bluuebunny/crossref_metadata_2025_split huggingface dataset:
Scaling migration speed in animals that run, swim and fly
Authors: Hedenström Anders 
Published: February 2003

AbstractOverall migration speed is likely to be a trait under selection pressure in animals migrating annually between habitats for reproduction and survival. A general expression was used for migration speed (Vmigr), accounting for energy accumulation and transport, and derive how Vmigr scales with body mass for three types of migratory locomotion: running, swimming and flying (powered and soaring flight). Migration speed is predicted to increase with increasing body mass in animals that run (∝m1/11), swim (∝m1/24) and fly by soaring (∝m0.22), whereas in animals migrating by powered flight it decreases (∝m−1/4). How the relative duration of fuel accumulation to that of migratory locomotion scales with body mass is also derived. This proportion should increase in animals that run and fly, but should remain unaffected by body size in swimmers. The suggestion is made that in runners and swimmers, selection for enhanced migration speed could provide an explanation to Cope's rule, i.e. the observation that body size gradually tends to increase over time.
Pseudonovibos spiralis: epitaph
Authors: Galbreath G. J. , Melville R. A. 
Published: February 2003

AbstractTimm et al. (2001) argue that Pseudonovibos spiralis actually exists as a new bovine species, and identify as such two frontlets in the Kansas Natural History Museum, U.S.A. This is not the first time these specimens have been the subject of dubious taxonomic identification; they were previously misidentified by Hoffman (1986) as female kouprey Bos sauveli. A further irony is that the original unmasking (Dioli, 1995) was accomplished by an author of the current defense.
Niche separation in sympatric jackals (Canis mesomelas and Canis adustus)
Authors: Loveridge A. J. , Macdonald D. W. 
Published: February 2003

AbstractNiche separation (along habitat use, activity and dietary axes) between two sympatric jackal species, Canis adustus and Canis mesomelas, was investigated in north‐west Zimbabwe. Diet of the two jackal species was flexible and opportunistic and dietary overlap between the jackal species was high. However, C. mesomelas ate more springhares Pedetes capensis, and C. adustus ate more safari camp refuse. To a large extent, differences in diet reflect availability within home ranges. Although interspecific home ranges overlapped by up to an average of 26%, the two species did not intensively use the same areas, and favoured different habitats. Canis mesomelas defended territories in the grassland habitat, which was also the favoured habitat of springhares, the predominant vertebrate prey species in the area. Canis adustus centred their home ranges on centres of human activity, benefiting from the regular, but low quality, anthropogenic food resources. In this study, C. adustus, with the more generalist dentition, had a broader niche than C. mesomelas (dietary diversity C. adustus=4.14; C. mesomelas=3.45). Within sympatric areas, differing activity times may further operate to decrease competition, allowing these canids to co‐exist. The activity times of the two species differed, with C. adustus being almost entirely nocturnal. Canis mesomelas, while mostly nocturnal, was also active during the morning and in the late afternoon. The jackals in this study did not have clear‐cut niches and it is probable that the extreme flexibility of canids in both diet and behaviour allows these species to co‐exist sympatrically over part of their range.
Reduced dispersal and opportunistic territory acquisition in male lions (Panthera leo)
Authors: Funston Paul J. , Mills Micheal G. L. , Richardson Philip R. K. , van Jaarsveld Albert S. 
Published: February 2003

AbstractLife‐history patterns in lions Panthera leo living in savanna woodlands of the Kruger National Park, South Africa, were investigated and compared with those of the Tanzanian ‘plains‐like’ ecosystems (e.g. Serengeti Plains and Ngorongoro Crater). First, lower levels of mortality in the juvenile age classes were found in Kruger lions, which in turn, extend the inter‐birth period. A further difference was a prolonged period of association of sub‐adult males with their natal pride, either directly or in a land tenure system that has not been described previously. Most (80%) of young male coalitions rather than becoming nomadic, remained close to their natal territory after leaving the pride, either as non‐territorial sub‐adults or adults and even as territorial adults. Only 20% of coalitions did not stay close to their natal range, one of which acquired a territory 20 km away from its natal pride. The pattern of territory acquisition, in fact, was one in which the majority of holders acquired territories close to their natal ranges. These behaviour patterns contrast markedly with those from ‘plains‐like’ ecosystems where dispersing males usually move far away from their natal pride's range (>200) km and often remain nomadic for extended periods of time. Dense bush and access to sufficient prey resources in the form of resident buffalo Syncerus caffer herds may be important factors allowing extended residence near the natal pride's territory. Buffalo were more available in our study area habitat than in neighbouring habitats, and comprised the majority of male lion kills. Extended male residence contrasts markedly with current theory on dispersal in polygynous mammals, which holds that only one sex (females for lions) gain an advantage by staying close to the territory of their natal pride. In Kruger it seems that both sexes gain an advantage by not dispersing far, and use currently undocumented mechanisms to avoid inbreeding.
Breeding biology of the reverse‐dichromatic, co‐operative parrot Eclectus roratus
Authors: Heinsohn Robert , Legge Sarah 
Published: February 2003

