bluuebunny/crossref_metadata_2025_split huggingface dataset:
Population and Sex Differences in Colour Vision in the European Minnow Phoxinus Phoxinus (Cyprinidae)
Authors: Hofstetter Catrin , Ward Paul I. 
Published: April 2008

Abstract
The abilities of males and females from two populations of the European minnow Phoxinus phoxinus to discriminate between disks of different colours were compared. Fish were trained to feed at a disk lit with 'orange-yellow' light. Their ability to discriminate this training colour from others was then tested. Fish from a stream population were more accurate than those from a lake population and females more accurate than males. We cannot be completely sure the fish discriminated on colour rather than perceived brightness, though we tried to control for the latter. There were no significant differences in the times taken to perform the tests. We suggest the different visual environments in the two habitats have selected for different visual abilities. As males and females spend most of the year in shoals together, it is argued that the difference between males and females has evolved because of the females' need to discriminate between males' sexual displays during the breeding season. The results show that a fish's sex and perhaps its population of origin should be considered in tests of visual ability.
Density Dependent Song Duration in the Grasshopper Omocestus Viridulus
Authors: Eiriksson Thorleifur 
Published: April 2008

AbstractAlthough duration of grashopper song is species specific, there is also considerable variation within species. One possible reason for this is that males are adjusting their singing tactics in relation to the density of competitors. Males are expected to sing shorter songs when other males are nearby to enhance the probability of hearing female response or to listen to other males. To test this hypothesis an experiment was performed by placing different numbers of Omocestus viridulus males in large outdoor cages and monitoring their singing behaviour. The results show that males sing on average shorter calling songs as the number of males increases. It was also found that males compensate for singing shorter songs by singing more songs, so the total time spent singing stays similar at all densities. The scenario is complicated by the singing of very short songs which are mainly, but not exclusively, used in male-male interactions. The probability that males sing rivalry songs increases with the density of males and the number of these songs increases as male-male interactions get longer. The results suggests that part of the variation in the duration of calling songs reported in several field studies is caused by a change in singing tactics at different densities of males. The function of rivalry songs is not clear. These songs may function in the spacing of males or may be an extremely short form of the normal calling song used when other males are very close.
Courtship Behavior of the Small-Mouthed Salamander (Ambystoma Texanum): the Effects of Conspecific Males On Male Mating Tactics
Authors: McWilliams Scott R. 
Published: April 2008

Abstract1. The courtship behavior of A. texanum consisted of a rapid nudging period followed by males producing many spermatophores, some of which were picked up by the female. Neither amplexus or leading by the male were integral components of courtship. Consequently, proposed geographic variation in A. texanum courtship remains unsubstantiated. 2. Courtship behavior of A. texanum and A. barbouri (formerly pond and stream form A. texanum, respectively) is very similar; only the location of courtship and perhaps the frequency of sexual interference tactics are different for these two sibling species. 3. A. texanum courtship is rapid, males produce large numbers of spermatophores per courtship and invest little courtship time per spermatophore, and intermale competition is extreme. 4. Male A. texanum promote their sexual success using sexual interference behavior (e.g. covering other spermatophores with their own) and to a lesser degree sexual defense behavior (e.g. forcefully nudging rival males). 5. Male sexual success is primarily enhanced directly - A. texanum males increase the number of spermatophores produced when at least two other males are courting the same female. The temporal allocation of these additional spermatophores is adaptive only if males are maximizing the number of ejaculates per female or breeding typically occurs in polygamous aggregations.
Song Function in Gibbons
Authors: Cowlishaw Guy 
Published: April 2008

AbstractThis paper examines variation in the singing behaviour of male and female gibbons in an attempt to construct a consistent framework to describe the function of both solo and duet song bouts. Functional hypotheses are described and tested with the available data. The song bouts of mated females are shown to be strongly associated with the pressure of territorial defence. Conversely, the solo song bouts of mated males show no relationship with territorial behaviour, but are associated with the (estimated) density of floating unmated males in the population. In accordance with the hypotheses under test, these results indicate that mated females sing to defend their territories, whilst mated males sing to repel males in defence of their mate and offspring. Contrary to previous hypotheses, the production of coordinated duets by male and female pairs is found to be unrelated to pairbonding. However, duetting is shown to be associated with encounters and aggression at the territorial boundary, in support of the claim that duetting advertises pairbond presence in order to intimidate neighbours and reduce the costs of territorial conflicts. The implications of these analyses for territorial and mating strategies in gibbons are discussed.
On the Ontogeny of Seed Harvesting Techniques in Free Ranging Ground Squirrels
Authors: Heschl Adolf 
Published: April 2008

