bluuebunny/crossref_metadata_2025 huggingface dataset:
The Evolution of Sex-Biased Dispersal in Lions
Authors: Pusey Anne E. , Packer Craig
Published: April 2008

Most female lions remain in their natal pride for their entire lives, but about a third emigrate before they reach four yrs of age. Most emigrating females leave either when they are evicted by an incoming male coalition or when the adult females of their pride give birth to new cubs. One cohort of females left because they avoided mating with males of their father's coalition. Cohorts of dispersing females leave together and form a new pride whose range almost always includes at least part of their natal range. Females that leave their natal pride suffer reduced fitness: dispersing females in the Serengeti first breed at a later age than non-dispersing females and dispersing Ngorongoro females suffer higher mortality. Dispersal patterns of large and small cohorts are such that pride size rarely exceeds or goes below the range of sizes that confers the maximum reproductive success per female. Pride fissions have no consistent effect on the average levels of genetic relatedness within prides. All males leave their natal pride. Most leave at a male takeover, but one male cohort was evicted by their fathers whereas several others left voluntarily during their fathers' tenure. A greater number of large male cohorts leave their natal pride than expected from their competitive ability and males rarely show an interest in mating until they enter a new pride. Larger male coalitions are more likely than small ones to gain residence in a pride adjacent to their natal pride, and also gain their first pride at a younger age. However, not all large cohorts are so successful because most cohorts of 6-8 males permanently split up soon after emigrating from their natal pride. About half of the secondary dispersal shown by resident adult coalitions is voluntary. Such voluntary secondary movements occur in three contexts: the coalition (1) annexes an additional pride thereby gaining access to more females (2) abandons one of several simultaneously held prides to spend more time with prides in which their cubs are younger and hence more vulnerable to infanticide (3) abandons one pride for another pride. In the third case males only abandon small cubs when going to much larger numbers of females, but they may abandon more females for fewer when their daughters are reaching maturity in the former pride. Males rarely reside in prides once their daughters have matured, and rarely return to breed in their natal pride. Compared to the large Serengeti population, the small isolated Ngorongoro population has lower levels of dispersal, higher levels of homozygosity and some deleterious effects of inbreeding.
Can Cannibalistic Hatchlings of the Land Snail Arianta Arbustorum Distinguish Between Sib and Non-Sib Eggs?
Authors: Baur Bruno
Published: April 2008

In the field hatchlings of the land snail Arianta arbustorum have been observed devouring eggs from sib as well as non-sib clutches. In the laboratory newly hatched A. arbustorum were tested for their ability to distinguish between eggs of different degrees of relatedness. In these experiments hatchlings did not discriminate between sib, other kin and non-kin eggs. Snails from three populations showed the same egg preferences, but they differed in their propensity for cannibalism. Despite the apparent lack of sib and kin recognition, egg cannibalism in A. arbustorum may be adaptive, even among siblings, because of the nutritional and energetic benefits.
Effects of Nestboxes On LH, Testosterone, Testicular Size, and the Reproductive Behavior of Male European Starlings in Spring
Authors: Dittami John , Gwinner Helga , Gwinner Eberhard
Published: April 2008

The effect of nestboxes on the vernal increase and decrease in reproductive activity was investigated in male European starlings (Sturnus vulgaris), held in outdoor aviaries. Male-only groups with (group 1) and without (group 2) availability of nestboxes were compared for the amount of song, for testicular size and plasma titers of luteinizing hormone (LH) and testosterone. Testicular size and LH differed significantly between the 2 groups, being higher in males with nestboxes. Similar differences, as well as differences in nestbox-related behaviors (sitting in front of a nestbox, inspecting it, and nestbuilding) were also found when individuals of group 1, in possession of a nestbox, were compared to those without. In another group (2), the seasonal dependence of nestboxes as a modifying factor was investigated. These males were given access to nestboxes later in the season, than the males of group 1, after April 7. The effects on physiological parameters at this time of year were negligible in that only a transient increase in LH was seen compared to group 3. Nestbox-oriented behaviors did not reach the same intensities as in group 1. These results demonstrate the importance of nest-site availability in modifying behavioral and physiological functions during the vernal reproductive cycle. At the same time they indicate a seasonal dependence in these modifying effects.
Leaf Size Recognition and Evaluation of Some Attelabid Weevils (2) Apoderus Balteatus
Authors: Sakurai Kazuhiko
Published: April 2008

