bluuebunny/crossref_metadata_2025_split huggingface dataset:
How Rearing History Affects Alarm‐call Responses of Belding’s Ground Squirrels (Spermophilus beldingi, Sciuridae)
Authors: Mateo Jill M. , Holmes Warren G. 
Published: March 2003

Juvenile, but not adult, Belding’s ground squirrels (Spermophilus beldingi) exhibit markedly different responses to alarm calls as a function of their environment. Compared with same‐aged, free‐living juveniles, captive juveniles (housed in large outdoor enclosures) are more likely to respond to playbacks, to exhibit more exaggerated initial responses (e.g. enter a burrow vs. freeze) and to remain alert longer following playbacks of alarm and non‐alarm calls. Two studies were conducted to identify the factors contributing to these response differences. Postemergent rearing environments (such as the opaque enclosure walls that limited visual and auditory stimulation in captivity, or the increased number of conspecifics and natural alarm calls that free‐living juveniles experienced) could not account for the majority of response differences between captive and free‐living juveniles (Study 1). To determine if the attenuated responses of free‐living juveniles were due to foraging pressures, we compared the behaviours of food‐provisioned captive juveniles with those of non‐provisioned captive juveniles. Although sample sizes were small, no differences were evident in the development or expression of responses as a function of foraging pressure. Next, the development of captive juveniles was compared with that of juveniles reared in the field but housed in captivity after emergence (Study 2). Differences in the response patterns of field‐reared and captive‐reared animals matched the differences reported previously, as the responses of field‐reared animals observed in captivity mirrored those of free‐living juveniles that remained in the field. Thus, the differences in alarm‐call responses originally observed between captive and free‐living juveniles are attributed to their pre‐emergent, but not post‐emergent, rearing histories.Captive pups experienced levels of auditory, visual, tactile, and olfactory stimulation that were greater than those typically experienced by free‐living pups. The increased exposure to conspecific alarm calls may have primed captive pups to respond more often and more intensely to the auditory stimuli they heard as juveniles. Sensitivity to early rearing environments may be adaptive for young ground squirrels if it facilitates the development of antipredator behaviour patterns that are appropriate for the local predator environment (e.g. openness of habitat, frequency of predators, availability of refuges).
Parasitized Salamanders are Inferior Competitors for Territories and Food Resources
Authors: Maksimowich Daria S. , Mathis Alicia 
Published: March 2003

AbstractParasites have been shown to impair the behaviour of their hosts, compromising the host's ability to exploit and compete for resources. We conducted two experiments to determine whether infestation with an ectoparasitic mite (Hannemania eltoni) was associated with changes in aggressive and foraging behaviour in the Ozark zigzag salamander, Plethodon angusticlavius. In a first experiment, male salamanders with high parasite loads were less aggressive overall than males with low parasite loads during territorial disputes. In addition, males with high parasite loads were more aggressive toward opponents with high parasite loads (symmetric contests) than toward opponents with low parasite loads (asymmetric contests). In contrast, males with low parasite loads did not adjust their level of aggression according to the parasite load of the opponent. In a second experiment, foraging behaviour of females was tested in response to ‘familiar’ (Drosophila) prey and ‘novel’ (termite) prey. Latency to first capture was significantly longer for parasitized than non‐parasitized females when tested with ‘familiar’ prey, but not for ‘novel’ prey. Our results suggest that parasite‐mediated effects may have profound influences on individual fitness in nature.
Determining Social Rank in Ungulates: A Comparison of Aggressive Interactions Recorded at a Bait Site and under Natural Conditions
Authors: Côté Steeve D. 
Published: March 2003

