bluuebunny/crossref_metadata_2025_split huggingface dataset:
Global phylogeography of the leatherback turtle (Dermochelys coriacea)
Authors: Dutton Peter H. , Bowen Brian W. , Owens David W. , Barragan Ana , Davis Scott K. 
Published: February 2006

AbstractAnalyses of mitochondrial (mt) DNA control region sequences from 175 leatherback turtlesDermochelys coriaceafrom 10 nesting colonies revealed shallow phylogenetic structuring of maternal lineages on a global scale. Eleven haplotypes were observed, and mean estimated sequence divergence,p= 0.00581, is much lower than the deepest nodes reported in global mtDNA surveys of the green turtleChelonia mydas, loggerheadCaretta caretta, and ridley turtlesLepidochelysspp. The leatherback turtle is the product of an evolutionary trajectory originating at least 100 million years ago, yet the intraspecific phylogeny recorded in mitochondrial lineages may trace back less than 900 000 years. The gene genealogy and global distribution of mtDNA haplotypes indicate that leatherbacks may have radiated from a narrow refugium, possibly in the Indian–Pacific during the early Pleistocene glaciation. Analysis of haplotype frequencies revealed that nesting populations are strongly subdivided globally (FST= 0.415), and within ocean basins (FST= 0.203–0.253), despite the leatherback's highly migratory nature. Within the Atlantic significant differences in haplotype frequency distributions andNmvalues < 2 are observed in pairwise comparisons between St. Croix (U.S. Virgin Islands) and mainland Caribbean populations, and between Trinidad and the same mainland populations. These findings provisionally support the natal homing hypothesis for leatherback turtles, although several proximal nesting populations were indistinguishable, suggesting recent colonization or less precise natal homing behaviour than documented for other marine turtle species. The evidence of natal homing, manifested on ecological time scales, may be erased in some populations by rapid rookery turnover resulting from climatic fluctuation and the ephemeral nature of nesting habitat on a geological time scale. The evolutionary effective population size (Ne) is estimated from mtDNA data to be between 45 000 and 60 000, a value that exceeds current global census estimates of 26 000 to 43 000 adult females.
Oligospermia and azoospermia in non‐reproductive male Damaraland mole‐rats Cryptomys damarensis (Rodentia: Bathyergidae)
Authors: Maswanganye K. A. , Bennett N. C. , Brinders J. , Cooney R. 
Published: February 2006

AbstractThe relationship between reproductive status and reproductive physiology was investigated in male Damaraland mole‐rats Cryptomys damarensis, an eusocial rodent that exhibits a marked reproductive division of labour. Testicular anatomical and histological morphometrics, selected sperm motion parameters and measurements of circulating plasma testosterone were studied in 44 males (17 reproductive and 27 non‐reproductive). Reproductive males were significantly larger than non‐reproductive males. Testicular mass of reproductive males, corrected for body mass, was significantly larger than in non‐reproductives. However, corrected testicular volume did not vary significantly between the two groups. Circulating plasma testosterone concentrations of reproductives and non‐reproductives were not significantly different (reproductive males 201.5 ± 56.5 pg/l vs 187.5 + 91 pg/l for non‐reproductive males). The quality of sperm was measured by the percentage of spermatozoa produced and the amount of immature sperm, and differed between the two groups. Reproductive males produced a greater proportion of motile sperm (77.8%) than non‐reproductives (56.3%). Non‐reproductive males were characterized by a greater proportion of immature sperm in the epididymis (79%) than the reproductives (25%). Interestingly, the spermatozoa of reproductive males were characterized by a greater percentage of head and tail defects. Oligospermia may be the result of a reduction in circulating follicle stimulating hormone, which acts upon the Sertoli cells of the seminiferous tubules, that in turn may be due to a lack of an opportunity to mate while in the confines of the colony in this obligate outbreeder.
Correlates of ball size and rolling speed in the dung beetle Kheper nigroaeneus (Coleoptera: Scarabaeidae)
Authors: Tomkins Joseph L. , Simmons Leigh W. , Knell Robert J. , Norris Keith A. 
Published: February 2006

