bluuebunny/crossref_metadata_2025 huggingface dataset:
Breeding biology of crimson rosellas (Platycercus elegans) on Black Mountain, Australian Capital Territory
Authors: Krebs Elizabeth A.
Published: August 2004

The breeding behaviour of crimson rosellas
(Platycercus elegans) in Canberra, Australia, was
studied between 1993 and 1996. Female rosellas initiated breeding in late
September or early October, laying a mean of 5.3 ± 0.1 (s.e.) eggs at
1–4-day intervals. Of all eggs laid, 50% fledged successfully.
Rosellas had the highest breeding success in the wettest year (1995), when
they bred earlier, laid larger clutches and fledged more young. Unexpectedly,
breeding success was not lowest in the driest year (1994), although fewer
birds attempted breeding and hatching success was low. In this study, poor
environmental conditions for breeding were counterbalanced by decreased levels
of conspecific interference through egg destruction. Overall, 55.8% of
all clutches initiated were destroyed during laying, and more than half of
this was attributed to rosellas. The reasons for egg destruction by rosellas
were not clear. Boxes where clutches were destroyed were not quickly
reoccupied and egg destruction was not highest when competition for nesting
hollows was most intense. Clutch size and egg-laying intervals decreased over
the breeding season, but the length of incubation did not. Large clutches did
not produce more fledglings, because more eggs failed to hatch, especially
early in the season. Eggs in a clutch hatched over a period of 0.5–7
days. Total hatching asynchrony increased over the breeding season and was not
strongly correlated with clutch or brood size. This suggests that female
rosellas initiated incubation at different times during laying. Clutches with
longer hatching intervals took longer to incubate. If females in poor
condition are inefficient incubators, female condition may affect the degree
of hatching asynchrony.
The diprotodontian ‘hypocone’ revisited
Authors: Tedford R. H. , Woodburne M. O.
Published: August 2004

A controversy has arisen over the terms to be applied to certain cusps of the
marsupial upper molar as the result of divergent views over the precedence of
functional or structural considerations. It is generally accepted that the
posterolingual cusp in the molars of mammals has arisen in a number of ways.
Regardless of origin they are often termed a ‘hypocone’ because of
their analogous occlusal relationship with the trigonid of the lower molars.
In diprotodontian marsupials, however, the posterolingual cusp is homologous
with the metaconule, as demonstrated by its linkage through the
postprotocrista with the protocone and metacone. This structural relationship
is important to the determination of homology, which is fundamental to
phylogeny reconstruction.
The influence of time of day and environmental conditions on the foraging behaviours of willie wagtails, Rhipidura leucophrys
Authors: Webb-Pullman Bianca Z. , Elgar Mark A.
Published: August 2004

The insectivorous willie wagtail, Rhipidura leucophrys,
exhibits a range of discrete, easily identified foraging behaviours that
include wagging the tail and flashing the wing. We investigated whether
wagtails adjust these, and other foraging behaviours, according to the time of
day and environmental conditions. The rates of tail-wagging and wing-flashing
were influenced by the time of day and light intensity. Tail-wagging was more
frequent at the start and end of the day, while wing flashing was more
frequent during the middle of the day. The rate of aerial prey captures was
also highest during the middle of the day and lower in the early morning and
late afternoon. These daily patterns of foraging behaviours correspond with
the patterns of insect activity, which was greater in the middle of the day
than in the early morning or late afternoon. The field data, together with
experiments using a model wagtail tail, support the view that tail-wagging and
wing-flashing are used to flush insect prey.
Molecular systematics of Australian rhinolophid bats (Chiroptera : Rhinolophidae)
Authors: Cooper S. J. B. , Reardon T. B. , Skilins J.
Published: August 2004

Genetic variation in two morphologically distinct species of Australian
Rhinolophus, R. megaphyllus, and
R. philippinensis, and a third putative species
(‘the intermediate’) were examined using allozyme electrophoresis
and sequencing of the mitochondrial DNA (mtDNA) control region with the aim of
resolving their taxonomic status. The surprising result was that no fixed
allozymic differences and low allozyme divergence existed among these three
taxa over 45 loci examined. In contrast, levels of intra-generic divergence
among eight species of Rhinolophus showed up to
50% fixed allozyme differences between species, indicating that low
allozyme divergence was not a common feature of the genus and that the three
Australian taxa are likely to be monophyletic and recently diverged.
Phylogenetic analyses of mtDNA sequence data revealed that populations of
R. megaphyllus and
R. philippinensis from Sabah, New Guinea, and Australia
were represented by distinct mtDNA clades and that the two species are
polyphyletic. These data suggest a reclassification of the different
geographic populations of R. megaphyllus and
R. philippinensis as separate species on the basis of a
phylogenetic species concept. Within Australia, three distinct mtDNA clades
were found, one of which showed ‘the intermediate’ in paraphyly
with R. philippinensis from Queensland, but does not
resolve the taxonomic status of ‘the intermediate’. Two mtDNA
clades were also found representing R. megaphyllus from
Queensland and R. megaphyllus from Victoria and New
South Wales respectively. The finding of genetic subdivision along the east
coast of Australia in an apparently continuously distributed bat species
raises questions of the origin and historical biogeography of these bats in
Australia.
Geographic variation in size and shape in the southern brown bandicoot, Isoodon obesulus (Peramelidae : Marsupialia), in Western Australia
Authors: Cooper Marie L.
Published: August 2004

