bluuebunny/crossref_metadata_2025 huggingface dataset:
Experiments on the Responses of a Rejector Species to Threats of Predation and Cowbird Parasitism
Authors: Bazin Ronald C. , Sealy Spencer G.
Published: May 2010

We presented freeze‐dried models of a nondescript sparrow (control), a female brown‐headed cowbird (Molothrus ater, Icterinae) and an avian nest predator to nesting eastern kingbirds (Tyrannus tyrannus, Tyranninae) during the egg‐laying and nestling stages to test for nest defense against the threat of cowbird parasitism. Both kingbird parents responded during 81% of the 183 trials. Kingbirds responded aggressively toward the cowbird model, but only slightly more so than to the control, and less than to the predator model. The level of aggression directed toward the predator increased between the laying and nestling stages. The results suggest that kingbirds at Delta Marsh, Manitoba, did not recognize the cowbird as a unique or dangerous threat, possibly because of low selection pressure on this rejector species for aggressive nest defense against cowbirds.
Pedogenetic Sociogenesis via the “Sibling‐route” and some Consequences for Stegodyphus Spiders
Authors: Wickler Wolfgang , Seibt Uta
Published: May 2010

Cooperative social life originated independently at least 3 times in the eresid spider genus Stegodyphus. The ultimate and proximate factors for sociogenesis have been analyzed in two African social species, S. dumicola and S. mimosarum.

More profitable hunting as the ultimate benefit of sociality can explain group sizes up to 30 individuals. Most groups are much larger, reducing average female fecundity. They benefit mainly from the shelter against predators provided by the compact silk nest as a heritable resource.

Sociogenesis is not based on extended maternal care but on interattraction and tolerance of juvenile spiders, retained throughout life in females. Their neotenic sociality came to overlap with advanced (pedomorphic) sexual maturity. This evolutionary pathway towards sociality is called the “sibling‐route”.

Negative side effects, accumulating with group size, may make sociality in Stegodyphus evolutionarily unstable.
Maternal Anxiety in Rhesus Macaques (Macaca mulatta)
Authors: Maestripieri Dario
Published: May 2010

This study assessed the extent to which emotional reactivity to the social environment influences maternal behaviour in macaques. Visual monitoring and scratching were used as behavioral indicators of maternal and social anxiety in small captive groups of rhesus macaques. Maternal visual monitoring of the infant and of other individuals proved better predictors of individual differences in maternal protectiveness than did characteristics of the mother‐infant dyad such as maternal age, experience and dominance rank, number of immature offspring present in the group, or sex of the infant. Unlike visual monitoring, maternal scratching was not linearly related to protectiveness. Mothers displaying low or high rates of scratching ranked low on protectiveness, and the most protective mothers were those who displayed intermediate levels of scratching. Although individual differences in maternal and social anxiety seem to be mediated by maternal age and experience, they might also be influenced by genetics and early experience.
Influence of Litter Gender Composition on Subsequent Maternal Behaviour and Maternal Aggression in Female House Mice
Authors: Musi Barbara , de Acetis Luigi , Alleva Enrico
Published: May 2010

It has been suggested that the sex‐dependent pattern of mother‐pup interaction that occurs early in infancy can affect some aspects of the animal's behaviour repertoire in adulthood. The aim of this study was to investigate the effects of litter gender composition (LGC) on subsequent maternal behaviour and aggression in the female house mouse. Albino mouse litters were reduced at birth to six pups according to two conditions: FM (3 females and 3 males) and FF (all females). At weaning (day 21), all mice were rehoused in unisexual groups. At adulthood (70–90 days) the females were mated and litters culled at birth to 6 pups (3 females and 3 males). On days 2, 4, and 6 after delivery the females were tested for maternal behaviour (10 min) and retrieval of pups. On day 6, at the end of the recording of maternal behaviour, the females were also tested for maternal aggression towards a strange adult male conspecific (5‐min exposure). In absence of differences in maternal behaviour scores, FM females showed shorter latencies for retrieval of the first pup on postnatal days 2 and 4. Maternal aggression was also significantly affected by the two conditions. FM females showed higher scores of both duration and frequency of aggressive grooming, defensive upright postures, fleeing and of the number of attacks. FF females spent more time self‐grooming, crouching, and on nest. These results support the hypothesis that a series of factors, such as olfactory, tactile, and acoustic stimulation provided by the pups, the variation of maternal behaviour depending upon LGC, and the qualitative and/or quantitative variation in social interaction with the opposite sex in infancy, contribute to the broad interindividual plasticity to cope in different environmental situations.
Mechanisms of Change in the Ontogeny of Black‐tailed Prairie Dog Time Budgets
Authors: Loughry W. J.
Published: May 2010