A leaf choice experiment was conducted and the behaviour of the female weevil was observed before she commenced cutting. The female always performed a sequence of stereotype behaviours preceding cutting. The results of this study indicate that the female firstly decides the number of eggs to be laid in the cradle and then starts looking for a leaf suitable for that number of eggs. While the female is making a cradle, she measures and perceives for different purposes three different distances on the leaf (or something that represents each of them: 1) the length of the whole leaf, i.e. the criterion of adequacy of a leaf for a cradle, 2) the leaf width, i.e. the criterion of adequacy of a leaf for a two-egg cradle, and 3) about 1 cm along the main vein from the leaf base, i. e. the determinant of the cutting site. These three are probably measured while the female is performing the stereotype walking. Measuring both leaf length and leaf width amounts to predicting the shape and the size of the cradle.
Memory Effect On Predatory Behaviour of Odontomachus Troglodytes (Formicidae - Ponerinae)
Authors: Dejean Alain
Published: April 2008

Naive hunting workers of Odontomachus troglodytes will attack larvae of the Chrysomelidae. These larvae exhibit a secretory reflexive defense. The first experiment showed that even if a hunter has palpated or attacked a chrysomeline larva only one time, it will avoid or flee this type of prey on subsequent encounters. The second experiment showed that this memory of the first contact lasts at least 28 days. The escape behaviour shown by the hunters is compared to other kinds of locomotion.
Intra-Specific Food Competition and Primate Social Structure: a Synthesis
Authors: Janson Charles H.
Published: April 2008

The results of the various studies in this volume lead to a series of predictions about the relationships of group size to various components of food intake. Individuals in larger groups should generally encounter fewer new food sources per unit foraging effort than they would alone (prediction 1); an exception may occur when large groups defend areas of high food density against small groups. In addition, individuals in larger groups generally will suffer reduced intake per food source encountered because of increased sharing with other group members, at least for food sources that supply little total nutrient relative to an individual's satiation level for the nutrient (prediction 3) or are scarce relative to the spacing between individuals in the group (prediction 5). Individuals in larger groups may compensate for such reductions in foraging efficiency by increasing rates of food encounter (prediction 2), using food sources with greater amounts of nutrient (prediction 4), or increasing total foraging effort per day (prediction 6). Reduced foraging efficiency for a particular nutrient may not affect total intake of that nutrient if other nutrients require greater daily foraging effort (prediction 7). Food competition is expected to be highest in species using small and scarce food sources, subject to a high risk of predation, and with large satiation levels. An appendix on statistical problems describes some of the pitfalls inherent in studies of the kind presented in this volume.
Effects of Patch Quality and Feeding Subgroup Size On Feeding Success in Vervet Monkeys (Cercopithecus Aethiops)
Authors: Whitten P.L.
Published: April 2008

Acacia tortilis flowers are an important food resource of vervet monkeys (Cercopithecus aethiops) in East Africa. This paper examines the effects of tortilis patch quality and feeding subgroup size on individual and group foraging success in vervet monkeys. Feeding variables examined included net caloric gain, foraging efficiency, pick rates, and foraging bout length. The data provide some evidence in support of the hypothesis -that patch quality significantly influences foraging success. Patches where flower pick rates were higher provided foraging for a greater proportion of the troop and provided more energy intake and higher foraging efficiency for individual troop members. Phenological data indicate that flower pick rates were a direct reflection of patch size and flower cover. On the other hand, data examined here provide no support for the hypothesis that feeding subgroup size adversely affects food intake or foraging efficiency within food patches. The lack of foraging costs appears to be due to adjustment of feeding parties to the size of food patches. Troop size, however, exceeded the average number of feeding sites per A. tortilis patch. As a consequence, low-ranking troop members suffered foraging costs due to exclusion from food patches. These analyses suggest that individual differences in benefits and costs of group foraging may play an important role in the history and evolution of groups.
Dominance Relationships Between Adult Plains Zebra Stallions in Semi-Captivity
Authors: Schilder Matthijs B.H.
Published: April 2008

The relationships between 4-5 adult zebra stallions, living in a safari park, were investigated over a period of 5 years. Asymmetries in the distributions of a number of behaviours could be explained by adopting dominance as an intervening variable. Dominance in stallions was of a bipolar nature with on the one hand behaviours representing subordinance and defence, and on the other hand behaviours reinforcing and confirming dominance. Expression of formal dominance seems to play a minor role. The dyadic relationships of stallions differed as to the number of behaviours reflecting dominance relationships. Although often linear rank-orders could be constructed, these rank-orders were not necessarily identical. This means that the concept of dominance is of only limited value for describing relationships between zebra stallions.
Exploring Primate Social Cognition: Some Critical Remarks1)
Authors: Kummer Hans , Dasser Verena , Hoyningen-Huene Paul
Published: April 2008

