A number of large new projects will be getting underway in 2019 as a result of ARC funding schemes. Dustin Marshall and Matt Hall are now Future Fellows and Giulia Ghedini has received a Discovery Early Career Researcher Award. Dustin and Giulia will be using marine invertebrates to look into impacts of global warming whilst Matt is tackling the importance of sex in the evolution of infectious disease.
Within a given species, often the greatest heterogeneity that a pathogen will encounter will be due to differences between males and females. Yet, up until recently, insight into this crucial topic was driven by research into one sex, typically males.
Matt’s recent work has shown that, in the water-flea Daphnia magna, not only is pathogen fitness lower in males, but so is a pathogen’s evolutionary potential. What is more, the relative proportion of males in a population can fundamentally alter the overall transmission potential of a pathogen.
This project was stimulated by Matt’s recognition that there is an absence of theory that explicitly considers how males and females can impact on the evolution and epidemiology of infectious disease. Matt is seeking to address this imbalance and integrate sex-specific effects into a general framework for disease evolution and epidemiology.
Matt will be using the water-flea Daphnia magnaand its associated pathogens to provide an experimental system in which he can manipulate infections in males and females, characterise the degree of differentiation, and generate predictive models.
Dustin will be investigating how temperature affects the life-history stages of feeding and non-feeding larvae. Marine life histories show strong biogeographic patterns: warmer waters favour species with feeding larvae and cooler waters favour species with non-feeding larvae. Warming could be particularly problematic for Australian species because in 2012, Dustin discovered that Australian coastal species predominantly have non-feeding larvae. This means that future temperatures increases could affect native Australian invertebrates disproportionately relative to other regions of the world. (Put in schematic from application here)
At the end of an intensive experimental period, Dustin will have quantitative estimates of how temperature alters the success of a range of species from the gamete to the juvenile. At this stage Dustin will work with collaborators to generate predictive models to determine
- how does temperature alter the relative advantages for each of the two developmental modes?
- how does temperature affect dispersal and connectivity among populations for each developmental mode? and finally
- how does temperature affect the distribution of marine organisms with feeding or non-feeding larvae?
Giulia will be investigating how global warming will affect entire ecological communities.
We already know that warming can affect individuals by reducing their body size and speeding up energy use, as well as reducing water viscosity. But what we don’t know is how these changes at the individual level might play out at the population and community level and affect the energy intake or expenditure of whole communities.
Giulia is particularly interested in this knowledge gap and will be investigating the implications of warming sea temperatures for important ecosystem functions such as productivity, food web stability or resistance to invasion.
Giulia has planned a series of experiments, using communities of easily manipulated, sessile, marine invertebrates, to explore 4 main questions.
- How do changes in community size-structure and composition under warming alter the energy intake (phytoplankton) and expenditure (oxygen) of marine invertebrate communities?
- Since the availability of energy can mediate biological invasions, does warming alter the energy usage of communities so that they are more susceptible to invasive species?
- Are the responses of invertebrate communities to warming mediated by changes in their food (phytoplankton)?
- Given that warming reduces water viscosity, how does this mechanical effect alter food consumption and metabolic expenditure in marine communities of different size-structure?