bluuebunny/crossref_metadata_2025 huggingface dataset:
Home range and spatial organisation of rock-dwelling carnivorous marsupial, Pseudantechinus macdonnellensis
Authors: Pavey Chris R. , Goodship Nicola , Geiser Fritz
Published: August 2003

We studied home-range size, range length and spatial organisation of fat-tailed false antechinus, Pseudantechinus macdonnellensis, at Ormiston Creek, central Australia. Animals were tracked using transmitters implanted into the body cavity. Mean home-range size was 0.76 ha based on the minimum convex polygon (MCP) method and 1.14 ha based on the fixed kernel method (95% contour). Mean size of core areas of the home range was 0.07 ha based on the 50% kernel contour. Mean maximum range length was 148.83 m. Males occupied larger home-range areas than females (MCP: 0.98 v. 0.31 ha, 95% fixed kernel: 1.50 v. 0.43 ha) and also had greater maximum range lengths (180 v. 86 m). Home-range areas showed little overlap within the sexes; however, ranges of males overlapped those of females by an average of 37.95%. By comparison with data from a previous mark–recapture study at the same site, radio-tracking produced home-range estimates (MCP) that were greater by a factor of 24.5 for males and 15.5 for females, whereas maximum range lengths were lower for females, but similar for males. The results of this study support the proposition that the rock-dwelling P. macdonnellensis has a more stable home range and undergoes fewer long-range movements than similar-sized arid-zone dasyurids that occupy open environments. These differences likely result from the stability in resources provided by rocky habitats, specifically year-round availability of insects, availability of plentiful shelter sites that are very effective thermal buffers in both summer and winter, and a diversity of accessible microclimates.
The diet of feral house cats (Felis catus) at a regional rubbish tip, Victoria
Authors: Hutchings Susan
Published: August 2003

The diet of feral cats (Felis catus) inhabiting a regional rubbish tip (dump) in Victoria was studied to determine whether cats utilised garbage or live prey from the surrounding heathlands for food. Between 30 and 50 cat scats were collected from the tip over two years in each of four sampling periods: spring 1997, autumn 1998, spring 1998 and autumn 1999. The scats were analysed to determine major dietary components, dietary breadth and seasonal overlap of diet. Bone fragments from meat scraps were the most frequent dietary item detected in the scats. Vertebrate prey species occurred less often in the cats' diet but a variety of both introduced and native species were represented. Analysis of dietary breadth confirmed that cats selected mainly meat and chicken scraps from the garbage but indicated that vertebrates were hunted opportunistically. Control measures are suggested to reduce cat numbers at regional rubbish tips to relieve potential impact on native wildlife.
Comparison of tooth morphology and wear patterns in four species of wallabies
Authors: Lentle R. G. , Hume I. D. , Stafford K. J. , Kennedy M. , Haslett S. , Springett B. P.
Published: August 2003

Tooth morphology of two browsing macropods (brush-tailed rock-wallabies and swamp wallabies), one grazing species (tammar wallaby) and one mixed feeder (parma wallaby) are compared. The dental action of a single tammar wallaby was studied by cinefluoroscopy. Cinefluoroscopy showed independent rotation of each hemi-jaw on occlusion in the tammar, and the disposition of molar striae suggest a similar pattern of jaw movement in all four species. There was a close relationship between incisor and molar action in both grazing and browsing species. Initial occlusion of the anterior facets of the incisors brought about a grasping action in browsing species and a fine cutting action in grazing species. In both grazing and browsing species these incisor actions were coincident with a cutting action by the transverse lophs during molar occlusion. Subsequent independent rotation of each hemi-jaw results in fine cutting by the lateral facets of the incisors, in both grazers and browsers, at the same time as the molar arrays perform a crushing action in browsers and a secondary cutting action in grazing species. Thus the teeth of the four species showed a number of similarities (independent rotation of each hemi-jaw) along with some differences (incisor and molar actions) that appear to represent adaptations for efficient aquisition and oral processing of browse or graze.
Roosting activity budget of the southern bent-wing bat (Miniopterus schreibersii bassanii)
Authors: Codd Jonathan R. , Sanderson Ken J. , Branford Alan J.
Published: August 2003

The roosting activity budget of the southern bent-wing bat (Miniopterus schreibersii bassanii) was observed using remote-controlled infrared-illuminated video-cameras. Bat activity was assessed using scan sampling, conducted in 98 two-hour observation blocks, with 605 scan samples (each of ~2.5-min duration) being collected. Activity was divided into three categories: 'at rest', 'grooming', and 'active' (including flying off). Bats spent an average of 62% of their time 'at rest', 16% 'grooming', and 22% 'active'. Bat activity was significantly influenced by time of day, the cave chamber that was occupied, the vertical location of the bats on the cave wall, and the type of cluster formed by the bats. During the day bats spent most time 'at rest' (overall mean 78%) compared with other times (overall means 43–54%). Levels of flight and 'activity' (relative to 'at rest') were significantly lower during the day than at other times. Bats on the walls of the maternity chamber, where the temperature was highest, spent less time 'at rest' (overall mean 51%) than did bats on the walls of cooler chambers (overall means 73–86% of time). Bats in the maternity chamber spent significantly more time 'active' and 'grooming' (relative to 'at rest') than did bats in other chambers. Microclimatic conditions within the cave environment appear to significantly affect the activity of bats whilst at roost.
Agonistic behaviour in final-instar larvae of Austrocnemis splendida (Odonata : Coenagrionidae), and a challenge to the 'Agriocnemidinae'
Authors: Rowe R. J.
Published: August 2003

