bluuebunny/crossref_metadata_2025 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

Analyses 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

The 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

Ball 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

We 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

The 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

The 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

European 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

This 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

Most 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

The 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.
Early Natural History in South‐East Asia
Authors: Gardiner Brian
Published: February 2006

This topic formed the basis of a joint meeting with the Society for the History of Natural History on 8 December 1998.
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

Whistle 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

In 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

Any 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.
Maximum diving depths for feeding attained by Bulwer's petrels (Bulweria bulwerii) during the incubation period
Authors: Mougin J.‐L. , Mougin M.‐C.
Published: February 2006

All 20 of the Bulwer's petrels Bulweria bulwerii of Selvagem Grande (30°09′N, 15°52′W) equipped with maximum depth gauges had dived during the feeding trips performed during the incubation period, the mean maximum depth being 2.4 ± 1.0 m (range: 1.0–5.3 m). The depth reached showed no correlation with the breeding experience of the birds, with the length of their trip or with their body size and there were no differences between males and females. Thus, the Bulwer's petrel are among the numerous Procellariiformes which perform regular but comparatively shallow dives, unlike shearwaters (Puffinus) and diving petrels (Pelecanoides) which can reach depths of several tens of metres.
Comparative analysis of dental fluorosis in roe deer (Capreolus capreolus) and red deer (Cervus elaphus): interdental variation and species differences
Authors: Kierdorf Uwe , Kierdorf Horst
Published: February 2006

The interdental and interspecific variation in the prevalence and severity of macroscopic fluorotic alterations of the permanent mandibular cheek teeth (P2–4, M1–3) was studied in 331 roe deer and 62 red deer exhibiting severe dental fluorosis. The material originated from the fluoride‐polluted region of the Ore mountains and their southern foreland (Czech–German border region). Scoring of dental fluorosis was based on an ordinal measurement scale with six scores (score 0: unfluorosed, scores 1–5: increasing severity of fluorotic alterations). The observed variation in dental fluorosis both within the cheek tooth row of a species and between certain homologous teeth of roe and red deer could be related to the development of the dentition in the two species, especially the timing of tooth crown formation in relation to weaning and the subsequent period, where the animals feed upon (fluoride‐contaminated) plant material. The lower prevalence (roe deer: 3%, red deer: 42%) and severity (fluorosis scores ð 2) of dental fluorosis in the M1compared to the other permanent cheek teeth were attributed to the fact that the crown formation of this tooth takes place largely (roe deer) or to a considerable extent (red deer) prenatally and during the period of milk feeding. It is assumed that during these ontogenetic stages several mechanisms (partial placental diffusion barrier to fluoride, low fluoride content of milk, rapid clearance of fluoride from the blood resulting from a high skeletal growth rate) to some extent protect the developing teeth from increased fluoride exposure. Therefore, in both species apparently only the (late) maturation stage of M1amelogenesis can be affected by fluoride in a way to induce visible enamel changes. The higher prevalence and severity of fluorotic lesions in the M2of red than roe deer was related to the fact that in the former species crown formation of this tooth, like in the P2–4and M3of both species, takes place completely post‐weaning.
Jaw anatomy of the blood‐sucking leeches, Hirudinea Limnatis nilotica and Hirudo medicinalis, and its relationship to their feeding habits
Authors: Orevi Miriam , Eldor Amiram , Giguzin Ida , Rigbi Meir
Published: February 2006

The triple jaws of the leeches Limnatis nilotica and Hirudo medicinalis (both Hirudinidae, Hirudininae) are compared, using the stereomicroscope and scanning electron microscopy (SEM). The jaws of Limnatis are relatively small, rounded and soft, bearing about 30 flat‐topped, rough‐surfaced teeth, and papillae which presumably secrete saliva. Limnatis sucks blood in stages from internal soft vascular tissue, often in the pharynx, and may stay inside the host for several weeks. Evidence is strong that it is unable to pierce external skin. Hirudo jaws are rigid, have no papillae and bear about 60 sharp teeth, each tooth possessing a secretory aperture on its side, close to the tip. In contrast to Limnatis, Hirudo is an external feeder. It pierces the skin and usually gorges itself with blood in one meal, after which it detaches itself from the host. It gains from six to nine times its weight in a meal, and remains satiated for 3–18 months. The ingested blood of Limnatis, unlike that ingested by Hirudo, is particulate and resembles a liver homogenate. This is probably a result of some scraping by its teeth as the jaws thrust towards a blood vessel. The relationship between jaw anatomy and feeding habits of L. nilotica and H. medicinalis is shown. Clearly, each species has adapted to the particular environment supplying its food (soft internal tissues, external skin).
Dining on diplopods: remarkable feeding behaviour in chlamydephorid slugs (Mollusca: Gastropoda)
Authors: Herbert D. G.
Published: February 2006

