Document Type

Thesis

Degree

M.S.

Degree Granting Department

Biology (Integrative Biology)

Major Professor

Lynn B. Martin

Keywords

behavior, corticosterone, early life, female choice, infection, LPS

Abstract

Some male sexually selected traits are sensitive to stressors early in life and provide females with information to discriminate among males with different developmental experiences. Moreover, female early life experiences could also impact which males they choose. Females might either choose honest traits indicative of male quality, no matter their own experiences, or they might choose mates to match or compensate for their own experiences. To determine how developmental stressors alter male sexually-selected traits and female preference thereof, I exposed zebra finches (Taeniopygia guttata, ZEFI) to i) lipopolysaccharide (LPS), an immunogenic, Gram-negative bacterial component, ii) corticosterone (CORT), an avian stress steroid, iii) both challenges (CORT/LPS), or iv) none of the above (control vehicles). Finches were exposed during development (12-28 days post-hatch) and male traits (e.g., body size, bill and cheek coloration) and female behaviors (e.g., general activity, male sampling effort, and male preference) were then measured in adulthood. Control males were predicted to express the most elaborate traits followed by LPS, CORT, and then CORT/LPS males. If female preference was generally driven by male quality, control females were predicted to be most selective followed by LPS, CORT, and CORT/LPS females. Alternatively, if female choice was contingent on her own experience, females might choose males with similar (i.e, matching) or distinct (i.e, complementarity) developmental histories. Of the male characteristics measured, only cheek coloration was impacted by treatment early in life; CORT/LPS males had duller, less orange cheeks than controls. For females, overall activity was reduced in CORT/LPS females. More importantly in regards to mate choice, females exhibited a blend of matching and complimentary behavior; females not exposed to LPS or CORT preferred males also not exposed to LPS or CORT. In general, females avoided LPS males no matter their own experience. Altogether, this study suggests that female mate preference is quite sensitive to early-life experiences and driven by a mix of choice of outright male quality and relative complementarity.

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