Molecular mechanisms underlying opportunistic seasonal reproduction in the male rodent pest Arvicola terrestris scherman

The fossorial vole Arvicola terrestris scherman (ATS) is a pest rodent in Central Europe that is subject to cyclical infestations, the frequency of which is steadily increasing in a global context of climate and environmental change. Due to the significant economic, agricultural, and sanitary issues associated with ATS outbreaks, research is being conducted to better understand the physiological, behavioral, and environmental characteristics of these phenomena. The work presented here consisted of comparing ATS males from summer and winter in terms of anatomical, systemic, and testicular gene expression parameters. Interestingly, two reproductive morphs of males with the same anatomical characteristics in terms of overall body weight and coat length were observed during the winter period. One morph is typical of this seasonal breeding species, showing significant winter regression of its reproductive organs, while the other morph is atypical, appearing to having preserved the male reproductive tissues and function. Histological and RNAseq analyses of the testicular tissue clearly define the distinct characteristics of these animals, confirming the maintenance of reproductive capacity in some winter males. Knowledge of these physiological changes is an important factor in defining relevant control strategies.