bluuebunny/crossref_metadata_2025 huggingface dataset:
Song Differentiation and Population Structure: the Example of the Whistled Songs in an Introduced Population of European Starlings Sturnus vulgaris in Australia
Authors: Adret‐Hausberger Martine
Published: May 2010

Whistled songs of male starlings were studied in Australia and results compared with previous ones in Europe. Starling whistle sonograms can be divided into general classes according to certain criteria. All or most males sing five whistled types (“species‐specific” themes), plus other (“individual”) themes. The basic repertoire of species‐specific themes is almost the same in Europe and Australia with the same characteristics and similar variation ranges. In both continents each male has a certain number of individual themes, but Australian repertoires tend to be smaller, with two species‐specific themes less and fewer individual themes. In all study areas dialects were based on local variations in species‐specific theme structure, but the Australian dialectal system is simpler than in Europe. Therefore basic characteristics seem to have been similarly transmitted across generations in both continents. But some of the differences (individual characteristics, repertoire size, frequencies) may stem from different habitat characteristics and also social structure, which could have greatly affected song differentiation.
Eavesdropping by Bats: The Influence of Echolocation Call Design and Foraging Strategy
Authors: Balcombe Jonathan P. , Fenton M. Brock
Published: May 2010

We used playback presentations to free‐flying bats of 3 species to assess the influence of echolocation call design and foraging strategy on the role of echolocation calls in communication. Near feeding sites over water,Myotis lucifugusandM. yumanensisresponded positively only to echolocation calls of conspecifics. Near roosts, these bats did not respond before young of the year became volant, and after this responded to presentations of echolocation calls of similar and dissimilar design. At feeding sitesLasiurus borealisresponded only to echolocation calls of conspecifics and particularly to “feeding buzzes”. WhileMyotis, particularly subadults, appear to use the echolocation calls of conspecifics to locate feeding sites,L. borealisappears to use the calls of a foraging neighbour attacking prey to identify opportunities for ‘stealing’ food.
Male Gibbon (Hylobates agilis) Singing Behavior: Natural History, Song Variations and Function
Authors: Mitani John C.
Published: May 2010

Male gibbons engage in elaborate singing performances during which they emit a variety of song types. Field observations, acoustic analyses and experimental playbacks were conducted to investigate the communicative significance of song variations and to test the hypothesis that unmated male gibbons use song to attract potential mates. Singing is progressively elaborated during the course of a performance, with louder, longer, syllabically more complex songs produced at the end compared to the start. Similarly, song complexity increases during vocal interactions with territorial neighbors. Field playbacks showed that complex songs elicit significantly faster approaches than the simple songs used to initiate performances. Additional observations and experiments revealed few differences between the singing performances of mated and unmated males, and that the reproductive status of singing males did not affect the responsiveness of gibbons to songs. These results suggest that increasing song complexity during performances represents a series of graded signals used intrasexually in territorial defense; current evidence does not support the hypothesis that male song performs an intersexual mate attraction function.
Agonistic Interactions of Juvenile Savanna Baboons
Authors: Pereira Michael E.
Published: May 2010

19 juvenile members of known genealogies in two wild baboon groups were studied over a 16‐month period to compare the ontogeny of agonistic experience and dominance relations for males and females. Juveniles of all age‐sex classes were disproportionately likely to receive aggression from and submit to adult males per unit of time spent in proximity. This pattern intensified with increasing juvenile age. With age, juvenile females more often submitted to unrelated adult females from higher‐ranking families, whereas this was not true for juvenile males. All juveniles received aggression from older group members more often during feeding than was expected by chance. High rates of agonistic interaction with unrelated adult females accounted for old juvenile females (3–5.5 years‐old) interacting agonistically more frequently than male age peers and young juveniles of either sex (1–2.5 years‐old). Adult females were also more aggressive toward females among young juveniles, suggesting that adult females target females among juveniles for aggression and resistance to rank reversal. Within juvenile age groups, males dominated all females and all younger males, irrespective of maternal dominance status. Dominance relations among female age‐peers were generally isomorphic with relations among their mothers. No juvenile targeted any older male for rank reversal. Males targeted all older females, whereas females typically targeted only older females from families lower‐ranking than their own. The strong sexual dimorphism in adult body size in baboons may explain why juvenile males' dominance relations with peers and adult females are not structured along lines of family membership as is true for the less dimorphic macaques. Acquisition of higher agonistic status probably allows juveniles of both sexes to increase their success in within‐group feeding competition during late stages of juvenility, which, in turn, could affect important life‐history traits such as age at menarche and adult body size.
Copulatory Behavior as Courtship Communication
Authors: Dewsbury Donald A.
Published: May 2010

