Molecular characterization of Drosophila C virus isolates

Reverse transcription coupled with polymerase chain reaction and restriction enzyme analysis was used to characterize 12 Drosophila C virus isolates from geographically different regions. A 1.2-kb fragment was amplified from cDNA and profiles from digestion with 20 restriction enzymes were generated. Analysis of the restriction fragment data gave estimates of nucleotide divergence of 0-10% between isolates. The isolates were grouped on the basis of genetic distance estimates derived from the restriction data. For the isolates from which a single genotype could be purified, a geographical pattern in the distribution of viral genotypes was identified. The 4 Moroccan isolates were very closely related to each other, differing in only 1 restriction profile. The 2 Australian isolates were each other's closest relatives, as were the 2 isolates first recovered in France. The PCR-RFLP technique used in this study has provided us with a simple procedure which can be used to characterize DCV isolates. A single enzyme, Tag I, generated 5 distinct and diagnostic restriction fragment patterns, which allowed easy assignment of isolates to one of the five viral genotypes identified in this study. (C) 1999 Academic Press.

Strong genetic structuring in a habitat specialist, the Oxleyan Pygmy Perch Nannoperca oxleyana

This study used allozyme and mitochondrial DNA variation to examine genetic structure in the Oxleyan Pygmy Perch Nannoperca oxleyana. This small-bodied freshwater fish has a very restricted distribution occurring only in some small coastal streams in south-east Queensland and northern New South Wales. It was expected that subpopulations may contain little genetic variation and be highly differentiated from one another. The results, based on allozyme and mitochondrial DNA control region variation were in agreement with these expectations. Allozyme variation was very low overall, with only one locus showing variation at most sites. The high differentiation was because a different locus tended to be polymorphic at each site. Mitochondrial variation within sites was also low, but some sites had unique haplotypes. The patterns of similarity among mitochondrial DNA haplotypes were not as expected from geographical proximity alone. In particular, although some northern sites had unique haplotypes, four sites spread along 200 km of coastline were remarkably similar, sharing the same common haplotype at similar frequencies. We suggest that these four streams may have had a confluence relatively recently, possibly when sea levels were lower, 8000-10 000 BP.

A method of analysing stream channel response to environmental change: gauge data for the Tully River

Gauging data are available from numerous streams throughout Australia, and these data provide a basis for historical analysis of geomorphic change in stream channels in response to both natural phenomena and human activities. We present a simple method for analysis of these data, and a briefcase study of an application to channel change in the Tully River, in the humid tropics of north Queensland. The analysis suggests that this channel has narrowed and deepened, rather than aggraded: channel aggradation was expected, given the intensification of land use in the catchment, upstream of the gauging station. Limitations of the method relate to the time periods over which stream gauging occurred; the spatial patterns of stream gauging sites; the quality and consistency of data collection; and the availability of concurrent land-use histories on which to base the interpretation of the channel changes.

Season-specific directional movement in migratory Australian butterflies

Large numbers of adults of certain species of butterfly flying in an apparently 'purposeful' manner are often noted by entomologists and the general public. Occasionally, these are recorded in the literature. Using these records we summarise information regarding the direction of movement in Australian butterflies and test whether there are consistent patterns that could account for known seasonal shifts in geographical range. The data were analysed using contingency tables and directionality statistics. Vanessa itea, Vanessa kershawi, Danaus plexippus, Danaus chrysippus and Badamia exclamationis flew predominately south in the spring-summer and north in the autumn-winter. Tirumala hamata has a strong southern component to its flight in spring but, as in Euploea core, appears non-directional in the autumn. For many supposedly known migratory species, the number of literature records are few, particularly in one season (mainly autumn). Thus, for Appias paulina, four of seven records were south in the spring-summer, as were six of nine records for Catopsilia pomona, and three of five for Zizina labradus. For Belenois java, flight records were only available for the spring and these showed geographical differences; predominantly north-west in northern Australia (Queensland) and south-west in southern Australia (Victoria, New South Wales). There were too few records for Papilio demoleus in the literature (four only) to draw any conclusions. Major exceptions to the seasonal trend of south in the spring and north in the autumn were Junonia villida, which showed a predominant north-westward direction in both seasons, and Eurema smilax, with a predominant southern or western flight in both seasons. We discuss these species specific trends in migration direction in relation to seasonal shifts in suitable habitat conditions, possible cues used in orientation and in timing changes in direction.