AbstractResearchers often assume that dyadic interactions at bait sites have similar outcomes to those occurring under natural conditions, but this assumption has seldom been tested. I used aggressive interactions recorded during 1994–97 among marked mountain goats (Oreamnos americanus) to compare dyadic relationships near an artificial salt lick with those observed under natural conditions. I also examined how observations recorded at the lick affected the structure of dominance matrices. The probability of winning an encounter was strongly and positively related to age, both under natural conditions and at the salt lick. The proportion of interactions that adult females lost to 2‐yr‐olds and the proportion won by the youngest individual among adult females, however, more than doubled at the salt lick compared to natural conditions. Two‐year‐old females were 22 times more likely to win interactions against 2‐yr‐old males at the lick than under natural conditions. A decrease in the directional consistency index revealed that the outcomes of repeated encounters of the same dyad were more inconsistent at the salt lick than elsewhere. When interactions recorded at the lick were added to female dominance matrices, the number of inconsistencies more than doubled and the strength of the inconsistencies increased 2–8 times compared to matrices restricted to interactions recorded under natural conditions. Interactions seen at the salt lick caused substantial changes in the hierarchical rank of individual goats. Because interaction rates were high and animals were very concentrated at the trap site, individual recognition may have been difficult, explaining the differences observed in dyadic relationships at the lick compared to natural conditions.
Meadow Voles (Microtus pennsylvanicus) and Prairie Voles (M. ochrogaster) Differ in Their Responses to Over‐Marks from Opposite‐ and Same‐Sex Conspecifics
Authors: Woodward Raymond L. , Bartos Kim , Ferkin Michael H. 
Published: March 2003

AbstractOver‐marking occurs when one individual deposits its scent mark on the scent mark of a conspecific. Previous studies have shown that meadow voles (Microtus pennsylvanicus) and prairie voles (M. ochrogaster) that were exposed to an over‐mark of two same‐sex conspecifics, later responded similarly to the top‐scent mark but differed in their response to the bottom‐scent mark. In the present study, we examined the responses of meadow voles and prairie voles to same‐sex and mixed‐sex over‐marks to ascertain whether their responses reflect the different tactics which males and females in promiscuous (meadow voles) and monogamous (prairie voles) species use to attract opposite‐sex conspecifics and to compete with same‐sex conspecifics. Males and females of both species spent more time investigating the mark of the top‐scent donor than that of the bottom‐scent donor of an over‐mark. Meadow voles exposed to a mixed‐sex over‐mark spent more time investigating the mark of the opposite‐sex conspecific independently of whether it was from the top‐ or bottom‐scent donor. In contrast, prairie voles spent more time investigating the mark of the opposite‐sex donor if it was from the top‐scent donor. These results suggest that: (i) over‐marking serves a competitive function; (ii) the scent marks of individuals attract multiple mates in promiscuous species such as the meadow vole; and (iii) the scent marks of individuals establish and maintain pair bonds between familiar opposite‐sex conspecifics in monogamous species such as the prairie vole.
Age‐Related Microhabitat Segregation in Willow Tit Parus montanus Winter Flocks
Authors: Brotons Lluís , Orell Markku , Lahti Kimmo , Koivula Kari 
Published: March 2003

AbstractIt is expected that through flexibility in behaviour, flock living birds respond to the asymmetries in resource access derived from dominance relationships. We analysed the microhabitat use of willow tits in winter flocks and assessed possible factors which shape habitat segregation between adults and juveniles in different temperature regimes. When foraging in mild conditions (ambient temperature > 0°C), flocks split up into subgroups with adults foraging in inner parts of trees more often than juveniles. However, no differences were recorded in the vertical position occupied in trees. In harsh conditions (< − 4°C), flocks re‐united and juveniles further moved to outer parts of trees, increasing horizontal segregation between age classes. In mild conditions, vigilance behaviour was not related to the position of birds in trees, but in harsh conditions, scanning frequency was higher in outer parts of trees only for adults. In mild weather, juvenile position in trees was associated with body size and mass. The foraging microhabitat segregation detected in harsh conditions fits the age‐related hoarding distribution previously described in the same population. This supports the hypothesis that hoarded food is important in determining future foraging habitat use. Adult preference and intraspecific competition for safer or richer inner parts of trees as foraging sites during harsh conditions seems to determine the habitat segregation between adults and juveniles. Furthermore, we suggest that in mild weather, when foraging in the absence of adults, juveniles balance the costs of using a potentially dangerous microhabitat with the benefits of building energetically cheap and large food reserves through hoarding. The expected patterns of microhabitat segregation may differ in parids, depending on whether predation risk or other factors such as food availability are the main factors controlling habitat quality.
Call Convergence within Groups of Female Budgerigars (Melopsittacus undulatus)
Authors: Hile Arla G. , Striedter Georg F. 
Published: March 2003

