Mia Vermaak

PhD Candidate

Primary Promotor: Prof. John S. Terblanche

Co-promotor: Dr Charlene Janion-Scheepers & Dr Kim Jensen


The focus of my research is to establish the trophic ecology of Acari and Collembola in agroecosystems by integrating field observations with laboratory trails. The field component will be the establishment and comparison of the Acari and Collembola diversity present in different management practices between apple and pear orchards, by collecting leaf litter for Tullgren extractions. The extractions will also determine the structure and stability of food webs using stable isotope analysis (SIA) of nitrogen and carbon (15N & 13C). SIA will enable us to see the seasonal and taxonomic variations within and between orchards.

Microclimate and macroclimate will be measured at all of the orchard study sites to substantiate laboratory conditions. Live extractions will be used to establish Acari and Collembola colonies, to enable us to conduct the laboratory component. Thermal physiology of Acari and Collembola species will be tested through cold acclimation and heat tolerance trails between predator and prey under controlled conditions. This will lead to understanding their key behaviours, constraints and dispersal dynamics, to ultimately gain insight to their trophic structure and its stability through space and time.