Geographic variation in body size and shape was examined among populations of
the southern brown bandicoot, Isoodon obesulus, in the
south-west of Western Australia, with a view to determining the possible
presence of adaptive divergence. Analysis of variance and canonical variate
analysis were employed to examine the variation in body weight, head length,
pes length and ear length among six locations. Significant sexual dimorphism
was detected for these morphological variables, with males being larger than
females. Significant geographic variation in overall body size and shape was
found for both males and females.
Correlations between body size and shape and each of five environmental
variables (mean annual rainfall, mean maximum summer temperature, mean minimum
winter temperature, relative humidity and latitude) were tested. Neither body
size nor shape was correlated with any of the five variables, but both were
related to habitat structure, with larger bandicoots being found in open
forest habitats, while smaller bandicoots were found among swamp reeds. If the
above variation has a genetic basis, these differences between locations may
represent adaptive divergence and thus be of importance when formulating a
conservation strategy for this species.
Comparative analysis of wing morphology, flight behaviour, and habitat use in flying foxes (Genus: Pteropus)
Authors: Richmond Jonathan Q. , Banack Sandra Anne , Grant Gilbert S.
Published: August 2004

We compared morphological indices, flight behaviour, and foraging and habitat
use in two sympatric species of flying foxes, the insular flying fox
(Pteropus tonganus) and the Samoan flying fox
(Pteropus samoensis), to test the prediction that
morphologically similar species overlap in ecology. Both species are fruit and
flower specialists, forage for patchily distributed food, fly with a foetus or
young, and transport large-seeded fruits. Patterns of major foraging activity
and foraging mode vary between species: P. samoensis is
predominantly diurnal and uses soaring flight for commuting and assessing food
resources, while P. tonganus is predominantly nocturnal
and commutes extensive distances between roosts and foraging areas. Our
results indicate that P. tonganus and
P. samoensis are morphologically and ecologically
similar, despite differences in flight behaviour. Differences in flight
behaviour are attributable to the time of day when most extensive flying
occurs for each species.
The ecology of sympatric scincid lizards (Ctenotus) in arid South Australia
Authors: Read J. L.
Published: August 2004

Ctenotus skinks are the most diverse and abundant
diurnal reptile genus at Olympic Dam, in the South Australian arid zone. The
home range, demography, reproduction and diet of five syntopic
Ctenotus species was studied over a 6-year period in
chenopod shrubland. Longevity frequently exceeded three years in
C. regius, four years in
C. schomburgkii and five years in
C. leonhardii, with a 7-year-old specimen of
C. leonhardii being recorded. Females of most species
tended to be larger and lived longer than males. Two eggs were typically laid
by each species in early summer. Annual reproductive effort, particularly in
C. leonhardii, varied considerably depending upon the
prevailing environmental conditions. All local species apparently occupied
home ranges, with maximum recapture radii in different species of 40–60
m. Ctenotus appear to be unspecialised insectivores,
although plant material and lizards are sometimes eaten by the larger species.
Biology of a weakly social bee, Exoneura (Exoneurella) setosa (Hymenoptera : Apidae) and implications for social evolution in Australian allodapine bees
Authors: Neville Tania , Schwarz Michael P. , Tierney Simon M.
Published: August 2004

Australian allodapine bees provide excellent material for comparative
approaches to understanding social evolution. The subgenus
Exoneurella occupies a cladistically basal position in
the Australian Exoneura group and comprises only four
species. We describe sociality in one Exoneurella
species, E. setosa, and combine this with other data to
infer some patterns of social evolution in allodapines.
E. setosa rears a first brood solitarily, although
staggered brood production and the production of a second brood in some nests
leads to a situation where older, recently emerged brood have the ability to
help rear their younger siblings and this overlaps with opportunities to lay
eggs. This is similar to the situation for two other phylogenetically distal
species of Exoneurella, as well as for members of the
genus Braunsapis, which is used as an outgroup for
Exoneura. When combined with other studies, our results
suggest that the opportunity for sib-rearing is a plesiomorphic trait for
Australian allodapines and this has been largely lost in a distal subgenus,
Exoneura sensu stricto. Instead, multifemale
brood-rearing colonies in this latter group mostly comprise individuals of the
same generation, and species exhibit large group size, univoltinism and kin
cofounding. This suggests that evolution can favour semisociality and
quasisociality, even when eusociality has already arisen.
Nest temperature and respiratory gases during natural incubation in the broad-shelled river turtle, Chelodina expansa (Testudinata : Chelidae)
Authors: Booth David T.
Published: August 2004

Temperature was monitored in three natural nests, and oxygen and carbon
dioxide partial pressure monitored in one natural nest of the broad-shelled
river turtle, Chelodina expansa, throughout incubation.
Nest temperature decreased after nest construction in autumn, remained low
during winter and gradually increased in spring to a maximum in summer. In a
nest where temperature was recorded every hour, temperature typically
fluctuated through a 2°C cycle on a daily basis throughout the entire
incubation period, and the nest always heated faster than it cooled. Oxygen
and carbon dioxide partial pressures in this nest were similar to soil oxygen
and carbon dioxide partial pressures for the first 5 months of incubation, but
nest respiratory gas tensions deviated from the surrounding soil over the last
three months of incubation. Nest respiratory gas tensions were not greatly
different from those in the atmosphere above the ground except after periods
of rain. After heavy rain during the last 3 months of incubation the nest
became moderately hypoxic (PO2 ~ 100 Torr) and
hypercapnic (PCO 2 ~ 50 Torr) for several successive
days. These short periods of hypoxia and hypercapnia were not lethal.
Reaching, grasping and manipulation of food objects by two tree kangaroo species, Dendrolagus lumholtzi and Dendrolagus matschiei
Authors: Iwaniuk A. N. , Nelson J. E. , Ivanco T. L. , Pellis S. M. , Whishaw I. Q.
Published: August 2004

