Visual and chemical ecology of the woodwasp Sirex noctilio

Abstract

This thesis investigated the visual and chemical basis of the globally invasive woodwasp Sirex noctilio. The thesis provides a synthesis of the knowledge on the colour vision and pheromone communication in the Symphyta, a basal group of Hymenoptera. The study then used this knowledge to characterise the molecular basis of colour vision and pheromone communication in S. noctilio. Three genes responsible for colour vision were identified in the genome of this wasp, and its expression and light sensitivity were characterised. The study then compared the evolution of these genes across all insects and show correlation with key morphological traits such as simple eyes and life history. Finally, the candidate characterised four compounds constituting a male pheromone, its production and its antennal sensitivity. The study advances our fundamental knowledge about vision and chemical communication in Symphyta and Hymenoptera in general, and has applied value for the surveillance and management of S. noctilio.