bluuebunny/crossref_metadata_2025_split huggingface dataset:
The von Bertalanffy growth model fitted to Planigale tenuirostris (Marsupialia: Dasyuridae) post‐weaning data
Authors: Read D. G. 
Published: May 2009

Post‐weaning growth of head length in the dasyurid marsupial Planigale tenuirostris was studied in laboratory raised individuals. Some lived to almost three years and growth continued throughout life, following the von Bertalanffy model. Males were larger than females in each age class and two‐year‐old females were larger than one‐year‐old males. The mean head lengths were: one‐year‐olds, 20·1 and 19·8 mm; and two‐year‐olds, 21·3 and 20·7 mm, for males and females, respectively. Based on the laboratory findings, in a free‐living population approximately 21% of males and 13% of females were aged two years or older. The range of head lengths produced by these growth patterns has possibly an important influence on resource partitioning and, as a consequence, on the structure of dasyurid communities.SummaryGrowth of head length in P. tenuirostris from the end of weaning throughout life was studied in the laboratory. The growth curves for males and females followed the von Bertalanffy model. Growth continued throughout life and in each age class males were larger than females, resulting in a range of head lengths among mature planigales. This range in sizes has potentially important implications with respect to population niche breadth, resource partitioning and species diversity in dasyurid communities.
Microhabitat use in a stream fish assemblage
Authors: Grossman G. D. , Freeman Mary C. 
Published: May 2009

We examined microhabitat use among fishes in a 37‐m section of Coweeta Creek, North Carolina. Numerical abundances of species changed substantially during the 17‐month study period. Microhabitat availability, however, did not change markedly during our investigation. Seasonal principal component analyses of microhabitat availability and fish microhabitat use data extracted two main patterns of non‐random microhabitat use. Clinostomus funduloides, Notropis eoccogenis and Semotilus atromaculatm were significantly over‐represented in deep areas with low to intermediate velocities and depositional substrata. Campostoma oligolepis, Coitus bairdi, Etheostoma blennioides, Rhinichthys cataractae and Salmo gairdneri all occurred in intermediate to deep microhabitats with moderate to high velocities and erosional substrata. Five of seven species exhibited seasonal variation in microhabitat utilization, whereas six species displayed size‐related variation in use. Size‐related variation was probably ontogenetic. We attributed most seasonal changes in microhabitat use to variations in microhabitat availability.We used canonical analysis of discriminants to identify factors maximizing interspecific differences in microhabitat use. This analysis indicated that species could be assigned to either a benthic or a water column guild. Species within a guild generally could not be differentiated statistically, whereas members of different guilds were readily separable. These patterns persisted throughout the study, despite changes in numerical abundances of assemblage members. There was no evidence of either exploitation or interference competition for microhabitat, consequently it is unlikely that spatial resources were limiting during our study.
Ecology of lacertid lizards in a desert area of eastern Morocco
Authors: Pérez‐Mellado Valentin 
Published: May 2009

Some basic aspects of the ecology of five lacertid lizards inhabiting the desert area of Tafilalet, in south‐eastern Morocco, are considered: Mesalina guttulata, occupying almost exclusively the hammada habitat; Mesalina olivieri, Acanthodactylus boskianus and Acanthodactylus scutellatus found on sand and bare‐ground reg; and Acanthodactylus longipes, inhabiting the sand‐dune habitat, the erg. Acanthodactylus scutellatus, A. boskianus, A. longipes and M. olivieri had a bimodal diel activity pattern; in M. guttulata daily activity was centred on the morning hours. All species exhibit fairly precise thermoregulation with a strong relation between body and substratum temperature, particularly for species occupying softer substrata. Mesalina guttulata had a diverse diet during both seasons observed, while in the remaining species termites and ants formed the bulk of the food.The foraging behaviour, diet and ecological characteristics of Lacertidae from the Tafilalet, especially the genus Acanthodactylus, seem to be optimal for the challenging environmental conditions of this desert area. The implications of the foraging strategy of Tafilalet's Acanthodactylus for other species of the genus are discussed.
Microbial digestion in the herbivorous lizard Uromastyx aegyptius (Agamidae)
Authors: Foley W. J. , Bouskila A. , Shkolnik A. , Choshniak I. 
Published: May 2009