In the copulatory behavior of many species of rodents, mounting patterns with ejaculation are preceded by mounts with nonejaculatory intromissions. Although not directly related to insemination, these intromissions have generally been treated as “copulatory” behavior. If we treat these nonejaculatory intromissions as courtship communication in the tactile modality, new relationships become apparent. Within the context of classical ethology, intromissions can be considered in relation to both proximate dynamics and ultimate effects. Within the sociobiological/behavioral‐ecological context, intromissions can be viewed in relation to manipulation, female assessment and choice, and honesty of communication. The intromissions synchronize, persuade, and orient at the same time as they manipulate the partner.
Simultaneous Discrimination Learning in Chicks: Spatial Representations and Object Characteristics
Authors: Vallortigara Giorgio , Zanforlin Mario
Published: May 2010

Chicks were trained to discriminate (1) between two boxes of the same colour on the basis of their positions; (2) between two boxes of different colours on the basis of their positions or on the basis of their colours. No significant differences between these tasks appeared. Addition of colour and position improved learning when the boxes were entirely coloured but not when differently coloured discs were placed over the lids of two identical boxes. It is argued that in simultaneous discrimination learning chicks rely primarily on the “relative” position of the goal objects (i. e. in relation to each other) and utilize featural information (colour) to segregate the goal objects as distinct perceptual units. Results also stressed the role of “object characteristics” as opposed to the traditional notion of “cues”.
Foundress Mortality after Worker Emergence in Social Wasps (Polistes)
Authors: Hughes Colin R. , Strassmann Joan E.
Published: May 2010

Worker emergence is a watershed in the development of a social insect colony because after workers emerge subordinate foundresses are less critical to the survival of the colony, and may be simply a threat to the egg laying monopoly of the queen. A widely‐held view is that after worker emergence the queen either kills or chases off subordinate foundresses in Polistes, as is the case in many ants. Our examination of changes in subordinate behavior and mortality after worker emergence reveals a more complex picture. Though foundress mortality increased significantly after worker emergence in 5 of 7 populations of Polistes (6 different species), this did not always result from increased queen or worker aggression toward subordinates. Senescence may also play an important role in subordinate foundress mortality. The two species in which subordinate mortality did not increase significantly after worker emergence were characterized by high rates of colony failure due to loss of all workers. This may indicate that subordinates remain in the colony after worker emergence in species where their continued presence is important to the success of the colony.
Non‐random Mating in the Dance Fly Empis borealis: The Importance of Male Choice
Authors: Svensson Bo G. , Petersson Erik
Published: May 2010

In the dance‐fly Empis borealis (Diptera, Empididae), females form swarms to which males, carrying a nuptial gift, come for mating. We examined whether males or females were choosy and/or competed for mates.

First, measurements of the size relationships between copulating males and females, nuptial gifts and the swarming females from different swarms were assessed. Second, male visiting time in differently sized female swarms was recorded.

Larger (wing‐length) females participated disproportionately in copulations in each swarm, but not for the population at large. Female mating status (virgin/non‐virgin) or proximity to oviposition (egg size) did not influence the likelihood of copulation. No assortative mating pattern was found: male size and size of nuptial gift did not correlate with size of the mating female.

The time spent by males in swarms increased with the number of females present and it took longer when males left a swarm without copulation than when doing so. Male visiting time per female was negatively correlated with number of females in swarms. Males more often left smaller than larger swarms without mating.

We conclude that E. borealis males discriminate among females but find no evidence for male competition or for female choice. It is still a question to what degree females compete for males.
Can Experience Alter the Avian Annual Cycle? Results of Migration Experiments with Indigo Buntings
Authors: Sniegowski Paul Donald , Ketterson Ellen D. , Nolan Val
Published: May 2010

Field experiments were conducted during 2 years testing whether premature release on their familiar, perennial breeding territories would cause indigo buntings (Passerina cyanea) to delete spring migration from their annual cycle. In the first year, male buntings were captured on their breeding territories in summer and held indoors for the winter on the photoregime that they would have encountered in nature as fall migrants and winter residents. The following spring they were released at the time buntings begin spring migration from the subtropics. Half were released on their breeding territories, to which they would normally have returned; half were released far to the south. Some of the males released on their territories remained and passed into breeding condition without having migrated, while some of those released to the south returned north to their territories. The results suggest that endogenous or photoperiodic mechanisms controlling the timing and occurrence of migration in this species can be overridden by experience. In the second year we tested alternative explanations for these results. Our second year's results seem to indicate (1) that birds that deleted migration in year one did not do so because of unfavourable weather and (2) that the birds that returned to their breeding sites in year one were actually migrating and not simply retracing their outward journey.
Changes in Nest Defense against a Brood Parasite over the Breeding Cycle
Authors: Briskie James V. , Sealy Spencer G.
Published: May 2010

