bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Huh Vocalization of White‐faced Capuchins: a Spacing Call Disguised as a Food Call?
Authors: Boinski Sue , Campbell Aimee F. 
Published: May 2010

AbstractWhite‐faced capuchins, (thus capuchins, predictably emit huh vocalizations at high rates within dense fruit patches. We sought to determine why white‐faced capuchins at the La Selva Biological Station, Costa Rica produce these food‐associated calls. Here we analyze the contexts in which this intra‐group vocalization was emitted, including the spatial responses elicited from other troop members. A cumulative 26.6 h of continuous focal samples and 3314 spectrograms (including 1643 huhs) were analyzed from a study troop with 16 focal subjects. The mean individual rate of huhs was greater (1) during foraging versus nonforaging activities; (2) during fruit foraging compared to both visual searching for foraging sites and foraging for arthropod prey; and (3) when the nearest neighbor was within a 10 m radius of the focal animal compared to when the nearest neighbor was at greater distances. A huh also predicted a significant increase in nearest‐neighbour distance; on average, mean nearest‐neighbor distance increased 3 m within 2 min following a huh vocalization. Null models of change in mean nearest‐neighbor distance over time were generated from the original data set by treating predetermined time points (140 s intervals) in the focal recordings as if those points marked instances at which huhs were produced by the focal subject. No significant alterations in nearest‐neighbor distance were detected within time lags up to 100 s in these null models, supporting the conclusion that huhs are causally linked with subsequent increases in nearest‐neighbor distances. Huhs were most evident when capuchins were within dense fruit patches, but these calls were produced across all foraging contexts. Our results suggest that huhs may not be food calls in the usual sense (i.e. informing others of the location of food sources to be shared), but may be more appropriately described as spacing calls. Huhs probably act to increase foraging efficiency by reducing overlap in foraging areas with other troop members.
Probing, Assessment and Management during Interactions between Ground Squirrels (Rodentia: Sciuridae) and Rattlesnakes (Squamata: Viperidae). 2: Cues Afforded by Rattlesnake Rattling
Authors: Rowe Matthew P. , Owings Donald H. 
Published: May 2010

AbstractThe predator‐prey relationship between California ground squirrels (Spermophilus beecheyi) and northern Pacific rattlesnakes (Crotalus riridis oreganus) is a useful system in which to explore risk assessment and management. Rattlesnakes are major predators of ground‐squirrel pups, but pose only a sublethal threat to adult squirrels. Adults approach, harass, and even attack rattlesnakes when confronted with them. A rattlesnake's response to such harassment can include rattling and striking.Not all rattlesnakes pose the same risk to an adult squirrel. Larger, warmer rattlesnakes strike in ways that may be more effective at overwhelming the defensive leaps of squirrels, and larger snakes can inject more venom if they are successful in landing a bite. It would therefore benefit squirrels to assess and respond appropriately to rattlesnakes of different body size and temperature. We looked for cues in rattling upon which such assessments might be based.We recorded and digitally analyzed the rattling sounds of snakes of different sizes, each tested at four different body temperatures — 10, 18, 27, and 35°C. Results indicate that warmer snakes rattle with faster click rates, higher amplitudes, and shorter latencies. Similarly, larger snakes produce rattling sounds of higher amplitude and lower dominant frequencies. Thus, rattling provides reliable cues about rattlesnake dangerousness. Nevertheless, this highly ‘informative’ characteristic of rattling has its origins in physical and physiological constraints, not in specialization for communication.Ground squirrels appear to probe for the information extractable from rattling, for example by pushing loose substrate at the snake and thus inducing it to rattle. Future reports will discuss the degree to which ground squirrels actually exploit these cues.
Call Variation in the Bufo microscaphus Complex: Implications for Species Boundaries and the Evolution of Mate Recognition
Authors: Gergus Erik W. A. , Sullivan Brian K. , Malmos Keith B. 
Published: May 2010

AbstractSince the Modern Synthesis, many species concepts have considered characters mediating mate recognition essential to both the identification and definition of species. To explore divergence in mate recognition systems, calls were recorded and toads measured from all three species of the monophyletic Bufo microscaphus species complex including five populations of Bufo californicus, three populations of B. microscaphus, and one population of B. mexicanus. Call duration, dominant frequency, and pulse rate were significantly related to temperature, but not snout‐vent length. When adjusted for temperature, calls of B. californicus had a significantly longer call duration, higher dominant frequency, and slower pulse rate than B. mexicanus and B. microscaphus, which did not differ from one another. However, the magnitude of variation among populations of B. californicus was similar to that between species. Discriminant analysis using call variables provided some separation of B. californicus and B. mexicanus from B. microscaphus, and cross‐validation analysis correctly classified approximately 75% of B. californicus and B. mexicanus. Given only slight divergence in mate recognition systems between B. californicus and the other two taxa, the biological significance of this difference remains ambiguous. Comparisons among B. americanus group members indicate that hybridizing taxa may or may not exhibit divergence in advertisement calls. Maintenance of independently evolving lineages may be driven by other evolutionary mechanisms. These results support the notion that species recognition is best viewed as an effect of mate recognition.
Escape Behavior and Predation Risk of Mainland and Island Spiny‐tailed Iguanas (Ctenosaura hemilopha)
Authors: Blázquez M. Carmen , Rodríguez‐Estrella Ricardo , Delibes Miguel 
Published: May 2010