The paper expresses the authors' views on the growing interest in primate social cognition, particularly among descriptive primate ethologists. Its characteristics are the hope to extract cognitive interpretations from field anecdotes, the free use of intentional language, and the untested and so far untestable idea that primate intelligence was selected in social contexts. We believe that 1) To understand how the animal itself represents the structure of its group or its habitat is perhaps the most ethological ethology there is and well worth pursuing. The study of social cognition, in particular, has long been neglected. 2) However, it requires of ethologists that they learn from established cognitive science and integrate its categories with their own. This is an interdisciplinary enterprise. 3) A traditional inductive study begins with anecdotes, which then are translated into hypotheses, which in turn are subjected to empirical tests including experiments. Sociobiology began to publish hypotheses without tests; the social cognition move now goes on to publish anecdotes without hypotheses, with a strong penchant for anthropomorphic interpretations in terms of social manipulation. This is little more than applying human prejudice. Phylogenetic and cognitive insights will come from testing alternative levels of organization in an animal's social knowledge about the same behavioral interaction. The experiment is the largely unavoidable method. Examples are given. 4) The speculation of the social origin of primate intelligence is tentatively interpreted in two possible directions. A version based on ROZIN's (1976) view that generalized mammal intelligence evolved from context-specific "Adaptive Specializations" seems the more accessible to ethological thinking and method.
Preference of Prey Size and Profitability in Barn Owls Tyto Alba Guttata
Authors: Ille Rottraut
Published: April 2008

Barn owls of the subspecies Tyto alba guttata which had been bred in captivity, and which had experience with prey, were examined for preferences in prey size (weight) under experimental conditions. They were offered a choice of larger and smaller prey of three weight classes (3/10 g; 10/40 g; 40/160 g) either active or inactive (laboratory mice, Mus musculus; laboratory rats, Rattus norvegicus). The frequency of choices of smaller prey increased significantly from the lowest to the highest weight class, and from inactive to active prey. Most frequently, the owls selected prey of 10 g and 40 g. It was shown that both prey size and activity had an equal influence on the decisions. Predictions were made as to which particular prey size a barn owl was going to choose. With increasing prey weight, the frequency of interrupted prey catching acts and conflict behaviour (mantling, feather ruffling) towards the prey, increased. The upper weight for acceptable active rats was about 80 g. One male, which had to supply his female and nestlings with food, subdued somewhat larger prey. Although relative profitability (net nutritive value/unit of time), calculated from the duration of handling prey, decreased with increasing prey weight, the barn owls chose the larger prey under certain conditions. I discuss a strategy which compromises time and energy costs with the search and subduction of the item.
Consequences of Joint-Territoriality in a Mixed-Species Group of Tamarin Monkeys
Authors: Peres Carlos A.
Published: April 2008

Groups of saddle-back (Saguinus fuscicollis) as moustached tamarins (Saguinus mystax) in a western Amazonian forest jointly defended home ranges larger than 100 ha, which were held in common throughout the year. Resources were defended by direct exploitation in extensive areas shared with other groups, or through intensive and frequent intergroup interactions along territorial boundaries. These interactions were expressed primarily during intergroup encounters, and affected the use of space, movements, time budget, and foraging success of tamarins. During encounters, animals of both species spent more time in energetically costly activities, such as rapid travel and intergroup chases, and less time in energetically positive activities, such as feeding and foraging. In addition, foraging success per unit of foraging effort within overlapping areas of the range periphery was lower than in exclusive areas of the range centre, particularly for saddle-back tamarins. The time and energy allocated by moustached tamarins to boundary contests was considerably greater than that of saddle-backs, despite the fact that only the latter species increased its foraging efficiency by shifting from exclusive areas in the group's range to those shared by other groups. This is probably because of saddle-back's greater use of depletable food supplies, such as small fruit patches and small microhabitats containing embedded prey items. These benefits are likely to justify the substantial amount of time and energy invested in territorial defence for both saddle-backs and moustached tamarins, but appeared to be highly asymmetric between species.
The Use of Pelage Pigmentation in the Recognition of Mothers By Domestic Goat Kids (Capra Hircus)
Authors: Ruiz-Miranda Carlos R.
Published: April 2008

Although it is known that the young play an active role in the formation of mother-young attachment in ruminants, there is scant knowledge of how neonates identify their mothers. This research investigated the use of visual cues, particularly pelage pigmentation, in maternal recognition by domestic goat kids. Observations on the use of auditory cues were carried out secondarily. The findings of this study were: (1) The analysis of error patterns revealed that goat kids performed phenotype matching on the basis of pelage pigmentation when seeking their mothers in two- and six-choice tests, at a distance of 10 m. Presenting the kids with a choice between two females of the same colour resulted in more vacillation, and fewer kids were able to go to their mother directly than when the adults were of different colours. The phenomenon was not evident when the kids were 3 days old. Because it occurred at all other ages, regardless of whether the mother was absent, covered, or fully visible, colour-matching seems to be an important aspect of maternal recognition. (2) Visual cues were important for recognition, as evidenced by the performance of kids when maternal cues were limited (i.e. the mother was covered). (3) The efficiency measures did not correlate strongly with maternal vocalizations when visual cues from the mother were not completely present or when pelage pigmentation was not a good cue for discrimination. On the contrary, kids unexpectedly vocalized more in the conditions in which they could discriminate on the basis of visual cues, that is, when the mother was bare rather than covered, and when she was paired with a doe of a different colour category rather than one of the same colour category. (4) Five-day-old domestic goat kids recognized their mothers efficiently, even within a group, and at a distance of at least 10 m. Most 3-day-kids were not able to find their mothers efficiently in the six-choice test. Errors were made at all ages. The observed performance is consistent with the abilities required of kids under natural conditions.
Developmental and Comparative Aspects of Social Play of Mantled Howling Monkeys in Costa Rica
Authors: Zucker Evan L. , Clarke Margaret R.
Published: April 2008