Empirical catchment-wide rainfall erosivity models for two rivers in the humid tropics of Australia

The concept of rainfall erosivity is extended to the estimation of catchment sediment yield and its variation over time. Five different formulations of rainfall erosivity indices, using annual, monthly and daily rainfall data, are proposed and tested on two catchments in the humid tropics of Australia. Rainfall erosivity indices, using simple power functions of annual and daily rainfall amounts, were found to be adequate in describing the interannual and seasonal variation of catchment sediment yield. The parameter values of these rainfall erosivity indices for catchment sediment yield are broadly similar to those for rainfall erosivity models in relation to the R-factor in the Universal Soil Loss Equation.

Relationships among climate, latitude and migration: Australian butterflies are not temperate-zone birds

We examined the distribution of butterflies over the mostly arid and semi-arid continent of Australia and analyzed the proportion of migrant species and species diversity with respect to an array of climatic and geographic variables. On a continent-wide scale, latitude explained virtually no variance in either proportion of migrants (r(2) = 0.01) or species diversity (r(2) = 0.03) in Australian butterflies. These results are in marked contrast to those for temperate-zone birds from three continents where latitude explained between 82 and 98% of the variance in frequency of migrants and also accounted for much of the variance in bird species diversity. In eastern Australia where rainfall regimes are similar to those in temperate Europe and North and South America, latitude explains 78% of the variance in frequency of butterfly migrants. In both eastern and central Australia, latitude also accounts for relatively high proportions of the variance in species diversity. Rainfall patterns and especially soil moisture are negatively associated with migration frequency in Australian butterfly faunas, both alone and in combination with other climate variables. Where moisture levels are relatively high, as in eastern Australia, measures of temperature are associated with migration frequency, a result consistent with findings for temperate-zone birds, suggesting latitude is a surrogate for temperature. The ultimate causes of migration in temperate-zone birds and Australian butterflies are the uneven temporal, and in Australia also spatial, distribution of resources. Uneven distribution is brought about primarily by temperature in temperate regions and by erratic rainfall over much of arid Australia. As a key determinant of productivity, especially in the tropics and subtropics, aridity is likely to be an important determinant of the global distributions of migrants.

Integrating attribute and space characteristics in choropleth display and spatial data mining

This paper develops an interactive approach for exploratory spatial data analysis. Measures of attribute similarity and spatial proximity are combined in a clustering model to support the identification of patterns in spatial information. Relationships between the developed clustering approach, spatial data mining and choropleth display are discussed. Analysis of property crime rates in Brisbane, Australia is presented. A surprising finding in this research is that there are substantial inconsistencies in standard choropleth display options found in two widely used commercial geographical information systems, both in terms of definition and performance. The comparative results demonstrate the usefulness and appeal of the developed approach in a geographical information system environment for exploratory spatial data analysis.

Allele and genotype frequencies of polymorphic cytochromes P4502D6, 2C19 and 2E1 in Aborigines from Western Australia

The polymorphisms of the important xenobiotic metabolizing enzymes CYP2D6, CYP2C19 and CYP2E1 have been studied extensively in a large number of populations and show significant heterogeneity in the frequency of different alleles/genotypes and in the prevalence of the extensive and poor metabolizer phenotypes, Understanding of inter-ethnic differences in genotypes is important in prediction of either beneficial or adverse effects from therapeutic agents and other xenobiotics. Since no data were available for Australian Aborigines, we investigated the frequencies of alleles and genotypes for CYP2D6, CYP2C19 and CYP2E1 in a population living in the far north of Western Australia. Because of its geographical isolation, this population can serve as a model to study the impact of evolutionary forces on the distribution of different alleles for xenobiotic metabolizing enzymes. Twelve CYP2D6 alleles were analysed, The wild-type allele *1 was the most frequent (85.8%) and the non-functional alleles (*4, *5, *16) had an overall frequency of less than 10%. Only one subject (0.4%) was a poor metabolizer for CYP2D6 because of the genotype *5/*5, For CYP2C19, the frequencies of the *1 (wild-type) and the non-functional (*2 and *3) alleles were 50.2%, 35.5% and 14.3%, respectively. The combined CYP2C19 genotypes (*2/*2, *2/*3 or *3/*3) correspond to a predicted frequency of 25.6% for the CYP2C19 poor metabolizer phenotype, For CYP2E1, only one subject had the rare c2 allele giving an overall allele frequency of 0.2%. For CYP2D6 and CYP2C19, allele frequencies and predicted phenotypes differed significantly from those for Caucasians but were similar to those for Orientals indicating a close relationship to East Asian populations. Differences between Aborigines and Orientals in allele frequencies for CYP2D6*10 and CYP2E1 c2 may have arisen through natural selection, or genetic drift, respectively, Pharmacogenetics 11:69-76 (C) 2001 Lippincott Williams & Wilkins.

