bluuebunny/crossref_metadata_2025_split huggingface dataset:
Arable habitat use by wood mice (Apodemus sylvaticus). 1. Macrohabitat
Authors: Todd I. A. , Tew T. E. , Macdonald D. W. 
Published: February 2006

AbstractWood mice Apodemus sylvaticus were radio‐tracked in an area covering three cereal fields, which was notionally divided into 5×5 m squares; each of these squares was classified to one of four habitat types (hedgerow, wheat, barley and oil‐seed rape). From a sample of 79 radio‐tracked wood mice, yielding 8500 fixes, we defined home‐range boundaries and estimated for two seasons: (a) the extent to which each habitat was present in each individual's home range relative to its overall availability in the surrounding landscape; (b) the extent to which each habitat was used by the mice relative to its abundance within a home range. Hedgerow ranked highest in preference (as distinct from use) for all comparisons made in both winter and summer. In winter, home ranges contained significantly more hedgerow than barley and wheat, and significantly more rape than wheat. Animals also used the habitats within their home ranges non‐randomly, with a significant preference for hedgerow. In summer, home ranges contained significantly less rape than other habitats. Habitats within home ranges were used at random. Seasonal patterns in habitat use appeared to be largely a response to seasonal disturbance and the availability of cover in the fields.
Arable habitat use by wood mice (Apodemus sylvaticus). 2. Microhabitat
Authors: Tew T. E. , Todd I. A. , Macdonald D. W. 
Published: February 2006

AbstractForty‐eight wood mice Apodemus sylvaticus were radio‐tracked over an estimated 1500 h yielding 9000 fixes. The mice were living in three contiguous arable fields, and showed that they respond to weedy microhabitat patches within superficially homogeneous crops. Plant species' abundance and the composition of the seed bank were assessed in quadrats taken in areas in which (a) mice foraged, (b) through which mice travelled, or (c) at random within each home range. Wood mice avoided foraging in areas with a high abundance of bare earth, and selected areas with a high abundance of Alopecurus myosuroides, Stellaria media, Avena fatua, Galium aparine or Bromus sterilis. The food plants apparently selected by wood mice differed markedly between months and between sexes. This may relate to the energetic and nutritional demands incurred by the contrasting reproductive tactics of male and female wood mice. There were no differences between seed bank samples taken from quadrats where the mice foraged, travelled through, or which were selected at random. Our study, the first large‐scale analysis of wood mouse microhabitat preference using radio‐tracking, reveals that whereas the mice do not react to heterogeneity on the scale of the mosaic of crop fields, they are greatly influenced by the dispersion of food plants within the superficially homogeneous crop itself.
Competition for acorns among wild boar (Sus scrofa) and small mammals in a Mediterranean woodland
Authors: Focardi Stefano , Capizzi Dario , Monetti Daniel 
Published: February 2006

AbstractObservations of the rooting activity of wild boar in a holly‐oak grove showed that in March–April the decrease of acorns in the diet (31%) was lower than their availability (82%). Moreover the occurrence of deep rooting events remains high despite the low occurrence of grass roots in the diet. These observations suggested that wild boar may exploit hoards of acorns collected by small mammals living in the study area (mainly wood mice Apodemus sp.). In order to test this hypothesis two experimental trials were set up to: (1) investigate whether wild boar were able to locate acorns buried in the ground (range 0–30 cm) and (2) establish if mouse burrows were more likely to be excavated than locations without burrows. The results clearly show that wild boar actively search for buried acorns, mainly in March (59%vs 31% in April and nothing in May) and that burrows are excavated significantly more than locations without burrows (ratio 2:1, respectively). Moreover, locations with burrows are characterized by a decline of rooting activity as a function of the distance from their centre (P= 0.02), which is absent in the control locations (P= 0.74). Our results show that wild boar are able to partly compensate for a reduced above‐ground availability of acorns by predating on hoards collected by small mammals. Since this occurs during a critical period for female wild boar when they are giving birth and lactating, this behaviour may strongly influence the population dynamics of both wild boar and small mammals.
Population dynamics of the spiny country rat (Niviventer coxingi) in a subtropical montane forest in central Taiwan
Authors: Wu Hai‐Yin , Yu Hon‐Tsen 
Published: February 2006

