Fishes rely upon conspecific-released bile acids to attain information required for various critical behaviors, the most commonly cited examples being migration and spawning. Numerous investigations have elucidated the underlying physiology and behavior of fishes cueing to conspecific bile acids, however the origins and evolution of such responses have yet to be discussed. In Chapter 1, bile acids are presented as a model to investigate how natural and sexual selection shape the design of aquatic chemical cues in a variety of contexts by synthesizing relevant chemical, physiological, and behavioral literature and providing hypotheses for contexts that have yet to be studied. In Chapter 2, I infer the origin of the sea lamprey (Petromyzon marinus) bile alcohol mating signal, 3 keto petromyzonol sulfate, by investigating the physiology and behavior of the ancestral silver lamprey (Ichthyomyzon unicuspis). I provide evidence that the use of 3kPZS as a mating signal evolved as a result of a sensory bias, whereas female preference evolved under natural selection rather than sexual selection. The hypotheses and supporting data presented aid to fill gaps in evolution and communication theory, for which the chemosensory modality is rarely considered.
Read
