bluuebunny/crossref_metadata_2025_split huggingface dataset:
Do Female Red‐winged Blackbirds Engage in a Mixed Mating Strategy?
Authors: Westneat David F. 
Published: May 2010

AbstractParentage analyses of broods of nestling red‐winged blackbirds (Agelaius phoeniceus) revealed that extra‐pair fertilizations (EPFs) accounted for 24% of the offspring. 8% of attempted copulations and 13% of male courtship displays during observations of focal females were by extra‐pair males. In addition, mates and non‐mates often chased and occasionally made physical contact with females; 34% of those chases in which contact was made were extra‐pair chases. Females behaved variably during both within‐pair and extra‐pair events; females crouched less and resisted more frequently during extra‐pair courtship than during within‐pair courtship. All extra‐pair events, whether natural or induced by male removal, were either resisted or accepted by the female. In 318 focal female‐hours of observation during the fertilizable period, no female was ever seen in another male's territory soliciting a copulation. In addition, removal of females' mates resulted in frequent extra‐pair courtship and copulation; all of these occurred on the removed male's territory. Some females left their mates' territories on occasion — these forays were nearly always off the study area, no female was ever seen copulating with an extra‐pair male while on these forays, and neither the frequency nor the duration of female forays correlated with the frequency of extra‐pair fertilizations within broods. There were no associations between extra‐pair fertilizations and female age, settlement order, nest order, or clutch size. The number of fledglings produced from a nest was significantly positively associated with the number of sires of the brood. Fewer offspring apparently starved in broods that were multiply sired, yet males did not provide courtship feedings during either within‐pair or extra‐pair copulations, nor was any paternal care provided to young sired through extra‐pair matings. The frequency of infertile eggs was low (< 1%); in those instances of infertile eggs the territory owner sired some young in the same nest or another nest on his territory. Fewer broods were a mixture of within‐pair and extra‐pair paternity than expected by chance. Clear evidence implicating a mixed strategy on the part of females could not be gathered. Because females behaved variably and because not all costs and benefits to females of extra‐pair copulations could be measured, it remains possible that female behavior patterns are either (1) part of a mixed strategy, or (2) part of a strategy minimizing the costs of copulation.
Variability of Forage Pecking in Pigeons
Authors: Siemann Martina , Delius Juan D. 
Published: May 2010

AbstractThe pecking of birds has been classically considered a fixed action pattern that is little modified by varying internal and external circumstances. Although recent research has documented several instances of variability, the stereotypy of pecking by pigeons continues to be stressed. The present study illustrates the adaptability of the response employing an accelerometric/videographic technique. It is demonstrated that it is influenced by several experimental conditions mimicking natural contexts. The effects of admixture of non‐nourishing grit, non‐removability of food items, degree of deprivation, application of head loads and grain size, on the detailed course of pecking are described. A number of different, recurring types of pecking patterns were recognized but even within these the frequency, timing, extent, speed, and/or vigour of several component movements varied specifically in response to the various experimental treatments. Appreciable inter‐ and intraindividual variations still occur under identical conditions. In conjunction with additional evidence it is concluded that the pecking of pigeons exhibits a remarkable flexibility that conforms poorly with a fixed action pattern characterization. Accelerometry promises to be an efficient and economic aid in the analysis of the sensory, neural and motor mechanisms of avian pecking.
Courtship Activity of Wandering and Burrow‐holding Male Uca arcuata
Authors: Murai Minoru 
Published: May 2010

AbstractThe male of Uca (Deltuca) arcuata, a vertical claw‐waving fiddler in the Indo‐Pacific, is used to court females by approaching them from his burrow or while wandering. Differences in the rate of encounters with females between burrow‐holding males and burrowless wandering males are found not to be significant. Burrow‐holding males less often cause displacement of wandering by females than wandering males do. Wandering of females caused by wandering males occurs as often as wandering of males caused by other males. Thus, burrow‐holding males tend not to reduce the number of their potential mates in the neighborhood.Burrow dwelling males are apt to start wandering after decreased encounters with females. Wandering males experience more interactions with other males than burrow‐holding males do. Most wandering males that displace burrow owners descend the burrows one or more times after displacing the owners. The extra fighting for temporary burrows is responsible for no increase of the encounter rate with females during wandering.
Experimental Evidence that a Desert Parasitoid Keeps its Host Cool
Authors: Ward David , Henschel Joh R. 
Published: May 2010