This study examines the behavioral mechanisms underlying changes in the time allocation patterns of black‐tailed prairie dog (Sciuridae: Cynomys ludovicianus) pups. Previous analyses of time budgets had revealed substantial differences between pups (young of the year) and adults, and that pup time budgets changed significantly over time. This paper shows that these differences were due to two mechanisms: pups generally differed from adults in the frequency of performance of different behaviors; however, changes in pup behavior over time were due to changes in both bout frequencies and durations. Other influences on bout durations were also examined. Time of day dramatically affected the duration of most behaviors, with vigilance bouts longest in the morning and feeding bouts longest in the evening. The presence of a pup's mother above ground and the height of the vegetation a pup was in had much less influence on bout durations. Multiple regression analyses were used to identify other potential influences (e.g., weather and social conditions) on bout lengths. Of these, the distance of a pup from the nearest burrow produced the strongest relationships.
The Effect of Weaning Weight on Offspring Fitness in Wild House Mice (Mus musculus domesticus): A Preliminary Study
Authors: Krackow Sven
Published: May 2010

Sex allocation theory is frequently applied to mammalian reproductive traits although the basic assumptions are rarely assessed. In particular, it has been proposed that the finding of negative correlations between sex ratio (percentage males) and litter size in a variety of mammals could ultimately be seen as an adaptation according to the Trivers‐Willard hypothesis. Thereby it is supposed 1) that individual young of small litters are weaned at heavier weight than young of larger litters, 2) that this litter‐size effect on individual weights persists into adulthood, and 3) that such small weight advantages increase male fitness more strongly than female fitness. In this study, during each of 4 trials, I introduced 4 male and 4 female mice from 8 different litters of wild‐caught breeding pairs to a semi‐natural enclosure and followed up the social and reproductive events for about 10 weeks. It appeared that small weight differences attributable to litter size variation had a significant positive effect on male fitness, but not on female fitness. As the sample size was small and the social development did vary considerably between trials, this result deserves further clarification.
Two Male Types of the Common Earwig: Male‐male Competition and Mating Success
Authors: Radesäter Tommy , Halldórsdóttir Hildur
Published: May 2010

A field‐collected sample of earwigs (Forficula auricularia) showed considerable variation and a bimodal distribution in male forceps lengths. Males could be separated into brachy types (74 %) with small forceps and macro types with long forceps. Female forceps lengths and the body length distributions of both males and females were unimodal. Staged encounters between males, matched for body size but of different forceps type, demonstrated a significant advantage for macro males in aggressive interactions. In experiments with more than one male together with a female, macro type males were able to dislodge and take over females already in copula. Males of the macro type achieve both a larger proportion of the copulations and significantly longer copulations. Experiments in the laboratory, where virgin females were placed in petri dishes with males of different types, revealed no difference in latency time to copulation. Neither was there any indication of female choice before copulation in experiments where females could choose between the two male types.
Experimental Changes of Hierarchical Rank in Polistes dominulus Christ Foundresses
Authors: Pratte Michel
Published: May 2010

Behavioural profiles of Polistes dominulus foundresses were studied after changes of hierarchical rank induced by transferring wasps between trigynous associations. Females were ranked on the basis of postures adopted in dyadic encounters, while time spent by individuals on 8 behavioural items was recorded and compared. A multivariate analysis showed that behavioural profiles depended mainly on the wasps' current rank. The previously held rank had little effect on the behaviour of females concurrently having beta rank, whereas some differences were observed among alpha females depending on their previous rank. Alphas that were previously betas spent more time at the nest, but were less active there than inveterate alphas. The profile characteristics of alpha rank seem to take longer to acquire than the beta profile. It is suggested that adopting the profile characteristic of a given rank may involve first occupying the territory consisting of the nest, secondly gradually producing appropriate responses to the various stimuli emanating therefrom, and thirdly, undergoing specific physiological changes.
Weaning and Parent‐offspring Conflict: Variation Relative to Interbirth Interval in Bison
Authors: Green Wendy C. H. , Rothstein Aron , Griswold Joseph G.
Published: May 2010

