Our research is focused on illuminating the role of genomic parasites in generating intragenomic conflict, predominantly working with insects, by elucidating the consequences for mating systems, the evolution of new traits, the creation of biological novelty, and the survival of populations. We pose our questions in the context of intense insecticide usage in agriculture and environmental stresses caused by climate change.

In fruit flies (Drosophila melanogaster), a transposable element (TE) inserted into the metabolic gene (Cyp6g1) confers insecticide resistance and increases female fecundity, but can decrease male mating success and alter male aggression. TE insertions and Cyp6g1 duplications are associated with sex differences in resistance. We investigate the impact of multiple TE insertions on resistance evolution and their potential SA effects. We also interrogate the molecular mechanisms responsible for SA, trying to understand how the same allele can lead to contrasting sexual effects between males and females. While examining the importance of these elements as evolutionary forces we also investigate their effect considering anthropomorphic, abiotic, and biotic factors that pose a threat to insect populations, such as insecticide usage and climate change. We offer the following projects:

The effect of transposable elements on fertility. Cyp6g1 is an important locus that confers resistance to multiple insecticides. An allelic series for this locus exist, with each allele conferring different levels of insecticide resistance. Importantly, different alleles also affect fly fitness, but in opposite ways - increasing female but reducing male fitness. This project aims to understand how the presence of a P-element in the Cyp6g1 BP allele can affect the female (and possibly male) fertility. P-elements are known to profoundly affect Drosophila fertility through hybrid dysgenesis. Flies with BP alleles in different genetic backgrounds will be assessed for dysgenic phenotypes in females (ovary atrophy). Using molecular techniques, the P-elements will be characterised to investigate their activity and contribution to the dysgenic phenotype.

Evolution of allelic polymorphisms in natural populations exposed to climate change. Natural populations are locally adapted to specific conditions. However, climate change is altering these conditions at an alarming rate. The effect of changing temperatures on natural variation is an emerging field of study with great importance. We propose to study how natural variation in Cyp6g1 allelic polymorphism, a gene responsible for conferring resistance to insecticides, change between populations that are locally adapted when exposed to new temperatures. Allelic frequencies of populations from north and south of the East coast of Australia will be assessed over multiple generations when exposed to different temperature ranges to quantify the contribution of each allele to temperature sensitivity. The temperature ranges will also be assessed for impacts on fitness and behaviour.

The synergism between temperature and insecticides for the demise of insect population. Insect population numbers are plummeting globally. Two important factors that may contribute to this ecological catastrophe are climate change and intense insecticide usage in agriculture. Using different mutant and wild-type Drosophila strains (sensitive or resistant to insecticides) this project aims to investigate how temperature and insecticides synergise. The tolerance to insecticide in males and females of different genetic backgrounds will be tested when flies are reared at different temperatures. Impacts on fitness and neurodegeneration (climbing ability and bang-sensitivity) will be assessed as well as the rescuing ability of antioxidants.

Prof

Nina Wedell

ARC Laureate Fellow

School of BioSciences

Prof

Nina Wedell

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