bluuebunny/crossref_metadata_2025 huggingface dataset:
Enduring social relationships in a population of crab‐eating zorros, Cerdocyon thous, in Amazonian Brazil (Carnivora, Canidae)
Authors: Macdonald D. W. , Courtenay O.
Published: May 2009

Crab‐eating zorros, Cerdocyon thous, in Amazonian Brazil weighed 5.2 kg (S.D. 0.6, n= 19), exhibited no sexual dimorphism, lived in social units of 2‐5 adults of > 1 year old, and occupied territories (restricted polygons) of 532 ha (range 48‐1042 ha, n= 21).

The zorros were omnivorous, fruit being the most frequent food (occurring in 57% of 72 faeces in the dry season) comprising 26.4% by volume of undigested faecal remains. Insects were frequently eaten (86%), and vertebrates rarely (15.2%).

Zorros were territorial. The ranges of neighbours overlapped minimally and were very stable in configuration, both from month to month and between dry and wet seasons. Members of each social unit shared on average 88.3% of 200 × 200m grid cells within their territory. Members of male‐female breeding pairs were within 100 m of each other for 63% of the activity period, their proximity being greatest during the mating season (July‐August). Parents travelled in close company with their adult‐sized offspring, and stayed within 100 m for up to 93.3% of the activity period.

Territories differed in habitat composition. Overall, zorros spent most time in wooded savanna (33.9%) and scrub (30.5%). They did not utilize habitats in direct proportion to their availability, using some more (e.g. scrub) and some less (e.g. open savanna) than expected. Habitat preferences differed between wet and dry seasons, with elevated habitats being favoured during the wet season.

Individuals differed in their habitat utilization, and parents had different habitat usage to their yearling offspring; this difference was exaggerated in the dry season when the yearlings used lowlying habitats apparently disfavoured by the parents. Differences in habitat utilization between group members were least in the wet season, when widespread flooding forced the shared use of higher ground.

Each of two social units larger than two individuals comprised a pair and their three adult‐sized offspring (totalling five males and one female). In three cases, a yearling daughter was present in the breeding season, but none of these bred. Non‐breeding offspring were seen frequently in the whelping area and in close company with the breeding pair's cubs. This is the first proof of group‐living in South American zorros.

Five dispersal events were monitored, and revealed a ‘good neighbour’strategy in which newly formed pairs set up their territories adjoining their natal territories. In each case individuals returned intermittently to their original territory where they were in close and amicable company with their parents. One male, having dispersed, returned home frequently without his mate to tend the next generation of his parents’cubs. Of four dispersing males, two subsequently returned to their natal group following the deaths of their mates at least 3‐13 months after their initial dispersal, in one case after breeding elsewhere.
Mechanical properties of bat wing membrane skin
Authors: Swartz S. M. , Groves M. S. , Kim H. D. , Walsh W. R.
Published: May 2009

The skin of the bat wing in functionally unique among mammals: it serves as a major locomotor organ in addition to its protective and regulatory functions. We used tensile testing to investigate the mechanical capabilities of wing membrane skin, and compared stiffness, strength, load at failure, and energy absorption among specific wing regions and among a variety of bat taxa. We related these characteristics to the highly architectural fibrous supporting network of the wing membrane. We found that all material properties showed a strong anisotropy. In particular, wing membrane skin shows maximum stiffness and stregth parallel to the wing skeleton, and greatest extensibility parallel to the wing's trailing edge. We also found significant variation among wing regions. The uropatagium (tail membrane) supported the greatest load at failure, and the plagiopatagium (proximal wing membrane between laterl body wall and hand skeleton) is the weakest and most extensible part of the wing. We believe that the increased load bearing ability of the uropatagium relats to its key role in capture of insect prey, and that the great extensibility of the plagiopatagium promotes development of camber near the wing's centre of lift. In interspecific comparisons, energy absorpion and load to failure were greatest in Artibeus jamaicensis, the largest bat in our sample and the species with the highest wing loading, suggesting that wing loading may play a role in dictating the fuctional design of wing membranes.
Dorsal galnds of Alligator mississippiensis: a histological and histochemical study
Authors: Cannon M. S. , Davis R. W. , Weldon P. J.
Published: May 2009

Several investigators have described in some crocodilians a row of round or oval organs, called dorsal glands, lying under scutes on each side of the dorsal midline. The function of these glands is unknown, but they are hypothesized to produce skin‐conditioning secretions. We investigated the anatomy and histochemistry of the dorsal glands of adult American alligators (Alligator mississippiensis). Twenty to 22 pairs of glands containing a viscous, often black, material were observed lying from the mid‐cervical to the anterior caudal regions in the axial musculature or on the inner surface of the dermis. The capsule of each gland consists of dense collagenous fibres and numerous short elastic fibres, and is surrounded by skeletal muscle. The single lumen is lined by one to several layers of cuboidal to columnar epithelium in varying stages of degeneration, indicating a holocrine secretory mode. The epithelial cell membranes often interdigitate and tight junctions and desmosomes occasionally are observed between them. The epithelial cells and secretory product contain slight to considerable amounts of lipid; glycoproteins may be present. Crystals exhibiting a dense core and/or layering occur in the epithelial cells and secretory product. Energy‐dispersive X‐ray analysis demonstrates calcium, copper, iron, lead, potassium, and zinc in the crystals. Mitochondria, vacuoles, and short segments of rough endoplasmic reticulum also occur in the cells.
Nestling feeding strategy of the British storm‐petrel Hydrobates pelagicus in a Mediterranean colony
Authors: Mianguez Eduardo
Published: May 2009

