The potential implications of rainforest history, hybridization, and climate change on the phylogenetics of a rare genus of herbs Romnalda (Dasypogonaceae) from New Guinea and Australia

There are many genera shared between Australian and Papua New Guinean rainforests. Species in the rare rainforest herbaceous genus Romnalda have a relictual and disjunct distribution within the major rainforest blocs of southern Queensland, north Queensland, and New Guinea. There are only four species in this genus: R. strobilacea , R. grallata , and R. sp. 'Cooper Ck' from Australia, and R. papuana from New Guinea. The Australian species have restricted distributions and high conservation status. Allozymes were used to study the genetic variation and distinctiveness of all four species. Genetic diversity varied significantly amongst the four species. The species in the centre of the genus distribution contained the highest genetic diversity, regardless of rarity. The undescribed R. sp. 'Cooper Ck' was identified as a clearly distinct species with morphological affinities to R. papuana , but genetic affinities to R. grallata. The study showed that, where the distributions of R. grallata and R. sp. 'Cooper Ck' overlapped, there was evidence of hybridization. Reproductive participation within populations was typically low with limited flowering synchrony. Populations of all four species were inbred, but higher levels of inbreeding were not correlated with lower genetic diversity. The timing of flowering appeared to be determined by climate. Altitudinal variation in phenological timing in R. sp. 'Cooper Ck' has led to genetic isolation within the species, but has also limited its genetic introgression with the co-occurring R. grallata . © 2008 The Linnean Society of London, Botanical Journal of the Linnean Society , 2008, 157 , 455–474.     

Habitat requirements of the threatened snake species Hoplocephalus stephensii (Elapidae) in eastern Australia

Abstract Although forested habitats in eastern Australia have attracted significant conservation‐related research, this work has focused strongly on endothermic vertebrates. Threatened reptile taxa have received less attention, but information on their habitat requirements should be central to management planning. The arboreal elapid snake Hoplocephalus stephensii is largely restricted to remnant forests in eastern Australia, and is listed as a threatened species under wildlife legislation. We collated 84 records of the current New South Wales geographical distribution of H. stephensii, and compared attributes of these locations to those of randomly chosen points within the same forests, in adjacent forests, in timber plantations and on freehold land across the geographical range of the taxon. Data on climatic and topographic characteristics of these sites were obtained from Geographic Information Systems databases and entered into a principal components analysis. Unsurprisingly, locations where snakes were recorded differed from the random sites in several respects (e.g. rainfall, elevation, seasonality of precipitation). Within a given forest, H. stephensii was generally found in areas similar to randomly chosen points. Comparison of vegetation communities used with those available within forests provided no evidence for active habitat selection. Comparisons of Geographic Information Systems‐derived data for snake‐collection localities along roads versus those within the forest revealed significant biases, and we warn that such methodological errors could generate spurious conclusions about non‐random habitat use by threatened species. In combination with previous data from radio‐tracking, we conclude that although H. stephensii is highly specialized in its arboreality and dependence upon hollow trees, its broad tolerance with respect to other factors (climatic conditions, vegetation communities, food types, etc.) allows populations to persist so long as large areas of forest with high numbers of hollow‐bearing trees are available. These requirements are similar to those of many other components of the Australian forest fauna. Thus, the findings of this study support the idea that the same kinds of management programmes can effectively conserve a wide range of taxa, if such programmes protect critical habitat components at suitable spatial scales.     

Insecticide resistance monitoring of field‐collected Anopheles gambiae s.l. populations from Jinja,eastern Uganda,identifies high levels of pyrethroid resistance