AbstractBall rolling in dung beetles is an energy expensive activity associated with elevated thoracic temperatures. The ability of individuals to engage in such energetically costly behaviour may be dependent on their body condition. Bilateral asymmetries arising from the interaction between an individual's genes and its environment have been hypothesized to reflect an organism's quality. A number of studies have shown that individuals with elevated levels of asymmetry perform less well under stress. We tested this hypothesis by measuring correlates of dung ball rolling speed in males and females of Kheper nigroaeneus (Coleoptera: Scarabaeidae). We found that larger beetles produced larger dung balls and rolled them faster along an experimental track. However, there was no relationship between ball rolling speed and the asymmetry of fore and hind tibia. There was also no relationship between the asymmetry of the beetle or the number of mites that it carried, and the level of mite infestation did not influence ball rolling speed.
Roosting behaviour of the tawny frogmouth (Podargus strigoides)
Authors: Körtner Gerhard , Geiser Fritz 
Published: February 2006

AbstractWe characterized the day roost sites of four pairs and one solitary tawny frogmouth Podargus strigoides in a woodland in south‐eastern Australia. The birds were equipped with radio transmitters which enabled us to locate them daily from autumn 1997 to late summer 1998. Tree species, tree size, roost height and orientation of the roosting bird were recorded. Over the study period tawny frogmouths frequented a large number of day roosts (up to 71 per pair). Birds rarely used the same roost over extended time periods and most roosts were used for less than 3 days. Mature trees with a girth of more than 0.5 m were preferred as day roosts. Tawny frogmouths exhibited a significant preference for the coarse and dark‐barked stringybark trees, but other tree species such as the smooth‐barked, light‐coloured gums were also frequented. However, when roosting in gum trees, dead branches were preferred, presumably as these have a coarser appearance than living branches and therefore provided better camouflaging. Especially during winter, the birds showed a significant selection of branches on the northern side of roost trees presumably to maximize sun exposure. During summer, two pairs maintained a significant northerly preference, whereas the others used roosts with random orientations. Small‐scale seasonal movements in the area used for day roosting were also observed, with two pairs selecting a distinct area with a south‐westerly aspect during summer which appeared to have less sun exposure. Our study suggests that tawny frogmouths select roosts to (1) minimize visibility from day predators and (2) to facilitate passive thermoregulation by sun‐basking.
Field body temperatures, activity levels and opportunities for thermoregulation in an extreme microhabitat specialist, the girdled lizard (Cordylus macropholis)
Authors: Bauwens Dirk , Castilla Aurora M. , Mouton P. le Fras N. 
Published: February 2006

AbstractThe girdled lizard Cordylus macropholis inhabits semi‐desert areas along the west coast of South Africa. Unlike many other small diurnal lizards living in open habitats, it exhibits extreme low levels of above‐ground activity and does not show overt thermoregulatory behaviours, such as basking or shuttling. It has an extreme low movement rate and confines routine activity to the microhabitat of the succulent Euphorbia caput‐medusae. We document this restriction of activity in time and space in relation to aspects of this lizard's thermal biology. Throughout the day, a majority of the lizards was found sheltering (‘covered’) among the branches of E. caput‐medusae plants, and surface‐active (‘exposed’) individuals were seen during only a restricted time period (i.e. 1100–1700 h). Mean body temperatures (Tbs) of both ‘exposed’ (29.4 °C) and ‘covered’ (28.4 °C) individuals were surprisingly low for a lizard inhabiting a hot and dry climate zone. This similarity of the Tbs of both groups, as well as the correspondence between the ambient temperatures in the plant microhabitat and the Tbs of ‘exposed’ lizards indicate that, for a considerable part of day, thermal conditions under plant cover allow achievement of Tbs at a similar level as that maintained by the ‘exposed’ lizards. Moreover, the absence of sightings of overtly basking lizards supports the view that C. macropholis warm up by adopting the ambient temperature in their shelters thereby reducing the time spent in surface activity. All lizards observed were within the periphery of E. caput‐medusae plants, indicating that C. macropholis is an extreme microhabitat specialist. The succulent provides more and safer hiding places than other common shrubs in the environment. In addition, estimates of ambient temperatures indicate that these plants offer superior opportunities for thermoregulation compared with other available shrub microhabitats.
Morphology, evolution and function of feeding in the giant anteater (Myrmecophaga tridactyla)
Authors: Naples Virginia L. 
Published: February 2006