The utilization of a diet rich in plant cell walls was studied in a large, desert‐dwelling, herbivorous lizard, Uromastyx aegyptius (Agamidae). The diet eaten by U. aegyptius in spring in the ‘Arava Valley, Israel, consisted almost entirely of leaves and fruits of short‐lived annual plant species. The leaves contained only moderate levels of fibre compared with grasses and tree leaves, but those fruits eaten were markedly higher in fibre and lignin. All items had notably high contents of ash.Following oral doses of [14C] cellulose, 14CO2 was detected in respired air from U. aegyptius, demonstrating that the cellulose was digested and that the lizards gained oxidative energy from cellulose degradation. The hind gut was the principal site of microbial activity and the apparent digestibility of the cell‐wall fraction was 69%. Similarly, the caecum/proximal colon had the highest concentrations of SCFA (76–120 mM).The mean rate of SCFA production at 40 C in vitro was 31 mmol/1 h‐1. Assuming that this is representative of daily production rate, 69 kJ/kg d‐1 would be made available to the animal. This is 47% of the mean digestible energy intake estimated in free‐living animals. Microbial fermentation contributes an important part of the energy budget of U. aegyptius but the effects of variation in body temperature on digestion and fermentation need further consideration.
Reduction in the number of young during pouch‐life in a small marsupial
Authors: Wooller R. D. , Richardson K. C. 
Published: May 2009

The honey possum Tarsipes rostratus, a shrew‐sized marsupial endemic to south‐western Australia, feeds exclusively upon nectar and pollen. Tarsipes has fewer pouch‐young, which remain in the pouch longer, than the young of sympatric insect‐feeding marsupials of comparable size. Tarsipes pouch‐young were recorded in every month of the year. Of all adult females caught, 68% had pouch‐young and 36% of the remainder had recently carried young. This continual reproduction is offset by an average lifespan of only about one year.Although Tarsipes have four teats, only very few of the largest females reared four young to independence. The number of pouch‐young was inversely related to their size, changing, on average, from 3.6 young immediately after birth to 2.4 young at pouch‐exit. Larger females gave birth to larger litters than smaller females and appeared more successful in rearing them. Variation in the initial litter size, and any subsequent reduction in litter size, might allow females to optimize offspring production during their short lifetime in relation to an unpredictable and specialized food supply.
The bioluminescent organs of the deep‐sea cephalopod Vampyroteuthis infernalis (Cephalopoda: Vampyromorpha)
Authors: Herring P. J. , Dilly P. N. , Cope Celia 
Published: May 2009

Vumpyroteuthis infernalis Chun is the sole member of the cephalopod subclass Vampyromorpha. The three putative types of photophore (fin base, dorsomedial or composite, and skin nodules) are described and it is concluded that the composite organ is not a light‐emitting structure. It has structural similarities to an extra‐ocular photoreceptor.The fin‐base photophore is capable of being everted from the pigmented pit in which it is seated. Its surface bears chromatophores which may modulate the emission and the photocytes contain an extensive network of microtubular elements and proteoglycan particles. The reflector is formed of a very thick layer of collagen fibrils in different orientations. The skin nodules are widely distributed over the animal. They have a collagenous reflector and core cells with structural similarities to those of the fin‐base photocytes.The photocytes have no morphological links with those of octopods or decapods. The thick collagen reflector, and absence of the iridosomal platelets present in the other subclasses, suggests an early separation of the Vampyromorpha from other coleoids.
The consequences for deer of ingesting oilseed rape (Brassica napus): feeding experiments with roe deer (Capreolus capreolus) and red deer (Cervus elaphus)
Authors: Sibbald A. M. , Iason G. R. , Bristow I. A. , Davidson G. C. , Smith W. H. Macfarlane 
Published: May 2009

