Parasitism and feather reflectance in mourning doves (Zenaida macroura)

摘要

udThe theory of sexual selection has proven to be an important factor in understanding the mechanisms behind the evolution of secondary sexual traits. The Hamilton and Zuk (1982) hypothesis of parasite-mediated sexual selection postulates that birds evolved ornamentation to indicate parasite resistance to potential mates. My research explores the relationship between parasite load and plumage coloration in hunter-harvested mourning doves. Plumage from seven body areas was collected, ectoparasites were quantified and blood smears made so that intracellular hematozoan parasites could be quantified. Tarsometatarsi were measured, and the testes of males were collected to determine any effects of parasite load on them. Plumage was subject to UV-vis photospectroscopy to determine the tristimulus color values of brightness, chroma, and hue. The results of this research indicate that blood parasites and ectoparasites affect plumage brightness, chroma and hue, but the effects are inconsistent across plumage locations and color values. From this, it can be concluded that hematozoan parasites and ectoparasites do not fully explain variations found in plumage coloration in mourning doves. This means that other factors, such as gut parasites, nutritional condition, and age must be considered as additional potential sources of plumage variation. My project lays the groundwork for future research into the causes of plumage color variation in mourning doves.