Journal Article

Testosterone‐Mediated Effects on Fitness‐Related Phenotypic Traits and Fitness

Oksanen, Tuula A., Mills, Suzanne C., Poikonen, Tanja, Grapputo, Alessandro, Koskela, Esa, Jokinen, Ilmari, Mappes, Tapio

2009

Overview

The physiological and behavioral mechanisms underlying life‐history trade‐offs are a continued source of debate. Testosterone (T) is one physiological factor proposed to mediate the trade‐off between reproduction and survival. We use phenotypic engineering and multiple laboratory and field fitness‐related phenotypic traits to test the effects of elevated T between two bank voleMyodes glareolusgroups: dominant and subordinate males. Males with naturally high T levels showed higher social status (laboratory dominance) and mobility (distance between capture sites) than low‐T males, and the effect of T on immune response was also T group specific, suggesting that behavioral strategies may exist in male bank voles due to the correlated responses of T. Exogenous T enhanced social status, mate searching (polygon of capture sites), mobility, and reproductive success (relative measure of pups sired). However, exogenous T also resulted in the reduction of immune function, but only in males from the high‐T group. This result may be explained either by the immunosuppression costs of T or by differential sensitivity of different behavioral strategies to steroids. Circulating T levels were found to be heritable; therefore, female bank voles would derive indirect genetic benefits via good genes from mating with males signaling dominance.

• Publisher: The University of Chicago Press,University of Chicago Press,University of Chicago, acting through its Press
• Subject: Animal and plant ecology / Animal behavior / Animal, plant and microbial ecology / Animals / Antibodies - blood / Antibody formation / Arvicolinae - immunology / Arvicolinae - physiology / Biological and medical sciences / Encounter groups / Environmental Sciences / Finland / Fundamental and applied biological sciences. Psychology / General aspects / Genetics / Genotype & phenotype / Global Changes / Heritability / Hierarchy, Social / Immune response / Immune system / Immunoglobulin G - blood / Linear Models / Male / Male animals / Mating behavior / Myodes / Phenotype / Phenotypic traits / Physiology / Radioimmunoassay / Reproduction / Reproductive success / Rodents / Spatial Behavior - physiology / Species Specificity / Survival Analysis / Testosterone / Testosterone - blood / Testosterone - immunology / Testosterone - physiology / Voles