AbstractThe wasp parasitoid Pseudopompilus humboldti (Hymenoptera; Pompilidae) in the Negev desert of Israel stores its paralyzed host, the spider Stegodyphus lineatus (Araneae; Eresidae), at the entrance of the spider's nest. The spider is moved by the wasp from the depth of the nest to the entrance in spite of increased exposure to visually‐searching predators, such as birds. We examined the hypothesis that this behaviour has evolved to prevent the wasp's host from overheating in this hot desert. Experimental manipulations of the position of the parasitized spiders demonstrated that spiders and wasp larvae could not survive the heat experienced deep in the spider's nest during summer. By contrast, in the cooler nest entrance, spiders and larvae survived, if they were overlooked by predators. This host‐storing behaviour is an adaptive trade‐off between thermoregulatory requirements and predation risk. This appears to be the first evidence that a parasitoid manipulates the temperature of its host, albeit for its own ultimate gain.
Basking and Antipredator Behaviour in a High Altitude Lizard: Implications of Heat‐exchange Rate
Authors: Carrascal Luis M. , López Pilar , Martín José , Salvador Alfredo 
Published: May 2010

AbstractThis paper presents an observational and experimental study of the basking behaviour and heat exchange rate of the montane lizard Lacerta monticola. The results obtained by these procedures were coupled in order to understand behavioural mechanims promoting effective thermoregulation at high altitudes. Heating rate was higher when body size was smaller, and substrate temperature and sun rays incidence angle were higher. The lizards cooled faster when body size and substrate temperature were lower, and when the body temperature of the lizard going into shadow was higher. Time exposed to sun and mean duration of basking periods were longer early in the morning, while bask frequency increased through the morning. Our results suggest that time devoted to basking is mainly obtained by regulating bask duration. Lizards obtained the necessary time for heating by means of long basking periods. Mean travel distance per minute and distance to the nearest refuge increased from early morning to midday. These behavioural variables were tightly correlated with the expected heating rate of individuals. Body size affects thermoregulatory behaviour as well as locomotor activity. Juvenile lizards, with small body mass and high surface‐to‐volume ratios, were subjected to faster heating and cooling rates, basked more frequently than adults (but during shorter periods), and devoted more time to locomotion than adults. The thermoregulatory behaviour of L. monticola is the result of the combination of shuttling heliothermy by basking and the exploitation of thermal opportunities offered by patches in shade through thermal exchange with the substrate.
Signalling of Nutritional Need by Magpie Nestlings
Authors: Redondo Tomás , Castro Francisca 
Published: May 2010

AbstractThe relationship between begging behaviour, chick nutritional state, and parental distribution of food within broods was studied in 4‐ and 5‐chick magpie Pica pica broods under natural conditions. Three components of the begging display (duration, latency, and posture) were highly correlated with each other and also with the emission and duration of begging calls. Begging performance was strongly influenced by the food intake of nestlings during the preceding 1‐h interval, indicating that begging may reliably reflect the nutritional need of nestlings. Daily growth during the preceding day, as well as average cumulative food intake by the brood during the preceding 24 h, seemed not to affect begging in a similar way. Begging signals employed by hungrier nestlings involved a higher degree of muscular activity, thus supporting the prediction that nestlings in greater need should employ more costly signals. Overall, those nestlings who begged more tended to obtain more food, but the relationship between feeding success and begging behaviour was weak due to a high variation between broods in the way that parents seemed to respond to variations in begging behaviour. Possible causes for this variation, and its implications for the evolution of reliable begging displays, are discussed.
Influence of Unrewarded Stimuli on the Classification of Visual Patterns by Honey Bees
Authors: Ronacher Bernhard 
Published: May 2010