Identification of genes implicated in toxin production in the cyanobacterium Cylindrospermopsis raciborskii

Cylindrospermopsis raciborskii is a bloom-forming cyanobacterium found in both tropical and temperate climates which produces cylindrospermopsin, a potent hepatotoxic secondary metabolite. This organism is notorious for its association with a significant human poisoning incident on Palm Island, Australia, which resulted in the hospitalization of 148 people. We have screened 13 C. raciborskii isolates from various regions of Australia and shown that both toxic and nontoxic strains exist within this species. No association was observed between geographical origin and toxin production. Polyketide synthases (PKSs) and peptide synthetases (PSs) are enzymes involved in secondary metabolite biosynthesis in cyanobacteria. Putative PKS and PS genes from C. raciborskii strains AWT205 and CYPO2OB were identified by PCR using degenerate primers based on conserved regions within each gene. Examination of the strain-specific distribution of the PKS and PS genes in C. raciborskii isolates demonstrated a direct link between the presence of these two genes and the ability to produce cylindrospermopsin. Interestingly, the possession of these two genes was also linked. They were also identified in an Anabaena bergii isolate that was demonstrated to produce cylindrospermopsin. Taken together, these data suggest a likely role for these determinants in secondary metabolite and toxin production by C. raciborskii. (C) 2001 John Wiley & Sons, Inc.

New status, species, distribution records and phylogeny for Australian mandibulate Chironomidae (Diptera)

All life-history stages of the Australian Podonominae (Chironomidae) genus Archaeochlus Brundin are revised, providing evidence for recognition of a separate clade, named here as Austrochlus Cranston. Based on molecular and morphological evidence, the clade contains two additional species: Austrochlus parabrundini Cranston, Edward and Cook sp. n. is described from Western Australia where its granite outcrop seepage habitat and geographical range is almost identical to that of the type species Austrochlus brundini Cranston, Edward and Colless (n. comb); Austrochlus centralaustralis Cranston, Edward and Cook sp. n. is described from ephemeral seepage/flows in the MacDonnell and James Ranges of central Australia. Molecular studies reported here confirm species distinctions, relationships to African taxa, and basal relationships within the Chironomidae. Modelled distributions provide evidence for range restriction by seasonal rainfall patterns.

Semiochemicals and social signaling in the wild European rabbit in Australia: II. Variations in chemical composition of chin gland secretion across sampling sites

The volatile components of the chin gland secretion of the wild European rabbit, Oryctolagus cuniculus (L.), were investigated with the use of gas chromatography. Studies of the chemical nature of this secretion by previous workers demonstrated that it was important in the maintenance of social structure in this species. This study identified 34 different volatile components that consist primarily of aromatic and aliphatic hydrocarbons. Especially common are a series of alkyl-substituted benzene derivatives that provide most of the compound diversity in the secretion. Samples of chin gland secretion collected from animals at three different geographical locations, separated by more than 100 km, showed significant differences in composition. This work suggests that variation among populations needs to be considered when undertaking semiochemical research. Alternate nonparametric methods are also used for the analysis of chromatographic data.

Extrinsic versus intrinsic factors in the decline and extinction of Australian marsupials

Recent attempts to explain the susceptibility of vertebrates to declines worldwide have largely focused on intrinsic factors such as body size, reproductive potential, ecological specialization, geographical range and phylogenetic longevity. Here, we use a database of 145 Australian marsupial species to test the effects of both intrinsic and extrinsic factors in a multivariate comparative approach. We model five intrinsic (body size, habitat specialization, diet, reproductive rate and range size) and four extrinsic (climate and range overlap with introduced foxes, sheep and rabbits) factors. We use quantitative measures of geographical range contraction as indices of decline. We also develop a new modelling approach of phylogenetically independent contrasts combined with imputation of missing values to deal simultaneously with phylogenetic structuring and missing data. One extrinsic variable-geographical range overlap with sheep-was the only consistent predictor of declines. Habitat specialization was independently but less consistently associated with declines. This suggests that extrinsic factors largely determine interspecific variation in extinction risk among Australian marsupials, and that the intrinsic factors that are consistently associated with extinction risk in other vertebrates are less important in this group. We conclude that recent anthropogenic changes have been profound enough to affect species on a continent-wide scale, regardless of their intrinsic biology.