The diet of southern African carnivorous slugs of the endemic family Chlamydephoridae is discussed. At least three species,Chlamydephorus bruggeni,C. burnupiandC. sexangulus, are predators of pill‐millipedesSphaerotheriumsp. The feeding behaviour ofC. sexangulusis described in detail and illustrated. It is suggested that the prey, once captured, is killed or immobilized by the introduction of a toxin through the intersegmental membrane joining the millipede's skeletal plates. The source for such a toxin may be the anterior pedal mucous gland. Predation on sphaerotheriid millipedes may be a behavioural apomorphy associated with a clade within the Chlamydephoridae, including taxa with longitudinal body keels and distinctive radula morphology, but it is evidently not confined to this clade. Whether the diet of such millipede‐eating slugs is limited to millipedes is unknown, but it is probable that at least some chlamydephorids feed on more conventional prey such as snails and earthworms.
Cub adoption by polar bears (Ursus maritimus): determining relatedness with microsatellite markers
Authors: Lunn N. J. , Paetkau D. , Calvert W. , Atkinson S. , Taylor M. , Strobeck C.
Published: February 2006

Sixteen microsatellite markers were used to determine the genetic relatedness between adult female polar bears and their accompanying cubs for three recent occurrences of natural adoption recorded in the Canadian Arctic. The estimation of the degree of relatedness was powerful and provided a high degree of separation between first order relatives and unrelated individuals with the loci used. The analysis showed that the cubs were unrelated to their adoptive mothers and that the mothers were unrelated to one another. Although the circumstances and mechanisms whereby these adoptive events occurred are unknown, the data do not support kinship theory as an explanation for the exchange of cubs. We suggest that these adoptive events probably represent instances of the misidentification of cubs by adult polar bears.
The biology and functional morphology of Fragum erugatum (Bivalvia: Cardiidae) from Shark Bay, Western Australia: the significance of its relationship with entrained zooxanthellae
Authors: Morton Brian
Published: February 2006

The shallow, offshore, hypersaline (∼ 60‰), benthic marine environment of Shark Bay, Western Australia, is dominated by the cockle Fragum erugatum. This small (< ∼ 11 mm long) bivalve occurs in large numbers (4000/m2) and probably completes its life cycle in 1 year. Cyclones with a periodicity of ∼ 50 years have, over the last 5000 years, deposited huge numbers of the shells of F. erugatum onto the shore as windrows, creating the unique Shell Beach, or Hamelin Coquina. In most anatomical respects, F. erugatum is a typical cockle, with a powerful digging foot, siphons formed by fusion of the inner mantle folds only, plicate ctenidia with a ciliation of type C(1) and powerful rejectory currents on the visceral mass and mantle. It is thus able to collect filterable material and digest it. The labial palps are, however, reduced, allowing the ingestion of only the finest particles of food via the acceptance tracts in the ctenidial axes and distal oral grooves. The waters of Shark Bay are hypersaline and oligotrophic, so what is the food source that supports such large numbers of filter‐feeding bivalves?Fragum erugatum possesses symbiotic zooxanthellae, as do its close relatives the giant clams (Tridacnidae), and probably obtains the same nutritional benefits from the association, which may facilitate survival in the hyperosmotic environment of Shark Bay. The association between giant clams and their zooxanthellae enhances shell growth and results in a long life expectancy and gigantism. Conversely, in F. erugatum the association facilitates a large population size (but short life expectancy), allowing it to dominate a unique, hypersaline, oligotrophic environment. Like giant clams, F. erugatum possesses a zooxanthella tube system linking the digestive diverticula of the stomach with the kidneys. Either accidentally or periodically, ingested zooxanthellae are transferred from the gut, via this tube, along with senescent zooxanthellae from the blood haemocoel, to the kidney tubules for lysosomal hydrolysis and eventual expulsion. In the light of this discovery, the functioning of the recently confirmed zooxanthella tube system in the Tridacnidae needs re‐examination and re‐evaluation.
Glycogen distribution in the larval salivary gland cells during the development ofDrosophila melanogasterandDrosophila auraria: an ultrastructural cytochemical study
Authors: Kosta Artemis , Dimopoulou Katerina , Drosou Victoria , Thomopoulos George N.
Published: February 2006