AbstractBees were trained to discriminate visual patterns in five experiments. The rewarded pattern (S+), was a 50‐mm black disc in all experiments; the unrewarded pattern (S–) was varied. Subsequently bees were given a choice between different stimuli in order to discover what bees learnt about five attributes of the training stimuli. The attributes tested were size, contrast, color, ‘compactness’ vs. ‘dissectedness’ (tests with ring‐patterns), and presence or absence of acute points (tests with discs, squares, triangles and stars). The significance of these attributes varied with the particular unrewarded pattern (S–) used in training (Figs. 1, 2). This is interpreted as a modification of the bee's selective attention to certain features during training. The results also indicate a difference in the salience of attributes. Differences in size or outline (presence of acute points) only influenced the bee's preference after a training that specifically required this distinction, while differences in contrast, colour and dissectedness were also significant when the training stimuli did not differ in that respect.
Power to Hold Sheltering Burrows by Juveniles of the Signal Crayfish, Pasifastacus leniusculus
Authors: Ranta Esa , Lindström Kai 
Published: May 2010

AbstractJuveniles of the signal crayfish reside during daylight hours in shelters. At twilight they leave for food, at daybreak they either return or find another shelter. We examined conflicts over burrow ownership. At low densities with equal numbers of shelters and crayfish 1/5 of the burrows were occupied. Increasing both the number of crayfish and shelters improved the occupancy close to 50%. Doubling the number of crayfish in relation to the number of shelters increased the occupancy up to 75%. In an experiment with 30 randomly selected crayfish and 15 sheltering holes available the burrow holders were about 1–2 mm longer in carapace length than those found freely moving in the aquarium. Shelter owners were rarely newly moulted individuals.Size asymmetry (2 mm difference in carapace length) between owner and intruder affected the outcome of the contest over burrow ownership. When intruders were larger than owners, takeovers occurred in about 80% of the cases tested. If the owner was large and the intruder small the takeover frequency was about 20%. When the owner and the intruder were of matching size takeovers were still observed in about 45% of the cases. The outcome of the ownership contest has a true meaning. In a nursery‐pond experiment, where low‐protein food was randomly scattered all around, no size differences were found in carapace lengths of crayfish juveniles residing in different shelters. However, when high‐protein food was introduced in a single spot, owners of burrows were significantly larger and more numerous in the nearby shelters than in the shelters furthest away from the food source. Therefore, when food is unevenly distributed the burrow ownership contests may potentially lead to size asymmetries between individuals. This may lead to large individuals nearby the food growing faster than small individuals further away from the food source, a process likely to further enhance size differences.
Calling Behaviour Influences Mating Success in Male Painted Reed Frogs, Hyperolius marmoratus
Authors: Passmore Neville I. , Bishop Phillip J. , Caithness Neil 
Published: May 2010

AbstractA detailed study was made of the natural calling behaviour of male painted reed frogs in the wild. Comprehensive minute by minute records of the vocal activity of males calling simultaneously in the breeding chorus were generated over a 19‐night period using a multi‐channel event recorder. With few exceptions, the period over which males called either spanned or extended beyond the time window when females sought mates in the chorus. Males varied little in calling persistence and the majority produced advertisement calls during each minute of the calling period. Aggressive interactions between males curtailed advertisement call production but fights were short‐lived, seldom repeated and limited to a small proportion (12.6%) of males. Call rate was independent of body size and varied widely among males active in the chorus at the same time and under the same environmental conditions. The relative call rate ranks of individuals were sustained over time. The call rates of mated males were high in relation to the rates of other males monitored in the chorus at, and prior to, the time of mating. Females usually preferred the higher of two call rate alternatives presented in a range of two‐choice phonotaxis experiments.
Absence of Mate Guarding in the Yellowhammer (Emberiza citrinella)?
Authors: Sundberg Jan 
Published: May 2010

