The topic of mate selection has always been an important one for researchers of animal behavior precisely because mate selection is vital to the species that those researchers are examining. No living organism can sustain life indefinitely and must eventually procreate to pass on their genetic information to the next generation. I have therefore chosen to study sexual selection and in particular the physiological traits that influence it by examining a species in which the factors effective mate selection are relatively transparent to the observer. In particular this research examines mate selection in the damselfly Calopteryx haemorrhoidalis.