AbstractWe investigated the relationships between predator avoidance behavior and predation risk by comparing the wariness of iguanas (Ctenosaura hemilopha) belonging to an island population with few predators with that of iguanas belonging to a mainland population under high predation pressure. We predicted that island iguanas would be less wary than mainland ones. Island iguanas allowed the closer approach of potential predators before their first reaction and fleeing. The responses of both sexes did not differ statistically, except for the frequent displays shown by males as the first reaction. These results suggest that island iguanas, which were probably introduced onto the island by man, have modified their behavior in response to a decline in predation risk, supporting the hypothesis that predation pressure can contribute to intraspecific variation in antipredator behavior. The results also quantify the tameness of prey on islands without terrestrial predators, and their consequent vulnerability if foraneous predators are introduced. No significant difference was found between the populations in the time needed by frightened iguanas to resume their normal activity, suggesting that the island iguanas could learn to recognize predators and develop a suitable antipredator behavior.
Evolution of Female Egg Care in Haremic Triggerfish, Rhinecanthus aculeatus
Authors: Kuwamura Tetsuo 
Published: May 2010

AbstractPaternal care is predominant among telcost fishes with external fertilization. This study describes maternal care in a haremic coral‐reef fish and discusses the possible factors leading to its evolution. Both sexes of the triggerfish Rhinecanthus aculeatus (Balistidae) maintained territories; some individuals for more than 8 years. Each male's territory overlapped 2‐3 female territories. Pair‐spawning occurred around sunrise. Only females cared for the demersal eggs until hatching, which occurred just after sunset on the day of the spawning. No predation was observed on eggs under the maternal care, but experimental removal of parental females decreased the hatching rate to nearly zero. Egg‐guarding females foraged as frequently as males, but less than half of non‐spawning days. Spawning occurred only in the periods of about 1 wk around the new or full moon, and individual females spawned up to three times in each period. Thus, the maternal care did not significantly affect the duration of the females' spawning intervals, while males would suffer mate loss if they performed parental care. In this situation, maternal care should be the evolutionarily stable strategy. Evolutionary transition from no care to maternal care and then to biparental care is suggested in the Balistidae.
Convenience Stores: Repeated Use of Some Cache Sites by Clark's Nutcrackers (Nucifraga columbiana)
Authors: Balda Russell P. , Kamil Alan C. , Carder Justin P. , Racz Christy L. 
Published: May 2010

AbstractField studies reveal that Clark's nutcrackers (Nucifraga columbiana) cache thousands of seeds in subterranean caches during the autumn in some years, and laboratory studies have shown that these caches can be recovered with high levels of accuracy. Over the life of a bird, numerous cache recovery cycles may be experienced and many of these may be in the same area. Birds may thus develop strong individual preferences for certain sites. These sites may become more memorable and used preferentially. These sites might also be more vulnerable to theft because of continual reuse. In this study, birds were allowed to cache and recover four times from the same set of potential cache sites in a large experimental room. Three of five birds used some cache sites more often than would be expected by chance. However, these birds did not place more seeds per cache, have higher recovery accuracy, or make more revisits to cache sites previously used. Birds did not create caches earlier in previously used holes until cycle 4, when birds actually cached in used sites significantly sooner than in previously unused ones. Birds neither recovered caches earlier from previously used sites nor made error probes earlier at them. Sites that were repeatedly used for caching were holes that were significantly closer to a centrally located feeder than less frequently used sites. Thus, some birds may develop slight preferences for some locations but these sites are not treated preferentially. Birds appear not to gain the advantages, nor suffer the consequences associated with repeated use of the same sites.
Temporal Pattern of Agonistic Interaction in Two Gerbil Species (Rhombomys opimus and Gerbillus perpallidus) Differing in Resistance to Social Pressure
Authors: Goltsman Michael E. , Volodin Ilya A. 
Published: May 2010