The social play of infant and juvenile mantled howling monkeys in Costa Rica was studied via focal sampling (529.2 h) of known individuals of known age over a 22-month period. Observations of adult males (291.2 h of focal samples), done over portions of 3 calendar years, provided supplemental data for the social play of adults. Developmental patterns of play are presented, and are compared with data available for other mantled howlers, other sites, and other species of howlers. Social play by infants and juveniles occurred at the rate of .56 bouts/h, represented 5.79% of the total focal observation time, and bouts had a mean duration of 6.19 minutes. Play by an adult male occurred at the rate of .03 bouts/h (.007/h for all 4 adult males combined), represented 0.24% of his total focal time, and had a mean duration of 5.0 minutes. Ontogenetically, social play began in the 8th week of life. Infants' rates of play and percentage of time spent in play increased from the I1 stage through the I3 stage, then decreased into the juvenile period (> 1 year of age). Mean durations of play bouts increased through the 3 infant stages, then decreased slightly in the J1 stage. The occurrence ofplay groups (3 or more individuals) increased through the infant and juvenile stages. As infants aged, a larger percentage of bouts occurred further from the infants' and juveniles' mothers. With respect to social variables, no overall developmental pattern was evident for playing with an older or younger partner, or a partner that was the offspring of a mother ranked higher or lower than one's own mother; different age classes showed different patterns. When an older sibling was available as a play partner, no preference for this relative was shown. I3's had the highest number of different play partners. Immature howlers played predominantly with other immatures (93% of their interactions). The behaviours observed during play were similar to those reported for other howlers; the behaviours emitted by an adult male were similar to those of the juvenile partner, as was the style and intensity of play. The social play of these mantled howlers is viewed with respect to social, demographic, and ecological variables. The play of howlers is both facilitated and constrained by these variables.
Sexual Selection in the Leopard Toad, Bufo Pardalis
Authors: Cherry Michael I.
Published: April 2008

Sexual selection was investigated in the leopard toad, Bufo pardalis, on the Cape Peninsula in the south-western Cape Province of South Africa. Over three breeding seasons, male mating success was not dependent on either snout-urostyle length (size) or weight, when data were analysed on both a nightly and a seasonal basis. Males did not engage in active searching for females, or attempt to displace other males in amplexus. This is most unusual for an explosive breeder, in which spawning takes place at a specific site. It is suggested that the absence of patterns of behaviour normally adaptive for explosive breeders may be associated with the fact that a congeneric species with a different chromosome number, B. rangeri, overlaps in both distribution and breeding season with B. pardalis over part of its range. Active searching might therefore lead to males finding a mate of the wrong species, which would be maladaptive, as no male was successful in obtaining more than one mating over the three-year study period. Alternatively, the absence of scramble competition in this species may reflect predation pressure.
Social Dispersion and Lekking in Uganda Kob
Authors: Balmford Andrew
Published: April 2008

Lek-breeding in Uganda kob was associated with extremely high population density (c. 140 animals/km2). Kob were typically found in unstable aggregations of more than one hundred animals, including several adult males. Females occupied unusually large, overlapping home ranges, but reasons for such widespread movements were unclear. The social dispersion of Uganda kob was therefore similar to that of other lekking ungulates, and confirms predictions of several recent hypotheses of lek evolution. However, resolution of alternative models is nevertheless difficult, since in practice these make very few exclusive predictions.
Absence of Parent-Young Recognition in Kittiwakes: a Re-Examination
Authors: Storey Anne E. , Anderson Rita E. , Porter Julie M. , Maccharles Andrea M.
Published: April 2008

Black-legged kittiwakes (Rissa tridactyla) appear to recognize their chicks later in development than do ground-nesting gulls, an observation which has been related to the lower mobility of the chicks in nests on narrow cliff ledges. We tested whether this apparent delayed recognition was due to a failure of chicks to identify themselves (few individual cues in calls), or a failure of either participant to discriminate its relatives (differential response to calls or visual characteristics). It appears that both processes are relevant: (a) the peep calls of kittiwake chicks have fewer identifying cues in them than the peep calls from chicks of the ground-nesting herring gull (Larus argentatus), and (B) both parents and chicks show low levels of responsiveness to kittiwake calls from their own or from other nests. These results are discussed in terms of the appropriate level of responsiveness in the cliff environment, and the adaptive significance of the presence or absence of strong positive responses to one's own family members.
Intraspecific Variation in Courtship and Copulation Frequency: an Effect of Mismatch in Partner Attractiveness?
Authors: Petrie Marion , Hunter Fiona M.
Published: April 2008

