FABI PhD candidate presents a special seminar on how Sirex noctilio sees colour 2019-08-02
PhD candidate Quentin Guignard presented a special seminar on the visual system of the European woodwasp, Sirex noctilio, at FABI on 29 July. In his presentation titled “Understanding colours vision in insects: aye, aye, eye”, Quentin shared with the audience what he had learnt during his time at the University of Wurzburg in Germany, where he learnt to operate an electroretinogram (ERG). Quentin spent three weeks at the institution after the Entomological Society of Southern Africa awarded him the ESSA Young Entomologists’ Travel Grant. One of the conditions of the grant was to give a public seminar on what he had learnt during his visit.
From the physics of the light to how lights is absorbed in the eyes, Quentin highlighted the importance of having different opsin proteins to be able to discriminate different colours. In his PhD, Quentin found three opsin genes in S. noctilio. Using the ERG, he could link the accurate spectrum of wavelengths absorbed by two opsins. An ERG experiment involves inserting an electrode in the eye of an immobilized insect and flashing different colours. The different depolarisations for each colour are transformed and analysed, and the visual spectrum modelled for each opsin.
Quentin explained how the ERG machine works, how to set up an ERG experiment and how the data are analysed. This data were used to show the link between the genetic basis and the physiological output of the opsins in S.noctilio.