Larval agonistic displays are reported from Austrocnemis splendida, a small coenagrionid damselfly. Sixteen major displays were distinguished. The agonistic behaviour repertoire of A. splendida is contrasted with published information on other coenagrionid larvae, especially with Agriocnemis pygmaea, putatively a member of the same subfamily. Marked differences in larval display behaviour between A. splendida and A. pygmaea provide evidence against a close relationship between these species. No support is found for including A. splendida in the Agriocnemidinae. It is postulated that the Agriocnemidinae are an artificial construct, its components linked through convergence in form of the reduced wing structures of these very small dragonflies.
Overlap and competition for nest holes among eclectus parrots, palm cockatoos and sulphur-crested cockatoos
Authors: Heinsohn Robert , Murphy Stephen , Legge Sarah
Published: August 2003

We examined the extent of overlap in the characteristics of nest holes used by eclectus parrots (Eclectus roratus), palm cockatoos (Probosciger aterrimus) and sulphur-crested cockatoos (Cacatua galerita) in patches of rainforest and woodland in and around Iron Range National Park, Cape York Peninsula, Australia. Eclectus parrots nested only in rainforest and palm cockatoos nested mostly in eucalypt woodland adjacent to rainforest. Sulphur-crested cockatoos nested in both habitats. Nest holes of eclectus parrots and rainforest sulphur-crested cockatoos were in trees of larger DBH (diameter at breast height) and higher off the ground than those of palm cockatoos and sulphur-crested cockatoos in woodland. Palm cockatoos differed from the other parrots in their use of deeper holes with entrances that faced skywards rather than sideways. Both palm cockatoos and woodland sulphur-crested cockatoos used nests with smaller entrances than eclectus parrots and rainforest sulphur-crested cockatoos. All species showed intraspecific competition for nest holes. Behavioural conflict was also common between sulphur-crested cockatoos and the other two species. Each year 9.7–25.8% of eclectus parrot nests were taken over either permanently or temporarily by sulphur-crested cockatoos. Only one palm cockatoo nest was taken over by sulphur-crested cockatoos. Nest-holes were destroyed by natural causes at similar rates in rainforest (3.8% per annum over 174 nest-years) and woodland (5.4% per annum over 93 nest-years). Four nest trees fell over, and the floor of the nest collapsed at a further four holes. Three woodland nest trees burnt down during dry-season fires (August–October). New eclectus parrot and rainforest sulphur-crested cockatoo holes originated from incipient hollows on the tree that were modified by the parrots. We discuss the intense competition between these large parrots in light of the apparent shortage of appropriate nest holes in Cape York rainforest and eucalypt woodland.
Comparisons of indices of molar progression and dental function of brush-tailed rock-wallabies (Petrogale penicillata) with tammar (Macropus eugenii) and parma (Macropus parma) wallabies
Authors: Lentle R. G. , Hume I. D. , Stafford K. J. , Kennedy M. , Haslett S. , Springett B. P.
Published: August 2003

We measured parameters of molar progression and dental function in the brush-tailed rock-wallaby (Petrogale pencilliata) (a browser/grazer) and compared them with data from the tammar wallaby (Macropus eugenii) (a grazer) and the parma wallaby (Macropus parma) (a grazer/browser).Although the mean value of the molar index (MI) was higher in rock-wallabies than in parma and tammar wallabies the mean rate of increase of log(MI) with log(body mass) was similar in the three species. Reported differences between these species in their rates of molar progression with age may therefore result from differences in their rates of bodily growth. The findings indicate that molar progression in the rock-wallaby is governed by the growth of the bones of the viscerocranium (mesial shift), rather than by diet-induced movement of the teeth within the bones of the viscerocranium (mesial drift), and was not influenced by the persistence of P4 premolars. It is therefore unlikely that differences in the rate of molar progression are directly linked to differences in diet.The relationship between functional dental parameters and body mass differed between brush-tailed rock-wallabies and tammar wallabies, species of differing dietary habit, but did not differ between brush-tailed rock-wallabies and parma wallabies, species of more similar dietary habit. Thus the total length of upper transverse lophine ridges and the interlophine distances of the M1 to M3 upper molars of brush-tailed rock-wallabies were not different from those of parma wallabies but were significantly greater than those of tammar wallabies. These differences can be interpreted in terms of greater emphasis on crushing/grinding of browse in the rock-wallabies and parma wallabies.
Molar progression and tooth wear in tammar (Macropus eugenii) and parma (Macropus parma) wallabies
Authors: Lentle R. G. , Hume I. D. , Stafford K. J. , Kennedy M. , Haslett S. , Springett B. P.
Published: August 2003