The aim of this paper is to present a verbal theoretical model that could account for the among pair variability in courtship and copulation behaviour that occurs both during and after pair formation in socially monogamous species. We assume that copulation acts to prevent mate loss, by reducing the availability of an individual to other potential partners. Variation in copulation and courtship frequency then arises as a result of variation in the risk of mate loss. Because of the constraints on free or ideal choice, pairs will form in which it may be possible for one individual to improve upon the quality of its partner. In a mismatched pair it will pay the poorer quality mate to guard the higher quality individual and prevent it from leaving to pair with a better quality mate. The poor quality individual will therefore solicit copulations at a high frequency while it's partner may not always respond. We predict that high levels of courtship and solicitation will relate to a high risk of mate loss and that a lack of response by a partner will relate to the potential opportunities it has to improve on partner quality. Our thesis is that variation in mating behaviour arises as a result of any deviations from assortative mating that may exist in a population.
Front Individuals Lead in Shoals of Three-Spined Sticklebacks (Gasterosteus Aculeatus) and Juvenile Roach (Rutilus Rutilus)
Authors: Bumann Dirk , Krause Jens
Published: April 2008

Fish shoals are usually seen as anonymous leaderless groups in which all individuals have the same influence on swimming velocity and direction. This hypothesis was tested by investigating swimming directions of shoals of roach (Rutilus rutilus) and three-spined stickleback (Gasterosteus aculeatus). In roach, the influence of front and rear fish on the shoal's swimming direction was compared by analysing video recordings. Front fish initiated new directions significantly more often and were followed by rear fish. In a second experiment two shoals of sticklebacks were released from two channels which were positioned at an angle relative to each other. The shoals usually appeared with a short time difference at the opening of the channels and then merged. Initially the two shoals faced in different directions based on the orientation of their respective channel and it was recorded which direction prevailed after the shoals had merged. The shoal that left the channel first, and therefore formed the front part of the merged shoal, clearly dominated the direction. Thus, both experiments gave evidence for front fish having a dominant influence on the direction of the shoal. In the context of sustained position preferences of individual fish, recently observed in roach, this suggests that fish shoals may have leaders over extended time periods.
The Effect of Uncertainty On the Food Intake of the Mongolian Gerbil
Authors: Forkman B.A.
Published: April 2008

The effect of an unstable environment on the food intake of male adult gerbils (Meriones unguiculatus) was investigated in a laboratory set up. The main result was an increase in the intake when the environment was variable and food abundance intermediate, compared to the intake in a superabundant and stable environment. The experiment consisted of three periods. During the base-line period of the experiment all animals had superabundant food. During the next period half the animals continued in the base-line environment and the other half were presented with a variable environment with food bowls that changed places between trials. During the final period the environmental situations for the animals were reversed. Food intake was stable during the base-line period. During the second period the animals in the variable environment ate more than the animals in the base-line environment. During the third period the intake for the animals now in the variable environment increased whereas the intake in the stable environment decreased. The conclusion of the present study is that Mongolian gerbils will increase their food intake in response to variable and diminished food access. These are factors that in a natural environment could predict food scarcity.
Male Bonds: Afilliative Relationships Among Nonhuman Primate Males
Authors: Van Hooff Jan A.R.A.M. , Van Schaik Carel P.
Published: April 2008

A deductively obtained model concerning the factors that determine male social relationships within the framework of primate social organization is discussed in the light of existing empirical evidence. Tolerance and affiliative bonding are expected to occur less easily between male than between female primates. Whereas females compete for resources such as food, males, in addition compete to obtain fertilizations. Unlike food, fertilizations cannot easily be shared. This undoubtedly hampers the formation of male coalitions and the development of male bonds. Indeed, male tolerance tends to be low especially in species where the spatial and temporal distribution of females is such that individual males may monopolize access to such females, thus facilitating inter-male contest. Nevertheless there are a number of species in which tolerance between adult male group members is remarkable. In some cases forms of coordination and mutual attraction exist that justify the qualification of 'male bonding'. An important factor supposed to conduce to the development of male bonding is the inclusive fitness benefit that support and tolerance between male relatives may bring. This would occur especially where circumstances permit male philopatry. The latter is expected in species where the nature of female competition for basic resources does not lead to strong female-bondedness and female nepotism, allowing females to become allopatric. There is evidence from various species that related males form bonds under the mentioned conditions. A special case of this is the formation of father-son bonds, noted in species with strong intermale contest and corresponding sexual dimorphism. A remarkable alternative, by the way, is the existence of mother-son bonds which last into adulthood and which contribute to a male's position. There are indications for such bonds in two species where males stay with their mother and where sexual dimorphism is low. Still kinship clearly is not a necessary factor for the development of male tolerance and of support between males. The factor does not play a role, for instance, in the short-term coalitions found in baboons. Here opportunism based on mutual or reciprocal benefits seems to play a decisive role. The evidence presented lends support to the idea that there is an order of priorities, in which, first, socioecological factors determine the spatial, hierarchical and affiliative relationships between females. These female relationships then set the scene for the males, in that these determine the options left open for the males to organize their patterns of competition, migration and bonding.
Social and Genetic Aspects of Paternity in Wild Long-Tailed Macaques (Macaca Fascicularis)
Authors: De Ruiter Jan R. , Van Hooff Jan A.R.A.M. , Scheffrahn Wolfgang
Published: April 2008