Weaning and parent‐offspring conflict were examined in bison (Bison bison). Maternal care and interactions with offspring during the first year were compared between mothers that did or did not conceive 4–5 mo postpartum; unlike barren mothers, pregnant mothers ceased nursing late in the first year. Pre‐estrus nursing bouts were shorter for pregnant mothers; however, neither overall nursing time nor other forms of maternal care differed between groups. Offspring of pregnant mothers spent more time resting in Months 1–5; their grazing time also increased more slowly, suggesting higher rates of parental investment for pregnant mothers. For both groups, time spent suckling decreased due to decreasing bout frequency rather than duration. As soon as mothers differed in reproductive status, nursing time and frequency diverged dramatically, increasing for barren while decreasing for pregnant mothers. However, interactions with offspring differed little. The percentage of suckling bouts ended by calves decreased in Months 1–9 for both groups. Frequencies of rejected suckling attempts and maternal aggression increased in Months 2–4 but not subsequently. Contrary to the expectation that parent‐offspring conflict is associated with the end of nursing, maternal aggression and nursing interruptions decreased in frequency with time. Because changes in interactions were gradual, there was no clear weaning period, i.e. when maternal care decreases most and conflict increases. Such changes were greatest in Months 1–3; however, suckling continued for 6–18 mo afterward. It appears that weaning occurs gradually, through maturational changes more than through parent‐offspring conflict.
Functional Monogyny and Dominance Hierarchy in the Queenless Ponerine Ant Pachycondyla (=Bothroponera) sp. in West Java, Indonesia (Hymenoptera, Formicidae, Ponerinae)
Authors: Ito Fuminori
Published: May 2010

Social organization of the queenless ponerine ant Pachycondyla (Bothroponera) sp. was studied in Bogor, West Java, Indonesia. Colonies had no morphologically distinct queens. Worker number per colony was 11 on average. Most colonies contained multiple mated workers (gamergates), however, only one of them laid eggs, whereas additional gamergates were sterile or ovipositing at a low rate, indicating that this ant species shows functional monogyny. Some virgin workers also developed their oocytes and actually laid eggs. Ritualized dominant — subordinate behavior was frequently observed and a linear dominance hierarchy was established among workers. The topranking individual was a fertile gamergate. Sterile gamergates positioned in lower ranks and they often engaged in foraging. Among virgin workers, callows and young workers monopolized higher ranks.
When Does Previewing the Landscape Affect Pigeon Homing?
Authors: Braithwaite Victoria A.
Published: May 2010

The importance of visual landmarks during homing in pigeons (Columba livia) remains a contentious issue. Three experiments which explore the role of visual landmarks at release sites are reported here. The effects of releasing homing pigeons after a 5‐minute period in either a clear or an opaque sided release box were investigated. In the clear sided box pigeons were able to observe local surroundings at a release site, but this view was obstructed in the opaque sided box. In experiment 1 pigeons were released from familiar locations close to home (between 2 and 5.6 km): being unable to view landmarks prior to release significantly slowed homing speeds. In experiment 2 pigeons were released at familiar locations further from home (between 8.4 and 10 km): being unable to view landmarks prior to release did not significantly affect homing speeds. In experiment 3 pigeons were trained to home from distant release sites but were tested at closer, unfamiliar sites located on the likely homing routes used by the pigeons in training. No significant difference in homing speeds were observed when pigeons were released from either the clear or opaque sided box. The significance of these results for understanding the role of visual landmarks within a pigeon's familiar area is discussed.
Homing after Displacement in Open or Closed Containers by the Digger Wasp Argogorytes carbonarius (Hymenoptera, Sphecidae)
Authors: Schöne Hermann , Harris Anthony C. , Schöne Hedwig , Mahalski Pauline A.
Published: May 2010

Initial orientation and homing time were recorded in Argogorytes carbonarius after displacement in “open” and “closed” containers during two periods: “first” release dates and “later” release dates. At the later releases “closed” wasps homed much better than at first releases and better than “open” wasps. At the first releases, on the other hand, the “open” wasps homed (slightly) better than the “closed” wasps. An interpretation relates the better homing of “closed” wasps at the later trials to route learning at the first trials and discusses the differences and peculiarities of homing from familiar terrain and of home orientation by path integration.
Role of Geosmin, a Typical Inland Water Odour, in Guiding Glass Eel Anguilla anguilla (L.) Migration
Authors: Tosi Laura , Sola Carla
Published: May 2010

Odours are one of the most important cues in anadromous migration in fish, but to date the substances responsible for freshwater attractiveness are not well‐known. This is the first report on the behavioural response of a long‐range migrating fish, the eel, induced by geosmin, an odorant produced by actinomycetes, which is widely distributed in freshwater. The high sensitivity of glass eels towards very diluted solutions of geosmin, the avoidance elicited by the unnatural combination of marine salinity and earth smell, and evidence of a strong attraction as the level of salinity is reduced, indicate geosmin to be identified as an important inland water marker involved in the orientation of glass eels towards freshwater.
Female Mate Preference and Male Mating Success of Ayu Fish, Plecoglossus altivelis (Osmeridae) under a Promiscuous Mating System
Authors: Iguchi Kei'ichiroh , Maekawa Koji
Published: May 2010

