bluuebunny/crossref_metadata_2025_split huggingface dataset:
Migratory Orientation: Magnetic Compass Orientation of Garden Warblers (Sylvia borin) after a Simulated Crossing of the Magnetic Equator
Authors: Wiltschko Wolfgang , Wiltschko Roswitha 
Published: May 2010

AbstractSince the birds' magnetic compass works as an inclination compass using the axial course of the magnetic field lines and their inclination, transequatorial migrants have to reverse their reaction with respect to the magnetic field after crossing the magnetic equator. Garden Warblers, long distance migrants breeding in Europe and wintering in tropical and southern Africa, were tested during autumn in the local geomagnetic field on the northern hemisphere. The experimental group was exposed to a field with horizontal field lines, simulating equator crossing, at the beginning of October; afterwards the birds were tested in the local geomagnetic field again. While the controls showed southerly tendencies during the entire season, the experimentals reversed their directional tendencies after staying in the horizontal field and now preferred northerly directions. In a field of the southern hemisphere, this preference corresponds to a southern course which would have meant the continuation of their migration flight.
You Can Get There from Here: Responses to Simulated Magnetic Equator Crossing by the Bobolink (Dolichonyx oryzivorus)
Authors: Beason Robert C. 
Published: May 2010

AbstractThe avian magnetic compass works as an inclination compass. Instead of using the polarity of the magnetic field to determine direction, birds use the inclination of the dip angle. Consequently, transequatorial migrants have to reverse their response to the magnetic compass after crossing the magnetic equator. When confronted with an artificial magnetic field that reverses the vertical component of the magnetic field, migrants such as the bobolink reverse their headings relative to magnetic north even in the presence of visual cues such as stellar patterns. Bobolinks, which breed in temperate North America and winter in temperate South America, were tested in a planetarium under fixed star patterns in a series of magnetic fields incremented each night from the natural field in the northern hemisphere through an artificial horizontal field to an artificial southern hemisphere magnetic field. The birds maintained a constant heading throughout the experiment and did not reverse direction after the simulated crossing of the magnetic equator as previous experiments predicted. In nature, this response would have meant continuation of their migration flight across the equator and into the opposite hemisphere. The switch from “equatorward” orientation to “poleward” orientation is probably triggered by experience with a horizontal magnetic field and/or visual cues. The ability to maintain an accurate heading while crossing the magnetic equator may be based on the use of visual cues such as the stars.
Dart‐poison Frogs and the Control of Sexual Selection
Authors: Summers Kyle 
Published: May 2010

AbstractIn some species of dart‐poison frogs (genus Dendrobates), males perform parental care. Some researchers have suggested that high relative parental investment by males in these species causes sex‐role reversal. I argue here that, in general, three factors cause sexual selection: inequality of relative parental investment, variance in mate quality, and variability of parental investment. I review evidence from my previous research that contradicts the hypothesis that unequal relative parental investment can explain female mating strategies in two species of dart‐poison frogs with male parental care. I then discuss the hypothesis that variability of male parental investment has an important effect on female mating strategies in these species.
Individual Distinctiveness and Possible Function of Song Parts of Short‐toed Treecreepers (Certhia brachydactyla). Evidence from Multivariate Song Analysis
Authors: Bauer Hans‐Günther , Nagl Willy 
Published: May 2010

AbstractSonagram analyses of short‐toed treecreeper (= STT) song by use of discriminant analysis revealed consistent individuality in the songs predominantly sung by each male (P‐songs).The P‐songs had been digitized and over 30 song variables were used in the analysis to separate different individuals. In the end, 7 of these variables were needed for a correct classification of 100% of the 203 P‐songs recorded of 39 individuals in 1986. Most of these variables were derived from the first part of the song. A similar analysis with data from 1987 showed that by use of all variables with unskewed distribution complete discrimination of all 271 P‐songs of 47 individuals ensued. The reduction of variables to the 10 most important led to the correct classifications of 99.5%. Using the 7 best discriminators of the 1986 data set 94.2% of the 1987 data were correctly classified, thus confirming the 1986 results. Wrong assignments were mainly due to P‐songs from second or third recording dates which in some cases could not be separated from other P‐songs of the same males by the analysis.Further analysis of the data showed that although the most important discriminators were found in the first part of the song, the combination of all characters of the end part would also allow for a virtually complete discrimination of individuals.The song features of STT P‐song are so distinctive that territory holders should have no difficulties in separating individuals (e.g. neighbours from strangers). Corresponding playback experiments have yet to be carried out on STT.
Competitive Mating Success and Attractiveness of Sterile and Fertile Males of Drosophila montana
Authors: Hoikkala Anneli , Liimatainen Jaana 
Published: May 2010