AbstractThis study compares temporal patterns of intraspecific agonistic interactions in two gerbil species in order to indicate interspecific differences in levels of social resistance. Both cross‐sex and same‐sex pairs of great gerbils (Rhombomys opimus Licht., 1823), and only same‐sex male pairs of pallid gerbils (Gerbillus perpallidus Setzer 1958) were observed during staged encounters on a neutral arena. Analysis of three latency measures—latency to first agonistic interaction; latency to overt aggression (attack and/or ‘arrested’ fight); and latency to establishment of a stable winner‐loser asymmetry among opponents—revealed both similarities and differences among the species. Latencies to first agonistic interaction were similar (did not differ significantly) among species and sexes. However, great gerbil males showed significantly more long latencies to establishment of a stable asymmetry among opponents, than great gerbil females or pallid gerbil males. So, the periods of symmetrical struggle in agonistic conflict last longer in great gerbil males, than in great gerbil females or pallid gerbil males. These differences in temporal pattern of agonistic interaction may reflect sex and species differences in resistance to social stress.
Food‐anticipatory Activity as a Cue for Local Enhancement in Golden Shiners (Pisces: Cyprinidae, Notemigonus crysoleucas)
Authors: Reebs Stephan G. , Gallant Bruno Y. 
Published: May 2010

AbstractThe goal of this study was to test whether food‐anticipatory activity, which is more subtle than feeding activity, can be used as a cue for local enhancement by fish. Golden shiners, Notemigonus crysoleucas, were offered a choice between spending time near a shoal of conspecifics normally fed at that time of day or a shoal normally fed at another time. Despite the fact that no food was delivered during the tests, the shoal that was normally fed at that time had more fish moving and more fish close to the surface, where food usually appeared, than the other shoal. This is evidence of food‐anticipatory activity. The choosing shiners, after being deprived of food for 24‐48 h, preferred to stay near the anticipating shoal rather than near the other one. When satiated, the shiners chose both shoals at random, indicating that hunger promotes the use of food‐anticipatory cues in shoal choice and local enhancement. The results also support the idea that food‐anticipatory activity can attract competitors for food and may therefore be costly. Food‐anticipatory activity might also attract predators, but the fact that satiated shiners did not actively avoid anticipating shoals indicates that the potential cost of predator attraction would be either low or mitigated by other factors.
Reproductive Benefits from Female Promiscuous Mating in a Small Mammal
Authors: Keil Anja , Sachser Norbert 
Published: May 2010

AbstractPromiscuous systems where both males and females mate several times with different individuals are widespread among mammalian species. As a consequence, females obtain sperm from more than one male and paternity is decided by sperm competition. In theory, females might gain ‘genetic benefits’ for their offspring from this mechanism. In a mating experiment we now demonstrate in the promiscuous rodent Galea musteloides that females which were paired with four males, and became pregnant, weaned more surviving offspring than females which were paired with a single male. Litter sizes did not differ between the two groups. The data support the hypothesis that promiscuous females copulate with several males to induce sperm competition and/or to enforce cryptic female choice and thereby increase the viability of their offspring.
The Direction of Celestial Rotation Affects the Development of Migratory Orientation in Pied Flycatchers, Ficedula hypoleuca
Authors: Weindler Peter , Liepa Varis , Wiltschko Wolfgang 
Published: May 2010

AbstractThe migratory direction in young passerine migrants is based on innate information, with the geomagnetic field and celestial rotation as references. To test whether the direction of celestial rotation is of importance, hand‐raised pied flycatchers in Latvia were exposed during the premigratory period to a planetarium rotating in different directions. During autumn migration, when their orientation behavior was recorded in the local geomagnetic field in the absence of celestial cues, birds that had been exposed to a sky rotating in the natural direction showed a unimodal preference of their south‐westerly migratory direction. Birds that had been exposed to a sky rotating in the reversed direction, in contrast, showed a bimodal preference of an axis south‐west‐north‐east. Their behavior was similar to that of pied flycatchers that had been raised without access to celestial cues. In Latvia, the magnetic field alone allows only orientation along the migratory axis, and celestial rotation enables birds to select the correct end of this axis. Our findings show that the direction of rotation is of crucial importance: celestial rotation is effective only if the stars move in the natural direction.
Anal Gland Secretion Codes for Relatedness in the Beaver, Castor canadensis
Authors: Sun Lixing , Müller‐Schwarze Dietland 
Published: May 2010

AbstractWe investigated how information about relatedness is coded in the anal gland secretion (AGS) of the beaver (Castor canadensis). Using gas chromatography, we found that individual secretion profiles did not change over time and location of the beaver and the variation in the AGS profile was smaller within an individual than between individuals. Therefore, the AGS is suituable for characterising individuality. We also found that related individuals shared more features in the AGS profile than did unrelated individuals. Hence, information about kinship can be coded in the AGS profile. These findings substantiate the behavioural kin recognition system using the mechanism of phenotype matching in the beaver.
Nest and Nestmate Recognition by a Fungus‐growing Ant, Apterostigma collare Emery (Hymenoptera: Formicidae)
Authors: Singer T. L. , Espelie Karl E. 
Published: May 2010