AbstractOccasionally, adult European ground squirrels can be observed to practise a quite complex behavioural technique to obtain seed grains from the top of tall grass plants (e.g. Festuca ovina: 10-70 cm, Poaceae). They bite through the stem of a plant at the basis and, subsequently, know how to handle the fallen stem so as to successfully reach the food. The present field study aimed to analyse the detailed ontogeny which, in growing ground squirrels, leads to this behaviour. Data for 5 juveniles belonging to one litter were collected during an observation period of 38 successive days after the animals' first appearance above ground (video recordings). They show that this behaviour emerges as the final result of a whole series of successive developmental steps involving increasingly more efficient techniques in which simple techniques are gradually elaborated to more sophisticated ones. The underling causal mechanism is supposed to be operant conditioning based on increasingly more complex motor activities involving the animal's paws. Despite frequent social contacts, learning through imitation or even through instruction by the mother turned out to be not an important factor. With regard to cognitive abilities, the observations suggest experiments to verify the hypothesis of a beginning object permanence in ground squirrels.
Song Sharing and Local Dialects in a Population of the European Wren Troglodytes Troglodytes
Authors: Catchpole Clive K. , Rowell Armanda 
Published: April 2008

AbstractSongs were recorded from a local population of 13 male wrens at Wraysbury Lakes, Berkshire, U.K. during 1991. Sonagraphic analysis revealed that there were 15 distinct song types in the population, and that each male had between three and six song types in his repertoire. Song sharing between neighbouring males was particularly high. Six of the males in the population were on the east bank of the lake, separated from the other seven on the west bank by 200 metres of open water. Although three song types were distributed over the whole area, six were unique to the east bank and six to the west. Any male could be classified as an east or west bank male, by the possession of several distinct song types unique to each 'dialect' area. So far, clear examples of dialects have been largely restricted to species with only one or two song types in their repertoires. Song sharing and the development of local dialects in the wren are discussed in relation to current views on mechanisms of social learning in songbirds.
The Relationship Between Individual Differences in Male Song Frequency and Parental Care in Blackcaps
Authors: Hoi-Leitner Maria , Nechtelberger Heidrun , Dittami John 
Published: April 2008

Abstract
Song rates in male blackcaps were examined over the course of the breeding season and compared with various aspects of mating and later parental behavior in individual birds. Song rates decreased steadily over the breeding season although relative individual rates remained constant. Early territory holders sang more and mated faster than late-comers. Song frequency was positively related to alarm call frequency during nesting but negatively related to male incubation and offspring feeding rates. Surprisingly, under the conditions studied, higher song rates were indicative of higher nesting success. This demonstrates the potential role of song frequency in the advertisement of territorial quality. There may well be either environmentally dependent differences in parental care as adaptations to temperature, food or predation pressure or simply a trade-off for males between singing and parental care, where early arriving males derive greater fitness benefits from singing, while late arriving males benefit more from engaging in parental care.
Antipredatory Behaviour of Feverish Tadpoles: Implications for Pathogen Transmission
Authors: Lefcort Hugh , Eiger Steven M. 
Published: April 2008

AbstractIn this paper we propose the hypothesis that pathogen-induced host defense responses result in altered host behaviors and enhanced predation. In particular we examine the effects of the acute phase response (whose effects include fever, reduced activity and malaise) on antipredatory behavior in bullfrog (Rana catesbeiana) tadpoles. This host response is associated with the preliminary stages of infection with many pathogens yet its behavioral effects have received little attention. Bullfrog tadpoles were injected with alcohol-killed bacteria to induce a response to infection and their ability to detect and avoid capture by predatory salamanders (Taricha granulosa) was explored. We predicted that acute phase responses increase tadpole vulnerability to predation by influencing thermoregulatory behavior and their ability to detect, and avoid capture by, salamanders. We found that the sterotypical effects of the acute phase response can lead to increased predation. Malaise affected the refuge seeking behavior of the tadpoles in the presence of salamanders. We suggest that for tadpoles provided with refuges, altered behaviors are a liability. This endogenous response may afford some parasites a potential pathway to their next host.
Reproductive Competition and Selection On Male Traits At Varying Sex Ratios in the Field Cricket, Gryllus Pennsylvanicus
Authors: Souroukis Konstantine , Cade William H. 
Published: April 2008