In this study, glycogen distribution during the development of larval salivary glands in twoDrosophilaspecies (D. melanogasterandD. auraria) was examined using the osmium tetroxide–potassium ferrocyanide technique at the ultrastructural level. Glycogen particles are found in big clumps in the salivary gland cells ofD. melanogasterduring the early third instar, mainly at the basal part of the cells; they are also found as scattered particles in the cytoplasm and very close to the apical plasma membrane during the secretory activity at this developmental stage. During the middle third instar, where the production of ‘glue’ secretory granules begins, glycogen particles are mainly scattered and they are seen near the Golgi complexes and secretory granules. No glycogen particles are seen during the late third instar and secretion of ‘glue’ secretory granules. Re‐formation of glycogen begins after spiracle eversion. In the larval salivary gland cells ofD. auraria, glycogen particles (scattered and in clumps) are seen in every developmental stage. In the larval fat body cells of both species, many huge clumps of glycogen particles are seen, independent of the developmental stage. These results indicate that glycogen provides an important source of energy during development ofDrosophilasalivary glands, but different species use glycogen at different metabolic pathways, according to their needs.
Postcranial adaptations for leaping in primates
Authors: Connour Jacqueline Runestad , Glander Kenneth , Vincent François
Published: February 2006

Leaping primates are specialized for hindlimb‐propelled locomotion within arboreal habitats. As a group, they include members of Galagonidae, Lemuriformes and Tarsiidae. Postcranial characters analysed here include humeral and femoral diaphyseal rigidity, articular surface areas and lengths. Data for leaper taxa are compared with corresponding data for less specialized small primates. The more generalized comparative primates include both closely related prosimians and distantly related platyrrhines (New World monkeys). In addition, the leapers are subdivided for further analysis according to body size and taxonomic association. Questions addressed concern the identification of functionally and/or phylogenetically linked traits in leaper postcrania. Results indicate that leapers as a group have relatively higher femoral diaphyseal rigidity and longer femora than do more generalized primates. These traits are also present in Pithecia pithecia, a platyrrhine leaper included for comparison. These enhanced properties probably function in resisting large hindlimb forces incurred during leaping, and in producing longer, more efficient leaps. Most of the large‐bodied lemuriform leapers are further distinguished in having relatively bigger femoral heads and reduced humeral rigidity. The small‐bodied leapers, galagonids and tarsiids, do not differ in either femoral head surface area or in any of the humeral properties from more generalized primates. Pithecia has a large femoral head like lemuriforms, but it is not reduced in humeral rigidity. Aspects of hip joint structure and mobility may be related to femoral head size in lemuriforms and Pithecia. Explanations regarding reduced lemuriform humeral rigidity are also explored. Differences between lemuriform primates are also present, most notably in aspects of the distal humerus. Indrids are characterized by relatively reduced trochleae, while many lemurids have relatively small capitula. These features are interpreted with regard to frequencies of suspensory behaviour and quadrupedalism.
Variation in abundance of foxes (Vulpes vulpes) between three regions of rural Britain, in relation to landscape and other variables
Authors: Heydon Matthew J. , Reynolds Jonathan C. , Short Michael J.
Published: February 2006

