bluuebunny/crossref_metadata_2025_split huggingface dataset:
Genetic variability and geographic structure of three subspecies of tigers (Panthera tigris) based on MHC class I variation
Authors: Hendrickson Sher L. , Mayer Gregory C. , Wallen Edward P. , Quigley Kathy 
Published: February 2006

AbstractGenetic variation at the major histocompatibility (MHC) class I loci was examined in captive and wild samples of three subspecies of tiger (Bengal, Panthera tigris tigris; Siberian, P. t. altaica; Sumatran, P. t. sumatrae) by Southern blot analysis using the domestic cat probe FLA 24. All captive populations showed at least moderate variability compared to other felids. Captive tigers were, on average, significantly more variable than wild tigers, but this was not consistent among subspecies. Significant geographic genetic population structure was found at the MHC class I loci among both captive and wild tigers. Phylogenetic analysis of both captive and wild tigers placed Sumatran tigers basally. In a combined phylogenetic analysis, captive and wild tigers of the same subspecies occurred near one another, indicating that the structure of the captive populations reflects that of the wild populations.
Predators and people: using human densities to interpret declines of large carnivores
Authors: Woodroffe Rosie 
Published: February 2006

AbstractThe current extinction crisis is caused primarily by human impacts upon wild populations. Large carnivores are especially sensitive to human activity; because their requirements often conflict with those of local people, predators have been actively persecuted in most regions of the world. In this paper, the impact of people upon predators is analysed by relating local carnivore extinctions to past and projected human population densities. There are strong associations between high human density and the loss of carnivore populations from a region. Interspecific variation in ability to survive at high human densities probably reflects species' ability to adapt to human‐modified habitats. However, regional and temporal variation in individual species' sensitivity to human density is more likely to reflect the activities of local people than the phenotypes of local carnivores. Local culture, government policy and international trade all influence human attitudes to predators and, therefore, the impact of people upon carnivore populations. The importance of these factors may mean that extinction risks for carnivores will continue to increase, even though human population growth is projected to deccelerate during the new millennium. This points to an urgent need for techniques to resolve conflicts between people and predators at either the local or landscape level.
Habitat selection by translocated black howler monkeys in Belize
Authors: Ostro Linde E. T. , Silver Scott C. , Koontz Fred W. , Young Truman P. 
Published: February 2006

AbstractHabitat selection by translocated black howler monkeys (Alouatta pigra) was studied in Belize, Central America. Ranging patterns of two recently translocated groups were contrasted with those of two groups in the same area with established home ranges, on a yearly and monthly basis. All groups concentrated their activities along stream beds at elevations below 200 m. Newly translocated groups increased the percentage of their monthly ranges in riverine areas (within 100 m of a water source) over the year of the study (with the exception of the last month) while established groups did not. Areas used more than five times by the monkeys contained larger trees and a greater relative coverage of major food species than low‐use areas even though they had a lower overall species richness and diversity. These monkeys may be selecting habitat within the forest based upon vegetative differences and ranging patterns may be affected by patterns of food availability.
Discriminant analysis of the terrestrial and aquatic habitat determinants of the smooth newt (Triturus vulgaris) and the common frog (Rana temporaria) in Ireland
Authors: Marnell Ferdia 
Published: February 2006

AbstractThe breeding site characteristics of the smooth newt (Triturus vulgaris) and the common frog (Rana temporaria) have been investigated in the Republic of Ireland and in Northern Ireland. A total of 278 waterbodies and their surrounding terrestrial habitats were examined in 60 National Grid 10‐km squares across the island: 33 habitat parameters were recorded. Discriminant function analyses were calculated which correctly classified 88.46% and 87.5% of the sites for the newt and frog, respectively. These analyses identified the terrestrial and aquatic habitat variables which were important in discriminating between the sites which were used and unused by each of the species. Terrestrial habitat factors, particularly the availability of terrestrial refugia, were found to be especially important in determining the suitability of the breeding sites for both species.
Comparative demography of red squirrels (Sciurus vulgaris) and grey squirrels (Sciurus carolinensis) in deciduous and conifer woodland
Authors: Kenward R.E. , Hodder K.H. , Rose R.J. , Walls C.A. , Parish T. , Holm J.L. , Morris P.A. , Walls S.S. , Doyle F.I. 
Published: February 2006