AbstractThe edentulous giant anteater (Myrmecophaga tridactyla) ingests food using a slender, elongated sticky tongue which can project to a distance greater than the cranial length. A large and elongated hyoid apparatus, including a long stylohyal, epihyal, reduced ceratohyal and fused basihyal‐thyrohyal fused to a partially ossified thyroid cartilage, supports the tongue. The fusion pattern and relative hyoid element sizes in adult Myrmecophaga differ from those in other xenarthran anteaters, tree and ground sloths, and armadillos. The hyoid bones have synovial joints with articular surfaces permitting great freedom of movement. A unique hyoid muscle arrangement enables Myrmecophaga to project the tongue with great speed and precise positional control. This muscle arrangement combined with an elongated secondary palate, accommodates the retracted tongue within the oropharynx without compromising the animal's ability to breathe. Maximum gape is reached at a few degrees of mandibular depression, but the oral opening is increased to 2 cm by the extreme length of the anterior facial region. Gape is further increased by medial rotation and depression of the unfused mandibular rami at the mental symphysis. This movement, even without mandibular depression, permits protraction and retraction of the elongated tongue. Mandibular rotation in lieu of depression and elevation simplifies jaw movements made by a smaller uniquely modified muscle mass over shorter distances, therefore increasing the speed with which anteaters can ingest food, and complements the extremely rapid tongue protrusion–retraction cycle.
Habitat correlates of European rabbit (Oryctolagus cuniculus) distribution after the spread of RVHD in Cadiz Province, Spain
Authors: Fa John E. , Sharples Colin M. , Bell Diana J. 
Published: February 2006

AbstractEuropean rabbit Oryctolagus cuniculus abundance was evaluated relative to habitat variables within two zones in Cadiz Province (south‐east Spain), 2 years after the spread of rabbit viral haemorrhagic disease (RVHD). The study areas were low‐lying regions of mixed pasture/agriculture, Mediterranean forest and matorral, west (Zone A) and east (Zone B) of the Sierra de Cadiz mountain chain. A total of 111 sites was selected to sample all existing habitat types. Relative rabbit density in each site was estimated using a pellet count method in one 50×2 m transect. Mean pellet densities were 21.05 pellet m−2 in Zone B and significantly lower, 5.85 pellets m−2 in Zone A. Physical variables, such as vegetation characteristics (density, height and patchiness of cover‐layer vegetation, etc.), topographical characteristics and human influences, cover‐layer vegetation species (woody stemmed shrub species or trees forming dense stands), and ground‐layer vegetation species (herbaceous species forming a low‐lying layer) were determined within transects. In addition to these variables, soil types, rock type and land form, as well as the presence of aquifers, irrigation, and the proximity of rivers, were determined for each site. Significantly higher pellet densities were found in mixed grassland/matorral and cork oak/matorral than in all other habitats. Pellet density was negatively correlated with density of ground‐layer vegetation, while high pellet densities were associated with medium‐height ground‐layer vegetation (50–100 cm). The presence of Entisols was negatively associated with pellet density. The cover‐layer species Pistacia lentiscus, Quercus coccifera, Quercus suber, Opuntia ficus‐indica and the ground‐layer grasses all showed positive associations with pellet density, while the ground‐layer species Echium gaditana and Scorpiurus vermiculatus were negatively associated with pellet density. Multivariate analyses identified the mixed grassland/matorral and cork oak forest/matorral habitats as explaining most of the variation in pellet density. The height of cover‐layer vegetation was negatively associated, while Opuntia and table‐and/calcareous sandstone were positively associated, with mixed grassland/matorral. Distance from habitation and human impact were negatively associated and Quercus suber was positively associated with cork oak forest/matorral. Comparison with previous studies suggest that the low pellet counts in this study represent very low rabbit densities and the population as a whole appears depleted and fragmented.
Body mass estimation in armoured mammals: cautions and encouragements for the use of parameters from the appendicular skeleton
Authors: Biknevicius A. R. 
Published: February 2006