KuhlmanniodendronFiaschi & Groppo, a new eastern Brazilian genus of Achariaceae sensu lato segregated from Carpotroche Endl. (formerly included in Flacourtiaceae)

Kuhlmanniodendron Fiaschi & Groppo, a new genus of the tribe Lindackerieae (Achariaceae sensu lato) is created to accommodate Carpotroche apterocarpa Kuhlm, a species previously described based on incomplete floriferous and fruiting material from the rainforests of Espirito Santo state, eastern Brazil. The genus is defined by a unique set of character states, including leaves with Clusia-like venation and scaly trichomes, flowers with glabrous stamen filaments and three free styles, and indehiscent fruits with a smooth surface (sometimes with vertical ribs when dried). A description and illustration are provided, with comments on geographical distribution, phenology and generic relationships, and an emended key to neotropical genera of Lindackerieae. (c) 2008 The Linnean Society of London.

Uncommon mechanism of egg incubation in the endemic Southern hermit crab Loxopagurus loxochelis: how is this phenomenon related to egg production?

The aim of the present work was to characterize the egg production of Loxopagurus loxochelis. A total of 71 ovigerous females were obtained, 28% of which were simultaneously incubating eggs at different developmental stages. This phenomenon can be the result of incomplete fertilization, or may represent a rapid gonadal cycle by this species in this area, which is, to our understanding, the best explanation of this phenomenon. Egg volume decreased 25.6% during the incubation period. The reproductive output based on dry and wet weight was 6.8 and 19.3%, respectively. Water was the prevailing component of the eggs, representing 86.0% of the total weight at initial stage, increasing to 95.1% at the final stage. Ash content increased at the same time as a decrease in the organic content occurred, indicating the consumption of yolk and absorption of salts from the water medium. In conclusion, we hypothesized that this population has the capacity to copulate and deposit another brood even before the release of the larvae from the previous one, intensifying the reproductive effort of these hermit crabs as a strategy of adaptation in a region considered the northern limit of the geographical distribution of this species.

Comparative reproductive biology of two southwestern Atlantic populations of the hermit crab Pagurus exilis (Crustacea: Anomura: Paguridae)

Pagurus exilis (Benedict, 1892) is an endemic South Atlantic hermit crab with a distribution ranging from Rio de Janeiro State, Brazil, to Buenos Aires Province, Argentina. The present study analyzed the reproduction of two populations at the extremes of this geographical distribution, and compared their reproductive period, fecundity, and changes in egg size and egg volume during the incubation period in order to assess the variability over this latitudinal range. Hermit crabs were collected monthly over a 2-year period. In total, 108 females were analyzed for Brazil (44 non-ovigerous and 64 ovigerous), and 141 for Argentina (87 non-ovigerous and 54 ovigerous). Reproduction in Brazil occurs year-round, with peaks in the fall and winter seasons; in Argentina reproduction occurs only in spring and summer. The Brazilian ovigerous females were significantly larger than the Argentina ones (Brazil: SL = 5.33 +/- 1.45 mm; Argentina: SL = 4.15 +/- 0.52 mm; P < 0.001). The fecundity was 1447 +/- 831 eggs (317 to 2885) in Brazil and 987 +/- 711 eggs (114 to 2665) in Argentina, with a trend towards higher fecundity in Brazil. Eggs in the Argentina population were larger than those in Brazil for all the three stages investigated, and no changes in egg volume were found during egg development for both populations. The reproductive traits of the two populations showed some important differences, which may reflect adaptations to local environmental conditions, demonstrating a high plasticity of reproductive features of the species in Brazilian and Argentine waters. The strategy adopted by the Argentina population involves a lower production of larger eggs compared to the population in Brazil; this lower production is associated with reproduction in cold-water regions.