We investigated the functional significance of molar progression and the influence of diet on the usefulness of molar progression as an index of age in two macropodid marsupials, the tammar wallaby (Macropus eugenii), a grazing species, and the parma wallaby (Macropus parma), a browser/grazer, by exploring the relationships between the index of molar progression and several skull and tooth parameters. We also tested allometric models that related molar progression and aspects of tooth morphology to body mass. Results support the notion that molar progression in these closely related macropods results from 'mesial shift'(forward movement resulting from growth of the bones of the skull bearing the dentary, the anterior viscerocranium) rather than from 'mesial drift' (forward movement of molars relative to the anterior viscerocranium).There were no significant differences between the two species in the rate of molar progression despite differences in diet. Instead, the greater reliance of tammar wallabies on grasses was reflected in differences in their tooth morphology from that of parma wallabies. The sum of the breadths of erupted molariform teeth of tammars increased significantly faster with body mass and with length of the anterior viscerocranium than in parma wallabies and approximated a theoretical model for compensation with metabolic body mass more closely than models based on other morphological parameters.The total mesiodistal length of dentition, the mesiodistal lengths of the component teeth of the proximal molar row, and the distance between the mesial and distal lophs were all significantly lower in tammar wallabies than in parma wallabies. These differences result in tammar wallabies having greater numbers of transverse cutting edges per unit of molar tooth length, which maximises the efficiency of comminution of long grass fibres.
Geographic song variation within and between populations and subspecies of the rufous bristlebird, Dasyornis broadbenti
Authors: Rogers Daniel James
Published: August 2003

This work investigated whether the songs of the rufous bristlebird, Dasyornis broadbenti, vary between populations that have become isolated through habitat clearance, in a similar way to that found between island populations of other bird species, separated by ocean. In addition, the extent of song variation between the two extant subspecies of D. broadbenti was investigated. The nature of song elements did not differ between isolated sites within each subspecies' distribution more than between sites sampled within continuous populations. However, multivariate analyses of spectral and temporal features suggested that these features differed between isolated populations more than within continuous populations. In addition, both the nature of song elements and spectral and temporal features differed significantly between the two extant subspecies of D. broadbenti. These taxonomic analyses of song thus supported recent revisions of the subspecific boundaries of D. broadbenti. While there was some evidence that temporal and spectral song features varied more between isolated populations than within a continuous population, it was difficult to eliminate the effect of distance on song variation. Although evidence for song variation as a result of isolation was not strong for this species, clearance of the habitat utilised by D. broadbenti is relatively recent. The suggestion that communication systems of animal populations can be disrupted following isolation through habitat clearance is one that warrants further investigation, especially in taxa with older histories of fragmentation. This study also highlighted the potential for using behavioural information to assist with taxonomic investigations.
Birth in the northern quoll, Dasyurus hallucatus (Marsupialia : Dasyuridae)
Authors: Nelson John E. , Gemmell Robert T.
Published: August 2003

Birth has been observed in a number of marsupial species and, in the studies to date, the newborn have crawled up to or across to the pouch. The method of birth in the quoll, a dasyurid, differs greatly from that observed in other marsupials. Births were recorded at normal speed using hand-held digital video cameras. Birth was heralded by a release of about 1 mL of watery fluid from the urogenital sinus followed by gelatinous material contained in either one or two tubes emanating from the sinus. The newborn, still encased in their placental membranes, were in the gelatinous material within a column. To exit this column, they had to grasp a hair and wriggle about 1 cm across to the pouch. In the pouch the newborn young had to compete for a teat. Although the quolls possessed 8 teats, the number of young in the pouch immediately after birth was 17, 16, 6, 16, 13 and 11 for each of the 6 quolls filmed. While birth has been described previously in another two dasyurids, the observers did not describe birth as reported here for the quoll. Nevertheless the movement of the newborn from the sinus to the pouch is so quick that this could have previously been missed. Filming birth from beneath and from the side allowed for a greater understanding of the birth process. Further studies are required to determine whether this use of a gelatinous material is part of the birth process in all dasyurids.
Validation of near-infrared reflectance spectroscopy to estimate the potential intake of Eucalyptus foliage by folivorous marsupials
Authors: Wallis I. R. , Foley W. J.
Published: August 2003

We validated an existing model of food intake by captive common ringtail possums (Pseudocheirus peregrinus), a folivorous marsupial, by feeding foliage from 18 individual Eucalyptus polyanthemos trees and measuring dry matter intake. Near-infrared reflectance (NIR) spectra of a sample of each foliage were recorded and compared against a previously derived model relating food intake in common ringtails and NIR spectra. We found excellent agreement between the predicted and measured food intake, with the standard error of prediction being 3.6 g kg(body mass)–0.75 day–1. NIR spectroscopy is a suitable tool for modelling complex attributes such as potential feeding rates of mammals. This makes it theoretically possible to remotely sense critical nutritional determinants of animal habitat on a landscape scale.
Ontogenetic changes of swimming kinematics in a semi-aquatic reptile (Crocodylus porosus)
Authors: Seebacher Frank , Elsworth Peter G. , Franklin Craig E.
Published: August 2003