Insecticide resistance in the malaria vector Anopheles gambiae s.l. (Diptera: Culicidae) threatens insecticide‐based control efforts, necessitating regular monitoring. We assessed resistance in field‐collected An. gambiae s.l. from Jinja, Uganda using World Health Organization (WHO) biosassays. Only An. gambiae s.s. and An. arabiensis (?70%) were present. Female An. gambiae exhibited extremely high pyrethroid resistance (permethrin LT₅₀ > 2 h; deltamethrin LT₅₀ > 5 h). Female An. arabiensis were resistant to permethrin and exhibited reduced susceptibility to deltamethrin. However, while An. gambiae were DDT resistant, An. arabiensis were fully susceptible. Both species were fully susceptible to bendiocarb and fenitrothion. Kdr 1014S has increased rapidly in the Jinja population of An. gambiae s.s. and now approaches fixation (?95%), consistent with insecticide‐mediated selection, but is currently at a low frequency in An. arabiensis (0.07%). Kdr 1014F was also at a low frequency in An. gambiae. These frequencies preclude adequately‐powered tests for an association with phenotypic resistance. PBO synergist bioassays resulted in near complete recovery of pyrethroid susceptibility suggesting involvement of CYP450s in resistance. A small number (0.22%) of An. gambiae s.s. ×An. arabiensis hybrids were found, suggesting the possibility of introgression of resistance alleles between species. The high levels of pyrethroid resistance encountered in Jinja threaten to reduce the efficacy of vector control programmes which rely on pyrethroid‐impregnated bednets or indoor spraying of pyrethroids.     

Impacts of drought and predicted effects of climate change on fish growth in temperate Australian lakes

Climate change is expected to negatively impact many freshwater environments due to reductions in stream‐flow and increases in temperature. These conditions, however, can already be found today in areas experiencing significant drought; current observations of species' responses to droughts can be used to make predictions about their future responses to climate change. Using otolith analysis, we recreated golden perch (Macquaria ambigua) growth chronologies from two temperate lake populations in southeastern Australia over a 15‐year period pre‐ and during a supraseasonal drought. We related interannual growth variation to landscape‐scale changes in temperature and hydrological regimes: fish growth declined as water levels in the lakes dropped during the drought, but this effect was offset by increased growth in warmer years. We hypothesize that golden perch are responding to fluctuations in food availability and intraspecific competition related to water level and to an optimization of physiological growth conditions related to increases in growing season length. Based on our analyses, we made predictions of future growth under a number of climate change scenarios that incorporate forecast deviations in stream‐flows and air temperature. Despite climatic models predicting significant declines in future water availability, fish growth may increase due to a disproportionate lengthening of the growing season. As the two lakes are at the limit of the southerly range of golden perch, our results are consistent with previous findings of climate‐change driven latitudinal range shifts in a poleward direction. We discuss assumptions concerning the constancy of ecological interactions into the future that warrant further study. Our research provides a novel application of biochronological analysis that could be used elsewhere to further our knowledge of species responses to changing environments.     

Characterization of simple sequence repeat markers derived in silico from Brassica rapa bacterial artificial chromosome sequences and their application in Brassica napus

A collaborative Brassica rapa genome sequencing project is currently in progress to aid the identification of agronomically important traits in Brassica species. As an initial stage, the ends of over 110 000 bacterial artificial chromosome clones were sequenced and mined for simple sequence repeats (SSRs). We present the characterization of 40 of these SSRs and their application in Brassica napus. The markers were screened against six Brassica species and Arabidopsis, and demonstrated reliable amplification, genome specificity, cross‐amplification and significant polymorphism. These SSRs will be useful for genetic analysis of Brassica germplasm.     

End-products of behaviour versus behavioural characters: a phylogenetic investigation of pupal cocoon construction and form in some North American black flies (Diptera: Simuliidae)

Cocoon spinning was analysed, using video recording and playback, in eighteen Nearctic black fly species, comparing nine Simulium species, six Eusimulium species, Stegopterna mutata, Cnephia dacotensis and Prosimulium mixtum. Fourteen behavioural characters were revealed that produced twenty-two equally parsimonious trees (CI = 0.93, RI = 0.96). Another tree was constructed on the basis of five characters relating to the cocoon structure (end-product characters). The goal of the study was to determine whether characters relating to behavioural components of black fly cocoon spinning or those based on end-products of the behaviour are superior for revealing phylogenetic relationships. This was accomplished by comparing both data sets to a phylogeny constructed with the use of cytological and morphological characters. If taxa are grouped according to end-products (the cocoons) there are some spurious groupings. The behavioural analysis only required one extra step to duplicate the morphological and cytological tree. In the case of black flies, it is more informative to use characters resulting from the analysis of the cocoon spinning behaviour than cocoon morphology.