AbstractThe demography of red and grey squirrels was studied by live‐trapping and radio‐tagging at 14 deciduous and conifer sites in southern Britain and at eight conifer sites for one year in northern England. Densities and productivity correlated with tree seed crops for both squirrel species in deciduous and conifer habitats. Productivity was reduced by high density of full‐grown squirrels relative to seed abundance. In oak‐hazel woods, demography of grey squirrels correlated with abundance of acorns but not of hazel‐nuts, whereas density and productivity of red squirrels correlated with hazel‐nut abundance. Correlations of female density and productivity with pine‐cone crops did not differ between red and grey squirrels. Predators ate many radio‐tagged grey squirrels in conifers, and annual survival was only 50% compared with 80‐82% for both species in other habitats. Grey squirrel populations in southern conifer sites were sustained by immigration, and at northern sites female density correlated with oak abundance within 500m. Failure to exploit acorn crops puts red squirrels at a competitive disadvantage in deciduous woodland. Red squirrels had higher survival than grey squirrels in conifers, which may give them an advantage in that habitat, but could also have been explained by a lack of predators on their island study site.
Red squirrels (Sciurus vulgaris) released in conifer woodland: the effects of source habitat, predation and interactions with grey squirrels (Sciurus carolinensis)
Authors: Kenward R.E. , Hodder K.H. 
Published: February 2006

AbstractFourteen radio‐tagged red squirrels were released in pine woodland containing grey squirrels. Movements of the squirrels were related to the tree species of the donor site. Survival after release was lower than for the grey squirrels: of 11 red squirrels that survived at least a week, only three survived more than three months and none for four months. More than half were eaten or cached by predators, mainly foxes; an experiment with grey squirrel carcasses indicated that they had been killed, not scavenged after death. Hypertrophied adrenals, disease and loss of weight indicated stress as another factor in the deaths. Data on overlap of core ranges, and reluctance of red squirrels to enter traps used by grey squirrels in the mixed population, indicated interference competition between the two species, with grey squirrels possibly dominant. We recommend: (i) that care should be taken to release translocated animals in similar habitat to their origin; (ii) that grey squirrels should be excluded from future release areas until red squirrels have settled and, before biodiversity is reduced by landscape management for red squirrels; (iii) more research to determine whether interactions with grey squirrels or differential predation will ultimately displace red squirrels in conifers.
Circadian metabolic and thermoregulatory patterns of red‐billed woodhoopoes (Phoeniculus purpureus): the influence of huddling
Authors: Boix‐Hinzen C. , Lovegrove B.G. 
Published: February 2006

AbstractCircadian rhythms of metabolic rate and body temperature were measured in groups of huddling and solitary red‐billed woodhoopoes (Phoeniculus purpureus) as a function of ambient temperature. Basal metabolic rates were 30‐60% lower than those of similar‐sized birds of other species. As a consequence, circadian amplitudes of Tb and VO2 fluctuation between the rest and activity phases of non‐huddling birds were also larger than expected. Circadian rhythms of metabolism save huddling and non‐huddling woodhoopoes 19‐34% of their potential daily energy expenditure. Birds huddling in groups conserved 12‐29% of the daily energy expenditure of non‐huddling birds at ambient temperatures of 20°C and below. However, at 30°C huddling birds used c. 12% more energy than non‐huddling birds. The various avenues of energy conservation employed by woodhoopoes are suggested to be beneficial in: a) augmenting the proximate benefits of cooperative breeding; and b) optimizing fitness in the drought‐prone sub‐Saharan savannahs which are heavily influenced by the El Niño Southern Oscillations.
Establishment of a captive colony of Bettongia tropica (Marsupialia: Potoroidae) by cross‐fostering; and observations on reproduction
Authors: Smith Meredith J. 
Published: February 2006