Semi-aquatic animals represent a transitional locomotor condition characterised by the possession of morphological features that allow locomotion both in water and on land. Most ecologically important behaviours of crocodilians occur in the water, raising the question of whether their 'terrestrial construction' constrains aquatic locomotion. Moreover, the demands for aquatic locomotion change with life-history stage. It was the aim of this research to determine the kinematic characteristics and efficiency of aquatic locomotion in different-sized crocodiles (Crocodylus porosus). Aquatic propulsion was achieved primarily by tail undulations, and the use of limbs during swimming was observed only in very small animals or at low swimming velocities in larger animals. Over the range of swimming speeds we examined, tail beat amplitude did not change with increasing velocity, but amplitude increased significantly with body length. However, amplitude expressed relative to body length decreased with increasing body length. Tail beat frequency increased with swimming velocity but there were no differences in frequency between different-sized animals. Mechanical power generated during swimming and thrust increased non-linearly with swimming velocity, but disproportionally so that kinematic efficiency decreased with increasing swimming velocity. The importance of unsteady forces, expressed as the reduced frequency, increased with increasing swimming velocity. Amplitude is the main determinant of body-size-related increases in swimming velocity but, compared with aquatic mammals and fish, crocodiles are slow swimmers probably because of constraints imposed by muscle performance and unsteady forces opposing forward movement. Nonetheless, the kinematic efficiency of aquatic locomotion in crocodiles is comparable to that of fully aquatic mammals, and it is considerably greater than that of semi-aquatic mammals.
Thermal energetics of Nyctophilus geoffroyi (Chiroptera : Vespertilionidae) at the southern limits of its distribution
Authors: Dixon K. J. , Rose R. W.
Published: August 2003

The energetics of the lesser long-eared bat, Nyctophilus geoffroyi, at the southern limits of its distribution was examined to determine whether this species shows any latitudinal variation in this aspect of its physiological ecology. Estimates of metabolic rate were obtained from the oxygen consumption of adult bats in a non-reproductive condition. Values for the thermoneutral zone were similar but thermal conductance was lower than for bats from mainland of Australia. Euthermic body temperature was higher (37.4 ± 0.2°C) and the ambient temperature at which N. geoffroyi entered torpor has a downward shift of 10°C at the southern limits of its distribution. The basal metabolic rate (1.12 ± 0.14 mL O2 g–1 h–1) also was lower than in lower latitudes. Thermal conductance of the bats in Tasmania was lower than that found in New South Wales or Western Australia (0.29 v. 0.38–0.39 mL O2 g–1 h–1 °C–1). All of these differences are apparently adaptations to a cooler environment.
Foraging behaviour in tammar (Macropus eugenii) and parma (Macropus parma) wallabies
Authors: Lentle R. G. , Haslett S. , Hume I. D. , Stafford K. J. , Kennedy M. , Springett B. P.
Published: August 2003

Captive parma and tammar wallabies, when offered ryegrass sward in plots, visited ungrazed plots more frequently and spent longer grazing on them than on plots that were previously grazed but not visibly depleted. There was no significant difference between the two species with respect to the pattern of time spent grazing between plots, but parma wallabies tended to visit ungrazed plots more frequently than tammar wallabies. When offered carrot pieces of different dimensions both species preferred carrot pieces of greater mass, regardless of shape. Both species favoured eating in the upright (bipedal) position despite the fact that the use of this position prolonged search time between bites. Although the two species are able to forage optimally when grazing, the greater efficiency of the bipedal posture in predator avoidance may result in the selection of larger food items whenever possible.
Frequency, composition and variation in external food stores constructed by orb-web spiders: Nephila edulis and Nephila plumipes (Araneae : Araneoidea)
Authors: Griffiths B. V. , Holwell G. I. , Herberstein M. E. , Elgar M. A.
Published: August 2003

Few examples of food hoarding have been documented in spiders, yet two Australian species of orb-web spiders, Nephila edulis and N. plumipes, typically incorporate previously captured prey into the web. The effect of prey density and prey-encounter rate on the storage behaviour of adult female N. edulis was tested in the laboratory. Prey density had a significant effect on the propensity to construct external caches: when more food was available, food caches were larger than when the supply of prey was limited. Caching behaviour also differed with the rate of prey encounter, even though the total amount of food supplied was the same. When prey were encountered at constant rates, spiders allocated more food to external storage compared with random encounter rates. Finally, we tested the quality of different prey types for external or internal storage. N. edulis were fed with blow-flies or crickets, and these prey were stored in the web, discarded or totally consumed. Crickets were typically consumed or stored, while flies were more frequently discarded. Field observations of the storage behaviour in N. edulis and N. plumipes found surprising differences in the composition of the cache. While N. plumipes incorporated only animal material, N. edulis also utilised plant material, suggesting that the storage band in N. edulis has other, non-food-storing functions. Field experiments indicated that the presence or absence of external stores in the web of N. plumipes had no influence on mortality, weight gain, or the presence of Argyrodes kleptoparasites.
The taxonomy and phylogeny of the 'Cherax destructor' complex (Decapoda : Parastacidae) examined using mitochondrial 16S sequences
Authors: Austin C. M. , Nguyen T. T. T. , Meewan M. M. , Jerry D. R.
Published: August 2003

This study uses nucleotide sequences from the 16S rRNA mitochondrial gene to investigate the taxonomy and phylogeny of freshwater crayfish belonging to the 'Cherax destructor' complex. The sequencing of an approximately 440-bp fragment of this gene region from freshwater crayfish sampled from 14 locations identified significant haplotype diversity. Phylogenetic analysis found three distinct clades that correspond to the species C. rotundus, C. setosus and C. destructor. C. rotundus is largely confined to Victoria, and C. setosus is restricted to coastal areas north of Newcastle in New South Wales. C. destructor is widely distributed in eastern Australia and shows significant phylogeographic structure, with three well supported clades. None of these clades, however, correspond to species previously recognised as C. esculus, C. davisi or C. albidus. The failure to genetically distinguish these morphologically defined species is consistent with reproductive information and morphological plasticity relating to habitat similar to that documented for other Cherax species.
The effect of inactivating tannins on the intake of Eucalyptus foliage by a specialist Eucalyptus folivore (Pseudocheirus peregrinus) and a generalist herbivore (Trichosurus vulpecula)
Authors: Marsh Karen J. , Wallis Ian R. , Foley William J.
Published: August 2003