AbstractThe attractiveness and the mating success of fertile (normal and brownie, br) and sterile (rudimentary testis, rt) Drosophila montana males were studied in female‐choice experiments (one female + two males). The normal males courted the sterile rt males nearly as much as they courted the females, while they courted other males less frequently. The females required a long courtship with the rt males and accepted them as their mating partner less often than normal males.The courtship behaviour of normal, br and rt males was recorded in single pair situations with a normal female. The courtships of the males of all types proceeded in a similar manner, but the successful courtships of the rt males included more licking and touching than those of the normal and br males. The licking and touching periods are probably the critical phases at which the females are able to detect differences in male fertility.
Femme Fatale — the Case of the Threespine Stickleback
Authors: de Fraipont Michelle , Fitzgerald Gerard J. , Guderley Helga 
Published: May 2010

AbstractIn addition to courting females, male threespine sticklebacks must guard their nests from attacks on the eggs by female cannibals. We hypothesized that the presence of females in high densities in tide pools adversely affects a male's health and reproductive success. In the laboratory males housed with conspecific females during the breeding season were in poorer physical condition and died sooner than solitary males and males housed with conspecific males or with heterospecific females.
Syntactical Organization of the Gargle Vocalization of the Black‐capped Chickadee, Parus atricapillus
Authors: Ficken Millicent Sigler , Popp James W. 
Published: May 2010

AbstractThe gargle is a complex call of the black‐capped chickadee Parus atricapillus associated with agonistic interactions. A large sample of calls was recorded from five sites in southeastern Wisconsin. Three sites were near one another and the other two with a different dialect pattern were more distant (all sites were within 15 km of each other). A typical call consists of about 6 notes selected from an array of about 15 different note‐types that are shared among individuals in the same population. Note‐types are given in many combinations, and any individual may deliver many different variations. Analysis of two‐ and three‐note sequences shows a syntactical organization with certain note‐types much more likely to precede or follow than others. In some cases linkage between note‐types was nearly complete. Some differences occurred among individuals and sites, but general organizational rules were similar. One effect on ordering was acoustical structure of the notes. Higher pitched, shorter duration notes were more likely at the beginning than the end of the call which often consisted of trills. Organization of the gargle was compared to that of the chick‐a‐dee call of the same species. Similarities include recombinant properties, general acoustic rules and syntax. A major difference may be that in chick‐a‐dee calls various note combinations constituting a call have different meanings, while the various note combinations comprising an individual's repertoire of gargles may be functionally equivalent.
The Dynamics of Colony Organization in the Primitively Eusocial Wasp Polistes dominulus Christ
Authors: Theraulaz Guy , Gervet Jacques , Thon Bernard , Pratte Michel , Semenoff‐Tian‐Chanski Sophie 
Published: May 2010

AbstractIn colonies of Polistes dominulus Christ, the behaviour of each wasp was recorded individually. We investigated first the relationships between the wasps' hierarchical ranks and their behavioural profiles; secondly, successive α individuals were removed to examine the effects of rank change, particularly accession to α rank, on the behavioural profiles. Four main types of behavioural profiles were observed. Although an individual's rank tended to determine its behavioural profile, the effects of the hierarchy were found to be based on a stepwise arrangement into large hierarchical groups.
Attempts to Determine the Roles of Visual and Olfactory Inputs in Initial Orientation and Homing of Pigeons over Familiar Terrain
Authors: Streng Andrea , Wallraff Hans G. 
Published: May 2010

AbstractThe role of familiar visual landmarks in pigeon homing is still unsettled. If they are involved, they must be thought to be utilized in parallel with olfactory signals. In order to recognize the effectiveness of either one of the input channels separately, vision and olfaction, it is therefore necessary to interfere with both of them.Pigeons were temporarily deprived of image vision by spectacles made of translucent white paper, producing a condition called V‐ as compared with the largely unimpaired condition V+. Access to olfactory signals was temporarily prohibited by charcoal filters before release and nasal anaesthesia upon release, resulting in condition O‐ versus unimpaired smelling of natural air in O+. Prior to the test releases, all the participating pigeons had been made familiar with the two or four test sites (and with other sites in the area) by training flights.According to decreasing levels of initial homeward orientation and homing performance, the four combinations of treatments are to be arranged in the following order: V+O+, V+O‐, V‐O+, V‐O‐. In the last type, no trace of initial homeward orientation remained, indicating that at least one of the two input channels need be functional to enable home‐related orientation. Over well known terrain, either alone seems to be more or less sufficient.The results are indicative but not definitely conclusive. Effects of visual impairment on behavioural activities in general cannot clearly be separated from orientation‐specific effects. Therefore, and because many pigeons refuse to fly in V‐ condition or fail to provide useful data, we stopped applying this method.
“Laughter” and “Smile” in Barbary Macaques (Macaca sylvanus)
Authors: Preuschoft Signe 
Published: May 2010