The ayu, Plecoglossus altivelis, is known to show wide variation in adult body size. We examined the spawning behavior in experimental spawning groups of fish in which male body size varied. Males never competed with each other for females or spawning site, while females spawned repeatedly, 17–97 times depending on body size, with previous or novel males. Males exhausted their sperm after a single mating episode, on average, regardless of body size. Moreover, repeated sperm production apparently reduced the residual lifespan. Females preferred mating simultaneously with more than one male and allowed males of body size similar to their own to mate more frequently. Thus the largest male within a spawning group was not always the most successful at mating, but mating success of any given male appears to depend upon body size distribution of females within the population. Female mate preference has apparently evolved to ensure complete fertilization under circumstances where males have been selected to economize sperm output during any one mating episode.
Mate Choice by the Male Convict Cichlid (Cichlasoma nigrofasciatum; Pisces, Cichlidae)
Authors: Nuttall Daniel B. , Keenleyside Miles H. A.
Published: May 2010

The influence of standard length (SL) and maximum body width on the attractiveness of female to male convict cichlids was examined in a choice apparatus. Preliminary experiments showed that maximum body width (abdominal swelling), ovary mass and ovary volume of females increased significantly over the 7‐d post spawning period. Variation in body width explained a moderate amount of the variation in ovary mass and volume. Therefore, body width is a suitable indicator of gravidity. Male convict cichlids were offered a simultaneous choice between two females that varied in standard length (SL) and/or gravidity. Choice was determined by amount of time the male spent near each female. Males chose the larger of two females when both were gravid but showed no choice when neither was gravid. In general, males chose the gravid female when one was gravid and the other was not, regardless of the difference in SL between them. Choice of female by males was not influenced by female behaviour in the test apparatus. We suggest that mate choice by convict cichlid males is based primarily on female gravidity and secondarily on female SL.
Nest Site Quality, Female Mate Choice, and Polygyny in the House Wren Troglodytes aedon
Authors: Johnson L. Scott , Searcy William A.
Published: May 2010

Many models proposed to explain the occurrence of polygyny in birds implicitly assume that females actively choose males offering the highest quality breeding situations. However, strong evidence of active mate choice by females in polygynous bird species is scarce. This study asked whether females in a polygynous population of house wrens Troglodytes aedon, a small, cavity‐nesting songbird, base their choice of a mate at least partly on characteristics of the nest site that he controls. Already‐mated males were randomly assigned one of two types of nest boxes to which they could attempt to attract secondary mates. Some males were given standard‐type boxes with small entrance holes in the front sides of boxes, while other males were given boxes with larger entrance holes located in the boxes' roofs. A preliminary experiment revealed that female house wrens overwhelmingly prefer front‐entrance to roof‐entrance boxes when both types of boxes are available on the same territory. Females chose mated males with front‐entrance boxes over mated males with roof‐entrance boxes significantly more often than expected by chance. This preference demonstrates that female house wrens do discriminate among potential mates and base their choice of a mate at least partly on characteristics of the nest site he has to offer. This observation is compatible with the hypothesis that female house wrens choose mated males because they gain access to high‐quality nest sites.
Acoustic Dueling in Tarbush Grasshoppers: Settlement of Territorial Contests via Alternation of Reliable Signals
Authors: Greenfield Michael D. , Minckley Robert L.
Published: May 2010

A field study of disputes over ownership of mating territories by male tarbush grasshoppers (Ligurotettix planum) revealed that most contests were settled ritualistically via the antiphonal exchange of acoustic signals. Males used a special aggressive signal, referred to as the “shuck” call, in these encounters. Individuals that never produced shuck calls invariably departed the contested sites, and a playback experiment showed that shuck calls elicited higher response levels from males than sexual advertisement calls. Approximately 1/5 of all territorial contests escalated to biting, grappling, or kicking.

The outcomes of territorial contests that were settled via purely acoustic encounters could not be predicted by the size of the participants. Prior residency was a predictor of winning in some contests, but often the competing males did not possess clear intruder/resident roles. However, a signal parameter that was a combined measure of the rate of shuck calls and their mean length predicted the winner of most acoustic encounters. Contests that escalated, though, were generally distinguished by participants that displayed comparable measures of all signal parameters save call length. A tradeoff occurred between call rate and length in most individuals. This, as well as the finding that call length did predict winning in escalated contests, implies that these signal parameters may reflect an individual's strength or motivation.

Contests in which the signal parameters of the males were similar tended to be prolonged and escalated. This relationship suggests that individuals assess the signals of their rivals and depart if they cannot match their call rate and length. That both call rate and length are assessed may enhance the reliability with which signals can be used to predict a rival's fighting ability in the event of escalation. Various simple mechanisms for signal assessment are proposed.