AbstractPopulation dynamics of the spiny country rat Niviventer coxingi were studied by mark–recapture methods from January 1982 to May 1983 in a subtropical montane forest at Chitou, central Taiwan. The population density was < 8 rats/ha. The annual pattern of population fluctuation was characterized by summer increase, autumn peak and spring decline. Adult recruits occurred mostly in summer and autumn 1982, whereas young rats joined the population as three cohorts: winter 1981, summer 1982 and winter 1982. Growth patterns differed between winter and summer cohorts, which was attributed mainly to the slow body weight increase in summer cohort males. Males, either adult or juvenile, survived the winter better than females, resulting in the shorter lifespans and the lower number of females in the population. Life‐history traits in female N. coxingi, i.e. short reproductive lifespan, few litters per life time and prolonged maternal care, along with the low breeding intensity, rendered the number of females the limiting factor for population increase. However, females may improve the survival and maturation of their offspring by prolonged maternal care.
Endemism, gigantism and extinction in island lizards: the genus Gallotia on the Canary Islands
Authors: Barahona F. , Evans S. E. , Mateo J. A. , García‐Márquez M. , López‐Jurado L. F. 
Published: February 2006

AbstractIn the Canary Islands five extant and two extinct giant lacertid lizards belonging to the endemic genus Gallotia are known. A comparative study of the living and subfossil specimens from the Western Canary Islands demonstrates that the extinct giant species Gallotia goliath and Gallotia maxima are synonymous with the living Gallotia simonyi. Characters formerly used in the diagnosis of the extinct species and subspecies fall within the range of intraspecific variation (ontogenetic and individual) of the living species. The only significant difference between living and subfossil populations of G. simonyi is size, and there is strong evidence to suggest that the reduction in size in living populations reflects shorter life expectancy, a factor that should be taken into account in the current conservation projects on this species.
The effects of bovine tuberculosis (Mycobacterium bovis) on mortality in a badger (Meles meles) population in England
Authors: Wilkinson D. , Smith G. C. , Delahay R. J. , Rogers L. M. , Cheeseman C. L. , Clifton‐Hadley R. S. 
Published: February 2006

AbstractThe mortality rates of badgers Meles meles were estimated, using data from a long‐term capture–mark–recapture study of an undisturbed badger population in south‐west England. Two life table methods were used: fusion and discounting. Badgers were allocated to a particular TB status for all or part of their lives according to their degree of infection with bovine tuberculosis Mycobacterium bovis. Separate life tables were created for animals with each TB status, and for males and females, and the estimated mortality rates were compared statistically. The progression of M. bovis infection, and the positions of M. bovis lesions were also analysed. The main findings are: (a) uninfected male badgers have a significantly higher mortality rate than uninfected females, (b) infected badgers which are not excreting M. bovis do not have a significantly higher mortality rate than uninfected badgers, (c) badgers which are excreting M. bovis have a much higher mortality rate than uninfected badgers, (d) male badgers appear to cope with M. bovis infection less well than females, and (e) there may be sex differences in the mode of spread of M. bovis in badgers.
Weapon strength and competitive success in the fights of shore crabs (Carcinus maenas)
Authors: Sneddon L. U. , Huntingford F. A. , Taylor A. C. , Orr J. F. 
Published: February 2006

AbstractWeapon size has been shown to be a better predictor of competitive success than body size (carapace width) in fights between shore crabs, Carcinus maenas. However, when the weapon size disparity is small between two opponents, it is still difficult to predict the victor. The role of weapon strength in pairwise fights between male shore crabs was investigated, to determine if relative force influences contest content, duration and outcome. Weapon strength was ascertained using a force transducer on live crabs, then fights between crabs were staged between size matched males. Winning crabs had major (crusher) claws and minor (cutter) claws that exerted a significantly greater force than losing crabs even when claw length was the same. Winners and losers were matched for carapace width, claw length and dactyl length but not claw height or claw length minus the dactyl. Winners had greater claw height and claw length to the dactyl in the major claw giving them a higher mechanical advantage when closing the claw and thus exerting a greater force. The forces exerted by the major and minor claws were analysed for any relationship between force and morphological measurements. Winning crabs appear to be fitter in having a better claw structure which exerts a greater force and they are more successful in agonistic interactions.
Orbit orientation and the function of the mammalian postorbital bar
Authors: Noble Vivian E. , Kowalski Erica M. , Ravosa Matthew J. 
Published: February 2006

AbstractThe visual predation hypothesis of primate origins was introduced by M. Cartmill in the 1970s. In outlining a series of predictions regarding changes in orbital orientation, he further posits that the formation of a bony postorbital bar is correlated with greater orbital convergence, which in turn appears to be linked to selection for increased stereoscopic visual acuity in a nocturnal milieu. A series of predictions related to this model is tested in living analogues that vary in postorbital bar formation: felid and herpestid carnivorans and the pteropodid megabats. Bivariate correlations and regressions, ANOVA and ANCOVA are used to assess the intrinsic allometric and non‐allometric factors thought to affect two aspects of orbital orientation, convergence and frontation. These angles of orbital orientation are then examined in an effort to determine how they are associated with the development of a postorbital bar. Cartmill suggested that convergent orbits develop from changes in relative orbit diameter and relative interorbital breadth. This study indicates that felids show only weak support for these predictions, while herpestids do not provide support and pteropodids show some support. Instead, in response to natural selection, convergence seems to develop to improve stereoscopic vision and depth perception in nocturnal predators. As predicted, felids show a significant positive relationship between orbital frontation and relative brain size. Analyses in herpestids, however, do not show significant relationships between frontation and relative palate length or relative brain mass. Pteropodids also do not support the model regarding intrinsic frontation factors. In both carnivoran groups, convergence and frontation are positively correlated, whereas they are not correlated in Pteropodidae. In partial contrast to Cartmill's predictions, we found that orbital convergence and/or orbital frontation are generally higher in carnivorans and bats with postorbital bars. Therefore, a greater emphasis on nocturnal stereoscopic visual predation and increased relative brain size both move the orbital aperture out of the plane of the temporal fossa and a postorbital bar thus provides adequate rigidity to the lateral orbital margin. In the more encephalized Felidae, orbital frontation is positively correlated with relative brain size; as smaller mammals have relatively larger brains, this explains why postorbital bars tend to be found in smaller felids. In herpestids and pteropodids, postorbital bars tend to occur in larger taxa which are more convergent than smaller forms.
Environmental factors influencing the presence and abundance of a log‐dwelling invertebrate,Euperipatoides rowelli(Onychophora: Peripatopsidae)
Authors: Barclay S. , Ash J. E. , Rowell D. M. 
Published: February 2006

AbstractThe microenvironments of decaying logs support a large invertebrate fauna, but are vulnerable to the effects of logging and land‐clearing. We present an analysis of the relationship between a number of environmental variables and the occurrence and abundance of the onychophoranEuperipatoides rowelliwithin decomposing logs in a forest in south‐eastern Australia. Aspect of slope is strongly associated with most of the environmental variables and is a good predictor of both presence and abundance of animals in logs; south‐easterly slopes show higher levels of log colonization, larger populations within logs and a larger median weight of both males and females than north‐westerly facing slopes. Degradation state of logs, log length, presence of termites and shrub cover are also associated with the presence of onychophorans, while log volume shows the most marked association with abundance.Euperipatoides rowelliprefers wetter logs, although there is considerable overlap between relative water content of logs with and without onychophorans. Log degradation state, an important factor in the presence of animals, is associated with years since felling, and our data indicate that logs become capable of supporting large populations ofE. rowelliafter a minimum of 45 years of decay. Thus future logging practices have important implications for the maintenance of suitable log environments for this species, and this result may be generalized to other log‐reliant fauna.
Pheromonally mediated colonization patterns in the velvet worm Euperipatoides rowelli (Onychophora)
Authors: Barclay S. D. , Rowell D. M. , Ash J. E. 
Published: February 2006