AbstractIn an observational study on semi‐free Barbary macaques it was investigated whether the phylogenetic roots of human laughter and smile can be traced back to the genus Macaca. On the basis of morphological similarity a ‘relaxed open‐mouth display’ as the phylogenetic precursor of the laughter, and a ‘silent bared‐teeth display’ as the possible ancestor of the smile can be distinguished in the repertory of the Barbary macaque. Behavioural sequences from focal animal protocols were analyzed in order to establish message and meaning of both displays. Relaxed open‐mouth display is regularly observed in the play interactions of juveniles. It is associated with partner‐directed behaviour, it is frequently answered by a relaxed open‐mouth display of the receiver, and accompanied by a special vocalization. Although up to 50% of the juvenile's play partners were higher ranking than themselves voluntary participation was the rule. Most characteristically, the behaviour patterns shown by both play partners are highly symmetrical and synchronized.Silent bared‐teeth display is typically accompanied by evasive or submissive body movements, and occurs primarily in dyadic interactions, mainly by the lower ranking individual. It is not an unidirectional sign of a linear dominance hierarchy, though. Silent bared‐teeth display is a frequent answer to aggressive behaviour shown by the receiver. After its performance, an increase of body contact between sender and receiver was observed. Behavioural sequences of senders and receivers are complementary, but lose their asymmetry after occurrence of the display.It is concluded that these results further support Van Hooff's (1972) view that human laughter and smile have different phylogenetic roots: while silent bared‐teeth display is a signal of submission and appeasement, relaxed open‐mouth display is rightly called the ‘play face’, and is an expression of fun.
Inter‐male Spacing and Aggression in African Painted Reed Frogs, Hyperolius marmoratus
Authors: Dyson Miranda L. , Passmore Neville I. 
Published: May 2010

AbstractInter‐male spacing and the role of aggression in the maintenance of spatial organization was examined in choruses of Hyperolius marmoratus males housed in a semi‐natural enclosure. The effects of chorus size on spacing patterns, nearest neighbour distances and male aggressive behaviour were examined. Males were found to reduce nearest neighbour distances as chorus size increased. This was accompanied by a shift in spacing pattern from even in small choruses (5–9 males) to random in choruses of 10 to 13 males. In choruses of 14, spacing patterns were once again even. The reason for these shifts is unclear but may reflect a sudden, rather than gradual increased tolerance by individuals to high neighbour call intensity as space to call from becomes more limited. The level of male aggression was influenced by chorus size and the time of night. In general, more aggressive interactions occurred in high density choruses. However, this did not translate into higher levels of individual male aggression as density increased. Individual male aggression was high in early evening choruses and declined to a minimum at peak chorusing time. High levels of aggression during early evening may reflect the establishment of calling sites by males, while the drop in aggression at peak chorusing time may occur in response to the presence of females in the chorus at this time or as a consequence of masking of neighbours calls.
The Flying Behavior of Homing Pigeons, Columba livia, Immediately after Release
Authors: Wiltschko Roswitha 
Published: May 2010

AbstractAfter release, homing pigeons are often observed to fly around at the release site before they depart. To assess the significance of this behavior, the bearings of pigeons were taken 1,2,3 and 4 min after release and analysed with respect to the mean vanishing direction of the group (Table 1) and the individual vanishing bearing of each bird (Fig. 3, Table 2). The data come from a series of experiments involving young untrained pigeons that were shown to orient using information obtained on the outward journey, older untrained pigeons (older than 12 weeks) and trained pigeons using local information (see R. Wiltschko & Wiltschko 1985).Analysis of behavior at the release site revealed that most groups of pigeons headed into the direction in which they finally departed almost immediately after release. Their flight directions showed a highly significant relationship to the vanishing bearing from the first min onward. Noteworthy exceptions were the young untrained control birds that seemed to fly around erratically, their bearings after one minute still unrelated to the individual vanishing bearing. Because these birds were shown to use information obtained during the outward journey, this finding indicates that flying around at the release site has nothing to do with determining the current home direction. Instead it might possibly serve to collect local release site information and match it with the home course as determined by information collected en route, thus to integrate it into the navigational ‘map’ of the spatial distribution of navigational factors.
Social Interactions and Familiarity in a Communal Halictine Bee Lasioglossum (Chilalictus) hemichalceum
Authors: Kukuk Penelope F. 
Published: May 2010