AbstractThe budgerigar (Melopsittacus undulatus) is a promising model species for the study of adult vocal learning. To date, several studies have confirmed the existence of vocal plasticity and, more importantly, rapid imitation of contact calls by adult male budgerigars. Vocal learning has not been investigated in female budgerigars, however. Since one likely function of the contact call is to denote group affiliation, we tested the hypothesis that female budgerigars, when placed into groups, would develop a shared contact call. We recorded the contact call repertoires of eight adult female budgerigars that were unfamiliar with one another, then placed them into two groups. Each group was deprived of visual contact with other birds. Recording sessions continued for the subsequent 8 wks, and behavioral observations were also conducted during this time. Within 4–7 wks, females in both groups converged on a common call type. This rate of convergence is slower than that observed in prior experiments limited to male birds, and much slower than vocal imitation by male budgerigars paired with females. Therefore, while our study documents vocal plasticity in adult female budgerigars, it also suggests that female budgerigars learn new vocalizations more slowly than males do.
Maternal Influences on Feeding and General Activity in Domestic Chicks
Authors: Wauters Aline‐Marie , Richard‐Yris Marie‐Annick , Talec Nolwenn 
Published: March 2003

AbstractThe aim of this study was to determine if and how the presence of a hen influences the behaviour of chicks and, more precisely, their food preferences. We observed two types of young, brooded and non‐brooded chicks in the presence of three different food types. Results revealed that brooded chicks performed more locomotion and more sustained feeding activities than non‐brooded chicks. Moreover, brooded chicks had different preferences from non‐brooded chicks and very clearly followed their mother's preferences. We concluded that social facilitation and local enhancement could play a significant role in determining the importance of feeding activities and preferences of brooded chicks.
Fighting and Mating Between Groups in a Cooperatively Breeding Mammal, the Banded Mongoose
Authors: Cant M. A. , Otali E. , Mwanguhya F. 
Published: March 2003

AbstractMany cooperatively breeding animals actively defend a territory containing resources such as food and shelter, which are essential for reproduction. Some observations, however, indicate that conflicts between groups are often triggered by the attempts of males or females, or both, to gain extra‐group copulations. We studied interactions between 12 groups of banded mongooses (Mungos mungo) in Uganda to test whether the frequency of inter‐group encounters was linked to the reproductive status of females, and conducted an experiment to examine the responses of individuals to mongooses from other groups. The rate at which focal groups fought with other groups was higher when its females were in estrous, suggesting that many fights take place over access to mates. Both males and estrous females were instrumental in instigating encounters with rival groups, and extra‐group copulation in the midst of a fight was observed on three occasions. We experimentally simulated encounters with foreign individuals by presenting each of six groups with cages containing a male and a female from a rival group. Subordinate males were the first to investigate these ‘intruders’, spent more time around the intruders' cages, and were more aggressive to the intruders than either dominant males or females. Subordinate males directed more attention and aggression towards the male intruder than the female intruder. We suggest that male banded mongooses actively seek extra‐group copulations in pursuit of paternity, while females may actively seek extra‐group copulations as a way of reducing inbreeding depression.
Why do Juvenile Chinese Pit‐Vipers (Gloydius shedaoensis) Select Arboreal Ambush Sites?
Authors: Shine Richard , Sun Li‐xin , Kearney Michael , Fitzgerald Mark 
Published: March 2003