This study examined manual dexterity and skilled limb movements in two species
of tree kangaroos (Dendrolagus lumholtzi and
D. matschiei) in order to evaluate the claim that claws
are detrimental to object handling and the view that all marsupials conform to
a ‘typical’ set of movements. The tree kangaroos demonstrated two
main differences from previously studied species: (1) a high degree of freedom
of movement of the upper forelimb; and (2) in one species
(D. matschiei), some independent digital movement. The
two species differed from one another in the mode of picking up food items and
the type of grasp used. These differences appear to be linked to differences
in feeding and foraging strategy between the two species, as well as to
anatomical differences. This study indicates that marsupials do not have a
common set of skilled forelimb movements and that claws do not impede
prehension.
Effects of egg load on the host-selection behaviour of Helicoverpa armigera (HÜbner) (Lepidoptera : Noctuidae)
Authors: Jallow Mustapha F. A. , Zalucki Myron P.
Published: August 2004

We examined the effect of age-specific fecundity, mated status, and egg load
on host-plant selection by Helicoverpa armigera under
laboratory conditions. The physiological state of a female moth (number of
mature eggs produced) greatly influences her host-plant specificity and
propensity to oviposit (oviposition motivation). Female moths were less
discriminating against cowpea (a low-ranked host) relative to maize (a
high-ranked host) as egg load increased. Similarly, increased egg load led to
a greater propensity to oviposit on both cowpea and maize. Distribution of
oviposition with age of mated females peaked shortly after mating and declined
steadily thereafter until death. Most mated females (88%) carried only
a single spermat-ophore, a few females (12%) contained two. The
significance of these findings in relation to host-plant selection by
H. armigera, and its management, are discussed.
The distribution of ants on the Wessel and English Company Islands, in the seasonal tropics of Australia’s Northern Territory
Authors: Woinarski J. C. Z. , Reichel Hanna , Andersen A. N.
Published: August 2004

A total of 74 ant species (from 23 genera) was recorded from 195 quadrats (50
× 50 m) from 39 continental islands off Arnhem Land, Northern Territory.
In general, the ant fauna comprised generalist species widespread on the north
Australian mainland. The functional group composition was also comparable to
that of similar environments on the north Australian mainland. The ant fauna
was not tightly structured. There were few habitat specialists, no species
showed a clear preference for smaller islands, and only a few species showed
unequivocal preferences for larger islands. There were no clear cases of
congeneric, or otherwise ecologically similar, species replacing each other on
different islands. In contrast to the north Australian mainland, there were no
significant differences between habitats in ant species richness. However, the
functional group composition varied significantly between the eight main
habitats sampled across the islands, in a manner consistent with that reported
for the mainland.
The number of ant species recorded per island was most closely related to
island size (80% of the deviance explained), but there was only slight
or no relationship between island size and the number of species at the
quadrat scale. Functional group composition varied between islands, with small
islands supporting a relatively high proportion of Generalised Myrmicinae
species. Low-lying (and presumably intermittently inundated) islands supported
a higher proportion of Dominant Dolichoderinae and few Specialist Predators
and Tropical Climate Specialist species. Very small islands supported a
relatively high proportion of Dominant Dolichoderinae species. These
differences are largely attributable to inter-island differences in habitat
availability and disturbance regimes, and to differences between functional
groups in dispersability, competitive ability and ecological flexibility.
Species richness was little influenced by the extent of island isolation.
Patterning in the ant fauna of these islands parallels that reported for
islands elsewhere.
Evaporative water loss and the role of cocoon formation in Australian frogs
Authors: Withers Philip C.
Published: August 2004

Measurements of evaporative water loss (EWL; mg min-1)
and resistance (R; sec cm-1) for various Australian
frogs indicate three general allometric patterns: non-cocooned and
non-‘waterproof’ frogs with EWL ∝
Mass0.30 and R independent of body mass at about
1–3 sec cm-1, cocooned frogs with EWL reduced
about 50–200-fold and R about 50–200 sec
cm-1, and ‘waterproof’ frogs with EWL
reduced about 5–100- fold and R about 5–100 sec
cm-1. Cocooned frogs have an exponential reduction in
EWL and fairly linear increase in R over time, corresponding to the temporal
addition of layers to the cocoon. The biophysical properties of cocoon are
generally similar for various species, although there is some variation in
both resistance per thickness (5–20 × 104 s
cm-2) and diffusion coefficient (0.4–2.4 ×
10 –5 cm2 s-1). The
hygroscopic property of frog cocoon resembles that of mammalian stratum
corneum, hair and wool, and mucopolysaccharides; there is a slight increase in
water content of cocoon over a wide range of humidities but a very steep
increase in water content and substantial hydration and swelling at
>96% RH. This extreme hygroscopic behaviour of frog cocoon at very
high RH may reflect less polymer cross-linking in frog cocoon and its high
digestibility. The prevention of over-hydration of frog cocoon in vivo may be
attributed to the restriction of high water content to only very high RH
(>96%).
Standard metabolic rate and preferred body temperatures in some Australian pythons
Authors: Bedford Gavin S. , Christian Keith A.
Published: August 2004