The paucity of evidence on eucalypt browsing by common brushtail and common ringtail possums suggests that ringtails preferentially eat foliage from trees within the subgenus Monocalyptus. In contrast, brushtails eat less eucalypt foliage than do ringtails and prefer trees from the subgenus Symphyomyrtus. Trees from these subgenera differ in their defensive chemicals. Both contain tannins but it appears that only the symphyomyrts synthesise formylated phloroglucinol compounds (FPCs). We fed possums foliage from several individual Eucalyptus rossii and E. consideniana, both monocalypts, to avoid the confounding factor of FPCs, and examined the effects of blocking tannins by dipping foliage in polyethylene glycol (PEG). Ringtails and brushtails differed in their abilities to eat foliage from these eucalypts. The ringtails ate much more than did the brushtails and showed a small (about 10%) but significant increase in feeding in response to PEG. The brushtails were reluctant to eat foliage from either eucalypt species but doubled their intake when leaves were coated with PEG. Even so, they still did not eat enough to meet maintenance requirements for energy and nitrogen. Neither ringtails nor brushtails preferred foliage from any individual E. rossii tree, suggesting that all trees were equally defended. However, brushtails preferred foliage from some E. consideniana to others. Monocalypt tannins are clearly important barriers to feeding in brushtail possums, but further research with higher doses of PEG will confirm whether they are the only deterrent chemicals in monocalypt foliage.
Influence of temperature on evaporative water loss and cutaneous resistance to water vapour diffusion in the orange-thighed frog (Litoria xanthomera)
Authors: Buttemer William A. , Thomas Craig
Published: August 2003

We evaluated the effect of ambient temperatures between 25 and 43°C on the rate of evaporative water loss (EWL) in eight adult Litoria xanthomera (average body mass = 7.3 ± 0.6 g). Frogs were placed in a cylindrical chamber that permitted them to fully conceal their ventral surfaces using a water-conserving posture. Their EWL was 7.1 ± 0.7 mg g–1 h–1 at 25°C and reached 28.0 ± 2.5 mg g–1 h–1 at 43°C. Agar replicas of the frogs were used to evaluate boundary-layer resistances associated with the EWL measurements and, thus, to permit evaluation of cutaneous resistance to vapour diffusion (rc) in live frogs. The rc of L. xanthomera was stable over the temperature range of 25–35°C, averaging about 28 s cm–1, and then declined stepwise with ambient temperatures above 37°C. The highest rc recorded for each individual over the range of temperatures studied averaged 32.0 ± 1.2 s cm–1. The thermolabile nature of rc demonstrates a well developed thermoregulatory control of EWL in this species, a trait very similar in pattern and extent to that previously measured in the closely related Litoria chloris.
Alternate functions for duet and solo songs in magpie-larks, Grallina cyanoleuca
Authors: Mulder Raoul A. , Bishop Helen , Cooper Michelle , Dennis Sophie , Koetsveld Melanie , Marshall Julia , Saunders Belinda L. , Langmore Naomi E.
Published: August 2003

Several possible functions have been proposed for antiphonal duetting in birds, including pair-bond maintenance, cooperative territorial defence and acoustic mate guarding. Previous work has suggested that duetting in magpie-larks was consistent with both defence of the territory and guarding the mate against usurpation. We conducted playback experiments designed to distinguish between these two functions. Responses of males and females to simulated intrusion (broadcasts of unfamiliar solo songs) suggested functional differences for solo songs and duets. Both sexes initiated more songs in response to same-sex conspecific song, suggesting that solo songs are used to deter same-sex rivals in the context of territory defence. Contrary to predictions of the mate-guarding and pair-bond maintenance hypotheses, the sex of playback song had no effect on the likelihood of either sex answering their partner's song to form a duet. Thus, duets are most likely to be performed for the purpose of cooperative territorial defence.
Female breeding-site preferences and larval feeding strategies of carrion-breeding Calliphoridae and Sarcophagidae (Diptera): a quantitative analysis
Authors: Archer M. S. , Elgar M. A.
Published: August 2003

Protection from the elements, predators and parasitoids, and access to food is critical for insect larvae. Therefore, adult female insects are strongly selected to deposit offspring in safe, nutritious locations. Additionally, larvae may move to new feeding sites as food becomes depleted at the natal site. Maggots of carrion-breeding flies exploit patchy resources and are at risk from predators, desiccation and competition. Natural orifices, body folds, fur and feathers are protective locations that provide ready access to food, but their suitability as ovi- or larviposition sites may vary according to the degree of decomposition and presence of other larvae. Accordingly, female preference for ovi- or larviposition sites, and maggot distribution at feeding sites may depend upon carcass condition. We conducted a field experiment to investigate the preferences of female carrion flies for ovi- or larviposition sites on piglet carcasses. We also recorded movement of maggots on carcasses over the first 48 hours after carcass exposure. Females initially preferred to deposit offspring in the mouth; however, this preference changed to the body folds by 24 hours after the carcass exposure. Maggot distribution also changed over time, and the pattern suggested that individuals moved from food-depleted sites to more favourable locations.
Development of juvenile Australian giant crabs, (Pseudocarcinus gigas Lamarck, 1818) (Decapoda : Oziidae), reared in the laboratory
Authors: Gardner Caleb , Welsford Dirk
Published: August 2003