AbstractOntogenetic shifts in habitat use are widespread, especially in ectothermic taxa in which juveniles may be an order of magnitude smaller than large adult conspecifics. The factors that generate such habitat shifts are generally obscure, but we studied an unusual system that allowed us to compare consequences of habitat selection between adults and juveniles. Pit‐vipers (Gloydius shedaoensis) on a small island in north‐eastern China feed almost entirely on seasonally migrating birds. During the spring bird‐migration period, individual snakes consistently re‐used either arboreal or terrestrial ambush sites. Snakes in trees were smaller (and more philopatric) than snakes on the ground. This ontogenetic shift in habitat use may reflect the difficulty of capturing birds on the ground, especially by small snakes. In laboratory trials, large (adult) pit‐vipers struck faster, further and more accurately than did small (juvenile) snakes. In experiments with free‐ranging snakes, the proportion of strikes hitting the bird was lower for juveniles than for adults, and lower for terrestrial snakes than for arboreal snakes. Additionally, adult snakes generally seized the bird by the head whereas juveniles frequently struck the body or wings (and thus, obtained a less secure grip). Arboreal ambush sites may facilitate prey capture not only because they give access to smaller birds but also because they render the bird's location more predictable and, hence, enable the snake to position itself optimally prior to the prey's arrival. Because juvenile pit‐vipers are less capable strikers, and are small relative to available prey items, they may benefit from the greater ease of prey capture from branches. Thus, the ontogenetic shift in habitat selection within this species may be because of ontogenetic shifts in the vipers’ ability to capture and ingest large, mobile prey.
Population Differentiation in a Complex Bird Sound: A Comparison of Three Bioacoustical Analysis Procedures
Authors: Baker Myron C. , Logue David M. 
Published: March 2003

AbstractWe examined three bioacoustical analysis methods for comparing complex sounds among different populations. We chose the D‐syllable of the chick‐a‐dee call of the black‐capped chickadee (Poecile atricapilla) because it is a broadband sound representative of a class of vocalizations, common in many animals, that resists simple subjective classification for comparative studies. We examined the properties of the D‐syllable in field‐recorded samples from three different populations. The first method of data extraction sampled the amplitude values of a spectrum obtained in a single fast Fourier transform (SFFT) taken at the midpoint of each D‐syllable using multi‐speech software. The second method employed spectrogram cross‐correlation (SPCC) to obtain a matrix of similarity values between D‐syllables in the samples using canary software. The third method calculated similarity values obtained from the evaluation of four acoustic features of the D‐syllables derived from multi‐taper spectral analysis (MTSA) using sound analysis software. Following data extraction by these three techniques, we used multivariate statistical procedures to reduce the data for examination of differences among populations and to represent in scatter‐plots the patterns of clustering of the sounds. We found that the SFFT in the middle of the D‐syllable provided the poorest population discrimination following statistical processing, the SPCC method produced the next clearest population separation, and the MTSA method resulted in the most distinct separation of the three populations of D‐syllables. In carrying out these comparisons, we discovered that the characteristic environmental noise of a recording area can influence the signal properties of broadband sounds being compared by automated procedures, and could lead to faulty conclusions unless appropriate care is taken to mitigate the noise in which the signals of interest are embedded. Consequently we re‐analyzed our data following noise reduction and found less discrete population separation overall. However, the methods of SPCC and MTSA retained the ability to separate populations, with MTSA providing the sharpest discrimination among groups.
Female Canaries (Serinus canaria) Associate more with Males that Contrast Strongly against the Background
Authors: Heindl Martin , Winkler Hans 
Published: March 2003