AbstractWe demonstrate that the males of the peripatopsid Euperipatoides rowelli secrete a pheromone from crural papillae, which acts as an attractant to both males and females of the species. Patterns of colonization of decomposing logs and differences in sex ratio between incipient vs established populations indicate that males are the initial dispersers and colonizers, finding suitable log habitats in an exploratory fashion, while females subsequently colonize logs. This results in a disproportionately high frequency of males in newly colonized logs, followed by a gradual increase in female proportion. We argue that females use the aggregating pheromone secreted by males to target appropriate rotting log microhabitats, resulting in a clumped distribution of females compared to a more random distribution for males among recently colonized logs. This mode of colonization reduces the time that animals, especially females, spend outside the safety of suitable logs, and the risk‐taking strategy of male exploration may explain the marked sex ratio bias in favour of females in the population. Rapid and non‐random dispersal may also account for the contradictory evidence of unexpectedly high rates of colonization of new logs, yet a paucity of animals in leaf litter samples. The possibility that pheromone trails play a part in the dispersal process is discussed.
Reproductive biology of the onychophoran Euperipatoides rowelli
Authors: Sunnucks Paul , Curach Natalie C. , Young Anthony , French Jordan , Cameron Ray , Briscoe Dave A. , Tait Noel N. 
Published: February 2006

AbstractThe reproductive biology of the ovoviviparous peripatus Euperipatoides rowelli was investigated from field collections and laboratory cultures. The sexes have different demographics. The frequency distribution of individual weight is essentially L‐shaped in females, but closer to normality for males: thus the sexes must exhibit different patterns of growth and/or mortality. Males are generally much smaller and rarer than females. The primary sex ratio seems to be 1:1 with equal investment in the sexes, while the tertiary ratio is highly female‐biased. Logs with fewer individuals tend to be male‐biased while well‐populated logs tend to be female‐biased. Males mature at 15–30% of the bodyweight of mature females. The weight frequency distribution of males without developed sperm in their tracts is strongly skewed to the lower weights, while that of males with sperm is more normally distributed, indicating that sperm production occurs as soon in life as possible. Males mature in their first year of life, if growth rates in culture may be extrapolated to the wild. In contrast to this rapid maturity in males, females may mature as late as their second or third years. Most mature females, and many prior to maturity, carry sperm in their spermathecae. After maturity, there is an approximately linear relationship between body mass and number of developing embryos. Reproduction in E. rowelli is significantly seasonal despite high individual variance, with a major bout of parturition in November–December (summer). A female can harbour one developed and one undeveloped batch of embryos in each uterus. Excesses of developed embryos in one uterus are counterbalanced by deficits of undeveloped ones, indicating that females can use their paired reproductive tracts independently. Individual females in culture can experience episodes of parturition approx. 6 months apart without re‐mating, thus gestation may be 6 months or more. Sperm in spermathecae remain capable of vigorous swimming for at least 9.5 months.
Higher testicular activity in laboratory gerbils compared to wild Mongolian gerbils (Meriones unguiculatus)
Authors: Blottner S. , Franz C. , Rohleder M. , Zinke O. , Stuermer I. W. 
Published: February 2006

