Publications by authors named "Michele Schiffer"

Article Synopsis
  • * An experiment on four Australian tropical tree species showed that warming leaves by 4°C for 8 months significantly reduced both stomatal conductance and photosynthesis by 48% and 35%, respectively.
  • * The study indicates that these mature trees may have a reduced capacity to act as carbon sinks in the future due to their physiological responses to increased temperatures.
View Article and Find Full Text PDF

Long-read sequencing is driving rapid progress in genome assembly across all major groups of life, including species of the family Drosophilidae, a longtime model system for genetics, genomics, and evolution. We previously developed a cost-effective hybrid Oxford Nanopore (ONT) long-read and Illumina short-read sequencing approach and used it to assemble 101 drosophilid genomes from laboratory cultures, greatly increasing the number of genome assemblies for this taxonomic group. The next major challenge is to address the laboratory culture bias in taxon sampling by sequencing genomes of species that cannot easily be reared in the lab.

View Article and Find Full Text PDF

Long-read sequencing is driving rapid progress in genome assembly across all major groups of life, including species of the family Drosophilidae, a longtime model system for genetics, genomics, and evolution. We previously developed a cost-effective hybrid Oxford Nanopore (ONT) long-read and Illumina short-read sequencing approach and used it to assemble 101 drosophilid genomes from laboratory cultures, greatly increasing the number of genome assemblies for this taxonomic group. The next major challenge is to address the laboratory culture bias in taxon sampling by sequencing genomes of species that cannot easily be reared in the lab.

View Article and Find Full Text PDF

Climate change is expected to increase the intensity and occurrence of drought in tropical regions, potentially affecting the phenology and physiology of tree species. Phenological activity may respond to a drying and warming environment by advancing reproductive timing and/or diminishing the production of flowers and fruits. These changes have the potential to disrupt important ecological processes, with potentially wide-ranging effects on tropical forest function.

View Article and Find Full Text PDF

The represent a diverse group of closely related to Although they have radiated extensively in Australia, they have been the focus of few studies. Here, we characterized the karyotypes of 12 species from several species groups and showed that they have undergone similar types of karyotypic change to those seen in . This includes heterochromatin amplification involved in length changes of the sex and 'dot' chromosomes as well as the autosomes, particularly in the group of species.

View Article and Find Full Text PDF

Understanding how environmental factors affect the thermal tolerance of species is crucial for predicting the impact of thermal stress on species abundance and distribution. To date, species' responses to thermal stress are typically assessed on laboratory-reared individuals and using coarse, low-resolution, climate data that may not reflect microhabitat dynamics at a relevant scale. Here, we examine the daily temporal variation in heat tolerance in a range of species in their natural environments across temperate and tropical Australia.

View Article and Find Full Text PDF

The Scaptodrosophila genus represents a large group of drosophilids with a worldwide distribution and a predominance of species in Australia, but there is little information on the presence and impacts of Wolbachia endosymbionts in this group. Here we describe the first Wolbachia infection from this group, wClay isolated from Scaptodrosophila claytoni (van Klinken), a species from the east coast of Australia. The infection is polymorphic in natural populations, occurring at a frequency of around 6%-10%.

View Article and Find Full Text PDF

Many Drosophila species differ widely in their distributions and climate niches, making them excellent subjects for evolutionary genomic studies. Here, we have developed a database of high-quality assemblies for 46 Drosophila species and one closely related Zaprionus. Fifteen of the genomes were newly sequenced, and 20 were improved with additional sequencing.

View Article and Find Full Text PDF

Background: The highly polyphagous Queensland fruit fly (Bactrocera tryoni Froggatt) expanded its range substantially during the twentieth century and is now the most economically important insect pest of Australian horticulture, prompting intensive efforts to develop a Sterile Insect Technique (SIT) control program. Using a "common garden" approach, we have screened for natural genetic variation in key environmental fitness traits among populations from across the geographic range of this species and monitored changes in those traits induced during domestication.

Results: Significant variation was detected between the populations for heat, desiccation and starvation resistance and wing length (as a measure of body size).

View Article and Find Full Text PDF
Article Synopsis
  • Researchers explored how certain Drosophila species adapted genetically to arid environments, focusing on their use of cacti and tolerance to extreme heat and dryness.
  • The study revealed high rates of gene gains linked to cactus use, with the most heat-resistant species showing significant genetic changes and positive selection for metabolism-related genes.
  • The findings imply that the rapid adaptations observed in these flies might make it challenging for species to keep up with the pace of climate change caused by human activities.
View Article and Find Full Text PDF

Wolbachia bacteria are common insect endosymbionts transmitted maternally and capable of spreading through insect populations by cytoplasmic incompatibility (CI) when infected males cause embryo death after mating with uninfected females. Selection in the Wolbachia endosymbiont occurs on female hosts and is expected to favour strong maternal transmission to female offspring, even at the cost of reduced CI. With maternal leakage, nuclear genes are expected to be selected to suppress cytoplasmic incompatibility caused by males while also reducing any deleterious effects associated with the infection.