We measured the responses of nesting least flycatchers (Empidonax minimus) to a model of the brood‐parasitic brown‐headed cowbird (Molothrus ater). A greater number of vocalizations, approaches and threat displays were directed toward the cowbird model than toward a control model of a fox sparrow (Passerella iliaca), suggesting that the cowbird was recognized as a threat. Flycatchers were more likely to give threat displays during laying when the consequences of brood parasitism were greatest; however, the intensity of all other defensive behavior did not change over the nesting cycle. We suggest that least flycatchers remained aggressive throughout nesting because cowbirds were also predators on eggs and nestlings.
An Analysis of Variability in the Feeding Motor Program of the Honey Bee; the Role of Learning in Releasing a Modal Action Pattern
Authors: Smith Brian H. , Menzel Randolf
Published: May 2010

Sequences of behavior are highly predictable (stereotyped) during some segments and less predictable during transitions between those segments. Statistical characterization of behavior must involve observation of the behavior under different stimulus conditions, which includes how stimuli associated with behavioral releasers come to trigger behavior during learning. For example, the feeding motor program (FMP) of the honey bee Apis mellifera (Hymenoptera: Apidae) during proboscis extension can be divided into three response phases (Rehder 1987). We conditioned honey bees in an olfactory conditioning paradigm with one or several rewarded trials during which an odorant was paired with the sugar‐water unconditioned stimulus (US); the latter elicits proboscis extension and feeding in properly motivated bees. By recording electromyogram activity from one of the muscles that move the proboscis during feeding, we quantified the bees' responses during an unrewarded test with either the conditioned odorant, a different (novel) odorant, or the sugar‐water US. Various parameters of the response phases of the FMP varied in a consistent manner across these experimental treatments, with certain stimuli eliciting stronger, more consistent responses. The different response phases followed one another in time with some variability and statistical uncertainty. For example, the length of an individual licking movement with the glossa was relatively invariant, and may indicate that this parameter can be used to differentiate the FMP into more basic, independent units. Our work shows how learned information may release action patterns in ways slightly different from traditional sign‐stimuli releasers.
Individual Variability, Social Structure and Division of Labour in the Ponerine Ant Ectatomma ruidum Roger (Hymenoptera, Formicidae)
Authors: Corbara B. , Lachaud J.‐P. , Fresneau D.
Published: May 2010

The social organization of an Ectatomma ruidum colony was investigated by individually marking all members and recording their behaviour using an automatic photographic technique. A hierarchical cluster analysis was used to determine functional groups describing this society. We then studied intragroup variability of the individual profiles and showed that there are different, complementary levels of approach to the division of labour in a society.
Foraging Guppies and the Ideal Free Distribution: The Influence of Information on Patch Choice
Authors: Abrahams Mark V.
Published: May 2010

10 male and 10 female guppies were each examined foraging for food at 2 separate feeders. The feeders provided food over a wide area so that individuals had equal access to the food. As the proportion of food at a feeder was altered, the proportion of fish using that feeder changed to match the availability of food. Thus, both groups of fish conformed to the predictions of the ideal free distribution (IFD) theory.

However, the behaviour of the two groups differed. During these experiments, males continued to shuttle between these feeders whereas females tended to remain at a feeder. Also, the female group conformed less well to an IFD on the first trial of each day but conformed more closely to an IFD in successive exposures to the same food distribution. The male group exhibited no improvement with increasing experience. For both groups, the relative influence of the previous day's experience on foraging decisions declined with time. However, unlike the male group, the female group relied on experience for their initial foraging decisions. It is possible that sampling by males provides the additional benefit of increasing their probability of encountering receptive females. This may account for the difference in information use by the male and female group.
Long‐term Retention of Many Visual Patterns by Pigeons
Authors: von Fersen Lorenzo , Delius Juan D.
Published: May 2010

Using a simultaneous discrimination procedure it was shown that pigeons were capable of learning to discriminate 100 different black and white visual patterns from a further 625 similar stimuli, where responses to the former were rewarded and responses to the latter were not rewarded. Tests in which novel stimuli replaced either the rewarded or nonrewarded stimuli showed that the pigeons had not only learned about the 100 positive stimuli but also about the 625 negative stimuli. The fact that novel stimuli enhanced discrimination performance when they replaced the many negative stimuli indicated that the pigeons had categorized the stimuli into two classes, familiar and less familiar. Long‐term retention was examined after a 6‐month interval. To begin with it seemed poor but a recognition test performed after the subjects had been retrained with a subset of the stimuli after an interval of 7 months confirmed that pigeons are capable of retaining in memory several 100 visual items over an extended period. It is proposed that the initial retrieval weakness was due to a forgetting of the contingencies between stimulus categories and response outcomes. Further tests involving variously modified stimuli indicated that while stimulus size variations had a negative effect on performance, orientation changes did not interfere with recognition, supporting the view that small visual stimuli are memorized by pigeons largely free of orientation labels. The experiment generally confirms that pigeons have the capacity of storing information about a large number of visual stimuli over long periods of time.
Male Defense of the Breeding Cavity and Factors Affecting the Persistence of Breeding Pairs in the Stomatopod, Gonodactylus bredini (Manning) (Crustacea: Hoplocarida)
Authors: Shuster Stephen M. , Caldwell Roy L.
Published: May 2010