Pythons have standard metabolic rates and preferred body temperatures that are
lower than those of most other reptiles. This study investigated metabolic
rates and preferred body temperatures of seven taxa of Australian pythons. We
found that Australian pythons have particularly low metabolic rates when
compared with other boid snakes, and that the metabolic rates of the pythons
did not change either seasonally or on a daily cycle. Preferred body
temperatures do vary seasonally in some species but not in others. Across all
species and seasons, the preferred body temperature range was only 4.9˚C.
The thermal sensitivity (Q10) of oxygen consumption by
pythons conformed to the established range of between 2 and 3. Allometric
equations for the pooled python data at each of the experimental temperatures
gave an equation exponent of 0.72–0.76, which is similar to previously
reported values. By having low preferred body temperatures and low metabolic
rates, pythons appear to be able to conserve energy while still maintaining a
vigilant ‘sit and wait’ predatory existence. These physiological
attributes would allow pythons to maximise the time they can spend
‘sitting and waiting’ in the pursuit of prey.
Incisor and molar wear in the tammar wallaby (Macropus eugenii Desmarest)
Authors: Lentle R. G. , Stafford K. J. , Potter M. A. , Springett B. P. , Haslett S.
Published: August 2004

The morphology of incisor and molar teeth of tammar wallabies
(Macropus eugenii Desmarest) is similar to that of the
archetypal grazing macropod (M. giganteus) but there are
some resemblances in the wear pattern of molars to that of
grazer/browsers. Incisor wear patterns show that cutting during biting is
by scissor-like action of the elevated labial enamel edge of an attrition
facet on each lower incisor being occluded with, and rotated supero-medially
across, the buccal surface of the upper incisor arcade. With increase in age
and body size, the cutting surface moves from anterior to lateral upper
incisors, progressive wear on the inner surface of the lateral upper incisors
permitting an increasing degree of incisor action coincident with medial molar
movement in Phase 2 occlusion, which is similarly achieved by medial rotation
of the jaw.
Significant distal movement of the reference point for molar index, along the
line of the upper jaw, with increase in body size, indicates that this index
does not measure the absolute mesial movement of molars in the plane of
occlusion. The estimated value of absolute mesial movement of the first upper
premolar along the line of the jaw (2.45 mm
year–1) is at the known limits of mesial drift.
Studies of size-related changes in the linear dimensions of various bony
landmarks on jawbone and skull indicate that the high rate of movement may
result from deposition of bone in the rear of the tooth row, i.e.
‘mesial shift’, as well as mesial drift. However, mesial shift may
not account for significant differences in rates of absolute mesial movement
of upper molars with gender.
With increase in body size, the caudal insertions of the masseter and
temporalis and the cranial origin of the line of action of masseter all move
distally along the plane of occlusion. However, a concurrent mesial movement
in the cranial origin of the line of action of the temporalis may act to
counter any distal movement of occlusive force along the jaw-line and to
decrease the relative force of the retraction component that opposes Phase 1
occlusion.
Factors affecting the volume and macrostructure of gastrointestinal compartments in the tammar wallaby (Macropus eugenii Desmarest)
Authors: Lentle R. G. , Stafford K. J. , Potter M. A. , Springett B. P. , Haslett S.
Published: August 2004

We explored the factors that govern the length, wet tissue weight and wet
digesta content of the gut components of 100 tammar wallabies
(Macropus eugenii Desmarest) shot on the same night, by
multivariate (discriminant) analysis and by allometric analyses based on
simple linear regression, and on reduced major axis regression. The slope
coefficient of the regression describing variation of whole gut content with
body weight was not significantly different from isometry. Similarly, stomach
length, content and tissue weight scaled isometrically with body weight, as
did small intestine tissue weight and content and colon content. Colon tissue
weight scaled allometrically with body weight. Length of caecum scaled to body
weight was similar to that of browsing species, shorter than that of gazing
species and varied with body size like that of larger species. Length of small
intestine scaled to body weight was shorter, and length of colon longer, than
that of similar-sized grazing species. There was a sexual dimorphism in gut
morphology, females having a relatively greater amount of tissue in the
stomach and colon, and a relatively longer caecum and colon. There was a
reciprocal variation in the weight of digesta in stomach and hindgut,
suggesting that hindgut content was evacuated as feeding proceeded. It appears
that the hindgut may contribute to overall digestive strategy under conditions
when reduction in feeding rate brings about a relative emtpying of the
stomach.
Revision of the species of the Iridomyrmex conifer group (Hymenoptera : Formicidae), with notes on their biology
Authors: Shattuck Steven O. , McMillan Peter
Published: August 2004

