Thesis title: The influence of phenotypic plasticity on the thermal physiology of Eccritotarsus catarinensis

Supervisors: Dr Iain Paterson and Dr Julie Coetzee

Tamzin is currently working on Eccritotarsus catarinensis (Carvalho)(Miridae), a biological control agent for water hyacinth, Eichhornia crassipes (Mart.) Solms (Pontederiaceae) which has failed to establish in some parts of South Africa due to climatic incompatibility. Some insects have the ability to change their thermal tolerance according to the temperatures they are exposed to, without a change in their genotype. This is known as phenotypic plasticity. Thermal tolerance of two populations of E. catarinensis from different climatic regions of the native range were tested using degree day models. This showed that each population’s thermal physiology matched their particular climate. However, after years of being reared under the same conditions in quarantine preliminary work done by Tamzin during her honours in 2015 showed that their thermal physiologies have converged, which may be the result of adaptation or thermal plasticity. This study aims to test whether E.catarinensis show phenotypic plasticity and if this explains their thermal physiology depending on the environment in which they live. Tamzin's masters will look at improving the biological control program of E. crassipes by increasing the chances of E. catarinensis establishment in colder regions.

Last Modified: Fri, 16 Mar 2018 15:44:20 SAST