Juvenile giant crabs (Pseudocarcinus gigas), sourced from laboratory-reared larvae, were ongrown through to the 7th crab stage over 2 years to allow identification of specimens collected for ecological studies. Morphological development through these stages is described. Each stage up to Crab 5 can be distinguished by changes in morphology of the appendages, primarily the 3rd maxilliped and antennule. Growth of juveniles under laboratory conditions was also recorded, with mean size of juveniles reaching 24.5 mm carapace length, 737 days after hatch.
A new species of Phyllurus (Lacertilia : Gekkonidae) and a revised phylogeny and key for the Australian leaf-tailed geckos
Authors: Hoskin C. J. , Couper P. J. , Schneider C. J.
Published: August 2003

Phyllurus gulbaru, sp. nov., is a highly distinct species of leaf-tailed gecko restricted to rocky rainforest of Pattersons Gorge, north-west of Townsville. The possession of a cylindrical, non-depressed, tapering original and regenerated tail separates P. gulbaru from all congeners except P. caudiannulatus. From this species P. gulbaru is separated by having a partially divided, as opposed to fully divided, rostral scale. Furthermore, the very small spinose body tubercles of P. gulbaru are in marked contrast to the large spinose body scales of P. caudiannulatus. An analysis of 729 bp of mitochondrial 12S rRNA and cytochrome b genes reveals P. gulbaru to be a deeply divergent lineage with closer affinities to mid-east Queensland congeners than the geographically neighbouring P. amnicola on Mt Elliot. In conservation terms, P. gulbaru is clearly at risk. Field surveys of Pattersons Gorge and the adjacent ranges indicate that this species is restricted to a very small area of highly fragmented habitat, of which only a small proportion receives a degree of protection in State forest. Further, there is ongoing, unchecked destruction of dry rainforest habitat by fire. Under current IUCN criteria, P. gulbaru warrants an Endangered (B1, 2) listing.
Shelter-site use by five species of montane scincid lizards in south-eastern Australia
Authors: Langkilde Tracy , O'Connor Dave , Shine Richard
Published: August 2003

Montane (cold-climate) habitats may impose severe thermal constraints on habitat use by ectotherms, favouring strong interspecific convergence in the attributes of suitable shelter-sites. We studied shelter-site use by five species of viviparous scincid lizards in Kanagra Boyd National Park, a montane (1200 m above sea level) forested region 160 km west of Sydney. We scored 21 attributes of 93 shelter-sites (13–20 per species), and the same attributes at unoccupied 'control' sites. These attributes included macrohabitat (e.g. canopy openness, substrate type, distance to waterbodies and logs) as well as shelter-site characteristics (e.g. type of cover-item, size of crevice). Hemispherical-lens photographs and gap-analysis software yielded estimates of solar radiation at each site, and data-loggers recorded temperature profiles in each occupied retreat-site. Principal Components Analysis of the data set identified eight axes of variation. Significant interspecific differences were evident on four of these axes, but with substantial overlap reflecting the broad syntopy of the taxa, plus similarities in characteristics of occupied retreat-sites (e.g. most lizard species utilised sun-exposed shelter-sites with logs nearby). Egernia species (cunninghami, saxatilis, whitii) typically used more open habitats than did Eulamprus (heatwolei, tympanum). Egernia cunninghami used very large crevices, whereas Eulamprus tympanum occupied heavily wooded macrohabitats. At this cold-climate site, interspecific similarities in the characteristics of utilised retreat-sites generated substantial overlap among species in the kinds of sites used, potentially intensifying interference competition among these taxa.
Plasticity in age and size at metamorphosis of Crinia georgiana tadpoles: responses to variation in food levels and deteriorating conditions during development
Authors: Doughty Paul , Roberts J. Dale
Published: August 2003

Adaptive phenotypic plasticity in life-history traits is predicted to evolve when populations occur in heterogeneous environments. Anuran larvae of many species cannot escape their aquatic environment until metamorphosis and therefore should show plasticity in response to conditions experienced as tadpoles. In this study, we manipulated the aquatic environments of Crinia georgiana tadpoles in the laboratory to mimic variation among ponds in resources and drying conditions in nature. This species breeds in very shallow water in winter and ponds frequently dry between bouts of rain, especially towards spring. Tadpoles kept in constant conditions at different levels of food metamorphosed at different body sizes but showed no plasticity in metamorphic timing. Tadpoles fed only lettuce metamorphosed at sizes similar to those of field-collected tadpoles, whereas tadpoles fed a more protein-rich food metamorphosed at unusually large sizes, indicating that the seeps where C. georgiana tadpoles occur are poor in nutrients. When we decreased food and water levels, tadpoles at later developmental stages were able to accelerate development and metamorphose earlier than tadpoles kept under constant conditions. Furthermore, tadpoles in very shallow water with no access to food metamorphosed earlier and at smaller body sizes than tadpoles with a more moderate decrease in depth that were able to continue feeding. Rapid development and the ability to accelerate metamorphosis in C. georgiana tadpoles are consistent with adaptation in a heterogeneous environment where larvae are under strong time constraints.
Seasonal energetics of the long-nosed bandicoot (Perameles nasuta) in coastal New South Wales
Authors: Thums Michele , Hume Ian D. , Gibson Lesley A.
Published: August 2003