Abstract
Intensity of male-male competition and sexual selection were studied in the field cricket, Gryllus pennsylvanicus, in an outdoor arena at four sex ratios, male-only (5:0), male-biased (5:2), unity (5:5) and female-biased (5:10). Fighting frequency was highest at male-biased and unity sex ratios. Fighting success was correlated with male body weight at all sex ratios. Calling duration and searching distance decreased with increased female numbers. Opportunity for selection was highest at the male-biased and lowest at the female-biased sex ratio. Selection gradients and differentials were calculated and demonstrated that direct and total selection was highly variable and often relaxed. Direct selection favored male weight at the male-biased sex ratio and total selection for weight occurred at unity. There was no selection on male weight at the female-biased sex ratio. Total and direct selection for increased calling duration occurred at the male-biased sex ratio. Only total selection for calling duration was found at unity, whereas direct selection acted against calling duration at the female-biased sex ratio. Selection did not act on searching at any sex ratio. Natural variations in sex ratios occur and fluctuations in selection on correlated male traits may maintain additive genetic variation for traits important in male-male competition.
Reconciliation, Consolation, and Redirection in Japanese Macaques (Macaca Fuscata)
Authors: Aureli Filippo , Veenema Hans C. , Van Panthaleon Van Eck Carel J. , Van Hooff Jan A.R.A.M. 
Published: April 2008

Abstract
We studied the occurrence of social interactions after agonistic conflicts in captiveJapanese macaques. We collected data on one group during the mating and the non-mating season and on another group during the mating season only. We compared the social interactions of the victim soon after a conflict with the social interactions of the same individual during control periods, using two different methods. The results obtained with the two methods were very consistent. We found clear evidence for the occurrence of reconciliation and redirection. However, there was no evidence for consolation even when we considered only affiliation between the victim and its own kin or between the victim and the aggressor's kin. Separate analyses for the two groups and the two seasons yielded very similar results.
Functions of Wild Gorilla 'Close' Calls. I. Repertoire, Context, and Interspecific Comparison
Authors: Harcourt A.H. , Stewart K.J. , Hauser M. 
Published: April 2008

Abstract
Individuals in social groups of a number of species produce and exchange among themselves frequent, quiet vocalisations. The function of most such vocalisations, here termed 'close' calls, remains obscure, because of the lack of any obvious context of behaviour associated with their production. In this first of two papers that attempt to determine the function of these calls in wild girilla groups, we describe the call repertoire, the age-sex distribution of frequencies of call-types, the contexts in which the calls are given, compare the above measures with available descriptions for the other African great apes, the common and bonobo chimpanzees, and briefly speculate on possible functions. We provide sonograms and 21 acoustical measures of 15 calls in total, including eight 'close' calls, recorded from identified individuals of two habituated heterosexual groups of wild gorillas (Gorilla gorilla) of average composition for the region. In so doing, we provide the most detailed description yet of any great ape's within-group vocalisations. The age-sex classes differed in their use of 'close' calls: adult males called the most in total, immatures the least; and while most classes gave all calls, they gave them at differing frequencies. The differences were consistent across the two-year study period. We suggest two main contexts of production, namely situations of potential separation, and potentially agonistic situations. Thus animals called when far from others and before changes in group activity, and they called when unusually close to one another, especially while feeding. In comparison to the closely related common and bonobo chimpanzees, gorillas apparently had no calls specific to subordinate individuals behaving submissively: subordinate gorillas gave calls in such a situation, but they and dominants gave the same calls (at our current level of analysis) in other situations also. Acoustically and functionally, the gorilla's 'close' calls can be separated into 'syllabled' grunts and non-syllabled' longer calls, we suggest. 'Syllabled' calls might function to maintain contact between animals, to coordinate activity, and to act as mild threats; 'non-syllabled' calls might function as appeasement signals, and to cohere and coordinate group movement when given at good feeding sites, both by attracting animals to the site, and by inhibiting competition at it.
Mother-Infant Relationships in Three Species of Macaques (Macaca Mulatta, M. Nemestrina, M. Arctoides). I. Development of the Mother-Infant Relationship in the First Three Months
Authors: Maestripieri Dario 
Published: April 2008

AbstractThis study compared mother-infant relationships in rhesus, pigtail, and stumptail macaques living in large captive social groups. Mother-infant pairs were focally observed in 4 weekly 30-min sessions for the first 12 weeks of infant life. Rhesus and stumptail infants were active earlier than pigtail infants, and rhesus mothers further encouraged infant independence by frequently breaking contact with them and rejecting them. Rhesus mothers also restrained their infants, presumably in circumstances where a danger for them was perceived. Pigtail mothers were more protective than rhesus mothers and not as encouraging of infant independence as rhesus mothers. Stumptail mothers scored low on both protectiveness and rejection measures. The functional significance of some differences in mother-infant relationships is tentatively explained on the basis of reproductive, ecological, and social characteristics of rhesus, pigtail, and stumptail macaques. Data on scratching behavior support the hypothesis that behavioral differences among macaque species are associated, at the proximate level, with differences in temperament or emotional reactivity.
Vigilance in Nxai Pan Springbok, Antidorcas Marsupialis
Authors: Bednekoff Peter A. , Ritter Ron 
Published: April 2008

