Female reproductive development is not activated by male California voles exposed to family cues.

Reproductive development of male California voles (Microtus californicus) is delayed when voles are raised in bedding taken from their family. In these experiments the effects of this chemically mediated puberty delay on male reproductive potential were examined. Males were paired with females for a 4-day period; the resultant uterine weights constituted a measure of male potency. In Experiments 1 and 2, 45-day-old males raised in clean or family bedding were paired with females. Regardless of whether cohabitation occurred in a clean, novel cage or in the male's home cage, only males reared in clean bedding caused significant growth of the female reproductive tract. In Experiment 3 the stimulus males were adults, either castrated or intact. Only cohabitation with an intact male stimulated female reproductive development. These data show that chemical cues present in family bedding impair the ability of young males to stimulate reproductive development in females and suggest that this effect is due to low circulating androgen levels in reproductively delayed males. Since chemical cues in bedding from solitary males did not activate uterine growth, the androgen-dependent deficit in delayed males may be behavioral. The relevance of these phenomena to animals living in a natural environment is discussed.