bluuebunny/crossref_metadata_2025_split huggingface dataset:
The function of daylight flying in British bats
Authors: Speakman J. R. 
Published: March 2009

A national survey of the incidence of daylight flying of bats in mainland Britain was organized from September 1985 until March 1988. A total of 420 records of daylight flying were received by 1 May 1988. One hundred and forty‐four reports were from winter (October to March), 271 from summer (April to September) and five were undated. Peak activity occurred during April and in August/September.Activity in both winter and summer was greatest between 12:00 and 16:00h. The numbers of bats involved in each sighting varied between 1 and 200. In summer 87% and in winter 91% of observations were of single individuals. Numbers of daylight‐flying bats, relative to roost visitor reports sent to the Nature Conservancy Council, increased with increasing latitude during both summer and winter. This means that an individual is more likely to fly in daylight the further north in Britain it lives. The effect of day‐to‐day variation in climatic variables on emergence was investigated for records from 1987. In April 1987 emergence occurred on days which followed significantly cooler nights than nights preceding days without emergence. During the remainder of the summer of 1987, however, no climatic effects were significant. During winter 1987 emergence occurred on days which were significantly warmer and sunnier.These data suggest that during summer the primary function of emergence during daylight is to feed to make good energy deficits that have accrued because of inadequate intake during nocturnal foraging. During winter, bats time their daylight emergences to coincide with good feeding conditions, as has been shown previously for winter nocturnal emergence. It is possible daylight emergence occurs during winter primarily because the endogenous cycle during hibernal torpor cannot accurately synchronize arousal with periods of darkness.
Morphological variation and age‐class determination in overwintering tadpoles of the tailed frog, Ascaphus truei
Authors: Brown Herbert A. 
Published: March 2009

The morphological variation and development of different age classes of Ascaphus tadpoles is described for a subalpine population in the North Cascade Mountains. Adult females lay eggs in mid July, and embryos develop into hatchling tadpoles in late August. The torrent‐adapted tadpoles develop in cold waters, overwinter in ice‐covered streams and complete metamorphosis in four years. In September/October there may be five age‐classes of tadpoles: cohort 0, hatchling tadpoles (total length (ToL) = 11 mm); cohort I, one‐year tadpoles (ToL = 32 mm); cohort 2, two‐year tadpoles (ToL = 36 mm); cohort 3, three‐year tadpoles (ToL = 42 mm); and cohort 4, metamorphosing tadpoles or recently transformed frogs (ToL = 20 mm). Determination of these age‐classes is based upon total length, body weight and hind limb and forelimb differentiation. The limb buds appear in the first year of tadpole development, but the forelimbs are hidden by the body wall and branchial chamber, and the hind limbs are concealed by the anal fold.Arguments are presented from the data of total size‐frequency and morphological differentiation and a review of the literature that the larval life period in montane populations is not two or three years, as is commonly accepted, but is approximately four years.
On the central nervous system of Smeagolidae and Rhodopidae, two families questionably allied with the Gymnomorpha (Gastropoda: Euthyneura)
Authors: Haszprunar Gerhard , Huber Georg 
Published: March 2009

The central nervous systems (CNS) of Smeagol manneringi Climo, 1980 (Smeagolidae), of Rhodope veranü Kölliker, 1847, and of Rhodope transtrosa Salvini‐Plawén, 1989 are redescribed in detail. The smeagolid CNS exhibits diagnostic pulmonate characters (procerebrum, cerebral gland, dorsal bodies). Sharing a distinctly structured abdominal ganglion and other peculiarities, the Smeagolidae are closely related to the Onchidüdae, and both families are united as Onchidioidea. The consequences of this close relationship for the origin and evolution of the Gymnomorpha are discussed and the value of the pulmonate CNS for phylogenetics is reconsidered. On the basis of neural characters, which are correlated with the mode of breathing organs, the Pulmonata are divided into Basommatophora, Systellommatophora (Otinidae and Gymnomorpha) and Eupulmonata (ord. nov.: Trimusculidae, Ellobüdae, Stylommatophora).In contrast, the CNSs of the rhodopid species lack the pulmonate attributes, but show diagnostic opisthobranch characters such as a rhinophoral nerve. Accordingly, the Rhodopidae are excluded from the Pulmonata and are classified as a separate order Rhodopemorpha among the Opisthobranchia.
Feeding ecology and foraging behaviour of the Namib Desert golden mole, Eremitalpa granti namibensis (Chrysochloridae)
Authors: Fielden L. J. , Perrin M. R. , Hickman G. C. 
Published: March 2009