In a field study of three groups of wild long-tailed macaques, Macaca fascicularis, observations on social behaviour could be related to genetically determined paternity. In contrast to what has been found in many previous studies on captive primate groups, we found a relatively strong correlation between male dominance rank and reproductive success. In a large group the high success of the alpha male compared to other males could be explained only partly by his higher copulation score. His success also resulted partly from better timing of his copulations during maximum fertility of the females, in comparison with other males. We must conclude either that the alpha-male has more access to fertile females, or that females have a preference for the alpha-male during their maximum fertility. The females clearly displayed promiscuous behaviour. This behaviour implies a risk to a female that a male other than the alpha-male with proven qualities will become the father of her offspring. One expects that there must be a social advantage related to this female strategy. In the absence of indications of any direct social advantages to the female of this sexual behaviour pattern, the ultimate explanation for this female promiscuity is most likely is aggression reduction. This could be either through the devaluating of any single copulation, or through the confusion of paternity and a resultant reduction in the risk of infanticide.
Predator Vigilance Costs of Allogrooming in Wild Blue Monkeys
Authors: Cords Marina
Published: April 2008

Although allogrooming in Catarrhine primates is often interpreted as if it were a costly behavior for the groomer, such costs have not been convincingly documented. This paper presents data on rates of vigilance for aerial predators, measured as looking up toward the sky, in wild blue monkeys engaged in allogrooming, and compares these vigilance rates to those occurring when the same individuals engaged in other activities, namely feeding and resting. Grooming individuals have much lower vigilance rates than resting or feeding individuals, suggesting that grooming individuals are more likely to be at risk of being preyed upon. These results are not caused by a systematic relationship in the sample between activity and either foliage density or time of day, two factors potentially related to levels of safety from predation. Nor was there evidence that blue monkeys avoid the vigilance costs of grooming by engaging in this behavior primarily at safe times or in safe locations. Although the data suggest that vigilance costs occur, they may accrue to the recipient ofgrooming as well as the groomer, and may be compensated for both partners by long- or short-term benefits.
Individual Variation in Foraging Movements in a Lake Population of Young-of-the-Year Brook Charr (Salvelinus Fontinalis)
Authors: Biro Peter A. , Ridgway Mark S.
Published: April 2008

We examined the variation in foraging movements in a population of young-of-the-year (YOY) brook charr living in the near-shore littoral zone of a lake. By repeating the methodology of an earlier stream study, we made direct comparisons between data from lake and stream populations. In general, the pattern of variation in foraging movements was similar between the two sites with greater variability and activity observed in the lake population. The dichotomous nature of the proportion of time spent moving in the stream was also observed in the lake population but in a reversal of the stream pattern. Charr that moved constantly while foraging represented the largest movement category in the lake. In general, variation in foraging movements were more strongly related to the rate of prey rejection, whereas environmental factors, such as distance from shore, submerged objects, and the amount of overhead riparian cover, were more strongly related to prey ingestion. This last finding directly contrasts with that found in the stream literature for YOY charr in still water where ingestion rate, as estimated using feeding attempt rate, increases with the mobility of YOY charr.
Habituation of a Predatory Response in the Stickleback (Gasterosteus Aculeatus)
Authors: Peeke Harman V.S.
Published: April 2008

Sticklebacks presented with a clear glass tube filled with live brine shrimp will initially attempt to capture them; however, the response wanes within minutes. In the case of females, the rate of initial response is enhanced and the rate of waning is influenced by the state of the female (gravid females are more responsive) and by the density of the prey (greater density results in greater responsiveness). The predatory-response habituation differs from habituation of territorial aggression and courtship in that the pre-decremental, incremental process is absent. In common with habituation of territorial aggression but not with courtship, there is little short-term recovery of the response. The differences are consistent with different functional requirements for an experience-based inhibitory mechanism involved in the modulation of stickleback behaviour.
Conflict Outcome in Male Green Swordtail Fish Dyads (Xiphophorus Helleri): Interaction of Body Size, Prior Dominance/Subordination Experience, and Prior Residency
Authors: Beaugrand Jacques P. , Payette Daniel , Goulet Claude
Published: April 2008