AbstractThe breeding biology and social system of the eclectus parrot Eclectus roratus, a species with a unique form of sexual dichromatism (red and blue females, green males) was examined. Our 4‐year study at Iron Range National Park on Cape York Peninsula, Australia, showed that females guarded their nest hollows in emergent rainforest trees for up to 9 months each year, often starting well before they laid their first clutches early in the dry season. During this time they rarely left the nest and relied on males for food, both for themselves and their nestlings. Intrasexual competition for scarce hollows and the threat of egg destruction by other eclectus parrots may explain this extreme guarding behaviour. Reproductive success was low. The combined effects of egg and chick loss to conspecifics and predators, brood reduction and flooding of hollows from heavy rain meant that only 18% of eggs and 27% of clutches produced a fledgling. Over 4 years, reproductive success amongst females was strongly skewed: 39% of females were never successful, and only 29% produced more than one fledgling per year. Eclectus parrots were found to breed co‐operatively with as many as five males feeding a single female at the nest. Multiple mating, involving one female and four males, was observed once. Despite an even sex ratio at fledging, the adult sex ratio was strongly male‐biased, suggesting higher mortality of females. Our data shows that reproductive variance for females is high, and suggests that a shortage of tree hollows and eligible females may enforce co‐operative breeding amongst males.
Assessing the breeding season diet of goshawks Accipiter gentilis: biases of plucking analysis quantified by means of continuous radio‐monitoring
Authors: Rutz Christian 
Published: February 2003

AbstractPlucking analysis is a standard method for assessing the breeding season diet of goshawks Accipiter gentilis. Results may be biased, however, due to differences in the detectability of remains of certain prey species and to selective prey transportation by hawks. This study investigated prey choice of three goshawk breeding pairs in the city of Hamburg, Germany, during 1997–99. Predation data obtained by continuous radio‐monitoring of the adult males were used to quantify biases of simultaneous plucking analyses, which were conducted in the nesting territories of the corresponding breeding pairs. A comparison of estimated average food requirements with actual biomass intake observed in two of the monitored goshawks (with sufficient sample sizes) indicated that it was possible to record virtually all kills that occurred during tracking sessions. Therefore, radio‐tracking data could be used to evaluate the accuracy of plucking analysis. Comparisons showed that the proportions of small birds and of feral pigeons Columba livia f. domestica were underestimated by the scanning method by 10% and 13%, respectively. The latter finding was unexpected as pigeons have large, conspicuously coloured feathers that are easy to detect. However, as goshawks plucked large prey more thoroughly at the capture site than smaller prey, a comparatively small number of their feathers were present in the nesting areas. This source of bias in plucking analysis has passed unnoticed in previous studies. It may have important implications for the interpretation of results of future projects that aim to estimate predation rates in goshawks and other bird‐eating raptor species.
Chemical communication in the giant panda (Ailuropoda melanoleuca): the role of age in the signaller and assessor
Authors: White A. M. , Swaisgood R. R. , Zhang H. 
Published: February 2003

AbstractAs a solitary species, giant pandas Ailuropoda melanoleuca appear to use chemical signals to maintain a communication network with individuals in the community with whom they have little direct contact. Chemosensory discrimination abilities undoubtedly play a large role in determining the efficiency of this communication system. The hypothesis that pandas could discriminate the age of the signaller was tested by presenting subjects with a simultaneous choice test between odours collected from adult and subadult donors. Twenty‐eight pandas were tested with three types of stimuli: male urine; male anogenital gland secretions; female urine. The results indicate that individuals from both age classes readily discriminate between adult and subadult odours emanating from all three odour types, showing a pronounced investigatory preference for adult odours in all cases. Female reproductive condition influenced general responsiveness to male odours, but did not significantly alter adult/subadult discrimination patterns. The prevalence of overt discrimination across odour types and age classes suggests an important and multifunctional role for this ability, and highlights the importance of studying chemical communication at all developmental stages. It is proposed that these results may be explained in part by: (1) assessment of competitive ability, which correlates with the age class of the signaller; (2) identification of potential mates that have attained reproductive maturity.
Correlations between call frequency and ear length in bats belonging to the families Rhinolophidae and Hipposideridae
Authors: Huihua Zhao , Shuyi Zhang , Mingxue Zuo , Jiang Zhou 
Published: February 2003