The pattern of chick feeding of the British storm‐petrel Hydrobates pelagicus in a Mediterranean colony was examined by weighing chicks at 24‐h intervals on different days during the nestling period. In order to calibrate daily mass increments (NET) against number of feedings, daily mass changes of chicks were regressed upon the sum of positive mass increments recorded overnight (SUM) during four nights. The average meal size delivered to chicks per night by one parent was 3.5 ß 1.3 g or 12% of adult weight. This was insufficient for sustaining constant chick mass during a day. On average 85% of chicks were fed each night, and the mean interval between feeds was 1.2 ß 0.5 nights. Nightly feeding frequencies differed among days, but this night‐to‐night variation was not related to meteorological conditions. Both food requirements necessary for chick body maintenance (zero‐growth) and meal size were relatively constant for ages up to 59 days. However, feeding frequency decreased throughout the fledging period, accounting for agespecific variation in growth rates until fledging. Food requirement and feeding patterns at Benidorm were different from North Atlantic colonies. None the less, growth patterns were almost identical, suggesting adjustment to maintain chick body mass at a determined level, as food delivery to nestling appears to be regulated to chicks’nutritional requirements.
The effect of domestication on brain size and composition in the mink (Mustela vison)
Authors: Kruska Dieter
Published: May 2009

The sizes of total brain, the five fundamental brain parts, and certain telencephalic structures were measured in wild mink (Mustela vison energumenos) and ranch mink of a Dark Standard strain of the same species. By means of intraspecific allometric methods for analysing the relationship between brain weight and body weight (net carcass weight), the volumes of the brain parts were compared in both groups. In general, total brain, as well as all the parts measured, were smaller in size in ranch mink independent of body size, age, and sex, indicating that domestication has led to a decrease in size. There were differences in the amount of decrease in various brain parts. These are discussed in connection with domestication time, with comparable results obtained in other species, and with regard to the functional importance of the brain parts.
Behavioural and ecological aspects of nuptial flights of the termitophilous phorids Termitophilomyia zimbraunsi and Mesopathusa modesta (Diptera: Phoridae) in Zimbabwe
Authors: Cumming Meg S.
Published: May 2009

Nuptial flights of Termitophilomyia zimbraunsi were observed over three years (1990‐1993) near the open chimney of an Odontotermes transvaalensis mound in Harare, Zimbabwe. Copulating phoretic pairs landed on the chimney; males quickly disengaged and flew away whilst females ran inside the vent and tore off their wing membranes. Agitated termite workers and soldiers swarmed the rim in a partially successful physical attempt to expel the phorids; the termites appeared to anticipate the threat of invasion. After acquiring the scent of the nest, female phorids ran underground to lay their large single eggs, probably in the hosts’fungus gardens. Nuptial flights occurred throughout the year but only in the early mornings, peaking in the hot dry season and being least in the hot wet season. The flights were highly temperature dependent (15.0‐17.9 °), usually occurring at relatively low light intensities but across a wide range of humidities. Phoresy and sexual dimorphism in wings, mouthparts, food and division of labour in T. zimbraunsi are discussed, as is its termitophilous habit and the responses of termites to it.

Although the females of Mesopathusa modesta are apterous, nuptial flight behaviour is very similar to that of T. zimbraunsi. Neither phorid is host‐specific, both species having been found on both Odontotermes latericius and O. transvaalensis mounds, although M. modesta is more common on O. latericius mounds.
Reason for externalization of the testis of mammals
Authors: Chance M. R. A.
Published: May 2009

Testes externalized in a scrotum are found only in those mammals whose present lifestyle (or that of their ancestors) involves jumping, leaping or galloping, thereby creating concussive hydrostatic rises in peritoneal pressure. This would be expected to expel the contents of the reproductive tract since it does not possess a sphincter. The lower temperature of the externalized testes is then seen as a secondary adjuvant adaptation to a cooler location than within the body cavity. The theory also explains the close phylogenetic relationship between the Proboscidea, Hyracoidea, and Sirenia, if it is assumed that their common ancestor was not endowed with the genes necessary for externalization.
Diet and foraging behaviour of group‐living meerkats, Suricata suricatta, in the southern Kalahari
Authors: Doolan S. P. , Macdonald D. W.
Published: May 2009