A second playback experiment suggested that the insects heard less effectively while they called. Timing mechanisms that preclude the overlap of calls during contests occur, and they may have evolved because of the importance of precise assessment of the signals of rivals. Such mechanisms circumvent the potential impairment in perception noted above and also generate a conspicuous feature of L. planum contests — mutual alternation of signals.
The Play Associations of Red‐necked Wallabies (Macropus rufogriseus banksianus) and Relation to Other Social Contexts
Authors: Watson Duncan M.
Published: May 2010

The partner preferences of a captive group of red‐necked wallabies (Macropus rufogriseus banksianus) during playfights were determined and the patterns of social relations formed compared to those in other social contexts. Wallabies preferred play‐partners of the same sex and of similar age and dominance status. Young males were most likely to initiate play. Females engaged in play almost exclusively with subadult males and, in particular, their male offspring. Play between females was not recorded. In play between males from different age classes, initiation and termination was independent of age. Termination was dependent on who initiated the interaction: initiators were less likely to terminate playfights than were recipients. Wallabies that had recently vacated the pouch were not the focus of social play in the colony.

Agonistic interactions also occurred most often between wallabies of the same sex and similar age and dominance but older males were most likely to initiate interactions. Initiation and termination of agonistic interactions was age‐dependent: older wallabies almost always initiated and won encounters with younger partners. There was no correlation among male dyads between their rates of play and agonistic encounters, dominance reversals were more common in play than in agonism, and the patterns of wins and losses in play and agonism were not correlated. There was some suggestive, but inconclusive evidence that the proportion of time males spent in close proximity at food and water troughs was positively correlated with their rates of play and negatively with their rates of agonistic interactions. There was also some evidence that males that played together often had more frequent affiliative interactions than those that did not. However, there was no correlation between rate of play by males and the proportion of time they spent resting together. These results suggest that the function of social play in the wallabies was motor training and not socialization. In addition, they indicate that play and agonism are causally‐distinct categories of behaviour. Based on this interpretation, the relationship between play and serious fighting in macropods and in eutherian mammals is discussed.
Do Brown Hares Signal to Foxes?
Authors: Holley Anthony J. F.
Published: May 2010

Of a total of 32 sedentary brown hares (Lepus europaeus) approached across open ground by foxes (Vulpes vulpes), 31 reacted when the fox was 50 m or less from them by adopting a bipedal stance directly facing the fox. Of five sedentary hares approached by foxes from nearby cover, none stood, three moved away and two adopted the squatting (primed for movement) posture. Hares stood before foxes in all heights of vegetation and on 42% of occasions were solitary. Hares did not stand before approaching dogs (Canis familiaris). The functions of this behaviour are considered and competing hypotheses of Predator Surveillance and Pursuit Deterrence are examined by testing predictions against results obtained. The results suggest that by standing erect brown hares signal to approaching foxes that they have been detected.
The Costs of Male Display and Delayed Plumage Maturation in the Satin Bowerbird (Ptilonorhynchus violaceus)
Authors: Collis Ken , Borgia Gerald
Published: May 2010

The costs associated with the evolution of male display traits has attracted much attention in regard to the type of traits that evolve and the timing of their expression. We investigate these costs by using testosterone implants to alter the development of male display traits in the satin bowerbird (Ptilonorhynchus violaceus). Testosterone implants advanced the development of adult display traits in males with juvenile plumage. We then measured the costs of early expression of these characters in treated males. Testosterone implants caused young males to (1) become more involved in behavior normally carried out by older males when visiting bowers, (2) build bowers, and (3) molt prematurely into an adult plumage. No difference was observed between the testosterone‐treated birds and controls in return rate or condition the year following treatment, suggesting that the physical costs of display are not high. We found that males in adult plumage are tolerated less, and are not displayed to as frequently as juvenile plumage males at the bowers of established bower holders. The causes of delayed plumage maturation are most consistent with the facilitated‐learning hypothesis. That is, early development of adult characteristics reduces the opportunity of young males to learn display behavior critical for later reproductive success.
Load Size Variation in the Eastern Chipmunk, Tamias striatus: The Importance of Distance from Burrow and Canopy Cover
Authors: Bowers Michael A. , Ellis Anthony
Published: May 2010

We examined the degree to which chipmunks foraging from dishes containing sunflower seeds varied cheek pouch load size according to both travel time (distance from burrows) and predation hazard (canopy cover). Results showed that larger loads were taken under cover at some distance from burrows than were taken from closer or more open sites. Distance effects appeared to reflect the influence of traveling times on quitting harvest rates as predicted by central place foraging models. Quitting harvest rates also appeared to be higher under low than under dense canopy cover; this trend was most pronounced at some distance from burrows suggesting that foraging decisions were made relative to both energetics and predator avoidance. Chipmunks appeared to employ a patch exploitation strategy that minimized the hazard:gain ratio.
Randomness in Ontogeny. On Antennal Grooming in the Milkweed Bug Oncopeltus fasciatus
Authors: Jander Ursula , Jander Rudolf
Published: May 2010