Water-turnover rates and field metabolic rates were measured in long-nosed bandicoots (Perameles nasuta) near Newcastle, New South Wales, over two summers and two winters. Water-turnover rates were higher in lactating than in non-lactating females, and higher in winter than in summer, possibly because of a relatively high proportion (50%) of females at or near peak lactation in one winter. There were no significant differences in field metabolic rates between seasons or among groups (males, lactating females and non-lactating females). The overall field metabolic rate of the long-nosed bandicoot was within 9% of the predicted value for a marsupial of its size, and similar to rates reported for most other bandicoots, both temperate and arid-zone species. Its overall water-turnover rate was within 18% of the predicted marsupial value, but higher than values reported for arid-zone bandicoot species. Comparison with other data indicates that seasonal changes in water-turnover rate are related to changes in reproductive status (especially lactation), as in this study, but for field metabolic rate, seasonal changes are related to changes in water status and thus productivity of the environment.
Taxonomy and historical distribution of the wallaby genus Lagostrophus
Authors: Helgen Kristofer M. , Flannery Timothy F.
Published: August 2003

The banded hare-wallaby (Lagostrophus fasciatus) is an endangered macropodid currently restricted to Bernier and Dorre Islands in Shark Bay, Western Australia. Historically, L. fasciatus was also recorded on the Australian mainland from far western Australia, where it became locally extinct early in the twentieth century. Here we discuss an overlooked museum specimen of L. fasciatus collected in the mid-nineteenth century near Adelaide, South Australia. This specimen considerably extends the known historical distribution of L. fasciatus, validates anecdotal reports of the species from South Australia made by early Australian naturalists, and forms the basis for our description of a new subspecies.
Tuning and switching a DNA polymerase motor with mechanical tension
Authors: Goel Anita , Astumian R. Dean , Herschbach Dudley
Published: August 2003

Recent single-molecule experiments reveal that mechanical tension on DNA
can control both the speed and direction of the DNA polymerase motor. We
present a theoretical description of this tension-induced “tuning”
and “switching.” The internal conformational states of the enzyme
motor are represented as nodes, and the allowed transitions between states as
links, of a biochemical network. The motor moves along the DNA by cycling
through a given sequence of internal states. Tension and other external
control parameters, particularly the ambient concentrations of enzyme,
nucleotides, and pyrophosphates, couple into the internal conformational
dynamics of the motor, thereby regulating the steady-state flux through the
network. The network links are specified by bulk-phase kinetic data (in the
absence of tension), and rudimentary models are used to describe the
dependence on tension of key links. We find that this network analysis
simulates well the chief results from single-molecule experiments including
the tension-induced attenuation of polymerase activity, the onset of
exonucleolysis at high tension, and insensitivity to large changes in
concentration of the enzyme. A major dependence of the switching tension on
the nucleotide concentration is also predicted.
Inositol hexakisphosphate mobilizes an endomembrane store of calcium in guard cells
Authors: Lemtiri-Chlieh Fouad , MacRobbie Enid A. C. , Webb Alex A. R. , Manison Nick F. , Brownlee Colin , Skepper Jeremy N. , Chen Jian , Prestwich Glenn D. , Brearley Charles A.
Published: August 2003

myo
-Inositol hexakisphosphate (InsP
6
) is the most
abundant inositol phosphate in cells, yet it remains the most enigmatic of
this class of signaling molecule. InsP
6
plays a role in the
processes by which the drought stress hormone abscisic acid (ABA) induces
stomatal closure, conserving water and ensuring plant survival. Previous work
has shown that InsP
6
levels in guard cells are elevated in response
to ABA, and InsP
6
inactivates the plasma membrane inward
K
+
conductance (
I
K,in
) in a cytosolic
calcium-dependent manner. The use of laser-scanning confocal microscopy in
dye-loaded patch-clamped guard cell protoplasts shows that release of
InsP
6
from a caged precursor mobilizes calcium. Measurement of
calcium (barium) currents
I
Ca
in patch-clamped protoplasts
in whole cell mode shows that InsP
6
has no effect on the
calcium-permeable channels in the plasma membrane activated by ABA. The
InsP
6
-mediated inhibition of
I
K,in
can also be
observed in the absence of external calcium. Thus the InsP
6
-induced
increase in cytoplasmic calcium does not result from calcium influx but must
arise from InsP
6
-triggered release of calcium from endomembrane
stores. Measurements of vacuolar currents in patch-clamped isolated vacuoles
in whole-vacuole mode showed that InsP
6
activates both the fast and
slow conductances of the guard cell vacuole. These data define
InsP
6
as an endomembrane-acting calcium-release signal in guard
cells; the vacuole may contribute to InsP
6
-triggered
Ca
2
+
release, but other endomembranes may also be
involved.
Malaria in Britain: Past, present, and future
Authors: Kuhn Katrin Gaardbo , Campbell-Lendrum Diarmid H. , Armstrong Ben , Davies Clive R.
Published: August 2003