The conifer species-group of the ant genus
Iridomyrmex is defined and revised at the species level.
The species I. conifer Forel,
I. setoconus, sp. nov. and
I. turbineus, sp. nov. are placed in the group, which is
limited to south-western Australia. A key to species is provided and
distributions are summarised. These ants show unusual nesting habits in that
thatched mounds are used during the cooler winter months and subterranean
nests are constructed during the hot summer months. This habit is not known to
occur in any other ant. These ants are opportunistic feeders utilising a
variety of food sources and will readily relocate nest sites in response to
changing resources.
The temporal characteristics of feeding activity in free-ranging tammar wallabies (Macropus eugenii Desmarest)
Authors: Lentle R. G. , Potter M. A. , Stafford K. J. , Springett B. P. , Haslett S
Published: August 2004

The feeding behaviour of four tammar wallabies
(Macropus eugenii Desmarest) inhabiting a bush pasture
ecotone in the Rotorua district of North Island, New Zealand, is described.
Feeding activity, monitored by feeding sounds, was crepuscular. Mastication
effort, as daily eating time corrected for metabolic body weight and
weight-related change in tooth surface area, was similar to that of the red
kangaroo, a species of greater equivalent dry-matter intake. Grazing events
were significantly longer than browsing events, and feeding events longer than
100 sec comprised 66.5% of total feeding activity. Grazing on farm
pasture took place only at night during fine weather in visits that averaged
6.5 h. The number of feeding events longer than 100 sec taking place within
the forest were significantly increased at night and were reduced during
periods of adverse weather. Overall, temporal spacing of feeding events did
not differ significantly by day and night but there was a significant overall
negative correlation between log-converted feeding-event duration and
interfeed intervals for all animals, particularly with feed events of less
than 100 sec duration. This differed from that obtained in laboratory studies
and may be due to grouping of feeding events according to spatial distribution
of food sources.
Determination of oestrus and mating in captive female brushtail possums, Trichosurus vulpecula (Marsupialia : Phalangeridae), from urine samples
Authors: Duckworth J. A. , Scobie S. , Jones D. E. , Selwood L.
Published: August 2004

Reproductive data were collected from captive brushtail possums,
Trichosurus vulpecula, by examining daily urine samples
for the presence of non-keratinised and keratinised epithelial cells,
polymorphonuclear leucocytes, and sperm. Around the time of oestrus there was
a massive increase in the number of epithelial cells and leucocytes in urine.
The pattern of cell shedding was similar in mated and non-mated females
undergoing either spontaneous ovulations or those induced by removal of pouch
young. There was no difference between fertile or non-fertile oestrous cycles.
During the 2-month sampling period, 97% of females showed changes in
cell numbers indicative of oestrus and 72% of females were confirmed to
have been mated by the presence of sperm. Conception rate was 74% and
offspring were born 16–19 days after mating. When pouch young were
removed, 85% of females were mated 7–15 days later and 77%
of mated females produced pouch young. Compared with vaginal smears,
collection and examination of urine was easier and faster, only one animal
handler was required, the method was less stressful for the possum, and cell
types in the sample were scored directly without the need for fixation and
staining.
Histone H3 and U2 snRNA DNA sequences and arthropod molecular evolution
Authors: Colgan D. J. , McLauchlan A. , Wilson G. D. F. , Livingston S. P. , Edgecombe G. D. , Macaranas J. , Cassis G. , Gray M. R.
Published: August 2004

The range of DNA sequences used to study the interrelationships of the major
arthropod groups (chelicerates, myriapods, hexapods and crustaceans) is
limited. Here we investigate the value of two genes not previously employed in
arthropod phylogenetics. Histone H3 data were collected for 31 species and
small nuclear ribonucleic acid U2 data for 29 species. The sequences provided
a total of 460 sites and 192 parsimony-informative characters. H3 analyses
showed substantial codon usage bias, but had a low consistency index (0.26).
Consistency indices were higher for the U2 data (0.49), suggesting that the
class of snRNAs may provide several phylogenetically useful genes.
The present data are not by themselves sufficient to clarify major arthropod
group relationships. Partitioned data for H3 and U2 are incongruent according
to Incongruence Length Difference tests. Although the most parsimonious trees,
based on combined analyses of all taxa, differ substantially from
morphology-based trees, anomalous groupings are weakly supported with only one
exception. The trees uphold monophyly of Onychophora, Branchiopoda, and
Malacostraca (rather than the rival Phyllopoda). Cladistic analyses
constraining the monophyly of morphologically defined classes do not
significantly distinguish between the main rival hypotheses of major clade
relationships. Combined (‘spliced’) analysis of both genes
improves topological congruence with morphological groupings relative to that
of either partition. Character congruence between H3, U2, and morphology is
increased by downweighting (but not excluding) transitions and third codons.
Analyses of four-taxon statements using PHYLTEST found significant support for
the basal position of the Crustacea among the euarthropods. This support may
be due to the similarity of chelicerates, myriapods and hexapods in percentage
GC content.
Helminth parasite communities of kangaroos and wallabies (Macropus spp. and Wallabia bicolor) from north and central Queensland
Authors: Beveridge I. , Chilton N. B. , Johnson P. M. , Smales L. R. , Speare R. , Spratt D. M.
Published: August 2004