AbstractThe mate guarding behaviour of male yellowhammer (Emberiza citrinella) was studied with special reference to the effects of age, body size (tarsus length) and coloration of males. Measurements of intra‐pair distance do at the most provide evidence for relatively lax mate guarding. On the other hand, patterns of male song activity and inter‐male aggression were more in agreement with the predictions of the mate guarding hypothesis. The reasons for the comparatively low mate guarding intensity in the yellowhammer may be that males do not need to guard their mates intensely. Age differences were found in song and aggressive activity, older males singing and fighting the most. Size had no effect on guarding behaviour. Coloration was correlated with inter‐male aggressiveness and conflict initiation propensity. Less colourful males fought the most in the pre‐fertile period of their mates, whereas colourful and old males fought the most during the fertile period. This suggests that coloration may be an indicator of individual fighting and guarding ability.
Cooperative Territorial Defense in the Australian Magpie, Gymnorhina tibicen (Passeriformes, Cracticidae), a Group‐living Songbird
Authors: Farabaugh Susan M. , Brown Eleanor D. , Hughes Jane M. 
Published: May 2010

AbstractComparison of populations that vary in cooperative behavior can point to factors that influence the evolution of cooperative breeding. In this paper we study cooperative territorial defense in two populations of the Australian magpie. These populations differed in social organization; in New Zealand group breeding was the norm and in Queensland simple pair breeding was the norm. We used caged territorial intruders to examine experimentally the participation of males, females, and juveniles in synchronous territorial defense. Within a population in Queensland and a population in New Zealand, adult males and females participated in cooperative defense significantly (p < 0.05 at least) more often together than alone. Between populations, Queensland pairs differed significantly (p < 0.01 at least) from New Zealand pairs in the level of response. As group size increased, percapita input in defense decreased in both populations. We discuss the importance of synchronous defense as a cooperative behavior in this species.
Mother‐Offspring Relationship in the Vicuña, Vicugna vicugna (Mammalia: Camelidae)
Authors: Vilá Bibiana L. 
Published: May 2010

AbstractThe vicuña mother‐offspring bond was studied during the calves' first and third months of life. Pairs kept in field and corral conditions allowed to compare mother‐offspring relationships between animals with and without management. Vicuñas belong to the “follower type” in the classic distinction among ungulate species between “followers” and “hiders”. In the field, mother‐offspring distances were small during the first month then increased. In the corral, mother‐offspring distance was greater than in the field in the first month and did not vary with age. In the third month, in both “conditions” mothers tended to avoid their calves more than in the first month. Although calves initiated approximately 90% of nursing bouts during both periods, the percent terminated by the mother was significantly higher in the third month than in the first (96% to 59%). The calves increased their grazing time from a few scans per h in the first month to half the sample period in the third month. The mother‐offspring bonds showed some quantitative differences between field and corral, but in both “conditions” the mothers nursed their calves successfully.
Colony Member Discrimination by Juvenile Columbian Ground Squirrels (Spermophilus columbianus)
Authors: Hare James F. 
Published: May 2010