AbstractIt is demonstrated that cross‐fostering is a practical way of improving the rate of increase of a rare species in captivity. Two adult Bettongia tropica were captured in northern Queensland and housed in captivity in Adelaide, South Australia. Eleven pouch young born in captivity to the wild‐caught B. tropica were transferred at 20 days old or older to B. penicillata foster mothers and nine were reared successfully. Of a further 10 young not fostered, six were reared by the wild‐caught mother. Fostering allowed the wild‐caught female to produce surviving young nearly twice as frequently as if she had reared them in her pouch.Sexual maturity occurred at 246‐523 days (x[bar] = 407.2 ± 59.9 days) in 4 males and at 185‐429 days (x[bar] = 300.5 ± 26.0 days) in 11 females. Breeding continues throughout the year and females undergo embryonic diapause whilst supporting a pouch young. The female reproductive system is remarkable for its relatively long urethra and lateral vaginae and consequently short urogenital sinus. The male reproductive system is unremarkable, having a carrot‐shaped prostate gland and three pairs of Cowper's glands, as do many other macropodoid species. Two pairs of paracloacal glands are found in males and females.
The colony structure and social organization of the giant Zambian mole‐rat, Cryptomys mechowi
Authors: Wallace E. D. , Bennett N. C. 
Published: February 2006

Abstract Cryptomys mechowi is a social subterranean mole‐rat which inhabits the mesic regions of south‐eastern and central Africa. Giant mole‐rats live in colonies of up to 11 animals in which reproduction is normally restricted to the largest male and female in the colony. In this preliminary study on a laboratory‐reared colony, the non‐reproductive members of the colony could not be placed into clearly defined, work‐related groups based on body mass. The colony showed a work frequency related division of labour. Reproductive animals performed little work, 3‐4% of the total work. The non‐reproductive caste was divided into two groups based on the amount of burrow maintenance activity: those performing between 7‐11% of total work and those ranging from 15‐22% of total work. Male members of the colony tended to perform more work than the females. The dominance hierarchy of the colony was found to be nearly linear, with a value of 0.83 calculated from Landau's linearity index. The reproductive animals were the most dominant in their respective gender. Dominance was not age‐related. However, non‐reproductive males tended to be more dominant than non‐reproductive females. Social organization within the giant Zambian mole‐rat is compared with other southern African Cryptomys species in the light of the eusociality continuum.
The reproductive cycle and determination of sexual maturity in male brown long‐eared bats, Plecotus auritus (Chiroptera: Vespertilionidae)
Authors: Entwistle A. C. , Racey P. A. , Speakman J. R. 
Published: February 2006

AbstractObservations of the external morphology of wild‐caught and captive male brown long‐eared bats (Plecotus auritus) revealed a marked seasonal pattern of spermatogenesis, similar to that established by histological examination of other temperate‐zone vespertilionids, with a peak in testes size in August and a lag between testicular growth and epididymal distension. This was followed by complete cessation of spermatogenesis and shrinkage of the testes to prepubertal size. The period of peak spermatogenesis coincided with a reduction in the incidence of torpor and also a decline in body mass. This suggests that torpor and spermatogenesis may be incompatible in this species. Outside the season of testicular growth and epididymal distension, sexual maturity could not be confidently determined in P. auritus by the pigmentation of the tunica vaginalis surrounding the epididymis, a characteristic which has become established in other species. Instead, the size and shape of the caudae epididymides appeared to be a better criterion for defining sexual maturity in this species. Most males underwent testicular growth and epididymal distension, and were assumed to have reached sexual maturity, at an age of 15 months. However, some individuals (29%), particularly those in good condition (relatively heavy individuals), showed a degree of testicular and epididymal development in their first autumn, i.e. at 3 months of age, indicating that the onset of puberty may be dependent on body condition. Poor body condition was associated with delayed spermatogenesis in adult males.
Intraspecific scarring in odontocete cetaceans: an indicator of male ‘quality’ in aggressive social interactions?
Authors: MacLeod Colin D. 
Published: February 2006