AbstractEcholocation calls of 10 species of rhinolophid and four species of hipposiderid bats were recorded in China. Close negative relationships were found within Rhinolophidae and Hipposideridae between call frequency and ear length. Multiple regression and residual analysis were used to evaluate the influences of forearm length and ear length on call frequency and ear size. Ear length proved to be a more important morphological parameter influencing the call frequency in rhinolophids but not in hipposiderids. Ears are largely shaped by echolocation calls in both families. The influence of body size on ear size was significant in rhinolophids but not in hipposiderids, and the enlarged ears of rhinolophids correlated with the lower frequencies that rhinolophids used relative to larger body size.
Twice every second year: reproduction in the pig‐nosed turtle, Carettochelys insculpta, in the wet–dry tropics of Australia
Authors: Doody J. Sean , Georges Arthur , Young Jeanne E. 
Published: February 2003

AbstractThe reproductive biology of female pig‐nosed turtles Carettochelys insculpta was studied for 4 years in the wet–dry tropics of northern Australia. Females matured at around 6 kg body mass (38.0 cm curved carapace length, 30.5 cm plastron length). Turtles produced egg sizes and clutch sizes similar to that of other turtle species similar in size. Turtles reproduced every second year, but produced two clutches within years, about 41 days apart. Thus, it appeared that females were energy limited, possibly due to the low available energy content of the dry season diet (aquatic vegetation). Life‐history theory predicts that some costly behaviour associated with reproduction exists, such that by skipping years turtles could reduce that cost and put the savings into future reproduction. Previous work revealed no behaviour associated with reproduction in the population. Within years, clutch mass did not differ between early (first) and late (second) clutches. However, early clutches tended to have more eggs per clutch but smaller eggs than late clutches, a new finding for turtles that has been demonstrated in lizards and other animals. Because the study spanned both years with ‘big’ and ‘small’ wet seasons, we were able to examine how the magnitude of the wet season influenced reproductive characteristics. Following big wet seasons, turtles produced larger, heavier, and more eggs per clutch than they did after small wet seasons. Relationships among body size, egg size and clutch size were evident after two big wet seasons but not apparent after two small wet seasons. Collectively, annual variation in reproductive characteristics and current life‐history theory suggest that a big wet season is a time of high energy accumulation for the turtles.
Evolutionary maintenance of sexual dimorphism in head size in the lizard Zootoca vivipara: a test of two hypotheses
Authors: Gvozdík Lumír , Van Damme Raoul 
Published: February 2003

Abstract Zootoca vivipara is a small lizard that shows sexual dimorphism in head size. Males have larger heads than females of the same body size. By observing matings and aggressive interactions between males in the laboratory, we investigated whether this sexual dimorphism could be the result of intra‐ and/or intersexual selection. Winners of male–male interactions had larger heads than losers. During mating attempts, males with larger heads succeeded in grasping a female faster than males with smaller heads. It follows that head size in Z. vivipara may affect male reproductive success both through intrasexual competition (fighting ability) and through intersexual selection (grasping ability). This suggests that sexual selection may be the cause for the sexual dimorphism in head size in this species.
Demographic and genetic structure of fossorial water voles (Arvicola terrestris) on Scottish islands
Authors: Telfer S. , Dallas J. F. , Aars J. , Piertney S. B. , Stewart W. A. , Lambin X. 
Published: February 2003

AbstractThe distribution of fossorial water voles Arvicola terrestris on 15 small islands in the Sound of Jura, Argyll, Scotland, was established and populations were characterized in terms of size, structure and genetic composition (12 microsatellites). The results are compared with similar data from four metapopulations of riparian water voles in mainland Scotland. Water voles occurred on six islands, one of which was occupied in 1994, but not on two islands occupied during the 1960s. Probability of occupancy was significantly associated with proximity to the nearest occupied island. Unlike voles on the mainland, which occupy fragmented patches of exclusively riparian habitat, voles on islands were fossorial and occupied large areas of continuous habitat. Spring population sizes were c. 10 times higher on the islands than colonies of mainland metapopulations. Individuals from three islands were genotyped and these populations had 50% lower levels of microsatellite polymorphism than the mainland metapopulations. Rates of inferred contemporary dispersal among islands separated by 1 km or more of sea were very low, according to large differences among islands in genetic composition, proportions of coat colour types and incidence of skin infection. None the less, the long‐term persistence of the island populations is likely to depend on such dispersal. Comparisons between island populations and mainland metapopulations indicate that in both fragmented systems the level of dispersal is the primary factor influencing genetic structure. The low genetic variability in the island populations may reflect either past historical events (founder effect and genetic drift) or present ecology (lack of immigration in closed and temporally fluctuating populations).
La structure des propositions adverbiales du français: arguments sociolinguistiques
Authors: Beaulieu Louise , Balcom Patricia 
Published: February 2003