In Caribbean Panama, nonreproductive male and female stomatopods are solitary and defend their own coral‐rubble cavities. When breeding pairs form, however, males assume all responsibility for cavity defense. To compare success in cavity defense and defensive tactics among paired and unpaired males, and to examine the tendency for paired stomatopods to exchange their present mates for larger (higher quality) individuals, we introduced same‐sized and 15% larger male, and same‐sized and 15% larger reproductive female intruders to paired and unpaired male residents in a balanced design. Paired males were more successful at cavity defense than unpaired males, evidently because paired males strike intruders more than unpaired males, and because intruders fight less intensely against paired males than against unpaired males. Paired males occasionally attempted extrapair copulations, but showed little tendency to abandon their mates in favor of larger females. Paired females, however, mated readily with intruder males that evicted resident males. Populationwide female breeding synchrony and prolonged female receptivity before oviposition reduce variance in male mating success and may force males to guard the breeding cavity to assure their paternity. Uncertainty about the reproductive condition of intruder females may prevent males from exchanging mates.
Acquired Recognition of Predator Odour in the European Minnow (Phoxinus phoxinus)
Authors: Magurran Anne E.
Published: May 2010

Naive European minnows (Phoxinus phoxinus) do not show a fright reaction when they first encounter the odour of a natural predator (the pike: Esox lucius) or the odour of a non‐piscivorous exotic (tilapia: Tilapia mariae). A conditioned fright response to both these odours will however develop if minnows experience them in a potentially dangerous situation, for example, in conjunction with Schreckstoff, the ostariophysian alarm pheromone. Although minnows respond to both odours the reaction to the tilapia odour is reduced. This suggests that a constraint on learning is involved. Olfactory recognition is particularly valuable for detecting predators that hunt in conditions where visibility is poor.
Sperm Competition and Copulation Intervals of the White Spoonbill (Platalea leucorodia, Aves, Threskiornithidae)
Authors: Aguilera Eduardo
Published: May 2010

Some aspects of sperm competition were studied in the white spoonbill (Platalea leucorodia) breeding in Doñana National Park (SW Spain). Shorter pair copulation intervals occurred during the prelaying period, when females were subjected to a relatively high frequency of extra‐pair copulations. Pair copulation intervals with an intermediate extra‐pair copulation by the male mate were longer than those without extra‐pair copulation. This result indicates that males need a time of recovery between copulations before they can perform another. Extra‐pair copulations by the females did not affect the length of intervals between pair copulations. There were no differences between the lengths of the intervals between an extra‐pair copulation by the female and the following pair copulation for cases in which the male mate detected an intruder male attempting copulation with his mate and those in which the intruder remained undetected. However, the correlations obtained between copulatory intervals for detected and undetected cases suggest a copulatory response by their mates, although affected by the required recovery time between copulations by the males. Finally, since extra‐pair copulations mainly occurred while male mates were collecting nest material, they engaged in this activity shortly after pair copulations, probably to avoid a last‐male advantage under the sperm competition pressure.
Measuring Dominance and Constructing Hierarchies: An Example Using Mule Deer
Authors: Tomback Diana F. , Wachtel Meryle A. , Driscoll Janis W. , Bekoff Marc
Published: May 2010

Important issues that are still unresolved in the study of animal social groups are how dominance is measured and how individuals are ranked. Based on observations of mule deer (Odocoileus hemionus hemionus), we constructed hierarchies for the same 26 bucks using five potential correlates of dominance and three measures based on the outcome of agonistic interactions. Data for each of six behavior measures were converted to ranks by six different numerical techniques.

Different measures of behavior resulted in different hierarchies. This was especially so when the hierarchy based on sparring rates was compared to hierarchies based on other criteria. Although our results showed that dominance is not a unitary concept, several measures of dominance were highly correlated with one another. Thus, one measure, in some instances, may be a good but imperfect predictor of dominance defined by other criteria.

For data sets based on index scores or rates of performing behavior, the mean difference and standard‐error difference ranking methods had distinct advantages. Both produced equally weighted ranks that minimized the effects of sampling errors.
Orange Spots as a Visual Cue for Female Mate Choice in the Guppy (Poecilia reticulata)
Authors: Long Kevin D. , Houde Anne E.
Published: May 2010

Previous studies have suggested that orange pigment in the color patterns of male guppies is a cue for female choice. This paper describes a manipulative experiment designed to test this hypothesis. The color patterns perceived by females were manipulated by varying the color of light used to illuminate the experimental aquaria. Orange light dramatically reduces the conspicuousness of orange spots to human observers, and probably also to female guppies. As in previous experiments, female guppies discriminated among males based on differences in the extent of orange pigment, under white, blue, and green light conditions. Under orange light, however, females no longer appeared to discriminate on the basis of orange spots. These results support the hypothesis that orange spots, rather than other correlated characteristics, are a basis for female choice under normal lighting conditions.
Kin Recognition and Maternal Care under Restricted Feeding in House Mice (Mus domesticus)
Authors: König Barbara
Published: May 2010

This study tests the hypothesis that female house mice (F1 generation of wild caught Mus domesticus) should preferentially invest in own offspring if confronted with young of different degrees of relatedness. The maternal behaviour of females with litters of 4 own and 4 unrelated alien young (cross‐fostered at day 1 of lactation) was analysed during a lactation period of 22 days both under ad libitum and under restricted feeding (food was restricted by 20%).