AbstractThe level of visible (i.e. white or unpigmented) scarring on cetaceans varies greatly between species, particularly for intraspecific scarring in odontocete cetaceans. In some species, unpigmented intraspecific scars may act as an indicator of male ‘quality’ during aggressive social interactions. Evidence to support this hypothesis was found in 18 species of odontocete cetacean. These were the narwhal (Monodon monoceros), the sperm whale (Physeter macrocephalus), the Risso's dolphin (Grampus griseus) and the family Ziphiidae (with the exception of Mesoplodon ginkgodens). The evolution of such signalling is related to the fact that teeth are not required for feeding on certain diets, primarily cephalopod‐based diets, and as a result the number of teeth has been reduced. However, some teeth have been retained, and selected, as weapons for male‐male competition. This has resulted in an increase in the level of intraspecific scarring and the greater need for a signal of ‘quality’ to avoid costly and dangerous fights. As intraspecific scarring became this signal, the repigmentation rate of scars was reduced, leading to all scars remaining permanently unpigmented in these species.
A new genus and three new species of deep‐sea holothuroids from the west coast of South Africa (Echinodermata)
Authors: Thandar Ahmed S. 
Published: February 2006

AbstractOne new genus and three new species of deep‐sea holothuroids, taken by the South African Division of Sea Fisheries R.S. Africana II routine trawls, off the west coast of the Cape Peninsula in South Africa in 1959, are described. A new genus Psolidothuria, perhaps referable to the dactylochirotid family Vaneyellidae, is erected for the new species P. octodactyla. The remaining new species are Paracucumaria capense, in the dendrochirotid family Cucumariidae, and Laetmogone perplexa, in the elasipodid family Laetmogonidae. P. capense was originally described as Trachythyone parva (Ludwig) by Thandar (1991). The diagnosis of the family Vaneyellidae is amended to accommodate the new genus.
Habitats of the song thrush Turdus philomelos in a largely arable landscape
Authors: Mason C. F. 
Published: February 2006

AbstractDuring three breeding seasons, 1994‐96, the habitats of song thrushes were studied in north‐east Essex, U.K., in 10 tetrads (total 40 km2) of mainly farmland habitat and 35 woods of differing sizes (range 0.1‐57.0 ha). Within tetrads, only 6 (3.5%) territories were found in farmland. Gardens held 123 (71.5%) territories, though this habitat made up only 2% of the total area, while 39 (22.7%) were in woodlands (1% of total area). Population densities were much lower in the tetrads than in earlier studies; this may be an indication of the severe population decline that the species has recently undergone. Densities in gardens differed less from those of previous studies.In the woodland study, the number of woods holding song thrush territories declined over the three years, while the proportion of total territories in the six largest woods increased. Densities in the woods were lower than those reported in earlier studies but the disparity was not as great as in farmland. Extinctions in the smaller woods was 20‐30% per annum, a rate similar to that for gardens: population extinctions did not occur in the larger woods.Some 40% of non‐garden territories in the surveys of both tetrads and woodland plots were within 100 m of a garden. Gardens may be currently acting as a refuge for song thrushes and an understanding of the ecology of the species in different types of gardens may be important in current conservation efforts for the species.
Predatory behaviour and parental care in Argyrodes flavipes, a social spider from Queensland
Authors: Whitehouse M. E. A. , Jackson R. R. 
Published: February 2006

Abstract Argyrodes flavipes illustrates a novel form of highly social behaviour in spiders. Although A. flavipes lives in groups, forages communally, and has parental care, it is also highly aggressive towards conspecifics. These observations, plus the relatively small group sizes, suggest that sociality in these animals may be more akin to that in social mammalian carnivores than in social insects. Most highly social spiders are thought to have developed sociality via the sub‐social route because of their high level of parental care. Although A. flavipes also exhibits high levels of parental care, its phylogenetic background and the fact that it needs to defend its young from conspecifics, suggest that both sub‐social and para‐social factors may have influenced its social development.
Energetics of burrowing, running, and free‐living in the Namib Desert golden mole (Eremitalpa namibensis)
Authors: Seymour R. S. , Withers P. C. , Weathers W. W. 
Published: February 2006

