ENDOCRINE CORRELATES OF CONTRASTING MALE MATING STRATEGIES IN THE EUROPEAN BADGER (MELES-MELES)

In mammals, testosterone secretion is known to respond rapidly to chan ges in males' immediate social environment. However, such changes do n ot take testosterone levels below the baseline required to maintain sp ermatogenesis, and so do not usually affect males' fertility. In this paper, we show that individual males' patterns of testicular activity reflect their social roles in a group-living carnivore, the European b adger (Meles meles), leading to individual and population differences in the seasonal patterns of both testosterone secretion and, apparentl y, spermatogenesis. In one badger population, some males left their na tal groups to become breeding males in neighbouring territories. These males had higher plasma testosterone levels, and appeared to sustain spermatogenesis for a longer period, than males which remained in thei r natal territories. In contrast, in a second (higher density) populat ion, males rarely transferred away from their natal territories, and a ppeared not to defend access to groups of females. Instead, males made forays to mate with females in neighbouring territories. In this popu lation males had a shorter period of testicular activity, and there we re no differences in testicular activity between immigrant and natal m ales.