Cross‐fostering and restricted feeding had no effect on the amount of time spent nursing until weaning. Under both feeding conditions the females did not differ in their maternal behaviour towards own and alien young: there were no significant differences either in the amount of time spent nursing own versus alien pups or in the time spent licking own versus alien young. Weight gain of own and alien = wild littermates did not differ significantly in mixed litters and was similar both under ad libitum and under restricted feeding. Such indiscriminate behaviour might be adaptive if female house mice prefer to communally nest with a relative and thus improve their inclusive fitness by investing in own and related offspring in a communal nest.

Under moderate restricted feeding females could not wean the entire litter but reduced litter size by cannibalizing on average 2.7 pups (75% of the pups were killed when they were 4–8 days old). Females with cross‐fostered litters killed as many own as alien young. This suggests that females cannot discriminate between own and unrelated young if cross‐fostering takes place at day 1 of lactation.

Besides testing kin recognition abilities, the experiments also allow analysis of the weaning strategy of females under food shortage. Under restricted feeding, body weight of the females was significantly lower during middle lactation than under ad libitum feeding. Weaning weight of young in reduced litters under food restriction (9–10 g) did not differ significantly from weaning weight of young in litters of 7–10 young, but was lower than that of young in similar sized litters (litter size 6), under ad libitum feeding. The maternal behaviour of cannibalizing some young under food shortage can be interpreted as a weaning strategy which results in the largest number of offspring that can be raised to a minimal weaning weight of 9–10 g. Such a weaning strategy might represent a favourable trade‐off between number and size of young produced.
Nest Defense by Red Jungle Fowl (Gallus gallus spadiceus) Hens: The Roles of Renesting Potential, Parental Experience and Brood Reproductive Value
Authors: Thornhill Randy
Published: May 2010

Reproductive‐effort theory predicts that parents of any given age should expend more parental effort (1) as their residual reproductive value declines, and (2) as the reproductive value of offspring increases. An observational and experimental study of nest defense by captive red jungle fowl hens was used to examine these two predictions. Both young and old individuals significantly increased defense of the second nest compared to the first nest within a season; this pattern occurred for the defense of both eggs and chicks. Old hens showed significantly greater defense of both eggs and chicks in each of the nests than did young hens. Both young and old hens were significantly more defensive of chicks than eggs in each of two clutches of a season. Hens also reduced their nest defense significantly at the end of a two to three‐day period after their chicks were replaced with eggs, and increased their nest defense after eggs were exchanged for chicks. Hens given four chicks showed more vigorous defense than hens given two chicks. When the brood size of hens with four chicks was reduced to one chick, the hens responded by exhibiting less vigorous nest defense. These patterns of nest defense in jungle fowl were not confounded by parental experience of hens, or differences in offspring quality that are related to time of breeding, maternal age, sire genetic quality or vulnerability of offspring to weather.
A Comparative Study of Agonistic Behaviour in Hairy‐footed Gerbils (Genus Gerbillurus)
Authors: Dempster Edith R. , Perrin M. R.
Published: May 2010

Intraspecific agonistic behaviour was investigated by means of staged encounters in Gerbillurus paeba paeba, G. p. exilis, G. tytonis, G. setzeri and G. vallinus.

Four groups of behaviour were identified by motivational analysis: i.e. “exploratory and solitary”, “aggressive”, “submissive”, and “sexual” behaviour. Frequencies of acts and levels of interaction differed among species and sexes.

Cluster analysis of behaviour data revealed three clusters which agree partially with the karyology and taxonomy of the genus. G. p. paeba and G. tytonis were very aggressive and highly active; female G. p. exilis and G. setzeri less so; while male G. p. exilis and G. vallinus were least aggressive and active, performing more contact‐promoting behaviour than other species. A range of social types is exhibited from solitary (G. p. paeba and G. tytonis) through semi‐tolerant (G. setzeri and female G. p. exilis) to tolerant (male G. p. exilis and G. vallinus).
Neighbor Call Amplitude Influences Aggressive Behavior and Intermale Spacing in Choruses of the Pacific Treefrog (Hyla regilla)
Authors: Brenowitz Eliot A.
Published: May 2010