AbstractThis study explores the relationship between body mass and femoral construction in armoured (dasypodids and manids) and unarmoured (caviomorph rodents) mammals. Predictive equations based on diaphyseal cross‐sectional parameters provided the most accurate estimates of body mass in caviomorph rodents and dasypodids. When these equations are applied to the estimation of body mass in manids, relatively low predictive errors (<20%) are found only when caviomorph equations derived with diaphyseal cross‐sectional area or moments of area are used. Dasypodid equations generally yield less accurate estimates for manids, so that armouring of the integument alone poorly discriminates femoral types. Other factors with potential to differentially impact femoral construction are also considered: although locomotor speed strongly influences mass–structure relationships within caviomorph rodents, the confounding influence of locomotor posture, fossoriality, and arboreality render these relationships less predictable across all three groups considered here. Limb structure and, hence, scaling patterns of each phylogenetic group are influenced by a unique mosaic of factors that is difficult to summarize quantitatively. The results of the study provide cautions as well as encouragements for the estimation of body mass for fossil species that have no adaptively similar living relatives.
The effect of food hardness on feeding behaviour in frugivorous bats (Phyllostomidae): an experimental study
Authors: Dumont Elizabeth R. 
Published: February 2006

AbstractMost New World leaf‐nosed bats (Phyllostomidae) are frugivores. Many of these species are sympatric and mechanisms of resource partitioning including vertical stratification and divergent foraging strategies have been described. This study investigates a previously unexplored but potentially significant factor in resource partitioning: the relationship between feeding behaviour and fruit hardness. Data summarizing ingestive and fruit processing behaviours were collected during feeding experiments from five sympatric frugivorous phyllostomid species: Artibeus jamaicensis, Dermanura phaeotis, Sturnira lilium, Carollia perspicillata, and Glossophaga soricina. Individuals were the subjects of feeding experiments that consisted of eating hard and soft fruits of similar size, shape, and mass. Variables analysed from videotapes of the experiments describe how fruits are placed in the mouth during ingestion, the frequency of head movements during biting, the number of bites used to remove a piece of fruit, and the number of chews used to process each mouthful of fruit. Results of chi‐square, log‐linear, R×C, and Kruskal–Wallis tests demonstrate that feeding behaviours vary significantly with fruit hardness both within and between species. Artibeus, Dermanura, and Sturnira are behaviourally specialized for feeding on relatively hard fruits. However, Carollia, and probably Glossophaga, lack these behavioural specializations. Both mechanical and ecological implications of intra‐ and interspecific behavioural variation are discussed. Differences in fruit handling behaviour are also used to make explicit predictions regarding interspecific variation in masticatory morphology. This study demonstrates that the relationship between fruit hardness and feeding behaviour may be an integral part of frugivore ecology. Overall, resource partitioning among phyllostomid frugivores is a result of complex interactions among and between bats and their food plants. Controlled experimental studies such as this one provide a crucial means of dissecting these complex interactions and gaining insight into the basis of frugivore diversity.
Reproduction, development and diet of Parasitellus fucorum (Mesostigmata: Parasitidae), a mite associated with bumblebees (Hymenoptera: Apidae)
Authors: Koulianos S. , Schwarz H. H. 
Published: February 2006

AbstractThe mite Parasitellus fucorum (De Geer) (Mesostigmata: Parasitidae) lives and reproduces in the nests of bumblebees. Despite its abundance on European bumblebees and its occasional invasion of honeybee nests, little is known about its basic life‐history traits and dietary requirements. This paper describes the mating behaviour, oviposition and development of P. fucorum under controlled laboratory conditions, and provides observations on the dietary preferences of its life‐cycle stages.
Quantitative analysis of tonal calls from five odontocete species, examining interspecific and intraspecific variation
Authors: Rendell L. E. , Matthews J. N. , Gill A. , Gordon J. C. D. , Macdonald D. W. 
Published: February 2006

