No asymmetry in the level of incest avoidance between mother-son and father-daughter pairs in the mandarin vole (Lasiopodomys mandarinus) (Rodentia: Arvicolinae)

. Animals of most species avoid close inbreeding, but the levels of incest avoidance (IA) vary both between and within species. Evolutionary reasons for this diversity are generally unclear. Comparison of IA between closely-related species and between within species categories (sexes, age classes or categories of kin pairs) could provide important tools to test hypotheses on the evolution of IA strategies. In this laboratory study we compared the likelihood of reproduction between mother-son and father-daughter pairs in a monogamous subterranean vole, Lasiopodomys mandarinus. The subterranean lifestyle is associated with impeded mates' encounters, costly dispersal, and relatively low value of each breeding attempt, which factors are expected to restrain the IA evolution. In polygynous uniparental animals, the predominance of father-daughter inbreeding over mother-son inbreeding is predicted. We aimed to test whether L. mandarinus, which exhibits a partial reversal of sex roles, displays an opposite pattern of asymmetry with a weakened IA between a mother and a son. Against the expectation, reproductive performance was dramatically reduced in both kin combinations. Mandarin vole's IA strategies follow the pattern typical for non-subterranean species with strong pair bonding, supporting the importance of mating system for IA evolution.