Is there a relationship between dominance rank and condition in captive male bank voles, Clethrionomys glareolus?

The sexual selection theory predicts that traits associated with male-male competition or female mate choice honestly reflects individual quality when they are costly and condition dependent. Dominance seems to be a reliable signal of male quality. The aim of this study was to investigate whether dominance rank, measured in terms of agonistic interactions and trait correlated with dominance, such as preputial gland mass, depends on condition in captive male bank voles. We used five physiological measures to characterize condition: body mass, neutrophils to lymphocytes ratio (N/L ratio), spleen mass, thymus mass and adrenal gland mass. Additionally, the condition of males was challenged with a T cell-dependent antigen, sheep red blood cells. Dominance rank was not significantly related to body mass, N/L ratio and adrenal gland mass but was positively correlated with immune defence organ mass. Moreover, testes mass was positively related to the N/L ratio. However, after Bonferroni correction, only the relationship between preputial gland mass and thymus mass remained significant. Results of this experiment showed condition dependence of dominance in captive male bank voles.