AbstractKin discrimination mechanisms allow the maximization of inclusive fitness via kin‐differential behaviour. Previous studies of kin discrimination in ground squirrels (Spermophilus spp.) have concentrated on the proximate mechanisms by which kin are discriminated from non‐kin. Few studies have examined the extent to which kin discrimination is expressed among free‐living squirrels, and none have examined the relative strength of potential alternative levels of social discrimination (i.e. kin, neighbour, group member).To elucidate the level at which juvenile Columbian ground squirrels (Spermophilus columbianus) discriminate among conspecifics, dyadic interactions between otherwise free‐living littermates, neighbours, non‐neighbouring members of the same colony, and individuals from two different colonies were staged in a neutral arena. Similar levels of cohesive and agonistic behaviour, and similar inter‐individual distances were recorded for all intra‐colony dyads while interactions between non‐colony members were characterized by decreased cohesion, increased agonism, and greater inter‐individual distances. The results suggest that siblings are not discriminated from nonsiblings, but that colony members are discriminated from members of other colonies.Although the functional significance of colony member discrimination is unclear, such discrimination produces amicable relationships among local group members and ensures xenophobic responses to non‐group members. Colony member discrimination may reduce costs of intra‐colony aggression, ensure the appropriate distribution of cooperation and reciprocal altruism to enhance direct fitness benefits that accrue via social grouping, and ultimately promote outbreeding among sexually mature individuals. Finally, the discrimination of colony members from non‐colony members could appear as an incidental byproduct of the operation of a mechanism promoting species recognition.
Ecological and Social Factors Affecting the Vocal Behavior of Adult Female Squirrel Monkeys
Authors: Boinski Sue , Mitchell Carol L. 
Published: May 2010

AbstractFocal recordings of the vocalizations of squirrel monkeys, Saimiri sciureus, occupying an undisturbed Peruvian habitat were collected to evaluate the importance of both the ecological and social functions of female vocal behavior. The rates and sequences of six call types were examined by context: single, double, and multiple chuck, peep, tweet, and tweet‐chuck. In contrast to laboratory studies, our findings emphasize the primacy of ecological functions in the wild, where calling permits females to operate as a convoy of spatially separated individuals in an arboreal habitat where visual contact is limited. Chuck calls are probably best interpreted as contact calls. The rate of chucks and tweet‐chucks increased when the nearest adult female was > 5 m away. However, call production did not predict a change in the spatial separation between a female and her nearest adult female. During travel, the rate of single and double chucks was greater and the rate of multiple chucks was reduced. No direct relationship was found between foraging activities and vocal behavior. Although secondary, social factors did have a subtle effect on vocal behavior: the larger the social alliance of a female, the lower the rate and repetitiveness of her chuck vocalizations. We also consider the role of variations in vocalization rates among primates and the differing conclusions of field and captive studies of squirrel monkey vocal behavior.
Territoriality and Male Mating Success in the Dart‐poison Frog,Epipedobates femoralis(Dendrobatidae, Anura)
Authors: Roithmair Margarete E. 
Published: May 2010

AbstractThe social and reproductive behaviour of the dart‐poison frog,Epipedobates femoralis, was studied in Amazonian Peru for 14 months. Males defended territories with advertisement calls and, ultimately, fighting. Territory size ranged from 0.25 to 26 m2and was positively correlated with duration of residence and calling activity of the owner. Females were not territorial and were never attacked when approaching calling males. Males and females only mated once and females sampled calling males before mating. Male mating success was closely correlated with territory size and calling activity. No correlation was found between male body size and mating success. Territories provide residents with sufficient space for mate attraction and reproduction without interference from rivals. Since territory size is dependent on calling activity which involves high energetic costs, it is suggested that territory size reveals male quality.
A Comparison of Living Singly and in Male‐female Pairs in the Prairie Vole, Microtus ochrogaster
Authors: Getz Lowell L. , McGuire Betty 
Published: May 2010

AbstractWe measured potential advantages of living singly as contrasted to in male‐female pairs in a free‐living population of the prairie vole (Microtus ochrogaster) in a high food habitat. Whereas adult females survived longer when living in a pair than when living singly, adult males survived longer when single and wandering throughout the study site than when paired. Estimated total number of offspring produced that survived to adulthood and became reproductive was similar for paired females (0.32 female and 0.36 male offspring/female) and females living singly (0.34 female and 0.25 male offspring/female). There was no correlation between the proportion of unpaired adult males in the population and either adult population density, adult sex ratio, or proportion of females that were living singly. These results support the hypothesis that living in pairs evolved in the original low food habitat of the prairie vole and represents a basic behavioral trait that is retained regardless of food resources in the habitats now occupied.