AbstractThe Mongolian gerbil has been used as laboratory animal since 1935. Breeding gerbils as an isolated laboratory population for decades may have led to a domestication process whose effects include changes in brain size. Quantitative changes in testicular activity could be assumed. Comparative intraspecific measurements were performed in 34 adult males of the laboratory strain (LAB) and in males raised as offspring of wild Mongolian gerbils (WILD) caught in central Mongolia (F1, n= 16; F2, n= 17). LAB and WILD were examined in January. Testicular spermatozoa were counted, proportions of different cell types were analysed using DNA flow cytometry, and mitotic and meiotic activity was calculated from DNA histograms. Intratesticular testosterone concentrations were measured with an enzyme immunoassay. In the WILD, testicular activity was lower and varied more. The overall weight, the efficiency of spermatogenesis (sperm/g testis) and resulting total sperm per testis were significantly less in offspring of wild gerbils. This corresponded with lower levels of haploid cells, total germ cell transformation of diploid cells to spermatids and meiotic transformation of spermatocytes to spermatids. The most profound difference was found in testicular testosterone concentration: the mean level was 405.7 ± 41.2 ng/g testis in LAB vs 6.4 ± 2.0 ng/g in WILD F1. All parameters changed in WILD F2 generation compared with F1 and diminished the differences with LAB. Differences between F1 and F2 were significant for testis mass, testis/body weight ratio, percentages of haploid cells and cells in G2/M phase, both germ cell transformations and testosterone concentration. The results suggest rapid, adaptive changes of male reproductive physiology in the early offspring generations from wild populations under laboratory breeding conditions. The breeding of Mongolian gerbils in the laboratory has influenced the testicular function resulting in increased spermatogenic activity and highly stimulated testosterone production.
Roosts used by the golden‐tipped bat Kerivoula papuensis (Chiroptera: Vespertilionidae)
Authors: Schulz M. 
Published: February 2006

AbstractUse of roosts by the golden‐tipped bat Kerivoula papuensis was investigated principally in the Richmond Range National Park, north‐eastern New South Wales and Mt Baldy State Forest in north‐eastern Queensland, Australia. Roosts were located primarily using radiotelemetry; although others were found by light tagging, visual location and nest searching techniques. In the main study site in the Richmond Range a total of 54 K. papuensis diurnal roosts were located, 96.5% occurring in the suspended nests of the yellow‐throated scrubwren Sericornis citreogularis (Pardalotidae) (93%) and the brown gerygone Gerygone mouki (Pardalotidae) (3.5%). At Mt Baldy, K. papuensis displayed greater variation in day roost selection, although 73% were in S. citreogularis nests. In both sites, day roosts were confined to the lower stratum of rainforest with a small proportion in eucalypt tall open forest with a rainforest subcanopy. Diurnal roosts were located at distances varying from 20 to 1200 m to the nearest major vegetation ecotone, ranging from along watercourses upslope to ridgelines. Diurnal roosts were predominantly occupied by single bats, with a maximum group size of eight individuals. All roosts in hanging nests were modified by the presence of a basal hole. Strong circumstantial evidence was provided that K. papuensis modified these roost structures in a manner allied to tent‐making bats. A single maternity roost was located in the hollow of a rainforest canopy tree, Flindersia australis (Rutaceae).
Ultrastructure of the neck membrane in dragonflies (Insecta, Odonata)
Authors: Gorb Stanislav N. 
Published: February 2006

AbstractThis study describes and quantifies the microsculpture and ultrastructural design of the neck membrane of adult Odonata using scanning and transmission electron microscopy. The membranous cuticle has a complex pattern of microfolds, which appear to have a specialized mechanical function. The membrane has two layers of cuticle: the epicuticle and exocuticle. The outermost layer is the electron‐opaque epicuticle, which repeats the shapes of the microfolds. The epicuticle has no fibrillar elements. The exocuticle is electron‐lucent and rather thin (0.5–1.5 μm) compared with the sclerite cuticle. The cuticle microfibrils in successive lamellae are at angles to each other. The epidermal cells underlying the membrane have an electron‐lucent matrix filled with electron‐opaque spherical vesicles of 0.1–0.4 μm in diameter. The behaviour of the membrane folds under loading was studied by shock‐freezing experiments; these showed that the shape of the folds changed in response to head movements, and stretched under loading. A comparison of the surface patterns of the membrane in 10 odonate species from seven families (Zygoptera: Coenagrionidae, Lestidae, Megapodagrionidae; Anisoptera: Cordulegastridae, Aeshnidae, Corduliidae, Libellulidae) had not revealed any correlation of the measured parameters with the size, sex or systematic position of species studied.