AbstractWhistle vocalizations of five odontocete cetaceans, the false killer whale P. crassidens, short‐finned pilot whale G. macrorhynchus, long‐finned pilot whale G. melas, white‐beaked dolphin L. albirostris and Risso's dolphin G. griseus, were analysed and summarized quantitatively. Recordings were acquired from a number of locations and encounters. Significant differences were found between species and, to a lesser extent, between locations. The calls of the two pilot whale species are distinct despite their close relatedness, and similar size and morphology. This may be due to selection pressures to maintain distinctiveness. The variance was partitioned into between‐species, between‐location (within species) and within‐location factors. For the frequency variables, variation between‐species is high relative to variation between locations. Thus geographic variation is a relatively minor effect, compared to the many processes which cause interspecific differences. The within‐location component includes such factors as social context, behaviour and group composition. This component is of a similar magnitude to the between‐species component, indicating that whistles vary considerably with these factors. Significant between‐location differences may be attributable to these confounding factors. For whistle duration, most of the variation occurred within location. There is less significant variation in duration across species compared with the frequency measures. This study highlights the need to collect samples across all potential strata whenever possible, and provides a framework for future, more comprehensive work.
Description of the leaf deer (Muntiacus putaoensis), a new species of muntjac from northern Myanmar
Authors: Rabinowitz A. , Myint Than , Khaing Saw Tun , Rabinowitz S. 
Published: February 2006

AbstractIn May 1998, an expedition into northern Myanmar obtained detailed descriptive data on a new species of muntjac called the leaf deer, first discovered on a survey the previous year and characterized primarily by its diagnostic DNA compared to other muntjac species. Weights, measurements, and physical data were obtained from 12 freshly killed leaf deer, along with partial measurements from 90 head pieces of leaf deer found in village huts. Except for the diminutive, unbranched antlers on males, averaging 3.2 cm long, older male and female leaf deer were similar in size and appearance, with average weights of 12.1 kg and 11.8 kg for males and females, respectively. When compared with other species, leaf deer are one of the smallest, and perhaps one of the most primitive, extant muntjacs. Two of the most distinguishing characteristics of this new species are the relatively long, equal‐sized canines in both older adult males (average 2.4 cm long) and older adult females (average 2.2 cm long), and the lack of spotting on the coats of a newborn and two juveniles estimated to be < 2 months old. All older males (n= 3) and 40% of older females (n= 5) had healed wounds on one or both ears. These wounds, in addition to the large canines in both sexes, may indicate that females as well as males compete actively for resources. Although still relatively abundant throughout mid‐elevation dense evergreen forests, between the northern extremities of the Mai Kha and Mali Kha Rivers in north Myanmar, the currently known distribution of the leaf deer is outside any protected areas. Persistent hunting by local people with snares, dogs, and crossbows for a thriving market trade in deer leather, have caused noticeable decreases in numbers of leaf deer captured over recent years and could threaten the future survival of this new species.
Gazelle (Gazella spp.) behavioural ecology: predicting animal behaviour for prehistoric environments in south‐west Asia
Authors: Martin Louise 
Published: February 2006

AbstractAny interpretation of archaeological animal bone assemblages benefits greatly from a knowledge of animal behaviour patterns and population dynamics, but there are difficulties in directly imposing modern data onto past, often non‐analogue environments, and in assuming species‐specific behaviour. This paper suggests that behavioural ecology – which stresses adaptation – provides a fruitful approach for predicting ethological details of past wild animal populations. The study focuses on the genus Gazella, whose remains are commonly found on archaeological sites in south‐west Asia in the period 20,000–7500 before present (BP), and whose role in human societies has been much debated. Following a behavioural ecological method, selected data from 18 modern observed gazelle populations are summarized, compared, and the factors that influence and constrain the animals' behaviour are discussed. The potential for using the principles of behavioural ecology to predict factors such as gazelle social structure, reproductive strategies and mobility patterns in past environments is considered, and the value of such an approach for zooarchaeological interpretation is demonstrated.