Eremitalpa granti namibensis is a small, blind insectivorous mole endemic to the sand dunes of the Namib Desert. Unlike most other subterranean mammals, E. g. namibensis lacks a permanent burrow system and forages for its prey on the dune surface at night. This study examines the natural dietary habits and foraging behaviour of E. g. namibensis in relation to resource abundance and distribution in the Namib dunes.Stomach content analysis revealed termites as the major dietary item with other invertebrates being of only minor importance. Biomass of potential prey items was found to be low and food resources patchily distributed. It is suggested that desert moles opportunistically exploit a sedentary prey resource which occurs in patches of high concentrations, hence avoiding the energetic costs implicit in pursuing more mobile prey. Qualitative and quantitative descriptions of nocturnal foraging paths were undertaken so that searching behaviour could be related to the variation and distribution of food items. It is concluded that movement patterns of moles are effective in encountering localized areas of high prey concentrations and in minimizing energy expenditure in an energy‐sparse environment.
Patterns in the production of latrines by water voles (Arvicola terrestris) and their use as indices of abundance in population surveys
Authors: Woodroffe G. L. , Lawton J. H. , Davidson W. L. 
Published: March 2009

Water vole latrines were studied on four of the principal rivers in the North Yorkshire Moors National Park. Water voles occupied ‘core’ and ‘peripheral’ sites on these rivers. Core sites were marked by latrines and held breeding colonies of voles; animals at core sites were readily captured. Peripheral sites were not marked by latrines, but showed erratic water vole activity as measured by activity indices (tracks m‐1 of muddy bank month‐1). It was never possible to catch voles at these peripheral sites, and there was no evidence of breeding.Latrines on core sites were not maintained outside the breeding season. The appearance of latrines coincided with the start of the breeding season, and while they were maintained, latrines provided a useful guide to the number of animals in the area. A curvilinear response was obtained between latrine production and date, with production rising steadily from early spring until mid‐to‐late summer, which suggests that latrines signal sexual activity.Future studies on the distribution of water voles should use a variety of techniques. Latrine surveys will only be applicable during the breeding season at core sites. Similarly, live‐trapping will only detect water voles at core sites. Tracking provides the best evidence that water voles are present at peripheral sites even though they may not be breeding or entering traps.
Food capture, appetite, digestion rate and efficiency in hatchling and juvenile Crocodylus porosus
Authors: Davenport J. , Grove D. J. , Cannon J. , Ellis T. R. , Stables R. 
Published: March 2009

Juvenile estuarine crocodiles captured insects and crabs at or above the water surface by leaps and lunges powered by the hind limbs and tail. The mouth opened as the head cleared the water; most prey were held by sidesnaps of the jaws. Such prey capture was accurate, deliberate and preceded by stalking. In contrast, submerged prey (e.g. prawns) appeared to be detected mainly by touch and detection was followed by undirected, inaccurate ‘snapping frenzies’ which were usually ineffective. Small prey items were swallowed whole under water. Large dense prey (e.g. crabs) were handled and swallowed on land or in very shallow water; large less dense prey (e.g. cockroaches) were swallowed during vigorous water‐treading in deep water, the head being maintained above the water surface.Young crocodiles ate satiation meals of 9–10% body weight (on a fresh food weight basis) at 30°C, and appetite returned over about 40 h as the stomach emptied. Total gut clearance time for a meal was 4–5 d. Evidence was obtained which demonstrated that young Crocodylus porosus Schneider deliberately eat gastroliths from an early stage. Such gastroliths are retained within the stomach (as were barium/polystyrene spheroids of 1 mm diameter) presumably by the action of the well‐developed pyloric sphincter. X‐radiographs demonstrated that gastroliths are dispersed throughout the stomach contents after a meal and presumably aid digestion.Assimilation rates for dry mass (77.5%), energy (85.2%) and protein‐N (97.4%) were high in normal juveniles. Animals exhibiting ‘runt syndrome’ showed strong appetite but slow food processing by the gut, together with poor assimilation, especially of protein (35.7%).
Seasonal dynamics of invertebrate drift in a Hong Kong stream
Authors: DUDGEON DAVID 
Published: March 2009

Drift samples were taken with paired nets on 19 occasions over a 12‐month period in Tai Po Kau Forest Stream (TPKFS), Hong Kong. Mean drift density (±1 S.E.) was 277·9 ± 25·0 individuals 100 m‐3; peaks in density were apparent during autumn and spring. One hundred and two taxa were recovered from the drift, and the total number of taxa drifting was positively related to water temperatures. Over 99% of the aquatic animals collected in drift samples were insects, 10 taxa of which constituted 67·3% of the entire catch. Baetid mayflies dominated the composition of the drift, comprising 40·4% of individuals caught.Seasonal changes in the drift of individual taxa were evident, reflecting significant relationships between drift densities and water temperature: Simulium T1 (Diptera). Anisocentropus maculatus (Trichoptera) and Amphinemura chui (Plecoptera) drifted most in winter, whereas Chimarra T1, Polymorphanisus astictus (Trichoptera), Helodes#1 and cf. Rhantus sp. (Coleoptera) were most numerous in summer. Drifting mayflies showed spring (Indobaetis sp., Cinygmina T1, Serratella T2), autumn (Baetiella sp., Pseudocloeon T2), or spring and autumn (Baetis nr pseudofrequentus) peaks which were not clearly related to water temperature. In only two cases (A. maculatus and P. astictus) was TPKFS drift seasonality associated with life‐cycle events. Overall, there was no evidence of community‐level trends in the periodicity of stream drift in this seasonal tropical habitat.
The effects of red fox Vulpes vulpes faecal odours on the feeding behaviour of Orkney voles Microtus arvalis
Authors: Calder C. J. , Gorman M. L. 
Published: March 2009

Orkney voles Microtus arvalis show avoidance of red fox Vulpes vulpes faecal odours, both in the laboratory and in the wild. Since these voles have been isolated from foxes since Neolithic times it is likely that these responses are innate rather than learned.When applied to young Scots pine saplings, the fox odour inhibited feeding by voles when alternative foods were available.
Effects of climate on reproduction in the European wild rabbit (Oryctolugus cuniculus)
Authors: Bell D. J. , Webb N. J. 
Published: March 2009

Reproduction in a population of European wild rabbits occupying parkland habitat in East Anglia showed an annual seasonality in terms of numbers of emergent young, male testes size and an index of female oestrous status. Weather conditions showed marked variation over the four‐year study period with significantly higher minimum ground temperatures and hours of daily sunshine, and less snowfall recorded during the second two years. Parailel shifts in reproductive seasonality were found with male testes size peaking in January and February as opposed to May and April, first female oestrus recorded one month earlier (January compared to February), and young emerging over an average of 5.5 instead of 4.5 months each year and their first appearance above ground advanced by two months from April to February. Mean annual productivity increased from 7.2 and 6.1 emergent young per female, to 10.1 and 9.1 over the four years, while the number of adults present in the population at the start of the breeding season increased from 22 to 45, with females always outnumbering males. The usefulness is demonstrated of a noninvasive index of vulva appearance, and morphometric measures of testes to determine female oestrous status and estimates of male testicular weight in wild populations.The reported changes in reproduction are probably mediated through the influence of climatic variables on the quality or quantity of food available to the rabbits. These data demonstrate the possible effects of predicted global warming on productivity in the rabbit and highlight the major influence of climate on reproductive seasonality in this important pest species.
Non‐invasive monitoring of avian reproduction by simplified faecal steroid analysis
Authors: Bishop C. M. , Hall M. R. 
Published: March 2009

The measurement of urinary steroid metabolites has proved a reliable method for monitoring reproductive changes in a variety of mammalian species. Development of related techniques for assessing avian reproductive function has shown that sexing of various species is feasible and that the following of individual reproductive changes may be possible. This paper reports on the use of a simplified procedure for assay of specific excreted steroids in a 1: 60 dilution of a 0.4 g dried faecal sample from male and female Japanese quail, and the monitoring of steroid hormone changes in the plasma and faeces throughout a photoperiodically induced reproductive cycle.Immunoreactive steroid measurements were made directly by radioimmunoassay (RIA) of ahquots of faecal homogenates in phosphate buffer and did not involve hydrolysis of steroid conjugates or organic solvent extraction. Measurements were made of immunoreactive testosterone, oestradiol‐3‐glucuronide (E‐3‐gl) and pregnanediol‐3α‐glucuronide (Pd‐3α‐gl). Plasma testosterone and progesterone concentrations, in males and females, were compared to faecal immunoreactive testosterone and Pd‐3α‐gl, respectively. Exposure to stimulatory long daylengths of 20L:4D (LD) resulted in a rise of both plasma and faecal testosterone followed by a reduction after subsequent transfer back to short daylengths of 8L:16D (SD). Male faecal immunoreactive testosterone levels were significantly correlated with the plasma testosterone concentrations (0.59, P<0.001, n= 70) and with the phase of the reproductive cycle. Faecal immunoreactive Pd‐3α‐gl levels increased following exposure to LD, and female values were well correlated with plasma progesterone concentrations (0.79, P <0,001, n= 56) and with the pattern of egg laying. Faecal immunoreactive E‐3‐gl levels were higher in LD than SD birds with higher levels in females compared to males, even under SD photoperiods.For long‐term monitoring of the reproductive status of Japanese quail, faecal immunoreactive testosterone and Pd‐3α‐gl measurements, in a 1:60 dilution of a random 0.4 g dried faecal sample, were found to be as reliable and informative as plasma testosterone and progesterone measurements, respectively.
The frontal and gular dermal scent organs of the marsupial sugar glider (Petaurus breviceps)
Authors: Stoddart D. M. , Bradley A. J. 
Published: March 2009

A study spanning two breeding seasons was carried out to examine the role of androgens in the control of the frontal and gular scent glands of the marsupial sugar glider Petaurus breviceps Waterhouse in a wild population. Animals were captured at monthly intervals and from these blood samples were taken and tissue biopsy samples were collected from the scent glands.Several histological parameters underwent seasonal changes which were related to changes in the plasma concentration of free plus albumin bound (‘biologically active’) testosterone. The parameters which showed significant change did so during the July‐September breeding season coinciding with the peak in biologically active testosterone concentration.Castration caused a significant decrease in the nuclear diameters of gular and frontal apocrine and sebaceous gland cells, and a decrease in gular apocrine cell height. These decreases were reversed with androgen replacement therapy.The nuclear diameters of apocrine tissue cells in both scent organs are positively correlated with the plasma level of biologically active testosterone. In the gular organ, but not in the frontal organ, the depth of apocrine tissue was significantly correlated with nuclear diameter. In castration and androgen replacement studies gular apocrine tissue responded more dramatically than did frontal apocrine tissue. This suggests that the gular organ is more sensitive to testosterone than is the frontal.
Circulating levels of luteinizing hormone and steroid hormones in relation to social status in the cooperatively breeding white‐browed sparrow weaver, Plocepasser mahali
Authors: Wingfield J. C. , Hegner R. E. , Lewis D. M. 
Published: March 2009