AbstractThe Namib Desert golden mole (Eremitalpa granti namibensis) is a small (c. 20 g), blind, sand‐swimming, chrysochlorid insectivore that inhabits the sand dunes of one of the driest and least productive areas of the world. Its food, largely termites, is sparse and occurs in widely distributed patches, and free water is unavailable. The moles forage by running on the surface and burrowing below the sand. We estimated their daily energy expenditure in the field to be 11.8 kJ d‐1 by constructing a ‘distance‐energy budget’ based on measurements of tracks in the sand and the energy cost of running (4.2 kJ d‐1), burrowing (3.2 kJ d‐1), and resting (4.4 kJ d‐1). We also measured field metabolic rate (12.5 kJ d‐1) and water turnover (2.3 ml d‐1) independently with doubly‐labelled water. The resting metabolic rate (0.5 ml O2 g‐1 h‐1 at 35 °C) is about a fifth of that predicted for a normal insectivorous mammal, and the daily field energy expenditure and water turnover are about a half. The low daily energy expenditure stems mainly from the low resting metabolic rate, which is associated with low body temperatures and metabolic depression. Moles save more energy during foraging by running on the surface of the sand, rather than burrowing under it. The gross energy cost of sand‐swimming (80 J m‐1) is 26 times more expensive than running on the surface (3.0 J m‐1), but is less than a tenth of the energy required by mammals that tunnel through compact soil. Nevertheless, it would be energetically impossible for the moles to obtain enough food by foraging only underground at our study site. The mean track length was 1.4 km, but only 16 m of it was below the surface. There is evidence that the track length and fraction underground depend on food abundance which is influenced by rainfall.
Vocalizations in red deer (Cervus elaphus), sika deer (Cervus nippon), and red × sika hybrids
Authors: Long A. M. , Moore N.P. , Hayden T. J. 
Published: February 2006

AbstractRutting calls of male and alarm calls of female red deer (Cervus elaphus), sika deer (C. nippon), and their hybrids were recorded from wild and captive‐bred populations. Vocal variations between these species and their hybrids (C. elaphus×C. nippon) were examined using multivariate analysis to determine whether these groups could be successfully discriminated. There were highly significant differences between the vocalizations of each group for both sexes (males: Wilks' Λ= 0.0233, P<0.0001; females: Wilks' Λ= 0.1338, P<0.0001). The greatest differences were between analogous calls of red and sika deer. Vocalizations of hybrids from both captive‐bred and feral populations were intermediate between the two parent species. The differences between the groups were most highly influenced by the pitch of calls. The results of this study indicate that the vocalizations of deer, rather than being learned or mimicked from similar species in their proximity, are strongly influenced by the genetic background of their parents.
Morphology of the kidney in a nectarivorous bird, the Anna's hummingbird Calypte anna
Authors: Casotti G. , Beuchat C.A. , Braun E.J. 
Published: February 2006

AbstractThe kidneys of Anna's hummingbird (Calypte anna) differ in several significant ways from those of other birds that have been examined. The kidneys of this nectarivore contain very little medullary tissue; 90% of the total volume of the kidneys is cortical tissue, with medulla accounting for only an additional 2%. More than 99% of the nephrons are the so‐called ‘reptilian type’), which lack the loop of Henle. The few looped (‘mammalian type’) nephrons are incorporated into only a few medullary cones per kidney. The loopless nephrons are similar to those of other birds. However, the looped nephrons differ in that they lack the thin descending limb of the loop of Henle, which is found in other birds and is thought to play an important role in the countercurrent multiplier system in the avian kidney. Instead, the cells of the nephron segment following the pars recta of the proximal tubule resemble those of the thick ascending limb, with the large populations of mitochondria that are typical of transporting epithelia and no reduction in cell height. The absence of a descending thin limb in Anna's hummingbird is not necessarily a correlate of the hummingbird's liquid diet, because thin limbs have been documented in the kidneys of two other hummingbird species, the rufous hummingbird (Selasphorus rufus) and the broad‐tailed hummingbird (Selasphorus platycercus). The functional correlates of the unique renal morphology in Anna's hummingbird warrant further study.