The occurrence of gastrointestinal helminth parasites in 40
Macropus agilis, 12 M.
antilopinus, 39 M. dorsalis, 28
M. giganteus, 29 M. parryi, 30
M. robustus and 26
Wallabia bicolor from north and central Queensland was
examined. A total of 124 morphologically defined species of helminth was
encountered, comprising 103 species of strongyloid nematodes, 6 species of
trichostrongyloid nematodes, 2 species of spiruroid nematodes, 4 species of
oxyuroid nematodes, 7 species of anoplocephalid cestodes and 2 species of
digenetic trematodes. Helminth communities in each macropodid host species
exhibited a high level of diversity, and were dominated numerically by
strongyloid nematodes. A high proportion of the helminth species was
restricted to a single host species and there was a low level of similarity
between helminth communities in different host species. Similarities that did
occur were not apparently related to the phylogenetic relationships between
hosts and are best explained by host switching between hosts sharing
overlapping habitats and feeding preferences. There was poor separation of the
helminth species into ‘core’, ‘secondary’ and
‘satellite’ members of communities.
Gut morphology and rate of passage of fungal spores through the gut of a tropical rodent, the giant white-tailed rat (Uromys caudimaculatus)
Authors: Comport Steven S. , Hume Ian D.
Published: August 2004

Gut morphology and rate of digesta passage through the gut in captive giant
white-tailed rats (Uromys caudimaculatus) were
investigated. Rate of passage was measured using a solute marker (Co-EDTA), a
marker of large particles (Cr-mordanted plant cell walls) and spores of the
ectomycorrhizal fungus Pisolithus spp. The mean retention time (MRT) of fungal
spores in the whole gut (48.4 ± 6.0 h), was long in comparison to that
found in other rodents of similar body mass and was intermediate to MRT of the
solute marker (45.4 ± 8.8 h) and the large particle marker (55.5
± 7.2 h). Thus, retention of spores is likely to be little affected by
being free or attached to pieces of ingested fruiting bodies. The stomach is
unilocular and hemiglandular and contains a large fundic diverticulum lined
entirely by non-glandular squamous epithelium. The significantly longer MRT
for the large particle marker than the solute marker suggests that some
selective retention of particles takes place, probably in the fundic
diverticulum of the stomach. We suggest that the large fundic diverticulum may
function in storage and possibly increased digestive efficiency of starchy
food items, and in retaining spores, especially when still attached to
fruiting bodies.
Goal-directed whisking increases phase-locking between vibrissa movement and electrical activity in primary sensory cortex in rat
Authors: Ganguly Karunesh , Kleinfeld David
Published: August 2004

We tested the hypothesis that behavioral context modulates phase-locking between rhythmic motor activity and concomitant electrical activity induced in primary sensory (S1) cortex. We used exploratory whisking by rat as a model system and recorded two measures: (
i
) the mystacial electromyogram (∇EMG) as a surrogate of vibrissa position, and (
ii
) the field potential (∇LFP) in S1 cortex as an indicator of electrical activity. The degree to which the ∇EMG and ∇LFP were phase-locked was compared for three categories of rhythmic whisking: (
i
) searching for an object with the vibrissae for a food reward, (
ii
) whisking in air for the goal of returning to the home cage, and (
iii
) whisking with no reward. We observed that the magnitude of phase-locking was nearly tripled for the two rewarded conditions compared to unrewarded whisking. Critically, increased locking was not accompanied by an increase in the amplitude of the cortical ∇LFP for the rewarded tasks. Additional experiments showed that there was no significant relation between the amplitude of a sensory-evoked response in S1 cortex and the magnitude of the locking between the ∇EMG and the ∇LFP during whisking. We conclude that the behavioral context of a whisking task can increase the modulation of S1 cortical activity by motor output without a concomitant increase in the magnitude of activity.
Potent block of Cx36 and Cx50 gap junction channels by mefloquine
Authors: Cruikshank Scott J. , Hopperstad Matthew , Younger Meg , Connors Barry W. , Spray David C. , Srinivas Miduturu
Published: August 2004

Recently, great interest has been shown in understanding the functional roles of specific gap junction proteins (connexins) in brain, lens, retina, and elsewhere. Some progress has been made by studying knockout mice with targeted connexin deletions. For example, such studies have implicated the gap junction protein Cx36 in synchronizing rhythmic activity of neurons in several brain regions. Although knockout strategies are informative, they can be problematic, because compensatory changes sometimes occur during development. Therefore, it would be extremely useful to have pharmacological agents that block specific connexins, without major effects on other gap junctions or membrane channels. We show that mefloquine, an antimalarial drug, is one such agent. It blocked Cx36 channels, expressed in transfected N2A neuroblastoma cells, at low concentrations (IC
50
≈ 300 nM). Mefloquine also blocked channels formed by the lens gap junction protein, Cx50 (IC
50
≈ 1.1 μM). However, other gap junctions (e.g., Cx43, Cx32, and Cx26) were only affected at concentrations 10- to 100-fold higher. To further examine the utility and specificity of this compound, we characterized its effects in acute brain slices. Mefloquine, at 25 μM, blocked gap junctional coupling between interneurons in neocortical slices, with minimal nonspecific actions. At this concentration, the only major side effect was an increase in spontaneous synaptic activity. Mefloquine (25 μM) caused no significant change in
evoked
excitatory or inhibitory postsynaptic potentials, and intrinsic cellular properties were also mostly unaffected. Thus, mefloquine is expected to be a useful tool to study the functional roles of Cx36 and Cx50.
Sulfur pollution suppression of the wetland methane source in the 20th and 21st centuries
Authors: Gauci Vincent , Matthews Elaine , Dise Nancy , Walter Bernadette , Koch Dorothy , Granberg Gunnar , Vile Melanie
Published: August 2004