Spotlight transect surveys with distance sampling were used to estimate spring (pre‐breeding) and autumn (post‐production) fox Vulpes vulpes densities in three contrasting rural areas of Britain during 1995–97. This was the first attempt in Britain to measure and compare fox densities over large geographical areas (630–1460 km2). Mean post‐production fox abundance was estimated to be 0.90/km2, 2.62/km2, and 0.59/km2 in mid‐Wales, the east Midlands and East Anglia, falling to pre‐breeding levels of 0.41/km2, 1.17/km2, and 0.16//km2 in spring. As relative measures of regional density, these estimates are strongly supported by independent indices of fox abundance, and by the simultaneous survey of two sympatric species, the badger Meles meles and brown hare Lepus europaeus, which demonstrate the absence of any terrain‐related bias. Absolute abundance is less easy to verify, but estimates of spring density based on breeding earth censuses support the transect surveys. For two of the three regions, fox density was close to levels predicted by extrapolation on the basis of landscape, but in the third region (East Anglia), fox density was substantially below prediction. Thus, results failed to support a hypothesis that fox abundance can be predicted solely on the basis of landscape and its close correlates. Rather, they favoured a competing hypothesis that an independent factor determines fox abundance in some regions. A likely factor is culling by man.
Demography of rural foxes (Vulpes vulpes) in relation to cull intensity in three contrasting regions of Britain
Authors: Heydon Matthew J. , Reynolds Jonathan C.
Published: February 2006

The impact of deliberate culling of fox populations has been much debated. Although a local (< 10 km2) impact has been accepted, previous authors have denied that culling has any impact on a larger scale because local losses are compensated through immigration. Rather, it has been claimed that at this scale fox density is determined by resources, mediated through social behaviour and breeding suppression. We determined the impact of culling on a regional scale (> 1000 km2), using data on culling (Heydon & Reynolds, 2000), fox density (Heydon, Reynolds & Short, 2000) and productivity. The three U.K. study regions (size 1238–2322 km2) were in mid‐Wales (A), the east Midlands (B) and East Anglia (C). High productivity in regions A and C was associated with low density, high culling mortality and high overall mortality (all relative to region B), indicating that density was suppressed by culling. In region B (moderate) breeding suppression was associated with a higher density and lower cull than in regions A and C, implying that fox density was closer to the maximum sustainable by resources. We conclude that the impact of culling in different regions of Britain is variable, dependent on the regional prevalence, methods, and history of culling. However, it is clear that in a range of circumstances culling can substantially depress fox numbers, and that current fox densities reflect a history of culling. This conclusion is fundamental in considering the management of fox predation in farming and conservation contexts.
Osteological differences between two sympatric forms of bottlenose dolphins (genus Tursiops) in Chinese waters
Authors: Wang J. Y. , Chou L.‐S. , White B. N.
Published: February 2006

Although there has been extensive research on bottlenose dolphins (genus Tursiops), much controversy over the classification within this genus still exists. Even though many morphological variants occur, the prevailing view is for a single species, Tursiops truncatus (Montagu, 1821). To evaluate this view, two sympatric forms of bottlenose dolphins inhabiting Chinese waters were examined using multivariate statistical analyses of osteological data for two meristic and 18 cranial morphometric characters from 71 specimens. Cluster and principal components analyses revealed clear osteological separation of the two forms. Furthermore, the distributions of the total number of vertebrae and several proportions of cranial characters were non‐overlapping between the two forms. These results provided strong evidence that the two sympatric forms of Tursiops in Chinese waters are isolated reproductively and do not support the current view of a monotypic genus. Classification functions of a discriminant analysis and a key of several characters were developed to help researchers identify unassigned specimens. Provisional names (T. truncatus and T. aduncus) were suggested, but a formal taxonomic revision of this genus is still required. However, regardless of the nomenclature, immediate amendments to all present wildlife conservation legislation are strongly urged.
Energetics and burrowing behaviour in the semifossorial degu Octodon degus (Rodentia: Octodontidae)
Authors: Ebensperger Luis A. , Bozinovic Francisco
Published: February 2006

