Genetic and behavioural basis of disease resistance in honey bees(Apis mellifera)

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The aim of this project will be to study fundamental aspects of the genetic and behavioural mechanisms that confer resistance to disease in honey bees (Apis mellifera). The honey bee is a good model organism for this type of study because of the large number of individuals in their colonies, their well-known division of labour, the existence of technology to manipulate their environment, and also because their genome has been sequenced. Behavioural and immune responses of honey bees to parasites will be examined. At the behavioural level, we will test the hypothesis that pathogens inhibit the expression of behaviours that confer resistance. At the molecular level, we will test the hypothesis that pathogens may activate or suppress specific innate defenses in the bees, depending on the nature of the pathogen as well as on the host genotype. We will also test the effect of potential immune inducing substances (activators) on the defense responses of individuals. The scientific approach will be to measure the expression of candidate genes associated to stress and immunity in honey bees of European and African origin (Africanized bees are presumably more resistant than European bees to parasites and diseases) exposed to parasites such as the mite Varroa destructor and the fungus Nosema ceranae. Behavioural assays will be used to assess grooming and hygienic behaviour in individual bees of the above genotypes that had been challenged with parasites. It is expected that this research will provide new insights into resistance and natural defenses of animals to pathogens. On the practical side, results of this project could shed light to better understand the collapse and death of more than one third of honey bee colonies in North America during each of the past three years, termed Colony Collapse Disorder. This unprecedented loss of colonies has endangered the continuous supply of honey bees as pollinators of flowering plants, which has strong economic implications.