Natural wetlands form the largest source of methane (CH
4
) to the atmosphere. Emission of this powerful greenhouse gas from wetlands is known to depend on climate, with increasing temperature and rainfall both expected to increase methane emissions. This study, combining our field and controlled environment manipulation studies in Europe and North America, reveals an additional control: an emergent pattern of increasing suppression of methane (CH
4
) emission from peatlands with increasing sulfate (

\documentclass[12pt]{minimal}
\usepackage{amsmath}
\usepackage{wasysym}
\usepackage{amsfonts}
\usepackage{amssymb}
\usepackage{amsbsy}
\usepackage{mathrsfs}
\setlength{\oddsidemargin}{-69pt}
\begin{document}
\begin{equation*}{\mathrm{SO}}_{4}^{2-}{\mathrm{-}}{\mathrm{S}}\end{equation*}\end{document}

) deposition, within the range of global acid deposition. We apply a model of this relationship to demonstrate the potential effect of changes in global sulfate deposition from 1960 to 2080 on both northern peatland and global wetland CH
4
emissions. We estimate that sulfur pollution may currently counteract climate-induced growth in the wetland source, reducing CH
4
emissions by ≈15 Tg or 8% smaller than it would be in the absence of global acid deposition. Our findings suggest that by 2030 sulfur pollution may be sufficient to reduce CH
4
emissions by 26 Tg or 15% of the total wetland source, a proportion as large as other components of the CH
4
budget that have until now received far greater attention. We conclude that documented increases in atmospheric CH
4
concentration since the late 19th century are likely due to factors other than the global warming of wetlands.
Autocatalytic self-propagation of misfolded prion protein
Authors: Bieschke Jan , Weber Petra , Sarafoff Nikolaus , Beekes Michael , Giese Armin , Kretzschmar Hans
Published: August 2004

Prions are thought to replicate in an autocatalytic process that converts cellular prion protein (PrP
C
) to the disease-associated misfolded PrP isoform (PrP
Sc
). Our study scrutinizes this hypothesis by
in vitro
protein misfolding cyclic amplification (PMCA). In serial transmission PMCA experiments, PrP
Sc
was inoculated into healthy hamster brain homogenate containing PrP
C
. Misfolded PrP was amplified by rounds of sonication and incubation and reinoculated into fresh brain homogenate every 10 PMCA rounds. The amplification depended on PrP
C
substrate and could be inhibited by recombinant hamster PrP. In serial dilution experiments, newly formed misfolded and proteinase K-resistant PrP (PrPres) catalyzed the structural conversion of PrP
C
as efficiently as PrP
Sc
from brain of scrapie (263K)-infected hamsters, yielding an ≈300-fold total amplification of PrPres after 100 rounds, which confirms an autocatalytic PrP-misfolding cascade as postulated by the prion hypothesis. PrPres formation was not paralleled by replication of biological infectivity, which appears to require factors additional to PrP-misfolding autocatalysis.
SspB delivery of substrates for ClpXP proteolysis probed by the design of improved degradation tags
Authors: Hersch Greg L. , Baker Tania A. , Sauer Robert T.
Published: August 2004

The ssrA-degradation tag sequence contains contiguous binding sites for the SspB adaptor and the ClpX component of the ClpXP protease. Although SspB normally enhances ClpXP degradation of ssrA-tagged substrates, it inhibits proteolysis under conditions that prevent tethering to ClpX. By increasing the spacing between the protease and adaptor-binding determinants in the ssrA tag, substrates were obtained that displayed improved SspB-mediated binding to and degradation by ClpXP. These extended-tag substrates also showed significantly reduced conditional inhibition but bound SspB normally. Both wild-type and mutant tags showed highly dynamic SspB interactions. Together, these results strongly support delivery models in which SspB and ClpX bind concurrently to the ssrA tag, but also suggest that clashes between SspB and ClpX weaken simultaneous binding. During substrate delivery, this signal masking is overcome by tethering SspB to ClpX, which ensures local concentrations high enough to drive tag engagement. This obstruct-then-stimulate mechanism may have evolved to allow additional levels of regulation and could be a common trait of adaptor-mediated protein degradation.
Strategies and mechanisms for host and pathogen survival in acute and persistent viral infections
Authors: Hilleman Maurice R.
Published: August 2004

Persistent viral infections causing serious diseases derive, primarily, from altered function of the immune system. Knowledge of the very complex composition and function of the innate and adaptive branches of the immune system is essential to understanding persistent infection. The best solution to the problem of persistent infection is by prevention using prophylactic vaccines. Hit and run viruses evade immune destruction by infecting new hosts and rarely persist. Hit and stay viruses evade immune control by sequestration, blockade of antigen presentation, cytokine escape, evasion of natural killer cell activities, escape from apoptosis, and antigenic change. Twelve prophylactic vaccines against hit and run agents exist, and there are only three vaccines against hit and stay viruses, all of which are of DNA composition. Several new vaccines against hit and stay viruses are feasible, but protective vaccines against RNA HIV and hepatitis C agents are highly unlikely, short of a major breakthrough. Therapeutic vaccines are very improbable without a magnitude of favorable new discoveries. In the meantime, antiviral chemotherapy, chemotherapy/prophylactic vaccination, and short interfering RNA silencing are worthy of intense investigation.
Energetic clues to pathways to biomineralization: Precursors, clusters, and nanoparticles
Authors: Navrotsky Alexandra
Published: August 2004