The energetics and burrowing behaviour of the semifossorial Octodon degus (Rodentia: Octodontidae) were investigated and compared with that of more specialized fossorial rodents. An open‐flow respirometry system was used to record energy expenditure of single degus inside respirometers partially filled with soft (moist) or hard (dry) soil. In addition, digging behaviour was recorded in groups of three animals inside a large terrarium under controlled conditions of food, photoperiod and temperature. In the field, the digging activity of degus was monitored, along with seasonal variations in rainfall, content of soil moisture and soil hardness. Mass‐specific metabolic rate during digging was found to be higher in animals burrowing in soft soils compared to hard soil. However, animals burrowing in soft soil removed more soil per min than animals in hard soil. Thus, gram per gram, excavating in hard soil was energetically more expensive. The digging cost of semifossorial degus tends to be either similar to or above those of similarly sized, but more fossorial, rodents. In the field, heightened digging activity coincided with the occurrence of rainfall, greater content of soil moisture and relatively soft soil conditions. Degus generally use their front feet and teeth to shear the soil; disposal of accumulated debris being carried out by moving their front and hind feet backwards. We also observed the establishment of digging chains when two or three individuals burrowed at the same site. As far as digging is concerned, the behaviour of degus is similar to that of other fossorial rodents, such as African bathyergids and the more closely related South American ctenomyids.
Mediterranean species of Eudendrium Ehrenberg, 1834 (Hydrozoa, Anthomedusae, Eudendriidae) with the description of a new species
Authors: Marques A. C. , Peña Cantero A. L. , Vervoort W.
Published: February 2006

A new species of Eudendrium from the Chafarinas Islands (south‐western Mediterranean) is described. The distinctive character of this species is its association with symbiotic zooxanthellae, a feature in common with Myrionema, the only other genus of the family Eudendriidae. The evolutionary implications of this similarity are discussed. A review of the Mediterranean species of Eudendriidae is presented, including data on the cnidome when available, biological data from the material studied, and a key to identify the Mediterranean species.
Habitat selection and coexistence of the Alpine chamois (Rupicapra rupicapra) and Himalayan tahr (Hemitragus jemlahicus) in the eastern Southern Alps, New Zealand
Authors: Forsyth David M.
Published: February 2006

Numerous field studies have attempted to assess competition between ungulates through the analysis of resource overlap. However, interpreting the results of these studies has been problematic because low overlap may be the outcome of historical competition and high overlap will result in competition only when that resource becomes limiting. In New Zealand, increasing densities of introduced Himalayan tahr Hemitragus jemlahicus have competitively excluded introduced Alpine chamois Rupicapra rupicapra, but where densities of tahr have been reduced the two species can coexist. This study evaluated the role of habitat selection in the coexistence of these two recently sympatric ungulates in Carneys Creek, eastern Southern Alps, New Zealand. Seasonal habitat selection was estimated by observing unmarked male tahr, female tahr and chamois monthly for 25 months. The proportional availability of six habitats (grassland, grass bluff, rock bluff, shrubland, scree and snow) was measured from aerial photographs taken in each of the four seasons. Although the null hypothesis that tahr and chamois select habitats similarly was rejected in three of four seasons, there was high overlap in preference for grassland and shrubland, and avoidance of scree and snow. Tahr were more often observed in grass bluff and rock bluff than were chamois. Overlap in habitat selection was greatest during winter when snow dominated the landscape, reducing the availability of vegetated habitats. Using Hurlbert's statistic, the niche breadth of chamois was significantly smaller than that of tahr in all seasons except autumn, in which they were similar. These results, together with anecdotal evidence from Carneys Creek, suggest that chamois increase their habitat specialization in the presence of tahr. Although differences in habitat selection are likely to have contributed to the coexistence of chamois with tahr, even relatively small increases in tahr density in some seasons could be expected to exclude chamois from some habitats in Carneys Creek.
Statistical power analysis: application to an investigation of dinosaur thermal physiology
Authors: Ruxton Graeme D.
Published: February 2006

It has been postulated that the variation in an animal's body temperature during different phases of bone deposition can be estimated from the variation in the ratio of two oxygen isotopes in phosphate recovered from its fossil. Using data from a fossil Tyrannosaurus rex skeleton, the previous researchers failed to reject the null hypothesis that the variation found in bones from the body core is significantly less than that found in the extremities; they also failed to reject the null hypothesis that the coldest and hottest parts of the body differed by less than 4 °C. This suggests that either both null hypotheses are true, or that they are false but the statistical tests used were not powerful enough to detect this. Here I use calculation of confidence intervals to differentiate between these two alternatives. In the first case, I find that the data are consistent with the variance in both the core and the extremity being up to 2.5 times that of the other. In the second case, I show that observations are consistent with temperature differences ranging from 2.6 °C to 6.4 °C. Hence, neither case provides any real support for the hypothesis that bone deposition in this specimen occurred under essentially thermostable conditions.