Genetic Tradeoffs in Resistance to Natural Enemies

University Of Cincinnati Main Campus, Cincinnati OH

Investigators

Abstract

In theory, tradeoffs between host resistance against parasites and host fitness traits play a key role in the maintenance of genetic variation and hence in determining the evolutionary potential of resistance. The proposed research encompasses a comprehensive empirical study of tradeoffs focusing on host life history and ecological traits, and will utilize a Drosophila-mite system as a model to address several key hypotheses. These hypotheses are that strains selected in the laboratory to be more resistant to parasitic mites will suffer, in the absence of the parasites, significant reductions in egg hatch success, ability to compete for limiting resources, survivorship and fecundity, and in defensive capabilities against other natural enemies. These enemies include an invertebrate predator and an insect-pathogenic bacterium. Another major emphasis will be to test for the presence of costs of resistance under variable environmental conditions to which the host organism is known to be exposed in nature. Many of the elements that mediate the Drosophila-parasitic mite association are seen in vertebrate host-ectoparasite interactions, and in associations between insect prey and their predators. Thus the results of the proposed work should provide data of importance toward understanding the mechanisms and evolution of resistance across a broad array of animal species. The data generated are also expected to help define criteria for choosing appropriate natural enemies, and especially mixtures of natural enemies, for effective biological pest control. The research should therefore help to reduce dependency on chemical pesticide and herbicide usage, and hence promote environmental health. Our general knowledge of multispecies associations and their ecological complexities should also be advanced. The research effort will contribute to the training of both undergraduate and graduate students, and it should be of practical and societal value as it is expected to help develop novel methods of sustainable biological control.