Abstract
We will study the coordinated expression of genes causing assortative mating in the European corn borer Ostrinia nubilalis (ECB), an important insect pest of agricultural significance over much of the northern hemisphere. Our aim is to set the scene for subsequent studies of natural and sexual selection in the wild in a framework of contemporary speciation. The ECB is polyphagous and thrives on a large number of host plants. At the same time its sex pheromone system is polymorphic. In spite of significant cross attraction and the formation of fertile hybrids under laboratory conditions, the different host races display almost complete reproductive isolation in the field. We hypothesize that male-produced courtship pheromones play a role in the female acceptance of courting males and thus limit gene flow between the races. We will identify these male pheromones, determine their role in mate choice, reconstruct the biosynthetic pathways leading to their production and dissect the genetics of pheromone differences between the populations. Differential expression of genes potentially involved in speciation will be investigated in both male and female corn borers by means of microarray techniques. Finally, an attempt will be made to sequence, clone, and functionally express the fatty acid reductase gene previously demonstrated to account for differences in female pheromone production between the E and Z pheromone strains.
Sweden