Slender‐tailed meerkats (Suricata suricatta) are small, diurnal, and gregarious mongooses which inhabit the semi‐arid regions of southern Africa. In the south‐western Kalahari, substantial fluctuations in productivity are caused by extreme seasonality in rainfall and temperatures. We observed the foraging behaviour of habituated meerkats from January to July, a period covering the entire birth season and stages of high and low prey availability. Insects were the most frequently occurring prey class (78.1%), of which larvae (33.4% total frequency) and adult Coleoptera (27.5% total frequency) were the most important prey items throughout the year. Reptiles were heavily utilized in terms of prey bulk‐an index of volume‐(19.9%), but not by frequency (9.2%). Consumption of Coleoptera was positively correlated with rainfall, and negatively with temperature. Meerkats used a mean of 6.7 ± 1.1 prey categories daily, and there were significant monthly differences in prey diversity in the diet. Dietary shifts were apparently related to fluctuations in prey availability and the presence of preferred prey. There were no differences between the sexes in dietary diversity or niche breadth, but pregnant and lactating females foraged at significantly higher rates than males. The timing of foraging activity altered over the months in response to changes in daylength and thermoregulatory constraints. Foraging behaviour and seasonality in foraging effort are described, and the implications of an insect prey base for meerkat socioecology are discussed.
Population dynamics of the wood mouse Apodemus sylvaticus (Rodentia: Muridae) in a Sitka spruce successional mosaic
Authors: Fernandez F. A. S. , Evansa P. R. , Dunstone N.
Published: May 2009

A population of wood mice, Apodemus sylvaticus (L.), was studied by capture‐mark‐recapture, in five 0.81 ha grids within a habitat mosaic produced by the felling of a plantation of mature Sitka spruce (Picea sitchensis Carriere). From May 1990 to June 1992, we estimated population sizes, survival (total and by weight classes), recruitment, and home‐range sizes, usually at monthly intervals, for the study area taken as a whole. Inter‐grid movements were frequent for both sexes, supporting the assumption that the population could be analysed in this way. Wood mice were more abundant in 1991 than in 1990, associated with increased seed supply. In both years, numbers were low in spring and increased gradually towards an autumn peak, which was of similar size in both years. Male home‐range areas varied seasonally, and were negatively correlated with population sizes, while female home ranges showed little seasonal variation. Survival and recruitment both declined sharply in late autumn, apparently in a densitydependent way. Except for this latter result, the population dynamics in a heterogeneous coniferous woodland were consistent with those described previously for this species in more homogeneous deciduous woodlands, suggesting that the same regulatory processes are operating in both habitats.
Individual success in mating balls of the grass snake, Natrix natrix: size is important
Authors: Luiselli Luca
Published: May 2009

Natricine colubrid snakes, including the grass snake, Natrix natrix, are frequently involved in complex social behaviour during the reproductive season. During these social behaviours, several males may simultaneously court a single female, resulting in a ‘ball’of mating snakes in which each male ‘combats’with rival males by ‘tail wrestling’(see Madsen & Shine, 1993). I performed some experiments in outdoor enclosures for testing the male‐male competition and the determinants of mating success in male grass snakes involved in such ‘ball’aggregations. I demonstrated that competition between males occurred both when a single female was available to multiple males and when two females were simultaneously available to males. The larger males achieved more copulations than the smaller ones, thus demonstrating that body size is a crucial determinant of the individual mating success. It was not clear which aspect of male body size is the most important in determining success in these mating ‘balls’, but it was evident that the age of the ‘fighting’male was not correlated with mating success. Larger females attracted more males than smaller ones, both in the field and in the enclosure. Furthermore, when the size difference between available females in the cage was high, only the largest female was courted and coupled.
The relationship between foraging behaviour and energy expenditure in Antarctic fur seals
Authors: Arnould J. P. Y. , Boyd I. L. , Speakman J. R.
Published: May 2009

By using time‐depth recorders to measure diving activity and the doubly‐labelled water method to determine energy expenditure, the relationship between foraging behaviour and energy expenditure was investigated in nine Antarctic fur seal females rearing pups. At‐sea metabolic rate (MR) (mean of 6.34 ± 0.4 W. kg‐1; 4.6 times predicted BMR) was positively correlated to foraging trip duration (mean of 4.21 ± 0.54 days; r2= 0.5, P < 0.04). There were no relationships between MR and the total number of dives, the total time spent diving or the total vertical distance travelled during the foraging trip. There was, however, a close negative sigmoidal relationship (r2= 0.93) between at‐sea MR and the proportion of time at sea spent diving. This measure of diving behaviour may provide a useful, inexpensive means of estimating foraging energy expenditure in this species and possibly in other otariids. The rate of diving (m.h‐1) was also negatively related to at‐sea MR (r2= 0.69, P < 0.005). Body mass gain during a foraging trip had a positive relationship to the time spent at sea (r2= 0.58, P < 0.02) and the total amount of energy expended while at sea (r2= 0.72, P < 0.004) such that, while females undertaking long trips have higher metabolic rates, the energetic efficiency with which females gain mass is independent of the time spent at sea. Therefore, within the range of conditions observed, there is no apparent energetic advantage for females in undertaking foraging trips of any particular duration.
The diel hauling‐out cycle of harbour seals in an open marine environment: correlates and constraints
Authors: Watts Peter
Published: May 2009