AbstractSocial organization in Hymenoptera is quite variable, but most group‐living species have a reproductive division of labor. Communal species, by definition, do not; all individuals work and all are reproductive. In order to understand the evolution and maintenance of such cooperative societies the essential first step is characterization of the behavioral interactions between individuals. In particular, it is important to investigate the influence of common group membership (familiarity) on these interactions.Circle‐tube arenas were used to observe the interactions between 42 pairs of field‐collected Lasioglossum (Chilalictus) hemichalceum females either from the same nest, from different nests but the same nest aggregation, or from different aggregations. Identical procedures were applied to 24 pairs of females from laboratory colonies. There was a striking lack of agonistic behavior with Lunging occurring in only 0.03% of all bouts, and C‐Postures (threat behavior) in only 19% of bouts using field bees and 27 % of bouts using females held in the laboratory. Passing was virtually ubiquitous, occurring in 98 % of all bouts. None of these behavior patterns is significantly associated with the level of familiarity between females. The lack of agonistic behavior and the indiscriminate cooperative behavior (Passing) suggest that all conspecifics are accepted and are treated similarly. This is in contrast to previous studies of L. (Dialictus) zephyrum that demonstrated both kin recognition and nepotism.While Avoidance behavior was rare, significantly more was seen between bees taken from different nest aggregations. Trophallaxis Solicitation occurred in 13 bouts between field bees. While the proportion of bouts in which this occurred is not associated with familiarity, the number of solicitations per bout is greater between females from different nest aggregations. These minor but statistically significant differences suggest that L. hemichalceum females can discriminate between familiar and unfamiliar individuals.Therefore the proximate mechanism underlying universal acceptance of all conspecifics cannot be a lack of recognition cue expression or recognition cue perception. Rather, it is due to a lack of clearly preferential treatment toward familiar individuals. This suggests that some component of fitness is positively associated with group membership per se, or group size.The high levels of mutual tolerance suggest, as do other lines of evidence (Kukuk & Schwarz 1987), that communal societies are not intermediate between solitary and eusocial species.
Electrolocation of Capacitive Objects in Four Species of Pulse‐type Weakly Electric Fish I. Discrimination Performance
Authors: von der Emde Gerhard , Ringer Thomas 
Published: May 2010

AbstractThe great variety of species‐typical electric signals (electric organ discharges, EOD) emitted by weakly electric mormyrid fish might be the result of evolutionary pressures stemming from the two main functions of the electro‐sensory‐motor system: electrocommunication and electrolocation. Employing a conditioned discrimination task we tested four species of mormyrids, emitting EODs differing in waveform, for their ability to detect capacitive properties of objects during electrolocation. Each fish could discriminate capacitive objects within a certain range of capacitive values, which was species specific. The upper and lower limits (upper and lower thresholds) of this detectable range were determined for each fish. In fish species emitting long duration EODs composed of mainly low spectral frequencies both the lower and the upper thresholds were shifted to larger capacitive values compared to fish species emitting shorter EODs. The upper limit of the detectable range was much more variable between species than the lower limit, which was relatively low in all fish. We interpret this as an adaptation of mormyrids to detect small capacitive objects, for example food items. All mormyrids could discriminate between a resistive object and a capacitive object even if the complex impedances of the two objects were identical. This implies that the fish are highly sensitive to small waveform distortions of their self produced EODs.
Post‐bite Elevation in Tongue‐flick Rate by Neonatal Garter Snakes (Thamnophis radix)
Authors: Cooper William E. 
Published: May 2010

AbstractA post‐biting elevation in tongue‐flicking rate was demonstrated experimentally in neonatal, ingestively naive garter snakes (Thamnophis radix). That the snakes also exhibited apparent searching movements suggests that strike‐induced chemosensory searching occurs in nonvenomous snakes lacking previous experience with food or prey chemicals. Two litters of neonates differed in numbers of tongue‐flicks emitted, but had similar relative magnitudes of response across experimental conditions. The existence of post‐bite elevation in tongue‐flick rate (and presumably strike‐induced chemosensory searching) argues for a genetic basis for these chemosensory behaviors in a nonvenomous species of snake, extending the recent finding that strike‐induced chemosensory searching is fully developed in ingestively naive neonatal rattlesnakes. Possible patterns of evolution of post‐bite elevation in tongue‐flick rate, and the strike‐release‐trail strategy of highly venomous snakes are discussed.