Nanoparticle and nanocluster precursors may play a major role in biomineralization. The small differences in enthalpy and free energy among metastable nanoscale phases offer controlled thermodynamic and mechanistic pathways. Clusters and nanoparticles offer concentration and controlled transport of reactants. Control of polymorphism, surface energy, and surface charge on nanoparticles can lead to morphological control and appropriate growth rates of biominerals. Rather than conventional nucleation and growth, assembly of nanoparticles may provide alternative mechanisms for crystal growth. The Ostwald step rule, based on a thermodynamic view of nucleation and growth, is supported by the observation that more metastable phases tend to have lower surface energies. Examples from nonbiological systems, stressing the interplay of thermodynamic and kinetic factors, illustrate features potentially important to biomineralization.
Therapeutic vaccines in autoimmunity
Authors: Sela Michael , Mozes Edna
Published: August 2004

Similarly to prophylactic vaccines whose purpose is to prevent infectious diseases, therapeutic vaccines against autoimmune diseases are based on their similarity to the putative causes of the disease. We shall describe here two such examples: a copolymer of amino acids related to myelin basic protein, in the case of multiple sclerosis, and a peptide derived from the nicotinic acetylcholine receptor (AChR), in the case of myasthenia gravis (MG). Copolymer 1 (Cop 1, glatiramer acetate, Copaxone) is a synthetic amino acid random copolymer, immunologically cross-reactive with myelin basic protein and suppresses experimental allergic encephalomyelitis in several animal species. Cop 1 slows the progression of disability and reduces relapse rate in exacerbating-remitting multiple sclerosis patients. It was approved by the Food and Drug Administration in 1996, and today is used by tens of thousands of patients. Cop 1 is a potent inducer of T helper 2 (Th2) regulatory cells in mice and humans, and Th2 cells are found both in the brains and spinal cords of Cop 1-treated mice. MG and experimental autoimmune MG are T cell-regulated, antibody-mediated autoimmune diseases. Two peptides, representing sequences of the human AChR α-subunit, p195-212 and p259-271, are immunodominant T cell epitopes in MG patients and in two strains of mice. Altered peptide ligand, composed of the tandemly arranged two single amino acid analogs, inhibitsin vitroandin vivoMG-associated autoimmune responses. The active suppression is mediated by the CD4+CD25+immunoregulatory cells and is associated with the down-regulation of Th1-type cytokines and the up-regulation of the secretion of IL-10 and the immunosuppressive cytokine, transforming growth factor β.
Modality maps within primate somatosensory cortex
Authors: Friedman Robert M. , Chen Li Min , Roe Anna Wang
Published: August 2004

The sensations of pressure, flutter, and vibration are psychophysically distinct tactile modalities produced by frequency-specific vibrotactile stimulation of different mechanoreceptors in the skin. The information coded by the different low-threshold mechanoreceptors are carried by anatomically and electrophysiologically distinct pathways that remain separate at least up to and including the input stage of primary somatosensory cortex (SI) in primates, area 3b. Little is known about the functional organization of tactile representation beyond that stage. By using intrinsic optical imaging methods to record from area 1, the second processing stage of SI, we present evidence that pressure, flutter, and vibratory stimuli activate spatially distinct cortical domains in area 1, further strengthening the foundation for modality-specific processing streams in SI. These modality domains exhibit an organization that is unlike the discontinuous modality maps in visual area V2 but more like the continuous visual orientation maps in V1. The results demonstrate that psychophysically distinct sensory modalities can have fundamentally different modes of cortical representation.
Towards Infusing Institutions and Agency into House Price Analysis
Authors: Kauko Tom
Published: August 2004

The article puts forward the argument that housing market and property value models currently lack an adequate methodological basis. In order to improve the conceptual framework of the economic analysis of housing market behaviour, necessary institutional parameters need to be included. This, however, causes further difficulties, because some of the institutions are predominantly informal and operate at the cognitive level of market behaviour. While the problem of overstrict assumptions at the aggregate level has been tackled successfully, the next fundamental problem to solve is how to disaggregate feasibly the demand-side analysis. One possibility for this is to generate preference profiles of actors with different institutional backgrounds, using a multicriteria decision technique such as the analytical hierarchy process (AHP).
Time for ethnography
Authors: Jeffrey Bob , Troman Geoff
Published: August 2004

Ethnography derives from traditional anthropology, where time in the field is needed to discern both the depth and complexity of social structures and relations. Funding bodies, seeking quick completion, might see ethnographies as unlikely to satisfy ‘value for money’ criteria, in spite of the rewards to be gained from time‐consuming ‘thick description’, and rich analysis that gets close to the lived experience of participants in social settings. However, ethnographic time need not only be perceived of as a lengthy and sustained period in the field prior to writing. The authors suggest that there are different forms of ethnographic research time, each with specific features, and drawing on their experience of ethnographic research they exemplify them. They conclude by suggesting that the selection of the appropriate form is dependent on the contingent circumstances of the research and the main purpose of the research, and suggest strategies for developing this work in contemporary circumstances.