title: Efficiency of delayed reproduction in Mus spicilegus.
abstract: To cope with seasonally varying ecological constraints, some mammals temporally suppress breeding or delay their first reproduction. In field conditions, mound-building mice (Mus spicilegus) born in spring begin to reproduce when 2-3 months old, whereas individuals born at the end of summer delay their first reproduction for 6-8 months until the following spring. In order to test age effects on reproductive performance in M. spicilegus, sexually naïve mice were paired when 2-3 months old or at 6-8 months of age, and surveyed for reproduction. We show here that under laboratory conditions the aging of these mice does not impair their reproductive efficiency. Thus, the hypothesis of a lower reproductive potential in these relatively aged females seems to be contradicted. More surprisingly, the latency from pairing to the first reproduction was greater in the 2-3-month-old adults than in the delayed reproducers (6-8-month-old mice). Mound-building mice that are old enough to have overwintered do not suffer significant reproductive declines, but appear to reproduce as well and more quickly than younger first-time breeders.
authors.affiliation: Laboratoire d'Ethologie Expérimentale et Comparée, Sorbonne Paris Cité, Université Paris Nord, F-93430 Villetaneuse, France.
authors.forename: Marie
authors.initials: M
authors.lastname: Lafaille
authors.affiliation: Laboratoire d'Ethologie Expérimentale et Comparée, Sorbonne Paris Cité, Université Paris Nord, F-93430 Villetaneuse, France.
authors.forename: Patrick
authors.initials: P
authors.lastname: Gouat
authors.affiliation: Laboratoire d'Ethologie Expérimentale et Comparée, Sorbonne Paris Cité, Université Paris Nord, F-93430 Villetaneuse, France.
authors.forename: Christophe
authors.initials: C
authors.lastname: Féron
mesh_terms: D000375:Aging / Q000502:physiology*; D000818:Animals; D005260:Female; D005298:Fertility / Q000502:physiology*; D008098:Litter Size; D008297:Male; D051379:Mice; D012098:Reproduction / Q000502:physiology*; D012621:Seasons; D012726:Sexual Behavior, Animal / Q000502:physiology