There has been much recent speculation that global warming may allow the
reestablishment of malaria transmission in previously endemic areas such as
Europe and the United States. In this report we analyze temporal trends in
malaria in Britain between 1840 and 1910, to assess the potential for
reemergence of the disease. Our results demonstrate that at least 20% of the
drop-off in malaria was due to increasing cattle population and decreasing
acreages of marsh wetlands. Although both rainfall and average temperature
were associated with year-to-year variability in death rates, there was no
evidence for any association with the long-term malaria trend. Model
simulations for future scenarios in Britain suggest that the change in
temperature projected to occur by 2050 is likely to cause a proportional
increase in local malaria transmission of 8–14%. The current risk is
negligible, as >52,000 imported cases since 1953 have not led to any
secondary cases. The projected increase in proportional risk is clearly
insufficient to lead to the reestablishment of endemicity.
Coarse-grained microscopic model of glass formers
Authors: Garrahan Juan P. , Chandler David
Published: August 2003

We introduce a coarse-grained model for atomic glass formers. Its elements are physically motivated local microscopic dynamical rules parameterized by observables. Results of the model are established and used to interpret the measured behaviors of supercooled fluids approaching glass transitions. The model predicts the presence of a crossover from hierarchical super-Arrhenius dynamics at short length scales to diffusive Arrhenius dynamics at large length scales. This prediction distinguishes our model from other theories of glass formers and can be tested by experiment.
Developmental amnesia: Effect of age at injury
Authors: Vargha-Khadem F. , Salmond C. H. , Watkins K. E. , Friston K. J. , Gadian D. G. , Mishkin M.
Published: August 2003

Hypoxic–ischemic events sustained within the first year of life can result in developmental amnesia, a disorder characterized by markedly impaired episodic memory and relatively preserved semantic memory, in association with medial temporal pathology that appears to be restricted to the hippocampus. Here we compared children who had hypoxic–ischemic events before 1 year of age (early group,n= 6) with others who showed memory problems after suffering hypoxic–ischemic events between the ages of 6 and 14 years (late group,n= 5). Morphometric analyses of the whole brain revealed that, compared with age-matched controls, both groups had bilateral abnormalities in the hippocampus, putamen, and posterior thalamus, as well as in the right retrosplenial cortex. The two groups also showed similar reductions (≈40%) in hippocampal volumes. Neuropsychologically, the only significant differences between the two were on a few tests of immediate memory, where the early group surpassed the late group. The latter measures provided the only clear indication that very early injury can lead to greater functional sparing than injury acquired later in childhood, due perhaps to the greater plasticity of the infant brain. On measures of long-term memory, by contrast, the two groups had highly similar profiles, both showing roughly equivalent preservation of semantic memory combined with marked impairment in episodic memory. It thus appears that, if this selective memory disorder is a special syndrome related to the early occurrence of hypoxia-induced damage, then the effective age at injury for this syndrome extends from birth to puberty.
Coexistence of periodic modulation of quasiparticle states and superconductivity in Bi
2
Sr
2
CaCu
2
O
8
+δ
Authors: Howald C. , Eisaki H. , Kaneko N. , Kapitulnik A.
Published: August 2003

In this article we show, using scanning tunneling spectroscopy, the
existence of static striped density of electronic states in nearly optimally
doped
Bi
2
Sr
2
CaCu
2
O
8
+δ
in zero field. This modulation is aligned with the Cu—O bonds, with a
periodicity of four lattice constants, and exhibits features characteristic of
a two-dimensional system of line objects. We further show that the density of
states modulation manifests itself as a shift of states from above to below
the superconducting gap. The fact that a single energy scale (i.e., the gap)
appears for both superconductivity and stripes suggests that these two effects
have the same origin.
Long-range enhancer–promoter interactions in the
Scr-Antp
interval of the
Drosophila
Antennapedia complex
Authors: Calhoun Vincent C. , Levine Michael
Published: August 2003

Long-range enhancer–promoter interactions are commonly seen in
complex genetic loci such as
Hox
genes and
globin
genes. In
the case of the
Drosophila
Antennapedia complex, the T1 enhancer
bypasses the neighboring
ftz
gene and interacts with the distant
Scr
promoter to activate expression in posterior head segments.
Previous studies identified a 450-bp promoter-proximal sequence, the tethering
element, which is essential for T1–
Scr
interactions. To obtain
a more comprehensive view of how individual enhancers selectively interact
with appropriate target genes, we used bioinformatic methods to identify new
cis
-regulatory DNAs in the ≈50-kb
Scr
-
Antp
interval. Three previously uncharacterized regulatory elements were
identified: a distal T1 tethering sequence mapping >40 kb from the proximal
tethering sequence, a repressor element that excludes activation of
Scr
by inappropriate enhancers, and a new
ftz
enhancer that
directs expression within the limits of stripes 1 and 5. Many of the
regulatory DNAs in the
Scr-Antp
interval are transcribed, including
the proximal and distal tethering elements. We suggest that homotypic
interactions between the tethering elements stabilize long-range
T1–
Scr
interactions during development.