A colony of harbour seals in the Pacific north‐west was monitored over two years, concurrent with a variety of environmental variables. Regression models described diel hauling‐out activity as: i) a photoperiodic cycle; ii) a function of other environmental factors; or iii) a cycle modified by environmental constraints. Throughout the year, the number of seals on shore followed a diel pattern with a midday peak. Seals hauled‐out in lower numbers in winter than in summer, and for a smaller proportion of the day (although for about the same proportion of the photoperiod). During the annual moult, numbers hauled were elevated around the clock, and the midday peak was skewed to late afternoon/early evening. Models that defined hauling‐out in terms of environmental factors were significant, but did not fit the data as well as models based on photoperiod. The strongest environmental correlates (such as tidal height) owed much of their explanatory power to artefactual similarities with the photoperiodic cycle. Four general conditions are presented which, if met, should always result in a diel hauling‐out cycle with a midday peak. The most fundamental of these involves a proposed ‘cost of immersion’which motivates pinnipeds tohaul‐outwhen not foraging. Two likely candidates for such a cost involve risk from aquatic predators and the energetic expense of sleeping while immersed.
Population ecology ofGoniosoma spelaeum, a cavernicolous harvestman from south‐eastern Brazil (Arachnida: Opiliones: Gonyleptidae)
Authors: Gnaspino Pedro
Published: May 2009

Goniosoma spelaeum (Mello‐Leitão) is a widespread trogloxene harvestman in caves of the Ribeira Valley in São Paulo State. It inhabits walls and ceilings near cave entrances. Populations inhabiting six selected caves of the region were analysed during this study. Mark‐recapture techniques were used to estimate population sizes. Populations vary from tens to hundreds of individuals in each cave, and vary throughout the year. Barra Bonita cave had the largest population and was used to identify other ecological features of the species. These harvestmen show a high degree of philopartry, and recapture rate was high. They remain motionless inside the caves during the day, leaving them after dark to forage, and return just after dawn. They always feed outside the caves and do not carry food into the caves. Soft‐bodied insects were the main food observed in the field. In the laboratory, they accepted plant and animal items and industrial foods. Their main predators are the spider Ctenus fasciatus, the heteropteran Zelurus travassosi, and the marsupial Philander opossum, and their main parasites are dipteran larvae (probably Phoridae).
Energy allocation in reproducing and non‐reproducing guinea pig (Cavia porcellus) females and young under ad libitum conditions
Authors: Raffel M. , Trillmich F. , Houner A.
Published: May 2009

Increase in body mass is an overall measure of growth which hides the dynamics of changes in body components. A study of the allocation of resources to growth versus reproduction is particularly interesting in guinea pigs (Cavia porcellus) where females mature early in the growth phase and produce highly precocial young while still growing rapidly.

In order to get information on energy allocation in guinea pigs, fat‐free mass (FFM) of young (1‐30 days) and adult females (reproducing vs. non‐reproducing) was determined by measuring TOtal Body Electrical Conductivity (TOBEC; indexed by TOBEC#) which was calibrated by Soxhlet extraction.

FFM was predictable from body length alone, but was best predicted as a function of (TOBEC#*length)0.5. Prediction was further improved by separating the data into two sets, for animals of 23 cm and of > 23 cm body length. Fat and total body water (TBW) can also be determined from TOBEC#, but the reliability of fat determinations is low unless samples of 5‐10 equally treated animals can be averaged. The formula developed by Pace & Rathbun (1945) for the estimation of TBW has frequently been used for all kinds of mammals, but is shown consistently to underestimate TBW even in guinea pigs.

Using our calibrations, we studied the development of FFM and body fat in young guinea pigs from birth to 30 days, and the development of FFM and fat stores in reproducing, primiparous, and non‐reproducing females of equal age.

Young were born with about 11% fat. Young in large litters (3‐5) had relatively and absolutely less fat reserves than young in small litters. In eight young measured on days 1, 3, and 5, fat declined until day 3 and returned to the mass at birth on day 5. Fat mass increased slowly during the lactation period, until day 20, and faster thereafter in weaned young. Relative to body mass, fat decreased from 11.2% at birth to 9.3% on day 30, with a minimum of 6.6% on day 20. Mass of fat on day 30 was independent of litter size. FFM began to grow linearly from day 5 onwards. Body water in FFM varied with age in an inverted U‐shaped pattern.

Reproducing females grew in FFM at equal rates to non‐reproducing females, but deposited less than half as much fat until day 210, by which time they had had two litters. Under ad libitum food conditions and a mild thermal regime, reproducing females allocated as much of the available resources to growth in FFM as non‐reproducing females, but reduced storage of fat, instead producing biomass of precocial young.
The diet of strap‐toothed whales (Mesoplodon layardii)
Authors: Sekiguchi K. , Klages N. T. W. , Best P. B.
Published: May 2009

