Kate Mitchell (PhD Candidate)

Climate change has been predicted to have a significant impact on most organisms, particularly those susceptible to temperature increases, such as rainforest communities. In light of the potentially devastating nature of climate change, it is important to understand how and why species’ responses may vary, and the advantages, if any, this may provide. Recent work has highlighted climate change-related conditions may actually favour certain organisms when under competition, with invasive springtail species found to have a greater desiccation resistance, and, therefore, ability to persist under warmer temperatures and decreased rainfall than their endemic counterparts. One possible explanation for this pattern is the increased phenotypic plasticity often shown in invasive species. The potential for phenotypes to vary in response to environmental cues may allow species to persist under changing conditions and facilitate an adaptive response. As such, phenotypic plasticity has been identified as an important short-term mechanism for organisms to deal with climate change. In order to adapt, however, there must also be heritable genetic variation for selection to act upon. Recent studies have shown that heritability is limited in certain traits within the same organism, most notably for desiccation resistance in the rainforest specialist, D. birchii. At this point, it is uncertain if this phenomenon occurs in other species, and, if so, if it is restricted to those more specialised. In any case, it should not be assumed that heritable variation is unlimited, and, as such, it is important to investigate this further to gain an overall understanding of species response to disturbance.

The purpose of my project is, therefore, to determine the effect the level of specialisation may have on an organisms’ ability to adapt to disturbance, in particular climate change. I intend to do this by investigating the phenotypic plasticity and heritability of traits expected to have fitness consequences in light of climate change i.e. desiccation resistance and thermal tolerance, along with those that may infer competition benefits, such as resource utilisation in tropical Drosophila species collected from rainforest, woodland, heathland and urban environments.