Milkweed bugs (Oncopeltus fasciatus, Lygaeidae) groom the distal segment of each antenna between the tibial combs of both forelegs. Variable numbers of grooming strokes compose a grooming bout. A total of 112 spontaneous grooming bouts, comprising all developmental stages, were videotaped, the angular movements of the forelegs were digitized, and the outcomes computer‐analyzed. Individual strokes of forelegs were measured by their angular amplitude and mean angular elevation. These two measures are randomly combined in the first instar and then differentiate during ontogeny into two distinct types: small amplitude strokes of high average elevation and large amplitude strokes of lower average elevation. The sequencing of small and large strokes within bouts is largely (97%) random in all developmental stages. The outcome of the analysis fits the general empirical rule that premature action patterns are more random than mature ones. Some traits do not follow this rule and are persistently highly random. It is suggested that excessive randomness in premature behavior is due to genetic underdetermination, and that incorporation of non‐genetic information helps to specify the less random mature behavior. Developmentally persistent behavioral randomness is explained by the behavioral‐entropy principle: traits in behavior vary randomly unless randomness is selected against.
Self‐reinforced Behaviour Does not Explain Contra‐freeloading in the Mongolian Gerbil
Authors: Forkman Björn A.
Published: May 2010

In various situations animals prefer to work for food even when free food is available. Several hypotheses have been put forward to explain this phenomenon, most of them either suggesting that a learned behaviour may be self‐reinforcing or that the animal has to perform a certain species specific behaviour.

Mongolian gerbils (Meriones unguiculatus) were used in the present study. Half of them were given access to a cage with one bowl with sunflower seeds, and another bowl with sand and 30 seeds, 20 min/d for 5 d. The amount of seeds eaten from each bowl and the time spent digging in the bowls, on the floor, and in the corners was recorded. The animals were then put in the same cage with one bowl with seeds but the other bowl now contained only sand (20 min/d for 5 d). For the other group the treatment was reversed.

Almost all digging took place in the 30 seed bowl, and most seeds eaten were taken from this bowl. When this bowl contained only sand the amount of digging went down drastically for that bowl. Nor was there any compensatory digging on the floor or in the corners of the cage.

The present results indicate that the self‐reinforcing hypothesis and the obligatory species specific response hypothesis are not enough to explain the contra‐freeloading phenomenon. A possible alternative hypothesis, that the behaviour is a way of exploring and reducing uncertainty is discussed.
Ecological and Behavioral Aspects of Nest Building in Wild Bonobos (Pan paniscus)
Authors: Fruth Barbara , Hohmann Gottfried
Published: May 2010

Data on nest building behavior were collected from free ranging bonobos (Pan paniscus). Considering the physical features of both nests and trees used for nest construction, bonobos appeared to show various preferences: (1) Trees with small leaves were chosen more frequently than expected; (2) The majority of nests were constructed in trees of the middle forest layer (15 to 30 m) and at a mean height of 16 m; (3) nests built during the day were located higher than night nests and differed in the general mode of construction (number of trees involved). Comparing nests made by mature males and females it became apparent that females (4) built nests higher, (5) constructed day nests more frequently and (6) used them for a longer time than males. Comparison of data collected at different study sites indicates site‐specific differences concerning selection of trees and location of nesting sites. Behavioral observations made clear that nests were not only used for rest but also for other activities like feeding, social grooming and play. Moreover, the study provided the first evidence that bonobos build nests also in order to avoid potential or imminent conflicts with other party members. Field observations indicate that these nests symbolize a taboo zone and show another facet of the social abilities of bonobos for the solution of intra group conflicts. It is suggested that this behavior derives from the spatial intolerance shown by females during the process of weaning.
Determinants of the Mating Success of Polyterritorial Pied Flycatcher Males
Authors: Rätti Osmo , Alatalo Rauno V.
Published: May 2010

Much attention has been paid to the polyterritorial mating system of some passerine birds. Here we report how a male's mating success is related to the behavioral traits of polyterritorial pied flycatcher (Ficedula hypoleuca) males. We found no evidence that the timing of polyterritoriality in relation to egg laying in the primary nest or the singing behavior of males have any influence on mating success. However, results show clearly that male mating success was improved with an increase in the distance between territories up to a distance of about 200–300 m whereupon there was no further enhancement of mating success. This finding is crucial for both the deception hypothesis and female‐female aggression hypothesis which have been put forward to explain polyterritorial polygyny. Males who establish a distant second territory seemed to allocate more time to singing there. The association, although weak, between singing activity and distance between territories makes it more difficult for females to use song rate as a cue to discriminate males with a secondary territory far from the primary territory, and these are the males that are least likely to feed the young of a second female. Males who established a second territory late in relation to egg laying in the primary nest did not take over a close second territory as might be predicted from female‐female aggression hypothesis.
Condition‐dependence and Sex Traits in the Male Great Bustard
Authors: Carranza Juan , de Trucios Sebastián J. Hidalgo
Published: May 2010