Abstract
Vigilance rates were surveyed on juvenile and adult female springbok in 3 positions (close edge, center, and far edge) in herds of 17 to 536 springbok in Nxai Pan N.P., Botswana. Rates were generally low. They decreased as group size increased but were not lower when other grazers joined springbok herds. Edge animals spent roughly twice as much time vigilant as central animals. Juveniles were slightly less vigilant than adults but this may reflect greater movement. Surprisingly, springbok were more vigilant in late mornings than in early mornings or afternoons. Springbok approaching tree clumps were more vigilant than matched individuals moving in the open. Preliminary data indicate that vigilance is higher at night than during the day and that territorial males have moderate to low levels of vigilance. In general, vigilance varied in ways expected to lower the risk of being taken by ambush predators such as leopards.
Effects of Testosterone On Nest-Box Occupation and Associated Behaviours By Male European Starlings (Sturnus Vulgaris)
Authors: Gwinner Helga , Gwinner Eberhard 
Published: April 2008

Abstract
In an aviary experiment carried out at the beginning of the breeding season in March and April, nest-box occupation and associated behaviours were observed in a group of 18 adult and 18 first-year male European starlings. Nine birds of each group carried a testosterone implant (T-males) and the other 9 an empty implant (C-males). When analyzed for effects of age, first year birds were significantly more active with regard to nest-box inspection and nest-building than adults. When analyzed for effects of treatment, T-males occupied more nest-boxes and visited their nest-boxes more often than C-males. Other activities like singing, nest-box inspection, nest-building and aggressive behaviour were not significantly different between T-males and C-males. We suggest that the absence of a significant effect of T on aggression may be related to the colonial nesting habits of the starling. Since T-males tended to be more active with regard to all behaviours studied testosterone may have led to a general increase in frequency and persistence of behaviour which in turn facilitated nest-box occupation.
Vigilance in African Mammals: Differences Among Mothers, Other Females, and Males
Authors: Burger Joanna , Gochfeld Michael 
Published: April 2008

Abstract
The time devoted to eating, vigilance (or scanning), walking and aggression was studied in one-minute focal animal samples as a function of sex, age, and motherhood for several African animals including African elephant, Burchell's zebra, Cape buffalo, Defassa waterbuck, impala, and Uganda kob. Between 24 and 45 percent of the variation in vigilance behavior was accounted for by location (center or edge of herd), sex, age and whether a female had young. Time of day entered the linear multiple regression models for two species, and surprisingly group size did not enter any of the linear multiple regression models in 1993. In general, females with young were more vigilant than their young or females without young. There were few gender differences in vigilance among animals without young, except that male zebra, wildebeest and waterbuck were more vigilant than females. Animals on the edge of herds devoted more time to vigilance than intermediate or central animals (regardless of sex or age class). Although there was no relationship between group size and vigilance in 1993 when all herds were considered, there was a decrease in vigilance with increasing herd size for impala and kob for herds less than 50. Moveover, herd size and vigilance were negatively correlated in our 1984-1985 study, due partly to differences in group sizes. In 1984-1985 animals were not migrating, and were in relatively small, discrete groups, whereas in 1993 some species were migrating in large herds that stretched for several km. We suggest that in 1993 herd size was above a threshold where increases in group size can lead to further decreases in vigilance. Under these circumstances, location in the herd becomes paramount: Outside animals can be directly exposed to attack. Consequently animals on the edge devote more time to vigilance than central animals.
Comparative Analysis of Time Spent Grooming By Birds in Relation To Parasite Load
Authors: Cotgreave Peter , Clayton Dale H. 
Published: April 2008

Abstract
Although grooming and other kinds of maintenance activity are important components of the behavioural repertoire of terrestrial vertebrates, comparative studies of the proportion of time budgets devoted to maintenance are lacking. Data were collated on the proportion of their time-budgets devoted to maintenance behaviour by 62 different bird species. On average, birds spend 9.2% of the day in maintenance activities, with the major component (92.6%) being grooming. Male birds devoted more time to maintenance than females, except in the case of ducks. Maintenance time does not appear to correlate with morphology, moult, latitude, coloniality or season. However, bird species known to harbour more parasitic louse species spend more time on maintenance than do host species with few lice.