Male Pacific treefrogs (Hyla regilla) aggregate in choruses during the breeding season. Within these choruses frogs distribute themselves nonrandomly. This study tested the hypothesis that the amplitude of neighbors' calls serves as a proximate cue in regulating the spacing of males in choruses, and that this is mediated by the incidence of aggressive‐encounter calls by resident males. The amplitude of neighbors' calls showed little interindividual variation. Advertisement calls were played to males at three amplitudes that spanned the range of neighbor‐call amplitudes measured between pairs of frogs. At playback amplitudes corresponding to the minimum neighbor‐call amplitudes observed in choruses, frogs gave predominantly advertisement calls and few aggressive‐encounter calls in response. As the playback amplitude was increased, subjects progressively decreased the number of advertisement calls and increased the number of encounter calls that they produced in response. The total number of calls (advertisement + encounter) given in response did not vary with playback amplitude. Intruders were likely to move away when a resident male gave encounter calls. In this way neighbor‐call amplitude regulates intermale spacing in choruses.
Digging Behaviour while Foraging by the European Badger, Meles meles, in a Mediterranean Habitat
Authors: Pigozzi Giorgio
Published: May 2010

Digging behaviour while foraging by the European badger (Meles meles) was studied in the Maremma Natural Park, central Italy, during late winter and spring of 1984 and 1985. Badgers digging for Lamellicornia larvae were successful in approximately 77% of the observed digging attempts. Digging success was similar among individuals and months and was positively correlated with the depth of the hole. A change of position while digging was associated with successful digging. Badgers always started their digging activity using only a foreleg at a constant rate and at a later stage used both forelegs alternately at a higher rate. The adoption of such technique is regarded as adaptive since it maximizes the chance of capturing the prey while reducing the energy expenditure due to digging. The reduced availability of those resources to be collected on the ground surface during late winter and spring is suggested as the possible cause of the energetically expensive digging behaviour.
Variation in Mating Systems of Fallow Deer (Dama dama) in Relation to Ecology
Authors: Langbein Jochen , Thirgood Simon J.
Published: May 2010

Variation in mating systems of fallow deer (Dama damaL.) was studied in wild and park populations and could be broadly distinguished into 7 categories: following, harems, dominance groups, stands, temporary stands, multiple stands, and leks. The ecological factors which exerted the greatest influence on mating systems were buck density, doe density, and habitat structure and tree cover, resulting in pronounced changes in the degree and type of territoriality observed. Individual male reproductive success was highly skewed in all systems. A greater range of concurrent mating strategies was observed in wild populations than in parks.
Orientation Cues Used by Hatchling Loggerhead Sea Turtles (Caretta caretta L.) During their Offshore Migration
Authors: Salmon Michael , Lohmann Kenneth J.
Published: May 2010

Sea turtle hatchlings ernerge from underground nests, crawl to the ocean and swim out to sea. The orientation cues used to maintain offshore headings are unknown. Our field experiments suggest loggerhead hatchlings on the Atlantic coast of Florida continue on offshore headings by swimming into oceanic swells and wind‐generated waves. Dependence on these cues appears complete when hatchlings are 3.0 km from shore. Because waves and swells usually approach from seaward directions, they are generally reliable guideposts.
Acquisition of Breeding Space by Nonbreeders in the Anemonefish Amphiprion clarkii in Temperate Waters of Southern Japan
Authors: Ochi Haruki
Published: May 2010

Behavior of Amphiprion clarkii, especially of nonbreeders, was investigated at the shore of boulders and rocks in Uwa Sea, southern Japan. All individuals except small ones under one year were tagged. Movements of A. clarkii between host sea anemones were usual in this study area where host anemones were abundant, unlike in the general habitat (coral reefs) of Amphiprion, where movements between hosts are restricted. Monogamous pairs established almost contiguous territories containing all hosts except small ones. Nonbreeders had home ranges on the fringes of the pairs' territories and sheltered in relatively small hosts. Breeding spaces were saturated with breeders and were available for nonbreeders only after disappearance of one or both members of an established breeding pair. Home ranges of nonbreeders of similar body size were spaced out, due perhaps to competition for breeding spaces. It is suggested that large nonbreeders refrained from becoming females to keep their gonads ambosexual, so that they could replace either sex in a territory as breeding space became available, or, in pairing with other nonbreeders, the larger fish of the pair could take the female role.
Male‐Female Interactions in Hairy‐footed Gerbils (Genus Gerbillurus)
Authors: Dempster Edith R. , Perrin M. R.
Published: May 2010

Staged 10‐min encounters between male and female gerbils of the same species were characterized by high levels of exploratory and solitary behaviour, variable levels of agonistic behaviour, and little contact‐promoting behaviour. Female Gerbillurus paeba paeba, G. p. exilis and G. tytonis dominated males of these species, while male and female G. setzeri and G. vallinus were equally aggressive.

Results of this study indicate that G. p. paeba, G. p. exilis and G. tytonis are aggressively solitary and that females behave aggressively towards unfamiliar males, while G. setzeri and G. vallinus are more tolerant. This is in partial agreement with findings for other gerbil species.
Experimental Analysis of the Symbiosis between Anemonefish and Sea Anemones
Authors: Miyagawa Kazuko
Published: May 2010

Fundamental problems of the anemonefish‐sea anemone symbiosis were experimentally analyzed, especially at the period of the first encounter of symbionts, using naive juvenile anemonefish.

