Understanding the ecological and evolutionary effects of heatwaves in tropical species and ecological communities


   College of Science and Engineering

   Applications accepted all year round  Competition Funded PhD Project (Students Worldwide)

About the Project

Heatwaves are considered one of the most threatening processes for our plants and animal species as the Earth’s climate warms. There is much to understand about how our species and the ecological communities they form will change and adapt through heatwaves. The complexity of communities in the Tropics may make them especially vulnerable to the effects of heatwaves, given that many species seem to be close to their critical thermal limits in these already-warm tropical environments. My lab, in collaboration with Assoc. Prof. Conrad Hoskin (JCU), Prof. Owen Lewis (Oxford University), Prof. Jon Bridle (University College London), and Dr Deanne Francis (JCU), is answering some of these questions using native species of rainforest Drosophila, as well as the associated wasp species that parasitise them.

PhD Project 1: Understanding rapid adaptation and maladaptation to heatwaves and the potential for genetic and evolutionary rescue.

Rapid selection during occasional heatwaves may lead to the rapid evolution of increased resilience to warming climate. This is called the ‘silver-lining’ effect, where populations that have experience heatwaves are expected to have evolved greater heat tolerance. However several key issues remain. Under what scenarios and how quickly does a ‘silver-lining’ occur in heat-wave affected populations? Can any beneficial heat adaptation that occurs following a heatwave survive the small population sizes selection creates, and decrease in fitness from subsequent inbreeding depression? Can the movement of individuals between heat-wave affected populations mitigate detrimental effects of heatwaves while maintaining heat adaptation? Once adaptations have occurred across a species’ range, will they interfere with each other, or reinforce each other when populations meet? What effect do co-occurring species have on these parameters? We will use the SLiM evolutionary simulation framework to investigate these and other questions. This project would suit a student who is familiar with (or motivated to learn) evolutionary and/or statistical computer simulations. Their major simulation results could also be tested empirically on experimental research using native Australian rainforest Drosophila species.

PhD Project 2: Understanding trait correlations following rapid climate adaptation in tropical insect communities.

A critical question in understanding the consequences of climate change for ecological communities is the likelihood of rapid trait evolution during extreme events. Of particular interest is whether heatwaves can make tropical insect communities more resilient to future increases in mean temperature, by causing rapid adaptation in thermal resilience. At the same time however, such rapid adaptation is likely to lead to shifts in other traits such as competitive ability or immune or parasitoid defence. Unfortunately, such correlations between traits may lead reduce the resilience of ecosystems to other sources of environmental pressure. A key question in evolutionary biology is whether such trait correlations come from hard ecological limits, or whether they can (after several generations) be circumvented by further evolution. You will use a combination of tropical fieldwork, quantitative genetics and genomics to compare populations and families of tropical Drosophila in their responses to heatwaves, and the fitness consequences of rapid evolution. There may also be scope to explore how changes in gene expression underpin such trait shifts. Your results will have critical and urgent implications for predicting the ecological resilience of tropical communities in the face of continued climate change.

PhD Project 3: Understanding the physiological and molecular-genetic responses to heat in tropical insects.

Climate change will result in more prevalent and intense heatwaves globally, therefore, understanding how organisms adapt physiologically to environmental changes is critical. Many insects, including Drosophila, are ectotherms that naturally seek temperatures within their physiological limits. However, what happens when insects are exposed to constant heat from which there is no escape? How do they modulate their physiological responses to survive long enough during a heatwave? How does extreme heat affect their development, activity/sleep cycles, food intake and energy stores? What molecular and genetic pathways are involved? You will use a combination of molecular biology, genetics, and physiology to investigate the effects of heat exposure on Drosophila. Your results will be critical for a greater understanding of the physiological effects of extreme heat and potentially uncover new molecular mechanisms that underpin such responses. 

Applicant information

The competitive scholarship is open to Australian and non-Australian applicants. The scholarship is funded by the Australian Government and includes a living allowance (> AUD29,000/year) plus a tuition fee waiver (worth > AUD40,000/year) for a total of 3.5 years. Therefore, these scholarships are extremely competitive.

To be a successful applicant, you will need:

  1. A strong background in evolutionary biology and/or evolutionary genetics;
  2. A first-class research-based Honours or Master’s degree at an institution of high repute. Your degree must have included a > 6 month research project that represents a significant contribution to the final mark and is assessed via a formal examination of a research thesis; and
  3. Published peer-reviewed research paper(s), preferably in the field of evolutionary biology and/or evolutionary genetics or relevant field.

If you are interested and fulfil all three criteria above, please email me with a CV and brief letter stating your interest, background, and how you fulfil all three criteria.

Applications are open for Australian and non-Australian applicants both living in Australia and overseas.

The application deadline for a 2025 JCU scholarship is 31 August 2024 (by 11:59 pm Australian Eastern Standard Time (AEST)). Therefore, please contact me by 1 June 2024 to discuss your suitability.

Biological Sciences (4) Computer Science (8)

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