The food habits of strap‐toothed whales (Mesoplodon layardii) were examined in detail using stomach contents from 14 stranded whales found on South African and New Zealand coasts. Although a few unidentified fish otoliths and crustacean remains were found in two of these stomachs, 24 species of oceanic squids (some of which occur at a great depth) accounted for 94.8% of counted prey items (n= 232).Histioteuthis sp. and Taonius pavo were the predominant prey species (25.0 and 17.2% by number, 21.4 and 19.9% by mass, respectively). The presence of sub‐Antarctic squid species suggested a northward migration to South African waters in late summer/autumn. Prey sizes were compared between males with fully grown strap‐teeth and females/immature males without erupted teeth, using dorsal mantle lengths (DML) and weights of squids estimated from beak measurements. Although females/immature males ate longer squids than males, there was no significant difference in the estimated weights of squids eaten by the two groups. The presence of fully‐erupted teeth in adult males, therefore, did not seem to influence the size of prey ingested, even though an adult male could only open its jaws about half as wide as a female. In general, the sizes of cephalopods eaten by strap‐toothed whales were not significantly different from those eaten by smaller odontocetes, such as spotted dolphins and dwarf sperm whales, but were significantly smaller than those eaten by larger odontocetes, such as false killer, long‐finned pilot, Cuvier's beaked, and southern bottlenose whales.
Reproductive pattern in the male Angolan free‐tailed bat, Tadarida (Mops) condylura (Microchiroptera: Molossidae) in the Eastern Transvaal, South Africa
Authors: Vivier L. , Van der Merwe M.
Published: May 2009

The reproductive pattern in male Angolan free‐tailed bats Tadarida (Mops) condylura was studied at two localities in the Eastern Transvaal during the period 1989‐1991. Males displayed a nine‐month breeding season extending from June to February. Following testicular recrudescence in early June, spermatogenic activity displayed two periods of peak activity in August/early September and November/early December. Although testes became involuted in March, baseline spermatogenic activity was maintained and tests never regressed to prepubertal conditions. Leydig cell morphology closely followed spermatogenic activity, with the diameter of Leydig cell nuclei displaying a concomitant seasonal pattern.
The mechanical properties of feather keratin
Authors: Bonser Richard H. C.
Published: May 2009

Feathers are subject to large aerodynamic forces during flight and must therefore be stiff and strong, yet also light. Published estimates of Young's modulus of the feather keratin composite vary widely in the literature, and it is suggested that this is predominantly due to test methodology rather than true interspecific differences. The factors influencing the Young's modulus of keratin are discussed, together with their functional implications. Damage resistance must also be good; feathers that are lost or broken can only be replaced infrequently, but regularly, at moult. Feather shafts appear to be very strong for their weight. The possible role of the medullary foam in preventing buckling failure is still unclear; medulla removal only appears to have a minimal effect on both the stiffness and strength of whole sections of the rachis. Melanic keratin has properties that make it more competent at resisting abrasive wear than nonmelanic keratin.
Associations of testate rhizopods (Protozoa) in the plankton of a Malaysian estuary and two nearby ponds
Authors: Green J.
Published: May 2009

Plankton samples were collected from the Chukai‐Kemaman estuary in Malaysia in order to determine the distribution of testate rhizopods in relation to salinity. Two nearby freshwater ponds were sampled for comparison.

In the ponds, 35 species of testate rhizopods were found, 13 of which were not found in the estuary. From the estuary 53 species were found, of which 31 were not found in the ponds. Some species appeared to have been lifted into the plankton by the rising tide. At a generic level, the Arcella species were very similar in both ponds and estuary (Sorensen Index 80), the Difflugia species were moderately similar (Sorensen Index 47), while Nebela and Quadrullela were present in the estuarine samples, but absent from the pond samples.

The salinity gradient ranged from sea water down to a conductivity of 27 μS. All the estuarine stations were tidal. The first freshwater testate rhizopods were found in a region where the conductivity was between 3000 and 4000 μS at high tide. Where the conductivity was below 1000 μS at high tide the number of species rapidly increased, and reached a maximum of 25 in the samples from the lowest conductivities. The flowering tree, Hibiscus tiliaceus, appears to be an indicator of the region where the first freshwater testate rhizopods might be encountered upstream from the sea.
Behavioural manifestation of conception 12 hours after mating in an asocial African rodent, Saccostomus campestris
Authors: Westlin Lilian M.
Published: May 2009

The pouched mouse, Saccostomus campestris (Cricetidae), is an African rodent, known to lead a solitary life, where the female is overtly aggressive towards all conspecifics, except during the very short time of sexual receptivity, when she will tolerate the presence of a male and mate with him. In the present study, males were introduced to sexually receptive females to study their behaviour after mating and correlate that to the endocrine status of the female at that time.

The present paper demonstrates that c. 12 hours after mating (and ovulation), the behaviour of female pouched mice reflects whether conception has occurred or not; conceived females became aggressive towards the male at that time, while non‐conceived females continued to be amicable towards the male during the subsequent phases of that and the following cycle(s), until conception occurred.

Aggressive behaviour was not associated with measurable plasma levels of testosterone, and owing to large intra‐ and inter‐individual differences, no relationship was confirmed between plasma levels of oestradiol‐17β and levels of aggression during the oestrous cycle.

Approximately 12 hours after mating, plasma concentration of progesterone was significantly higher in females that had conceived than in those that had not. This could not be correlated with the occurrence of aggression in these females, however, as there were no differences in progesterone levels between single, cycling females and mated non‐pregnant females at any stage during the cycle.