The results differed markedly from those of previous studies using adult fish. Naive juveniles of five Amphiprion species in the coastal region of Japan have an innate protection against their symbiotic anemones. Furthermore, juveniles of all four species examined were almost comprehensively protected from Amphiprion‐symbiotic anemone species. Naive juveniles recognize their species‐specific partner‐anemones via chemical factors released by the latter, thus leading to a species‐specific partnership. Visual cues do not play a large role in partner‐recognition at the first encounter.

Possible reasons for the vast difference between the results of the present work and those of previous studies are discussed.
Functional Analysis of the Myrmecophilous Relationships between Ants (Hymenoptera: Formicidae) and Lycaenids (Lepidoptera: Lycaenidae)
Authors: Fiedler Konrad , Maschwitz Ulrich
Published: May 2010

Myrmecophilous lycaenid larvae possessing a dorsal nectar organ release strong recruitment behavior in ants attending them. Larvae lacking a functional dorsal nectar organ are unable to release such recruitment behavior. Thus, the dorsal nectar organ with its carbohydrate secretions is responsible for the release of the recruitment behavior. The importance of the dorsal nectar organ for the evolution of mutualistic trophobiotic associations between myrmecophilous lycaenid larvae and their attending ants is discussed.
Ultrasound‐induced Parental Behaviour in House Mice is Controlled by Female Sex Hormones and Parental Experience
Authors: Ehret Günter , Koch Michael
Published: May 2010

Ultrasounds of a lost mouse pup release pup approach in adult mice and lead to pup retrieving if parental motivation is sufficient. Here, we investigate the effects of oestrogen and progesterone and parental experience on ultrasonic key‐stimulus preference and on pup retrieving. Tests with various groups of inexperienced, pup‐experienced, gonadectomized and hormone treated females and males lead to the following major results: Female sex hormones are not necessary for establishing maximum retrieving rates in mice experienced with pups, they are necessary for spontaneous retrieving to occur in inexperienced mice, they support the achievement of experience with pups and, if present during the time of formation of experience, lead to a superior and prolonged performance of retrieving and ultrasonic key‐stimulus preference. Ultrasound discrimination does not occur spontaneously but only in mice experienced with pups. It is suggested that parental motivation sensitizes selective attention for pup cues and thus makes ultrasound preference possible. Parental motivation is regarded as a state in which the salience of releasing stimuli from the pups is selectively enhanced through hormones and long‐lasting internal changes induced by experience with pups.
Intra‐pair Cooperation, Fledgling Care, and Renesting by Northern Mockingbirds (Mimus polyglottos)
Authors: Zaias Julia , Breitwisch Randall
Published: May 2010

Male and female northern mockingbirds (Mimus polyglottos) cooperated in dividing labor between care of fledglings and renesting. This study during two breeding seasons demonstrated a temporal division of labor in this multi‐brooded passerine. Both parents fed newly fledged young. One to four days after young fledged, males reduced feeding rates and began nest‐building. Males delayed initiation of nest construction in proportion to the number of fledglings present. During nest‐building, females provided more food to fledglings. Mates then switched roles. Females finished building nests, laid the next clutches, and began incubation; males fed fledglings until they were independent. Within pairs, males fed fledglings more than did females in one of two years. Both sexes defended fledglings against potential predators, although males provided stronger and more frequent defense. This is the first detailed description of a monogamous passerine that clearly demonstrates lack of brood division while renesting. Division of broods is largely precluded by the temporal division of labor, a behavioral mechanism increasing the probability of renesting. Attempts at renesting, in turn, are favored by a high level of nest predation in this population.
Agonistic Interactions of Juvenile Savanna Baboons
Authors: Pereira Michael E.
Published: May 2010

19 juvenile members of known genealogies in two wild baboon groups were studied over a 16‐month period. Males and females in two age classes were compared regarding third‐party aggression and support given and received during agonistic interaction. Young juvenile males and females (1–2.5 years‐old) were supported predominantly by their probable fathers. The adult males supported without regard to the family ranks of juveniles and their opponents. Old juveniles (3–5.5 years‐old) no longer had probable fathers in their groups and rarely or never received support from adult males. Females received considerable maternal support and, with age, most often received support from unrelated adult females. Males rarely received support from either their mothers or unrelated adult females. 100% of adult female support for and against 11 of the 12 females reinforced existing rank relations among matrilines. In contrast, only about half of adult female support of males reinforced matrilineal rank relations. Juvenile females exploited aggression among adult females during rank acquisition: they supported high‐ranking adults during attacks on females they had targeted for rank reversal. In contrast, males attacked adult females in support of peers or young juveniles. Females also solicited support during fights more often than males. They most often solicited adult females, whereas males directed their rare solicitations toward other males. Despite low maternal rank, one female targeted all older females for rank reversal except the adults of her group's top‐ranking family. She was the only female to receive support from adult females that contradicted existing rank relations among matrilines, and the only female ultimately to achieve stable adult rank above families outranking her own. Adult female baboons appear to structure the development of rank relations for juveniles in their groups. Juvenile females are typically limited to acquisition of familial status, while males are free to achieve rank over whichever group members they can independently intimidate.
Acoustical Entrainment of Circadian Activity Rhythms in House Sparrows: Constant Light is not Necessary
Authors: Reebs Stéphan G.
Published: May 2010