We have begun an intensive series of investigations into the environmental and endocrine mechanisms regulating cooperative breeding in a semi‐arid tropical environment. A colour‐marked population of white‐browed sparrow weavers (Plocepasser mahali) was studied at a field site near Nyamaluma Camp, Luangwa Valley, Zambia (13dG S). This species breeds from October to April, although some clutches may be found as early as August and young may be fed until May.Non‐disruptive techniques were employed to monitor annual cycles of gonadal development, body mass and fat reserves, and small blood samples were collected to measure circulating levels of reproductive hormones and corticosterone. All individuals were released after sampling and the social and reproductive activities recorded by systematic behavioural observations. Each individual could thus be identified as: (1) a breeding adult; (2) a related helper (i.e. offspring of the breeding male and female within the group); or (3) a non‐related (=invader) helper (these birds helped defend territory but did not help feed young; they were not related to the breeding pair and usually originated from outside the group).Breeding males had larger testes and higher levels of testosterone than either related helpers or invader helpers. In females, all status groups had follicles up to 2 mm in diameter, but only breeding females ovulated. There were no differences in plasma levels of reproductive hormones among different status females, except for higher circulating luteinizing hormone (LH) in invader female helpers during the first part of the breeding season. Although plasma levels of testosterone were highest in breeding males, the maximum titres were two orders of magnitude less than in males of passerine species from temperate regions. Furthermore, injections of a peptide hormone GnRH (gonadotropin‐releasing hormone) increased plasma LH levels in both males and females, and were followed by rises in testosterone levels only in males, but not over the normal maximum seen in February. GnRH‐induced high levels of LH did not affect testosterone concentrations in the blood of females.Results obtained thus far indicate that the hormonal control of aggression in white‐browed sparrow weavers is different from that predicted by investigations on north temperate species. Whether these phenomena are typical of tropical species, particularly cooperative breeders, remains to be determined. Since most of the world's species of birds live in the tropics, and a substantial fraction of them breed cooperatively, more investigations are needed to establish the hormonal basis of reproductive behaviour and cooperative breeding. Given the baseline data already collected, the white‐browed sparrow weaver will be a useful model.
Activity and weight loss in relation to solar radiation in the polymorphic land snail Cepaea nemoralis
Authors: Chang Hsueh‐Wen 
Published: March 2009

Shell spectral reflectance, activity and weight loss in the land snail Cepaea nemoralis were examined to test whether solar radiation has different effects on the behavioural and physiological responses of different morphs. A uniform area from the empty shells of different morphs was cut and a spectrophotometer was used to measure the spectral reflectance at wavelengths from 220 nm to 800 nm. Snails were put into cages made of mesh hardware cloth, and their activities were observed from dawn onwards on two hot, dry days. Weight loss of snails under shade and under direct sunlight was also measured.The results show that unbanded morphs reflect more light than five‐banded ones, but the yellow morphs reflect only a little more than pink morphs. Five‐banded morphs became inactive more quickly than unbanded ones from dawn onwards, but the differences in activity patterns were not significant between pink and yellow morphs. There are significant differences in percent weight loss between snails placed under direct sunlight and under shade. The weight loss of different morphs under shade was not statistically different. But when exposed to sunlight, five‐banded morphs lost more weight than pink and yellow unbanded morphs.Because of their lower reflectance of solar radiation, the five‐banded morphs are, in a hot, arid climate, at a selective disadvantage compared to unbanded morphs. However, they can avoid such selective disadvantage by actively seeking a shaded area, as all other morphs do in the field. Such behavioural habitat selection could help the maintenance of genetic polymorphisms in natural populations.