The presence of a male, vaginal stimulation, and prolactin are not presumed to be involved in suppression of aggression in female pouched mice.
Variation in cohort mandible size as an index of roe deer (Capredus capreolus) densities and population trends
Authors: Hewison A. J. M. , Vincent J. P. , Bideau E. , Angibault J. M. , Putman R. J.
Published: May 2009

This paper examines the effects of increasing population density on the skeletal development of roe deer as indexed by variation in the size of the mandible. We tested for density‐dependence in total jaw length and minimum diastema height among cohorts in a single, intensively studied population in France. A strong relationship of average adult jaw length of both males and females with deer density in the year of birth of a given cohort was observed, and presumably reflects inadequate nutrition of juveniles at high population density. No such relationship was observed for the minimum diastema height which remained constant over the range of densities studied. This relationship was exploited to investigate population trends of roe deer in Britain. In nine populations, where equivalent data were available for between 16 and 28 separate cohorts, a consistent pattern of variation in cohort jaw size was observed, with a decrease in average total length, but not diastema height, towards the present. This trend is discussed in relation to changes in habitat structure in the coniferous forests of Britain. The utility of cohort jaw length as a management tool to index population trends of roe deer is highlighted.
Thermoregulation, energy metabolism, and torpor in blossom‐bats, Syconycteris australis (Megachiroptera)
Authors: Geiser F. , Coburn D. K. , Kourtner G. , Law B. S.
Published: May 2009

Since little information is available on torpor in bats of the suborder Megachiroptera, we investigated whether the small (18 g) blossom‐bat Syconycteris australis displays torpor in the laboratory. Bats entered daily torpor when food and water were withheld for one night and the air temperature (Ta) was below about 26°. Torpor began shortly after lights went on in the morning and lasted for a maximum of 12 hours. During torpor at Ta18°, metabolic rates fell to a minimum of about 15% of that in resting individuals at the same Ta, and to about 40% of the basal metabolic rate. The body temperature (Tb) during torpor was metabolically defended at or above about Tb 18°. Individuals that did not enter torpor in the morning reduced their Tb from about 34.5°, observed in resting individuals that had been fed during the previous night, to values between 30.2 and 32.8°, and the resting metabolic rate fell by about 25%. The ability to undergo short periods of torpor may explain why the distribution range of S. australis extends much further south than that of other small Australian megachiropteran bats.
Cell renewal in the epidermis of the loach Misgurnus anguillicaudatus (Cypriniformes)
Authors: Tsai Jong‐Chang
Published: May 2009

Cell kinetics of the epidermal cells of normal juvenile loach (Misgurnus anguillicaudatus) were studied with autoradiography. Fish were labelled with single tritiated thymidine injections and killed at regular time intervals. Three cell types are identified by light microscopy, namely the epithelial cells, the club cells and the mucous cells. Epithelial cells are the only cell type that is involved in cell proliferation and, like the epithelial cells in the epidermis of other teleosts, proliferation of these cells occurs at all epidermal layers. The club cells and the mucous cells seem to be differentiated from the epithelial cells. Based on the time‐course study of the labelling index and the grain count halving method, the generation time of the epithelial cells is estimated to be 4 days. From the labelling index of double injections, the duration of the S phase is determined as 8.3 h. Significant cell loss from the outermost layer and cell translocation from the lower layer to the upper layer within 4 days are inferred from the fluctuations of the labelling index curve. The renewal of these cells in the tissue seems rapid in comparison to the epidermis of terrestrial vertebrates.
Age‐related reproductive success in solitarily and communally nesting female dormice (Glis glis)
Authors: Pilastro A. , Missiaglia E. , Marin G.
Published: May 2009

The factors underlying the occurrence of communal nesting in a natural population of fat dormouse (Glis glis) breeding in nest‐boxes have been analysed on the assumption that such behaviour is adaptive. Since co‐nesting females were previously shown to be close kin (prevalently mother‐daughter pairs), they were expected to obtain kin‐selected benefits not enjoyed by solitary breeders. The only advantage so far detected accrues to the younger partner, which gives birth, on average, several days earlier than it would as a solitary breeder and thus allows its progeny to attain a heavier weight by the time of hibernation. On the other hand, pup predation in the nest, presumably caused by the older female towards the younger's litter, was occasionally recorded. On the whole, it is perhaps more plausible that communal nesting results from delayed dispersal of yearling females when a high population density limits breeding space, as proposed for other small rodents.
THE ZOOLOGICAL SOCIETY OF LONDON STAMFORD RAFFLES LECTURE 1996 From Gaia to Noah: human responsibilities in nature
Authors: Tickell Sir Crispin
Published: May 2009

Sir Crispin Tickell is Warden of Green College, Oxford; Chancellor of the University of Kent at Canterbury; Chairman of the Climate Institute of Washington, DC; Director of the Green College Centre for Environmental Policy and Understanding; Chairman of the Government's Advisory Committee on the Darwin Initiative; and Convenor of the Government Panel on Sustainable Development.