In two experiments, in the growing season March–May, freshly harvested double‐low oilseed rape (Brassica napus) plants were fed ad libitum to penned roe deer (Capreolus capreolus) and red deer (Cervus elaphus). In Experiment 1, oilseed rape was fed to five roe and 12 red deer as 60% of their daily dry matter (DM) intake for four weeks, after a two‐week dietary change‐over period. The rest of the diet comprised cattle‐rearing pellets (33%) and freshly cut heather (Calluna vulgaris) plants (7%). In Experiment 2, oilseed rape was fed to seven roe and eight red deer as 100% of the diet for up to six weeks, after a two‐week change‐over period.In both experiments, Heinz bodies were found in roe deer blood 2–3 weeks after the start of the change‐over period, with a fall in mean packed cell volume (PCV) and blood glutathione (GSH) concentration. In Experiment 2, after 5–8 days of feeding on 100% oilseed rape, four roe deer showed signs of inappetance and were changed to a diet of 80% oilseed rape. At the same time, the other three roe deer had very low PCV (< 60% of normal values) and oilseed rape feeding was discontinued for those animals. The red deer showed no symptoms of haemolytic damage nor any change in blood GSH concentration in either experiment, but showed a gradual fall in PCV in Experiment 2. No other ill‐effects were observed in any of the animals.Intakes of oilseed rape (gDM/kg0–75/day) were lower for the roe deer than the red deer in both experiments. The severity of haemolytic anaemia in the roe deer was related to the proportion of oilseed rape in the diet, rather than the amount ingested. It was concluded that the health of roe deer ingesting oilseed rape may be affected if other foods are not available.
Ontogenetic and anatomic variation in mineralization of the wing skeleton of the Mexican free‐tailed bat, Tadarida brasiliensis
Authors: Papadimitriou Helen M. , Swartz Sharon M. , Kunz T. H. 
Published: May 2009

We examined patterns of variation in the mineral content of the wing skeleton of the Mexican free‐tailed bat, Tadarida brasiliensis. We ashed humeri, radii, metacarpals II‐V, and phalanges of digit III, and quantified mineralization differences among elements at specific ages, and ontogenetically for each element. The most mineralized elements are the humerus and the radius, followed by the metacarpals, of which the third and fifth are the most mineralized. The proximal and middle phalanges of the third digit exhibit the lowest mineral content, and the distal phalanges have no mineral content according to our ashing protocol. Histological examination shows a thin (< 10 μm) shell of unmineralized osteoid surrounding a cartilaginous core in distal phalanges. Mineral content of each bone increases linearly with age during post‐natal development, but there are differences in the rate and extent of this increase among the different elements.The mineralizaton differences we observed parallel substantially different bone loading patterns found in different parts of the wing in other studies. The humerus and radius are subjected to large torsional loads during flight, while the metacarpals and phalanges experience dorsoventral bending. The high mineral content of the humerus and radius and the low mineral content of the metacarpals and phalanges may resist torsion proximally and promote bending distally. Furthermore, the decrease in mineral content along the wing's proximodistal axis decreases bone mass disproportionately at the wing tips, where the energetic cost of accelerating and decelerating limb mass is greatest.
On habitat selection by the goral Nemorhaedus goral bedfordi (Bovidae, Artiodactyla)
Authors: Mishra C. , Johnsingh A. J. T. 
Published: May 2009

Habitat selection, diet, and escape behaviour of grey goral (Nemorhaedus goral bedfordi) were studied in Majhatal Harsang Wildlife Sanctuary (MHWS) in the Indian Himalaya. Five trails covering a total length of 8.5 km were monitored in the morning hours for availability of habitat components and their use by goral. Habitat components quantified were: vegetation type, tree density, shrub understorey, shrub height, and slope angle. Diet composition of goral was determined through faecal analysis. Information on escape strategy was gathered by recording the escape areas used by disturbed animals.Goral fed almost entirely on grass (92.2% in the cold season and 98.3% in the warm season). They preferred open vegetation communities with good grass cover and avoided shrub‐rich patches, especially areas where the shrub height exceeded their shoulder height. Goral selected patches with fresh grass sprout and were partial to steep (>30°) slopes.In the morning, goral avoided most forested vegetation types in the area owing to extensive understorey. However, there was high use of forest cover with little understorey ‘for escape’ (32%, n= 200). Other escape terrain used were cliffs (31%), open gullies (16%), and rocky areas (13%).
Pronounced heterochely in the ghost shrimp, Neotrypaea californiensis (Decapoda: Thalassinidea: Callianassidae): allometry, inferred function and development
Authors: Labadie Linda V. , Palmer A. R. 
Published: May 2009