The relative contribution of asymmetries in prior experience, size, and prior residency to the determination of dyadic dominance between unacquainted individuals was examined using pairs of green swordtail fish, Xiphophorus helleri. Four types of encounters were staged between an intruder and a smaller resident: (1) both had experienced prior vicctory; (2) both had experienced prior defeat; (3) the intruder had experienced prior victory and the resident prior defeat; and (4) the intruder had experienced prior defeat and the resident prior victory. In a fifth condition in which two intruders met, one was a prior subordinate and the other a prior dominant smaller in size than its opponent. In all these encounters, the superiority in lateral surface of one fish varied between 0 to 30% over that of its opponent. Results showed that (1) when size differences between contestants were within the range of 0-10% and there was an asymmetry in prior social experience, conflicts were essentially resolved according to prior experience with prior winners systematically defeating prior losers; (2) prior residency of 3 h was an advantage only when both opponents had experienced prior defeat before meeting and when size asymmetries were small (e.g. < 20%). It was not an advantage between prior winners or between a prior winner and a prior loser; (3) when large size asymmetries existed (e.g. 20-30%), size uniquely determined dominance outcome and nullified other advantages or disadvantages due to prior social experience and prior residency; and (4) at intermediate levels of size asymmetries (e.g. 10-20%), size partially cancelled any advantage due to a prior victory, and gradually became paramount in accounting for victories.
'Pop' Goes the Dolphin: a Vocalization Male Bottlenose Dolphins Produce During Consortships
Authors: Connor Richard C. , Smolker Rachel A.
Published: April 2008

Studies of dolphin communication have been hindered by the difficulty of localizing sounds underwater and thus identifying vocalizing individuals. Male bottlenose dolphins (Tursiops sp.; speckled form) in Shark Bay, Western Australia produce a vocalization we call 'pops'. Pops are narrow-band, low frequency pulses with peak energy between 300 and 3000 Hz and are typically produced in trains of 3-30 pops at rates of 6-12 pops/s. Observations on the pop vocalization and associated behavior were made as part of a long-term study of bottlenose dolphins in Shark Bay. During 1987-88 seven dolphins, including three males, frequented a shallow water area where they were daily provisioned with fish by tourists and fishermen. The three males often produced pops when accompanied by single female consorts into the shallows. Fortuitously, the males often remained at the surface where pops were audible in air, enabling us to identify the popping individual. All 12 of the female consorts in the study turned in towards males at a higher rate when the males were popping than when they were not popping. All 19 occurrences of one form of aggression, 'head-jerks', were associated with pops. We conclude that pops are a threat vocalization which induces the female to remain close to the popping male during consortships.
Distance and Social Recognition in Hens: Implications for the Use of Photographs as Social Stimuli
Authors: Stamp Dawkins Marian
Published: April 2008

The role of close (less than 30 cm) examination or scrutiny of other birds in social recognition was confirmed by showing that before approaching a hen whose identity was unknown, hens behaved similarly whether that bird was familiar or unfamiliar to them, but after examining the other hen they temporarily kept further away from unfamiliar hens (Expt 1). Hens chose flock-mates rather than unfamiliar birds as feeding companions even when all that was visible of the target birds were their heads and necks, confirming the role of these regions in recognition (Expt 2). They showed this preference for familiar birds whether they could see either the front or the side views of the heads of the target birds but attempts to confirm this result with photographs rather than live birds resulted in no significant preference being shown (Expts 3 and 4). The reasons for this lack of transfer from live birds to photographs and its implications for presenting artificial visual stimuli such as photographs and video to hens are discussed.
Lek-Like Spawning Behaviour and Different Female Mate Preferences in Roach (Rutilus Rutilus)
Authors: Wedekind Claus
Published: April 2008

I studied the scarcely known mating system of roach. Individually marked fish were kept in a pond with a glass wall that allowed observations of spawning. The roach showed a lek-like mating system which has not been described previously, with bourgeois males and reproductive parasites (i.e. simultaneous parasitic spawning), both tactics used by the same individuals. Females had the possibility to choose freely among the males but could probably hardly avoid multi-male fertilization. Most females spawned repeatedly during the observation period. They showed strong individual preferences with different females preferring different males or spawning sites.
Contexts and Patterns of Injuries in Free-Ranging Male Baboons (Papio Cynocephalus)
Authors: Drews Carlos
Published: April 2008

