about 76 members that split into two new troops. The events leading to this troop fission will be described and its possible causes will be discussed.Troop fission among baboons is generally attributed to the withdrawal of low‐ranking females from the main group, as a result of the cost of food competition and its effect on their reproductive success. At Mkuzi, no evidence for food competition among females was recorded in terms of rank‐related time spent feeding or other time—budget components, feeding‐bout length, diet composition or context of female aggression. Moreover, no evidence for rank‐related differential reproductive success was found in terms of inter‐birth intervals or infant survival. Female mortality was, however, related to dominance rank, with circumstantial evidence suggesting that cause of mortality was predation by leopards. Rate of female disappearances, aggression levels among females, and the percentage of time they spent in proximity to other adult troop members increased after fission.Relatively short inter‐birth intervals and extremely low infant mortality rate at Mkuzi resulted in a small number of receptive females at any one time, and therefore in high costs of male sexual competition as expressed in the high levels of male aggression and woundings, both reduced after fission.It is suggested that this troop fission may have been initiated by the resident males, triggered by the high cost of sexual competition, and forced on the females, who were, consequently, subjected to higher risk of predation. The troop fission was preceded by a long process of increasing tendency for sub‐trooping. It was initiated by the four resident males who kept a large distance apart from each other, herded oestrous female associates away from others and were followed by other females. The females generally tended to stay close to associates, males and females. These parties were followed by the peripheral and immigrant males who had no female associates, and eventually two distinct daughter troops were formed.
Temperature‐limited Activity in the Garter Snake Thamnophis melanogaster (Colubridae)
Authors: Manjarrez Javier , Drummond Hugh 
Published: May 2010

AbstractMany garter snakes, Thamnophis melanogaster, at a desert pond first started foraging for tadpoles when mean water surface temperature was about 20 °C (at 0945–1015 h), and the number of snakes tripled when water temperature reached about 24 °C (at 1100–1130 h). In two years, snakes foraged in April and May, but not in March when water never reached 23 °C and only exceeded 20 °C for a few hours after the usual foraging hours. Snakes in the laboratory dedicated increasing amounts of time to underwater foraging as air and water temperatures increased from 9 °C to 29 °C, and their rate of attacks on fish increased steeply and progressively above an apparent threshold lying between roughly 19 °C and 24 °C, up to at least 29 °C. Temperature may limit T. melanogaster's foraging at the pond to the hours after roughly 0900 h and to the period after roughly March, despite evidence that prey abundance is maximal in March.
Individual Distinctiveness in Brown Bears, Ursus arctos L
Authors: Fagen Robert , Fagen Johanna M. 
Published: May 2010

AbstractIndividual brown bears, Ursus arctos, behave differently from each other. Consistent behavioural differences suggest that each bear has its own distinct personality. On Admiralty Island in south‐eastern Alaska, we collected longitudinal data during three years of summer salmon runs on seven individual brown bears that could be recognized from year to year. Bears fed on vegetation and on salmon along a tidal creek. Ratings of individual bears by observers on different aspects of behaviour, comparisons of behavioural frequencies, and long‐term observations of individual activities served to assess personality differences. Individual bears varied in five ways: 1. Some bears were lively, animated and playful in social situations and during solitary activities such as travelling or fishing. Other bears' movements and general demeanour seemed dull and humourless; 2. Some bears were irascible, others socially uninvolved and unreactive; 3. Some bears were expert at fishing but others fished ineptly; 4. Some bears were confident with other bears but others lacked confidence in social situations; 5. Some bears were often active and alert. Others rested more frequently and for prolonged periods.
Mating Behaviour in a Hermaphroditic Flatworm with Reciprocal Insemination: Do They Assess Their Mates during Copulation?
Authors: Peters Anne , Streng Andrea , Michiels Nicolaas K. 
Published: May 2010

AbstractIn the freshwater planarian Dugesia polychroa (Tricladida, Paludicola), both animals fulfil the male and female role simultaneously in any given copulation. This study presents the first detailed account of the copulatory behaviour, timing and frequency in this species. We also describe an experimental set‐up that enables continuous, undisturbed observation of large numbers of animals.D. polychroa pairs copulate repeatedly in the lab (up to eight times in 5 d). Animals that were kept in isolation for longer, were more likely to copulate. The mating behaviour lacks a behaviourally recognizable precopulatory courtship sequence, suggesting that precopulatory assessment is absent or only marginally important. Copulation duration ranged from a few minutes to 2.5 h and showed a distinct bimodal distribution. Two copulation types were recognized: short (<35min) and long (≥35min). Histological analysis showed that sperm transfer is rare during short copulations, but after long copulations all animals had received sperm and sperm transfer was reciprocal in all pairs where both partners could be investigated. Hence, only long copulations are ‘true’ copulations with sperm transfer. Pairs with short copulations (40 % of all pairs) had fewer long copulations, but a higher overall copulatory activity. Copulation rate is constant over 5 d for both copulation types. It does, however, fluctuate with the time of day: most (long) copulations take place at night. Pairs that copulated more often, also produced more cocoons. We argue mat in‐copula assessment during the first 30 min of the copulation determines whether copulations are sometimes interrupted before sperm are transferred and that this explains the occurrence of short and long copulations.