To understand their function and ontogeny better, we conducted a morphometric analysis of claw size and shape variation in the strikingly heterochelous, north‐eastern Pacific ghost shrimp, Neotrypaea (formerly Callianassa) californiensis. Master claws approached 25% of total body weight in mature males, but rarely exceeded 10% in females. Minor claws were less than 3% of body weight in both sexes. The proportions of right and left master claws did not differ significantly from 50:50. Males exhibited a greater positive allometry than females in both master and minor claw size, though master claws differed more than minor claws. Sexual dimorphism was also observed in master but not minor claw shape: compared to females, mature male master claws: a) were proportionally higher relative to their length; b) exhibited a deeper propodal notch and consequently a larger gape; c) developed a more slender and more distally hooked dactyl; and d) exhibited more well‐developed teeth about the periphery of the claw gape.The shape of the conspicuous gape in mature male master claws bore a close resemblance to the cross‐section of similar‐sized master claws. The shape of this gape, and the presence of fine teeth about its periphery, strongly suggests that master claws function in a highly stereotyped form of grappling during agonistic encounters or perhaps during mating between similar‐sized conspecifics. In addition, a landmark morphometric analysis of relative growth suggested that the pronounced propodal notch develops via localized deformations near the base of the fixed finger rather than via a more generalized contraction of the ventral manus region. Finally, a preliminary survey suggests that the distinctive propodal notch, which may be diagnostic of the hypothesized grappling function, has evolved at least twice in the Callianassidae, once in the Callianassinae and once in the Callichirinae. Sexual selection may have significantly influenced the evolution of these unusual master claws.
New findings in body mass regulation in zebra finches (Taeniopygia guttata) in response to photoperiod and temperature
Authors: Meijer T. , Rozman J. , Schulte M. , Stach‐Dreesmann C. 
Published: May 2009

Small birds in temperate zones increase body mass in winter (Lehikoinen, 1987). We investigated daily and annual variation of body mass and fat reserves of locally‐reared Australian zebra finches Taeniopygia guttata, by exposing them to different photoperiods, feeding periods, and temperatures.Experiments with long and short photoperiods and long and short feeding periods, showed that long photoperiods increased body mass and fat reserves of the zebra finches, and readiness to breed, independently of the actual feeding period.Furthermore, the zebra finches in indoor aviaries with constant temperature (22‐24°C) and in outdoor aviaries with ambient temperature, both exposed to the natural daylength changes of Bielefeld, Germany (52 °N), had high dawn body mass in summer (12.9 and 12.0‐12.4g, respectively) and low in winter (10.7 and 11.1 g, respectively). Thirty to sixty percent of these mass changes were related to changes in fat reserves, so that the finches had only 0.1‐0.2g of metabolizable fat reserves in short photoperiods (or in winter), which increased up to 1.5g in long photoperiods (or in summer).Indoor finches consumed more seeds in summer than in winter (3.3 vs. 2.7g/day), while outdoor finches consumed 4‐5g of seeds per day throughout the year, which probably represented the limit of energy intake for a 11‐13g bird (Kirkwood, 1983). Nightly mass loss, increasing from 0.7g in summer up to 2.0g in winter, was highly positively correlated with night length, not influenced by ambient temperature. Foraging before dawn and after dusk, roosting with well‐filled crops, and decreasing body mass and fat reserves, seem to be adaptations of zebra finches for survival in winter. The summer fattening probably accelerates reproduction in this opportunistic breeder, by allocating more time to reproductive behaviour and more endogenous nutrients to egg‐formation.
A comparison of the strengths of gastropod shells with forces generated by potential crab predators
Authors: Preston S. J. , Revie I. C. , Orr J. F. , Roberts D. 
Published: May 2009