Injury in male baboons (Papio cynocephalus) was investigated as an indicator of damaging fights in order to provide a framework for analyses of conflict resolution and dynamics of agonistic competition in primates. The vast majority of wounds were canine slashes resulting from intraspecific face-to-face combat. Wounds were more common in males than females. In males they concentrated on the right side of anterior parts of the body, principally the head. Wounds took on average three weeks to heal. Aggressive conflicts represented 10% of all interactions between males. Less than 1% of aggressive contests led to injury. The individual rate of injury from fights with other males was on average once every 1.5 months. The winner of damaging fights was sometimes the wounded individual. The number of wounds per damaging fight was not related in a simple way to the presence of proceptive females or to recent immigration events. Four fights yielding the highest number of injuries, however, involved recent immigrations or attempts to immigrate by adult males in their prime. Contexts of male injury observed during infliction include challenges to the resident alpha male by newcomers, intertroop encounter, fights over proceptive females or unusual foods, redirected aggression, defense of a female and a fight unrelated to any obvious resource. This study and anecdotal reports from the literature point at various implications of injury to male baboons, including physical impairments which can constrain feeding efficiency, limit access to resting sites and safe retreats, cause a drop in dominance rank, jeopardize mating success and even result in death. Severely injured males typically reduce interaction rates, retreat to the periphery of the troop or emigrate temporarily. Although most wounds are small and heal well, the potentially high costs of injury probably exercise strong selection pressure on contestants for means of peaceful conflict resolution, given that during fights both baboons risk injury irrespective of their competitive abilities. The potential fitness consequences of inflicted injury can explain the evolution of the formidable canine weaponry of some male primates.
The Relationship Between Pregnancy Block and Infanticide in House Mice (Mus Musculus Domesticus) During Lactational Pregnancy
Authors: Coopersmith Carol B. , Lenington Sarah
Published: April 2008

Recently mated female house mice separated from their mates and exposed to unfamiliar (strange) males often undergo pregnancy disruption. A favored explanation for this phenomenon, known as pregnancy block, is that it has evolved as a female counterresponse to potential infanticide by males. Curiously, pregnancy block is believed not to occur during lactational pregnancy, even though that lactational pregnancy is thought to be common in house mice. We examined the potential for male-induced pregnancy block to occur during lactational pregnancy in female mice after lactation disruption by both male infanticide (Expt 1) and litter removal (Expt 2). Strange males were paired with females that had both recently given birth to a first litter and potentially been reimpregnanted by the original stud male during postpartum estrus. Hence, some of the females' second litters were sired by the stud males and pregnancy block could then be detected as a drop in the delivery rate of such litters among these experimental females relative to control females that were not exposed to strange males. Pairs remained housed together until after a second litter was born. Thus, we were also able to measure the influence of prolonged heterosexual cohabitation on infanticide by strange males towards subsequent litters. If, as some have found, non-sexual contact with a pregnant female suppresses male infanticide, then the importance of male infanticide as an explanation for pregnancy block is further drawn into question. When strange males were introduced to lactating dams approximately one and a half days postpartum (Expt 1), male infanticide effectively halted lactation. However, none of these females subsequently showed pregnancy block. In contrast, when strange males were introduced to dams approximately one day postpartum and lactation was interrupted even earlier (Expt 2), pregnancy block did occur. There was no evidence for a cohabitation-induced reduction of male infanticide in either experiment; most strange males initially categorized as infanticidal subsequently killed females' second litters, provided they had not sired those litters. Despite the lack of cohabitation effects on male infanticide, because pregnancy block may only occur under restricted conditions during lactational pregnancy, the role of male infanticide in shaping the evolution of pregnancy block may be less straightforward than previously thought.
Individual Specialisation and Encounters Between Harvester Ant Colonies
Authors: Brown Mark J.F. , Gordon Deborah M.
Published: April 2008

This study examined how individual specialisation contributes to neighbour-stranger discrimination in the red seed-harvesting ant, Pogonomyrmex barbatus. The following hypothesis was tested: is there a group of ants (detectives) that specialise in interacting with non-nestmates and thus have the opportunity to learn the colony-specific odour of neighbouring colonies? Encounters were staged between laboratory colonies. Ants were marked and observed in successive encounters. There is no specialisation for interaction; the results showed that all ants were equally likely to interact with non-nestmates. The frequency of fighting between P. barbatus colonies varies from day to day. The following hypothesis was tested: do some ants (fighters) specialise in fighting when they interact with non-nestmates. There is specialisation for fighting; a few ants tended to fight when they met non-nestmates. There was no day-to-day effect of encounters on the number of foragers in the laboratory arena. Without specialised detectives, neighbour recognition must arise either from frequent interactions between foragers of neighbouring colonies or from communication among nestmates about the odour of neighbours. Shifts in the number of specialised fighters present in the foraging pool may underlie the day-to-day variation in fighting intensity observed in the field.