Sir Crispin was a member of the Diplomatic Service. He was Chef de Cabinet to the President of the European Commission (1977–80), Ambassador to Mexico (1981–83), Permanent Secretary of the Overseas Development Administration (1984–87), and British Permanent Representative to the United Nations (1987–90). He was also President of the Royal Geographical Society (1990–93), and Chairman of the International Institute for Environment and Development (1990–94).

He is the author of Climatic Change and World Affairs (1977 and 1986), and Mary Anning of Lyme Regis (1996). He has contributed to many other books on environmental issues (including human population increase and biodiversity). His interests go very wide, and include business and charities. More personally he cherishes mountains, pre‐Colombian art, and palaeo‐history.
The functional morphology of Mactrinula reevesii (Bivalvia: Mactroidea) in Hong Kong: adaptations for a deposit‐feeding lifestyle
Authors: Barnes Penelope A. G. , Morton Brian
Published: May 2009

The shallow subtidal mactrid bivalve Mactrinula reevesii is a deposit‐feeder in the southern and south‐eastern oceanic waters of Hong Kong. Buried obliquely, large quantities of fine sediment are taken into the mantle cavity and sorted on enormous labial palps. The small ctenidia probably have little value in collecting material, amounts taken in being too large. The mid gut is long and complexly folded inside the visceral mass. It is also capable of distension, although superficial visceral muscles maintain internal tonus. The rectum is narrow and creates compact faecal pellets.

Most interest is in the ventral mantle margin which is, posterior to the pedal gape and the base of the inhalant siphon, united by a sheet of cuticle. There is no fourth pallial aperture. There are, however, two pairs of flaps extending along the posterior third of the internal ventral mantle surface. These arch over left and right mantle rejection tracts which transfer unwanted material to the base of the inhalant siphon for final expulsion. The mantle flaps prevent such material from being returned to the anterior end of the mantle cavity, for palp reprocessing, when new material arrives. They, thus, maximize sorting efficiency by separating unsorted from sorted and rejected material.

Other mactrids have similar mantle flaps which they use in different ways, including the channelling of unwanted material to a fourth pallial aperture for expulsion, as in Lutraria lutraria. The Mactridae have thus evolved a unique method of increasing the efficiency of pseudofaecal waste rejection which has thereby facilitated the deposit‐feeding lifestyle by the diverse representatives of this family.
Habitat occurrence and prey distribution of a multi‐species community of shrews in the Siberian taiga
Authors: Churchfield S. , Sheftel B. I. , Moraleva N. V. , Shvarts E.A.
Published: May 2009

The habitat occurrence and invertebrate prey distribution of nine species of shrew in the mid‐taiga of central Siberia were investigated. Species richness ranged from 4–9 shrews per habitat. Sorex araneus and S. caecutiens were numerically dominant in all seven habitats (44 and 36% of the total catch, respectively) while Sorex minutus, S. tundrensis, S. isodon, and S. roboratus each constituted 4–6% and Sorex minutissimus, S. daphaenodon, and Neomys fodiens were rare (< 1% each). There was no overall correlation between abundance of shrews and invertebrate prey, but flood‐plain habitats supported the greatest abundance and species richness of shrews, and high density and biomass of prey. Oligochaete‐eating shrews were twice as numerous here as in other habitats, coincident with high abundance of oligochaetes. The large, earthworm‐feeding Sorex roboratus occurred only here. The more acid, typical taiga habitats had lower adundance and species richness of shrews. They had the lowest density and biomass of prey, particularly oligochaetes, and far fewer oligochaete‐eating shrews. The relative paucity of shrews in bush‐meadow habitats, despite abundant prey, implied that habitat structure influences shrew distribution. Differential numbers of certain species in the presence or absence of larger congeners also suggested that interspecific competitive effects influence habitat selection by shrews. The high species richness of shrews here in the mid‐taiga may be accounted for by the heterogeneous nature of the constituent habitats which provide niches for small and large species of shrew with a range of feeding habits.
Activity patterns and interactions of red foxes (Vulpes vulpes) in Oxford city
Authors: Doncaster C. P. , Macdonald D. W.
Published: May 2009

The activity patterns of red foxes (Vulpes vulpes L.) living and breeding in urban areas of Oxford, and the interactions between individuals, were analysed from detailed radio‐tracking data on 17 adults. Foxes were nocturnal and active during the night for a mean of 6h 52min min, irrespective of the time of year. The number of active/resting periods increased in autumn and winter, and in winter and spring the night was characteristically divided into several short cycles of activity of 2–2 1/2 h each, interspersed with similar periods of rest. The foxes occupied mutually exclusive group ranges and group members remained within 50m of each other for up to one‐third of the time spent active at night. The implications of fox spatial relationships for rabies transmission are discussed.
Mechanisms of swallowing and airway protection in infant mammals (Sus domesticus and Macaca fascicularis)
Authors: Crompton A. W. , German R. Z. , Thexton A. J.
Published: May 2009

