The Reproductive Ecology of the House Mouse

Abstract

This paper attempts to integrate the physiological and ecological perspectives of the reproductive biology of the house mouse (Mus musculus). The endeavor is made within a larger context to provide a prototype for mammalian reproductive ecology in general. Specifically, the environmental regulation of the reproduction of Mus musculus is examined in relation to its ecological opportunism and, in particular, in relation to its history of global colonization. House mice can live as commensals of man or under totally feral conditions. Stable, high density, commensal populations are characterized by an insular division of the living space into demeterritories, each dominated by a single male. Feral populations typically are characterized by temporal, spatial, and social instability. Territoriality is improbable under such conditions, particularly given the necessity for large home ranges in most feral habitats. In both feral and commensal populations, however, male aggressiveness promotes the large-scale dispersal of young, all of which are potential colonizers. Of the ten or so environmental factors known to influence reproduction in house mice, seven probably are of routine importance in natural populations: diurnal modulation by daily light:dark cycles; caloric intake; nutrition; extreme temperature; agaonistic stimuli; socio-tactile cues; and priming pheronomes. The last two factors named operate directly on the secretion of luteinizing hormone or prolactin; the others act at many points in the reproductive system. Reproduction in the house mouse seems divorced from photoperiodically induced seasonality; indeed, this species breeds well even in constant darkness. Seasonal breeding may or may not then occur, depending upon dietary considerations, with or without a secondary interaction with variation in ambient temperature. There is no evidence for a dependence upon secondary plant compounds. Some of the effects of priming pheromones that have been observed previously in laboratory mice probably play no meaningful role in wild populations. The remaining pheromonal phenomena can be conceptualized as a single cueing system that has three components: (a) urinary cues of socially dominant males can accelerate ovulation in females, adult or prepubertal; (b) female urinary cues may elevate pheromonal potency in adult males, thereby forming a feedback loop by which the females elicit their own ovulation; and (c) the male's action on prepubertal females can be blocked by urinary cues emanating from other females. When all of the above is viewed in toto, the reproductive biology of the house mouse seems uniquely suited to support ecological opportunism. The relatively few environmental inhibitors of reproduction in this species should enhance the ability of dispersing young to colonize an exceptionally wide variety of habitats and climates...

Breeding of house mice and the mast seeding of southern beeches in the Orongorongo Valley, New Zealand

“…Although commensal mouse populations breed year round (Bronson 1979), feral house mice in temperate ecosystems are seasonal breeders (Bronson 1979;Pye 1993;Singleton et al 2001; this study). In New Zealand they typically breed only in spring and summer (Efford et al 1988;Ruscoe 2001).…”

“…Therefore, food shortage does not appear to explain the suppression of breeding in post-mast years relative to non-mast years. Direct social effects (Bronson 1979) were also unlikely to be responsible as peak densities were probably less than 10 mice/ha (Fitzgeraldetal. 1981).…”

Reflexive testosterone release: A model system for studying the nongenomic effects of testosterone upon male behavior

“…Alternatively, reflexive testosterone release may have indirect benefits to the female that stimulated release [39]. For example, by stimulating a male's testosterone secretion, the female promotes his release of an androgen-dependent urinary pheromone.…”

Energy Allocation in Mammalian Reproduction

“…We hope to show that (1) precise measurements of energetic constraints and consequences of reproductive behaviors must be incorporated into studies of mammalian behavior and (2) behavioral flexi-863 bility {e.g., in duration and/or frequency) may dramatically alter the relative energetic costs of specific reproductive events (see also Goldstein, 1988). Although we primarily address problems related to mammalian reproduction, we believe a general merging of energetics and behavioral perspectives, encompassing multiple measures of costs, will foster more complete analyses of the costs of reproduction in most organisms (see also Bronson, 1979;Calow, 1981Calow, , 1984Altmann, 1983Altmann, , 1986Knapton, 1984;Bennett, 1986;Costa and Gentry, 1986;Halliday, 1987).…”