AbstractMale birds with bright plumage colors which entail production costs and increased predation risks should be able to emphasize the handicap function of their ornaments when they present themselves against a contrasting background. Contrast with the background may accentuate the signal's costliness and make the male more conspicuous to predators. Both effects should contribute to increase male attractiveness. It is therefore conceivable that the extent to which the male plumage contrasts against the background modifies female choice behavior as it improves the discrimination of mates. We tested this hypothesis in domesticated canaries (Serinus canaria). In the first experiment, yellow females could choose between two yellow males presented in front of a yellow and a white background, respectively. In the second experiment we replaced the yellow males with white ones. In experiment 1 females associated significantly more with yellow males which contrasted strongly against the white background. In experiment 2 there was at least a trend for preferred associations with the white male in front of the yellow background. We found no support that male properties per se were chosen. We could further clarify that females associated with the contrasting male and not with a particular background color. Thus, our study demonstrates that not only inherent properties of the sender but also the interaction of bird color with the signaling environment may influence mate choice.
RFLP analysis as a tool for identification of lignicolous basidiomycetes: European polypores
Authors: Fischer M. , Wagner T. 
Published: March 2003

SummaryRestriction fragment length polymorphisms were generated for 52 species of lignicolous European polypores belonging to 31 different genera. An enzymatically amplified portion of the nuclear‐encoded ribosomal DNA was found to be about 1800–1900 bp long for most taxa. After digestion with Hpa II, 44 distinct phenotypes were detected for the species under study; application of the additional restriction endonucleases, Hin 6 I and Hinf I, resulted in 48 species‐specific and two genera‐specific phenotypes. The procedure described should allow for a reliable identification of unknown mycelia of lignicolous fungi.
Treatment of oak decline using pressurized injection capsules of antifungal materials
Authors: Fernandez‐Escobar R. , Gallego F. J. , Benlloch M. , Membrillo J. , Infante J. , de Algaba A. Perez 
Published: March 2003

Summary Quercus ilex and Quercus suber trees growing at several sites in Extremadura, Western Spain, that were showing symptoms of oak decline were injected with potassium phosphonate, quinosol or carbendazim using a low‐pressure method of trunk injection composed of a pressurized capsule system. A team of four people injected between 120 and 189 trees per day, depending upon the density of the undergrowth vegetation. This labour cost represented, approximately, 15–20% of the total cost of the treatment. The potassium phosphonate‐injected trees showed a significant improvement in vegetative growth within 2 years of the injection treatment, and they also showed some recovery from the decline symptoms during the third year. Only one injection treatment of an average of 3.5 capsules (corresponding to 24.5 g phosphonic acid) per tree of approximately 36 cm in diameter, was necessary to reduce the disease severity significantly. Indirectly, these results corroborate the implication of Phytophthora cinnamomi in oak decline within Spanish Quercus woodlands.
Detection and quantification of Phytophthora species which are associated with root‐rot diseases in European deciduous forests by species‐specific polymerase chain reaction
Authors: Schubert R. , Bahnweg G. , Nechwatal J. , Jung T. , Cooke D. E. L. , Duncan J. M. , Müller‐Starck G. , Langebartels C. , Jr H. Sandermann , Oßwald W. 
Published: March 2003

SummaryOligonucleotide primers were developed for the polymerase chain reaction (PCR)‐based detection of selected Phytophthora species which are known to cause root‐rot diseases in European forest trees. The primer pair CITR1/CITR2, complementing both internal transcribed spacer regions of the ribosomal RNA genes, gave a 711 bp amplicon with Phytophthora citricola. The Phytophthora cambivora specific primer pair CAMB3/CAMB4, producing a 1105bp amplicon, as well as the Phytophthora quercina specific primer pair QUERC1/QUERC2, producing a 842 bp amplicon, were derived from randomly amplified polymorphic DNA (RAPD)‐fragments presented in this paper. All three primer pairs revealed no undesirable cross‐reaction with a diverse test collection of isolates including other Phytophthora species, Pythium, Xerocomus, Hebeloma, Russula, and Armillaria. Under the PCR conditions described the detection of a well discernable amplicon was possible down to 100 pg (P. cambivora), 4pg (P. quercina), and 2pg (P. citricola) target DNA. This diagnostic PCR system was able to detect P. citricola, P. quercina, and P. cambivora in seedlings of pendunculate oak (Quercus robur) and European beech (Fagus sylvatica) which were artificially infected under controlled conditions.