Protection of the airway, necessary for continued respiration, is a problem for mammals because of the relative positions of the oesophageal and laryngeal openings in the pharynx. In human infants, and all other mammals, infant and adult, the epiglottis contacts the posterior surface of the soft palate, providing a continuous passage from the nasopharynx to larynx. The function and movements of the epiglottis during swallows are debated as to whether the epiglottis bends to protect the airway or remains erect and leaves the airway open during the swallow. Using high‐speed cineradiography, we examined swallows in detail for a precocious infant, Sus domesticus, the miniature pig, and the more altrical primate, Macaca fascicularis. Infant pigs swallowed in two different ways: down the midline of the oropharynx, over a bent epiglottis, and laterally, around an erect epiglottis, and presumably open airway. The epiglottis of infant macaques never bent, and milk always travelled laterally, through the pyriform recesses and around the larynx. The macaque airway was closed superiorily, however, when the soft palate sealed against the posterior pharyngeal wall. A hypothesis that could account for this pattern of swallowing involves an ontogenetic change from swallows travelling laterally through the pyriform recesses in young infants to swallows travelling over a bent epiglottis in more mature infants. This change would accompany maturation associated with weaning and the need to protect the airway from the larger and less fluid boluses of masticated solid food.
Deroceras juranum—a Mendelian colour morph of D. rodnae (Gastropoda: Agriolimacidae)
Authors: Reise H.
Published: May 2009

The terrestrial slug Deroceras juranum Wüthrich, 1993 (Gastropoda: Agriolimacidae) has been described as an endemic species of the Swiss Jura Mountains (Switzerland) where it occurs at high altitudes. The species description was mainly based on its characteristic blackish‐violet body colour. Breeding experiments and comparative studies of the genital anatomy and mating behaviour indicate that D. juranum is nothing but a colour morph of the usually cream‐coloured D. rodnae Grossu & Lupu, 1965. The body colour seems to be coded by a single locus with two alleles, of which violet is dominant over cream. Topographical colour variation has also been observed in arionid slugs. Its possible biological (i.e. selective?) meaning is discussed. The slugs are able to reproduce uniparentally with their offspring showing recombination.
Ontogeny of the maxillary barbel muscles in Clarias gariepinus (Siluroidei: Clariidae), with some notes on the palatine‐maxillary mechanism
Authors: Adriaens D. , Verraes W.
Published: May 2009

Siluroids are characterized by the presence of a palatine‐maxillary mechanism, which enables a controlled mobility of the maxillary barbels. In Clarias gariepinus, the ontogeny of this mechanism is studied and described as well as those muscles related to the maxillary barbel. Two muscles are distinguished: (1) retractor tentaculi, connecting the maxilla to the suspensorium, and (2) extensor tentaculi, running from the ventro‐lateral face of the skull to the posterior half of the palatine. These typical catfish muscles are derived from muscles that are present in generalized teleost fishes. The retractor muscle is believed to be derived from the A3 muscle of the adductor mandibulae complex. The extensor muscle is formed from the anterior fibres of the adductor arcus palatini. The palatine is rod‐like in C. gariepinus and articulates with the orbitonasal lamina in larval specimens and with its ossification, the lateral ethmoid, in juvenile and adult specimens. The articulation occurs via a long cartilaginous strip on the dorsal face of the autopalatine, thereby enabling both a rotation and a restricted sliding.
Sperm storage in a seasonally reproducing African vespertilionid, the banana bat (Pipistrellus nanus) from Malawi
Authors: Bernard R. T. F. , Happold D. C. D. , Happold M.
Published: May 2009

Spermatogenesis in the banana bat (Pipistrellus nanus) from southern Malawi began in the hot, wet season (February to April) and spermatozoa were released to the cauda epididymides at the beginning of the cool, dry season (May). Mating occurred between mid‐June and early July, in the middle of the cool, dry season. After mating, spermatozoa were stored by the female until ovulation in August and by the male until at least September. The period of female sperm storage effectively lengthened the reproductive cycle so that early spermatogenesis occurred during the second half of one hot, wet season and births at the beginning of the following hot, wet season. During the period of sperm storage, males and females roosted together and group membership was labile, suggesting that the mating system may be promiscuous (both males and females mating with more than one partner) and that sperm competition may occur. The similarity between the chronology of reproduction in Malawi, Kenya, and South Africa leads us to propose that sperm storage occurs at all three localities.
Multicentre randomised controlled trials in obstetrics and gynaecology: an analysis of trends over three decades
Authors: Raza A , Chien PFW , Khan KS
Published: May 2009

To assess the trend in multicentre randomised controlled trials (RCTs), a database of 670 RCTs was assembled from four generic obstetric and gynaecological journals (Acta Obstetricia et Gynecologica Scandinavica, British Journal of Obstetrics & Gynaecology, Obstetrics & Gynecology and American Journal of Obstetrics & Gynecology) for 1975, 1980, 1985, 1990, 1995, 2000 and 2005. During this period, there was an inflationary trend with the proportion of published multicentre RCTs (from 12.9% in 1975 of all RCTs to 23.8% in 2005; P = 0.008). Multicentre RCTs had multiauthored publications (OR = 2.90; 95% CI 1.99–4.22) and more often received external funding (OR = 2.41; 95% CI 1.70–3.48) than single centre RCTs. The inflationary trend in multicentre RCTs requiring funding and collaboration represents the increasing complexity of medical research necessary to underpin evidence‐based practice.