Cycles of presence/absence of social factors can sometimes entrain the circadian activity rhythms of diurnal animals kept under constant light. This might represent a special case of photic entrainment; social factors might awaken the subjects and make them see the light at times when they are normally unaware of it because of sleep. The present study attempted to falsify this hypothesis by entraining the activity rhythms of house sparrows (Passer domesticus) kept in constant darkness. The zeitgebers used were daily 2‐h playbacks of conspecific vocalizations, and daily 1.5‐h acoustical (non‐conspecific) disturbance. 7 birds were tested; four (all males) entrained to both stimuli, while the other three (all females) mostly showed relative coordination. Entrainment took place when the stimuli coincided with the late part of the birds' normal sleep time. No anticipatory activity preceded the daily stimulus presentations. In a second experiment, 8 more male sparrows in constant darkness began their free‐running activity earlier (phase‐advanced) on days that followed the presentation of a single 2‐h bout of acoustical disturbance in the last half of their normal sleep time. Stimulus presentations at other times had no effect. Opening the eyes and seeing the light are not necessary for acoustical (and social) entrainment, but other physiological consequences or correlates of sleep interruption may be involved.
Transmission Effects on Temporal Structure in the Advertisement Calls of Two Toads, Bufo woodhousii and Bufo valliceps
Authors: Ryan Michael J. , Sullivan Brian K.
Published: May 2010

We measured degradation of temporal structure in the advertisement calls of two species of toads (Bufo woodhousii and B. valliceps) as a function of transmission distance. Degradation, measured as the ratio of the amplitudes of pulse and interpulse interval, increased with distance and was significantly greater in B. valliceps than in B. woodhousii. These results are compared to previous reports of neural thresholds for units in the torus semicircularis that are responsive to the interaction of depth and rate of amplitude modulation in B. woodhousii and B. americanus. We suggest that the degradation of temporal structure that we measured has behavioral and neurophysiological consequences for communication.
Cultural Evolution in Song Dialects of Yellow‐rumped Caciques in Panama
Authors: Trainer Jill M.
Published: May 2010

The histories of five colony‐specific song dialects of yellow‐rumped caciques (Cacicus cela vitellinus) were recorded for three breeding seasons in Panama. Dialects consisted of 5 to 8 song types shared among all male members of a breeding colony. The number of song types that occurred at more than one colony decreased with distance between colonies. Color‐banded subadult and adult males frequently dispersed between years to other dialect areas where they adopted the local songs. About 78% of all song types were distinct from songs present the previous year at the same colony. During a breeding season some song types changed gradually, with all males adopting parallel changes. Gradual change in songs at colonies appeared to account for more new song types than did introduction of songs by dispersing males. Because song types changed gradually in constant directions, the cause of these changes may be cultural adaptation in which individuals benefit by adopting certain songs, rather than copy‐error or cultural drift.
Motivational Referents of Contact Calls in Japanese Monkeys
Authors: Masataka Nobuo
Published: May 2010

Very specific vocalizations (girneys) are interchanged extensively between Japanese monkeys before they establish grooming contact. I undertook acoustic classification of vocalizations tape‐recorded in a captive group, and found that they could be divided into two broad classes according to the position of the peak of the tonal element relative to the whole call length. Sequelae analyses revealed that the two variants were linked with different probabilities of the caller's subsequent behaviour. When the peak occurred in the first third of the girneys their callers were likely to groom the signal recipients, while when the peak occurred in the final third of the calls, their vocalizers tended to receive subsequent grooming. Playback experiments showed that the animals really perceived those variants. Japanese monkey contact call variants have specific and distinctive motivational referents.
Correlations between Courtship Success, Aggressive Success, and Body Size in a Picture‐winged Fly, Drosophila silvestris
Authors: Boake Christine R. B.
Published: May 2010

Relations between courtship success, aggressive success, and body size were examined in a laboratory study of the lekking Hawaiian fly, Drosophila silvestris. Courtship was studied by placing one male and one female in a cage together at a time, and aggression was observed with caged pairs of males. Aggressive success was positively and highly significantly correlated with body size, but uncorrelated with courtship success. Surprisingly, courtship success was negatively correlated with body size, although this relationship was not significant. Courtship success and aggressive success were not correlated. These results suggest that selection favors an intermediate optimum body size in this species.