D'après Emonds (1985), les conjonctions de subordination du français sont des prépositions qui ont comme complément TP, une projection dont la tête est Temps. Selon Jones (1996), le complément de ces prépositions est un CP, une projection dont la tête est Complémenteur.Cet article présente une analyse sociolinguistique des conjonctions de subordination du français acadien parlé dans le nord-est du Nouveau-Brunswick au Canada (FANENB) qui montre que l'hypothèse de Jones rend mieux compte des données du FANENB et de celles du français normatif. L'explication la plus simple des divergences observées entre les propositions adverbiales de ces deux variétés se résume à une différence dans la spécification du trait [interrogatif] du complémenteur et à la force ou la faiblesse de ce trait.
Identifying a French-specific laughter particle
Authors: Ellis Yvette 
Published: February 2003

Aspirated sounds placed in a stream of talk prior to the onset of laughter are oriented to by interactants as minimal-equivocal laugh particles. These particles are available to carry out various interactional tasks, signalling an opportunity for co-participants to co-ordinate their laughter, to join in an episode of shared laughter for example. They may also contribute to keying actions as non-serious.The analysis of data from my corpus of French talk-in-interaction has revealed several instances of a voiceless palatal fricative following a word-final high front vowed [i]. This sound will be shown to occupy interactional slots generally associated with minimal-equivocal laughter particles. From evidence of its placement in sequences of turns keyed as non-serious, accompanying dispreferred actions, and in a terminal position in interactional sequences, the voiceless palatal fricative will be shown to be oriented to by French speakers as a minimal-equivocal laugh particle.
Phonostylistique des annonceurs de la radio: Etude prosodique de textes radiophoniques
Authors: Oakes Leigh 
Published: February 2003

En dehors des lexiques spécialisés et des structures syntaxiques spécifiques, c'est la prosodie qui fait que tous reconnaissent sans hésitation les textes radiophoniques. Ceux-ci se distinguent clairement du parler spontané et, dans une certaine mesure, d'autres formes de l'écrit oralisé: l'accentuation barytonique, des patrons rythmico-mélodiques spécifiques et une prosodie qui assume un rôle particulier dans l'organisation de la phrase seraient tous motivés par un désir de la part de l'annonceur de faire apparaître une qualité professionnelle.Après un bref survol des descriptions du style oral des présentateurs faites par d'autres chercheurs, nous proposons ici de faire une analyse qualitative et quantitative de nos propres données recueillies en 1994 auprès des annonceurs de Radio France Internationale, dans le but de confirmer, modifier ou réfuter quelques-unes des hypothèses proposées auparavant. Enfin, nous mettrons en lumière quelques aspects de la prosodie des annonceurs de radio qui restent à étudier de plus près.
Potential uses for geographic information system-based planning and decision support technology in intensive food animal production
Authors: Colby Michelle M. , Johnson Yvette J. 
Published: February 2003

AbstractAlthough geographic information systems (GIS) have been used in many disciplines, the available technology in planning and decision support has only recently begun to be used in intensive animal production, in areas such as confined animal feeding operations. GIS-based planning and decision support systems have the potential to enhance many aspects of intensive animal production, such as disease monitoring and prevention, emergency management and nutrient waste disposal. Current uses of GIS in animal production are reviewed. Potential uses are illustrated using the example of the poultry industry on the Delmarva Peninsula, USA.
Natural enemies of the maize cob borer, Mussidia nigrivenella (Lepidoptera: Pyralidae) in Benin, West Africa
Authors: Sétamou M. , Schulthess F. , Goergen G. , Poehling H.-M. , Borgemeister C. 
Published: February 2003

AbstractMussidia nigrivenella Ragonot is a pest of maize cobs in West Africa. It significantly reduces maize yields and grain quality, with quantitative losses of 2–25% at harvest, and up to 10–15% indirect losses due to an increase in storage pest infestation levels. Infestation by M. nigrivenella also significantly increased the susceptibility of maize to Aspergillus flavus infection and subsequent aflatoxin contamination. Surveys conducted in different agro-ecological zones of Benin on cultivated and wild host plants during 1994–1997 revealed one egg parasitoid, three larval parasitoids and one pupal parasitoid attacking M. nigrivenella. Egg parasitism was scarce on all host plants sampled and in all four agro-ecological zones. Parasitism by larval and pupal parasitoids was usually less than 10%, and varied with host plant species. Both larval and pupal parasitoids were rare or absent in cultivated maize fields. The solitary chalcidid pupal parasitoid, Antrocephalus crassipes Masi, was the predominant species, contributing approximately 53% of the observed mortality. Logistic regression analysis indicated that this parasitoid was more prevalent on fruits of Gardenia spp. (Rubiaceae) than on the other host plant species including maize used by M. nigrivenella, and was most abundant between February and September. The differences in parasitoid diversity and parasitism between Benin and other regions suggest that there are opportunities for biological control through introduction of exotic parasitoids or using the ‘new association’ approach, which uses natural enemies of closely related host species that occupy similar ecological niches to the target pest.