View Article and Find Full Text PDF

While numerous insect studies have demonstrated the effects environmental conditions, genetic variation and other factors have on thermal resistance, often showing patterns consistent with adaptive plasticity and local adaptation, few experiments have considered the effects of multiple factors simultaneously. Here however, we have investigated the impact of sex, rearing conditions, hardening, population, and laboratory rearing period on adult heat resistance in stocks of Drosophila hydei, a cosmopolitan species that occurs across a range of climatic zones. We show that population and putative laboratory adaptation effects are larger than those associated with rearing temperature and hardening, although there was also a notable interaction between hardening and sex, in that females showed a cost of hardening that was not present in males.

View Article and Find Full Text PDF
Article Synopsis
  • * In the newly described Drosophila pandora, researchers identified two Wolbachia strains: a CI strain that leads to high maternal transmission and an MK strain that kills male offspring, with both strains appearing to have unique genetic backgrounds.
  • * Population studies show that Wolbachia infections are widespread in Drosophila pandora, but the MK strain is rare; CI strain females likely have a fitness advantage, impacting infection dynamics and sex ratios in different breeding environments.
View Article and Find Full Text PDF

There is increasing interest in comparing species of related organisms for their susceptibility to thermal extremes in order to evaluate potential vulnerability to climate change. Comparisons are typically undertaken on individuals collected from the field with or without a period of acclimation. However, this approach does not allow the potential contributions of environmental and carry-over effects across generations to be separated from inherent species differences in susceptibility.

View Article and Find Full Text PDF

The morphology of male genitalia whilst stable within species, exhibits huge interspecific variation. This variation is likely to be as a result of sexual selection due to the direct involvement of these reproductive structures in mating and sperm transfer. In contrast, internal soft tissue components of the genitalia are generally poorly investigated as they are not directly involved in physical and mechanical adequacy during sperm transfer.

View Article and Find Full Text PDF

Several evolutionary hypotheses help explain why only some species adapt readily to new conditions and expand distributions beyond borders, but there is limited evidence testing these hypotheses. In this study, we consider patterns of neutral (microsatellite) and quantitative genetic variation in traits in three species of Drosophila from the montium species group in eastern Australia. We found little support for restricted or asymmetrical gene flow in any species.

View Article and Find Full Text PDF

Grape phylloxera, Daktulosphaira vitifoliae (Fitch) (Hemiptera Phylloxeridae) is a damaging pest of grapevines (Vitis spp.) around the world, and the management of this pest requires early detection of infestations. Here, we describe the development and validation of a sensitive DNA test for grape phylloxera that can be applied to soil.

View Article and Find Full Text PDF

Although fragmented rainforest environments represent hotspots for invertebrate biodiversity, few genetic studies have been conducted on rainforest invertebrates. Thus, it is not known if invertebrate species in rainforests are highly genetically fragmented, with the potential for populations to show divergent selection responses, or if there are low levels of gene flow sufficient to maintain genetic homogeneity among fragmented populations. Here we use microsatellite markers and DNA sequences from the mitochondrial ND5 locus to investigate genetic differences among Drosophila birchii populations from tropical rainforests in Queensland, Australia.

View Article and Find Full Text PDF

Divergence among populations can occur via additive genetic effects and/or because of epistatic interactions among genes. Here we use line-cross analysis to compare the importance of epistasis in divergence among two sympatric Drosophila species from eastern Australia, one (D. serrata) distributed continuously and the other (D.

View Article and Find Full Text PDF

The prospect for successful biocontrol using immunocontraception is threatened if there is adaptation to the vaccine through natural selection of individuals that are genetically resistant to the contraceptive agent. To assess this possibility we examined the literature and found that little relevant data are available for any species on the appropriate trait, fertility variation among immunized individuals, or about appropriate population and genetic parameters influencing the likelihood of a selection response. Some data are available on variation in antibody response to immunocontraceptives, but the relationship between antibody response and fertility levels is poorly documented.

View Article and Find Full Text PDF

Clines for size and stress resistance traits have been described for several Drosophila species and replicable clines across different species may indicate climatic selection. Here we consider clines in stress resistance traits in an Australian endemic species, D. serrata, by comparing levels of variation within and among isofemale lines initiated with flies collected from the eastern coast of Australia.

View Article and Find Full Text PDF

Heritabilities and evolvabilities for morphological traits were compared between two environments in Drosophila melanogaster using parent-offspring comparisons. One of the environments was favorable. The other stressful environment involved a combination of repeated cold shocks, poor nutrition, and ethanol added to the medium, which markedly decreased viability.

View Article and Find Full Text PDF

A PHP Error was encountered

Severity: Notice

Message: fwrite(): Write of 34 bytes failed with errno=28 No space left on device

Filename: drivers/Session_files_driver.php

Line Number: 272

Backtrace:

A PHP Error was encountered

Severity: Warning

Message: session_write_close(): Failed to write session data using user defined save handler. (session.save_path: /var/lib/php/sessions)

Filename: Unknown

Line Number: 0

Backtrace: