Evolutionary neuroethology of olfaction in Ostrinia

The European corn borer (ECB), Ostrinia nubilalis (Lep.: Pyralidae) is a serious pest in Europe and in US. It has two pheromone strains, which are produce and respond to opposite ratios of the two pheromone components, E11- and Z11-tetradecenyl-acetate. Therefore, the ECB is a good model organism for the study of evolution sexual communication and the olfactory circuitry in insects.

Mapping pheromone detection in the brain of the European corn borer is done in two steps. First, the antennal lobes are visualized with antibody staining (A) and then reconstructed (B). Second, brain interneurons are physiologically characterized, filled (C, yellow) and reconstructed (D, E) to verify their innervation pattern. We study the neuroethology of Ostrinia using a comparative approach. We recently discovered a novel mechanism that can account for saltatory shifts in pheromone preference. In male O. nubilalis a single gene causes pheromone receptors (pORs) to swap between sensory neurons. The swap reverses the preference for the ratio in their two pheromone component blend, and supports the coexistence of two races. Using a multidisciplinary appproach involving molecular biology, physiology and immunocytochemistry, I will elucidate the mechanisms that underly this swap.

We will reconstruct the evolutionary history of pheromone preference in sibling species of ECB. These species are highly interesting as their pheromones differ in structure, ratio, or composition, which signify evolutionary changes at different levels of integration: pORs, expression pattern in antenna, and wiring in the brain.

Funding

Carl Tryggers Stiftelse

Personnel

Zsolt Karpati, Anneli Nordén, Teun Dekker