AbstractThe ability of Apterostigma collare workers to differentiate their nest from other nests and their nestmates from non‐nestmates was examined. In field tests, workers that were removed from their nest were accepted back into their own nests, but were rejected when they were placed onto a nearby (≤ 1 m) nest or a distant (≥ 100 m) nest. In the laboratory, when given a choice between a fragment of their own nest and a fragment of a second nest (near or distant), workers selected their own nest material rather than the material of the second nest. For the nestmate recognition bioassay, two workers from one nest were placed together in an arena with a worker from a second nest. In most bioassays, the nestmates were tolerant of each other, but they were intolerant of the non‐nestmate. The results demonstrate that A. collare workers have the ability to recognize nestmates and their nests. The results also suggest that each nest of A. collare is an independent colony.
The Protector Species Hypothesis: Do Black Skimmers Find Refuge from Predators in Gull‐billed Tern Colonies?
Authors: Pius Sandra M. , Leberg Paul L. 
Published: May 2010

AbstractThe protector‐species hypothesis explains mixed‐species coloniality on the basis of benefits individuals of a species may receive by nesting with another species, the ‘protector’ species, that responds aggressively to potential threats. The reactions of nesting individuals to both natural and model predators were observed to determine whether black skimmers (Rhynchops niger) gain an antipredator advantage by nesting with gull‐billed terns (Sterna nilotica). Observations of natural predators were gathered from three mixed‐species and three single‐species (black skimmers) subcolonies. Natural predators most commonly encountered by the colonies were herring gulls (Larus argentatus), laughing gulls (Larus atricilla), and ruddy turnstones (Arenaria interpres). Gull‐billed terns responded to the gulls, but not to the turnstones, in higher proportions than did black skimmers. Two decoys, a mink and a gull, were used to simulate predatory encounters, and a duck decoy was used as a control at two mixed‐species and one single‐species subcolonies. Gull‐billed terns responded in significantly higher proportions than did skimmers to all decoy treatments in the mixed‐species subcolonies. Mobbing of both natural and model predators by the terns suggests that skimmers may gain a reproductive advantage by nesting with these terns. However, the response of black skimmers to both natural and simulated predators was independent of the presence of gull‐billed terns in the colony, indicating that black skimmers may not perceive these objects as threats, or may react differently to predators than do gull‐billed terns.
Parameters of Mating Effort and Success in Male European Ground Squirrels, Spermophilus citellus
Authors: Millesi Eva , Huber Susanne , Dittami John , Hoffmann Ilse , Daan Serge 
Published: May 2010

AbstractBehavioural and physiological changes during the reproductive period were documented in male European ground squirrels including: initiated conflict, scent marking, locomotion and range size, as well as testis size, scrotal pigmentation, testosterone levels and changes in body mass. Spring emergence dates in adult males varied but preceded those of females. Gonadal maturation was complete in adult males at emergence. Most yearlings did not mature and emerged with females. After a quiescent premating phase, male range, range overlap, conflict rates and locomotion increased at female emergence. The synchrony of females, their small ranges and short latencies to ovulation produced a highly male‐biased operational sex ratio (OSR) and potential for scramble competition polygyny. In contrast to other ground squirrel species, each female apparently mated with only a single male. Scramble competition did appear to occur, in that males tried to contact as many females as often as possible before copulation. Females placed high temporal prerequisites on males. Costs of scrambling were documented by body mass loss during mating, which covaried with the number of ‘acquired’ females. Testicular regression occurred earlier, and fattening, moult and onset of next hibernation were delayed in successful males. The determinant factor in these costs was found to be mass loss intensity during the main mating period. Surprisingly, this factor was best related to feeding changes and not to locomotion or aggression. Time budget constraints perhaps imposed by the female, with compounding influences of exercise and stress effects of conflict, then negatively affected ensuing seasonal activities. The individual changes may adversely affect individual survivability and/or future reproductive success.
Morphological and Behavioural Traits Affecting the Intensity and Outcome of Male Contests inGallotia galloti galloti(Family Lacertidae)
Authors: Molina‐Borja Miguel , Padron‐Fumero Monica , Alfonso‐Martin Teresa 
Published: May 2010

AbstractThis study describes the sequence of behaviour during aggressive encounters between male ‘tizón’ lizards (G. galloti galloti) and assesses the effect of morphological and behavioural traits on the outcome and intensity of staged aggressive encounters between males. Aggressive encounters ranged from only throat extension to escalated fights with biting and rolling over. Winners were heavier, had longer heads, and performed tongue‐flicking, throat extension and biting at a higher rate than losers. The rate of aggressive behaviour increased with decreasing difference in snout‐to‐vent length, head length and head width of the contestants. The results are in agreement with some predictions of the sequential assessment game model in that probability of victory increased with the difference in fighting ability and that the rate of aggressive behaviour was higher in contests between animals of similar size.