Insects are the most successful group of animals, both in terms of the overall number of insects and the number of insect species. This success is due, in large part, to their ability to adapt to a wide variety of habitats and environmental conditions. One reason for this adaptability is that insects possess an extremely versatile excretory system that helps balance the intake and elimination of water, ions, and small molecules. Within the excretory system, urine is produced by an organ called the Malpighian tubules. The focus of this project is the Malpighian tubules of the fruit fly Drosophila melanogaster, and specifically on the ability of a small molecule, tyramine, to increase urine production by the tubules. The proposed experiments will employ measurements of Malpighian tubule function in flies in which the expression levels of specific genes have been altered by molecular genetic techniques. It is expected that such experiments will characterize some of the genes that are necessary for tyramine to affect tubule function; specifically, the genes necessary for tyramine synthesis and detection will be identified. The identification of these genes will be important for a more complete understanding not only of insect excretory function, but also of other aspects of insect physiology and behavior in which tyramine is thought to play a role, such as feeding and reproduction. In the long term, such understanding could be important in the development of new controls for insect pest species. Finally, this project will contribute to the education of the graduate and undergraduate students who will conduct many of the proposed experiments.