Secondary sex traits involved in the courtship display of the male great bustard (Otis tarda) are analyzed in the light of condition‐dependence theory. Heaviest males at the start of the mating period further gained about 30% in body mass. Both display performance and development of morphological traits involved are mainly determined by body mass. Males who developed sex traits were among those in good physical condition, although not the current physical condition but weight of the male correlates with the development of sex traits. We discuss the idea that weight may be a good indicator of overall physical condition during development up to maturity, rather than just the current condition at a given season. Our results show a discontinuity both in display performance and in the development of morphological traits — i.e. birds of weight below a certain threshold neither performed the display nor fully developed the secondary sex traits. This constitutes evidence of cost reduction by males when expected benefits from mating are low, and is consistent with the viability‐conditioned expression of the traits.
Stages in Formation of Social Relationships — An Experimental Investigation in Kangaroos (Macropodoidea: Mammalia)
Authors: Ganslosser Udo
Published: May 2010

A stage concept for the development of social relationships between unfamiliar individuals has been proposed by Kummer. This concept, originally derived from studies of Old World Primates, describes changes in developing relationships by types of interactive behaviour (fighting, presenting, mounting and grooming) that regularly occur in this sequence during the formation of dyads and triads. Kummer also formulated a set of rules predicting stage sequence, velocity, final stage, triadic and polyadic influences depending on individual status.

The present investigation describes stages in the formation of relationships of macropodoids as well. Typical behaviour patterns for the sequence are avoidance, social exploration, aggression, one‐sided amicable behaviour, mutual amicable behaviour and in some species social play. Transition to new, especially nonaggressive stages, was found to be initiated by higher status animals. Duration, number of skipped stages, inversions (rare events!) and highest stage reached per dyad depend on the participants' status and triadic/polyadic influences, as predictable by Kummer's proposed rules.

A comparison of 3 species demonstrates the influence of socio‐ecological factors that seem to be species‐characteristic. The stages can thus be used to describe not only different qualities of individual relationships but also ‘social dispositions’ sensu Mason.
Waving Display in Females of Uca polita and of other Australian Fiddler Crabs
Authors: von Hagen Heinrich‐Otto
Published: May 2010

Since 1979 it is known that, in Australian species of Uca, female waving exists in addition to usual male display. The present paper deals mainly with female waving in U. polita studied in Darwin (North Australia). A few remarks on U. dampieri, U. vomeris, U. seismella and U. hirsutimanus are added. The species mentioned are members of two species groups or subgenera, which characterizes female waving as an ancestral (plesiomorph) trait.

Frame by frame analysis of film sequences (open air shots) indicate homology of movements in the two sexes of U. polita. As in males, waving of females can be combined with locomotion on radial paths starting from the burrow entrance and the display is performed in series with a corresponding number of gestures. Unlike males, waving females mostly use both their chelipeds and tend to show shorter durations with regard to many of the waving parameters chosen. However, significant differences refer only to a limited number of parameters.

The biological context of female waving was gathered from films and field observations. High intensity waving is released by conspecifics approaching from far (wanderers without burrows) and from the neighbourhood. Typically, only females and small males elicit high intensity display in a resident female. Waving normally stops in presence of larger males, especially of the male living in a resident breeding unit with the female in question.

In spite of this, a pure agonistic (defensive) character of female waving is unlikely. Advertising of breeding condition seems to play a role similar to that in males. The few displaying females that exist in a given colony (about 2.5% in U. polita) show signs of special sexual excitement: brightening of carapace colours and sometimes spontaneous performance of waving, i.e. display immediately after emergence from the burrow in absence of any conspecific.
Population Differences in Responses of Fathead Minnows (Pimephales promelas) to Visual and Chemical Stimuli from Predators
Authors: Mathis Alicia , Chivers Douglas P. , Smith R. Jan F.
Published: May 2010

Fathead minnows (Cyprinidae: Pimephales promelas) from a population that is sympatric with predatory northern pike (Esocidae: Esox lucius) exhibited a fright reaction to the visual stimulus of a live northern pike significantly more often than minnows from a population that is allopatric with pike. The fright response included increased use of shelter, dashing and freezing. Minnows from the pike‐sympatric population also exhibited a significantly greater fright response, measured as a reduction in activity, following exposure to chemical stimuli from pike (i.e. water from a tank that had contained a pike) than did minnows from the pike‐allopatric population. There was no significant change in activity by minnows from either population following exposure to chemical stimuli from nonpiscivorous peacock gudgeons (Eleotridae: Tateurndina ocellicauda), suggesting that the difference between the two populations is specific to stimuli from pike rather than a general difference in response to chemical stimuli from heterospecific fishes. Fathead minnows apparently utilize at least a two‐tiered predator recognition system that incorporates both visual and chemical cues.
A Quantitative Analysis of Secretion‐Grooming Behaviour in the Water Bug Plea minutissima Leach (Heteroptera, Pleidae): Control by Abiotic Factors
Authors: Kovac Damir
Published: May 2010