Carcinus manenas, Liocarcinus puberandCancer pagursare thought to be three likely crab predators of the gastropodCalliostoma Zizyphinum.In order to compare the strenghts of predators and their prey, the whole shell and aperture lip strengh of white and pinkCalliostomamorphotypes and the maximum forces exerted by the chelipeds of three crab species were measured. Although white shells were thicker than pink shells,Calliostomacolour morphotyes did not differ significantly in either the force required to break the shell lip or the whole shell. BothLiocarcinus puberandCarcinus maenashave dimorphic chelipeds and their “crusher” chelipeds deliver almost double the forces generated by the‘cutter’chelipeds. In constrast,Cancer pagurushas monomorphic chelipeds both delivering similar forces.When compared withCalliostomashell strenght, the forces generated by the‘crusher’chelipeds of mostL. pubertested were, in general, sufficient to break the shell lip ofCalliostomashells, whereas forces generated by the‘cutter’chelipeds of only the larger individuals were sufficient to break the shell lip. InC. manenas, forces generated by both the‘cutter’and‘crusher’chelipeds often exceeded the minimum recorded force required to break the shell lip and the‘crusher’cheliped reached the minimum force required to break wholeCalliostomashells. Both chelipeds of allC. pagurustested generated forces in excess of the minimum required to break the shell lip, and the proportion of individuals capable of generating the minimum force required to break the whole shell increased with the size of the size of the crab.Carcinus maenasandCancer paguruswere capable of breaking both the shell lips and the whole shells of a wider range of shell sizes thanL. puber.
Life history, secondary production and microdistribution of Stenopsyche angustata (Trichoptera: Stenopsychidae) in a tropical forest stream
Authors: Dudgeon David 
Published: May 2009

The ecology of the net‐spinning caddisfly Stenopsyche angustata (Stenopsychidae) was investigated in Tai Po Kau Forest Stream (TPKFS), New Territories, Hong Kong, over a two‐year period (1977‐79). Quantitative benthic samples were taken from different microhabitats in the stream on 45 occasions and, in combination with light‐trap catches of adult caddisflies (taken during 1983‐84 and 1985), were used as a basis for investigating the life‐history pattern and estimating secondary production of this species. Annual production over the period 1977‐79 was 940.4 mg AFDW 0.5m−2, and was slightly higher in 1977‐78 (1004.1 mg AFDW 0.5 m−2) than in 1978‐79 (926.1 mg AFDW 0.5 m−2). This variation reflected slight inter‐year differences in mean population densities and biomass of S. angustata, which ranged from 41.1 individuals 0.5 m−2 and 113.3 mg AFDW 0.5 m−2 in 1977‐78 to 38.6 individuals 0.5 m−2 and 105.9 mg AFDW 0.5 m−2 in 1978‐79. Mean values of these parameters over the two‐year study period were 39.8 individuals 0.5 m−2 and 109.4 mg AFDW 0.5 m−2. Stenopsyche angustata appeared to be bivoltine in TPKFS, but growth was rather asynchronous with some adult emergence and continuous recruitment throughout the year. Production: biomass ratios were almost constant (varying between 8.74 and 8.87) over the two years of the study.Mean densities of Stenopsyche angustata varied significantly across TPKFS. Larvac were most abundant in midstream microsities, and least numerous close to the stream banks. Population densities in intermediate microsites were significantly less than in midstream, but significantly greater than at bankside microsites. Stepwise multiple regression analysis and multivariate statistics (principal components analysis followed by regression) were used to investigate the relationship between larval densities in each benthic sample and the sediment characteristics, detrital standing stocks, and algal biomass in the microenvironment where the sample was taken. Regression analysis revealed that S. angustata microdistribution was influenced by sediment grain‐size characteristics (kurtosis of the grain‐size distribution), and algal biomass (specifically, the amounts of chlorophyll b), and the relationship between algal biomass and larval densities was negative. Multivariate statistics followed by regression analysis confirmed the interactive effects of both biotic and abiotic influences upon S. angustata abundance. Approximately 20% of the variance in abundance in TPKFS was attributable to sediment characteristics and algae, but it seems plausible also that current speed had a direct effect on the microdistribution and abundance of S. angustata through an influence on the rate of supply of food to the filter‐feeding larvae.