Sarah Naomi Kalisvaart, council member

About my research

Plants are under constant threat of attack by a wide range of insects herbivores. One way plants cope with this threat, is by releasing a “cry for help”: the plant will excrete volatile compounds to attract the natural enemies of the herbivore that is attacking. Parasitoid wasps are an example of such natural enemies and are widely used as a biocontrol agent in agriculture. Parasitoid wasps are carnivorous insects that lay their eggs in or on an insect host, sometimes with the help of symbiotic agents such as polydnaviruses and venom. When a parasitoid wasp parasitises its host, the host undergoes a series of changes in both behaviour and physiology. Because of these behavioural and physiological changes, a plant may perceive a parasitised herbivore differently from a non-parasitised one and change its defensive response. An altered plant response following parasitism could influence the other organisms that are living on or in proximity of the affected plant. We know very little about what ecological consequences this change in plant response has on the rest of the insect-plant community, or what role these symbiotic agents may play in this effect.

In my project, I aim to explore the plant-mediated ecological effects that parasitoids and their symbionts have on the insect-plant community. By isolating the symbiotic agents of the parasitoids and micro-injecting them into the caterpillar host, I can specifically research their effect. I perform greenhouse studies to research the plant-mediated effect parasitoids have on the performance of insect herbivores; behavioral studies to look at the preference of heterospecific parasitoids; laboratory experiments to thoroughly explore the altered plant response through RNAseq, phytohormone-, glucosinolate- and volatile analyses; and finally, field studies to relate the results of the greenhouse and lab to the outside in practice.