The pigmy backswimmer, Plea minutissima, from time to time leaves the water to apply its antimicrobial metathoracic gland secretion to its water‐repellent ventral pubescence (“secretion‐grooming”) which is enclosed by an air sheath when submerged and has a respiratory function. Secretion‐grooming keeps the hairs free of microbial contamination and thus hydrophobous and functional. The grooming behaviour is regulated by abiotic factors. It is released by an increase in light intensity or water temperature, with a sudden rise in temperature being particularly effective. The higher the temperature and light intensity, the faster the grooming act is performed and completed. The grooming motivation is higher at a higher ambient temperature, but declines once the behaviour has been brought to completion. As a consequence the highest grooming activity in the field is observed in summer on the first sunny day after a prolonged period of overcast days. The tying of secretion‐grooming to abiotic factors probably serves to destroy epizoic microorganisms before they begin to multiply more rapidly at higher temperatures. The mechanisms regulating the secretion‐grooming behaviour of Plea may be of significance also for the regulation of certain other insect behaviours (e.g., flight behaviour).
Social Structure and the Development of Helping Behaviour in the Bell Miner (Manorina melanophrys, Meliphagidae)
Authors: Poiani Aldo
Published: May 2010

The hypothesis that bell miners (Manorina melanophrys) improve their alloparenting skills during the period spent as helpers was tested by means of comparing: a) the frequency of nestling care activities, b) the frequency of nestling attendance “mistakes”, c) the gizzard contents and items brought to nestlings, and d) interactions at the nest with the breeders, for helpers of different ages. Results show that young birds made fewer feeding visits to the nestlings and made more empty (i.e. non‐feeding) visits than older helpers. The few “mistakes” detected were also made by young helpers. The proportion of food items brought to the nestlings consisting of arthropods was smaller for very young helpers (≤ 3.8 months) than for older helpers. Sexually mature helpers also had relatively more arthropods than psyllid sugary covers (a food item very easy to locate and capture) in their gizzards than immatures in winter, but this difference was marginally not significant.

Young helpers must learn their place within the group hierarchy, but no clear division of labor in the alloparental activities studied was detected, which might have increased the effect of learning during the period birds spent as helpers.
Social Organization of a Maternity Group in the Noctule Bat, Nyctalus noctula (Chiroptera: Vespertilionidae)
Authors: Kozhurina Eugenia I.
Published: May 2010

Social organization of a captive group of noctule bats, N. noctula, was studied by frequent censuses of bats at roost sites during one summer season. Numerous nonrandom associations as measured by information indices of similarity (Kullback 1959; Semkin 1972; Zakharov et al. 1987) were found between related and unrelated individuals. The social group structure revealed by multidimensional scaling analysis was affected first of all by the history of group formation, and also by bat age and sex. Spatial bonds were in general stronger between related than unrelated bats. However, nearly all closest associations observed were formed by at best distantly related bats; family membership influenced the socio‐spatial positions of noctules far less than the above‐mentioned variables did. It is suggested that emergence and persistence of nonrandom associations is mainly due to individual attainment of a certain level of comfort in company of familiar conspecifics whose behaviour is predictable, and thus reduction of aggression within a group. Other benefits of stable associations would be derived from this primary function.
Communal Roosting of Wintering Red KitesMilvus milvus(Aves, Accipitridae): Social Feeding Strategies for the Exploitation of Food Resources
Authors: Hiraldo Fernando , Heredia Borja , Alonso Juan Carlos
Published: May 2010

Social feeding strategies of wintering red kites are analyzed in relation to age, food, roost‐sites and differences from kite residents. Whereas young and adult wintering kites gathered at roost sites almost daily, adult residents did not, and immature residents only occasionally. Kites using roost sites feed more often on prey prelocated by others, while lone roosters also forage and discover food alone. After finding food, kites tend to shift to a new roost site and foraging area. Two details of the ‘information centre’ hypothesis are confirmed in our study: carcasses are unpredictably found patches, divisible between several individuals. But carcasses disappeared fast in the study area, and no increase with time in the number of birds consuming a carcass was observed, so that information transmission was unconfirmed. When kites leave the roost in groups no leader is detectable. It seems that other types of social foraging are operating, and the model best matching our results is network foraging.