Trade-offs between growth and reproduction in female bison.

摘要: The extent to which (a) larger females produce more or offspring, (b) reproduction imposes costs, and (c) the benefits of early outweigh costs was examined for female bison (Bison bison) with data from an 8-year period. Description ontogenetic patterns indicated that reproductive performance reached a plateau near end growth period; changes age in fecundity were little related those body weight during typical lifespan (age 3–18 years). Examination inter-and intra-individual variation showed relationship between depends on subjects. Larger juveniles matured earlier fecund (though smaller) as adults. In contrast, post-pubertal negatively reporductive performance, although positively associated pregnancy rate. Fecundity not generally lower years after than barren years, spite loss, suggesting did impose significant fitness costs. On other hand, offspring quality when mothers reproduced successive rather alternate years. Early maturation resulted immediate including reduced infertility year first parturition. However, there long-term benefits: 7–9 highest early-maturing lowest late-maturing females, success is greater despite growth. present study, trade-offs appear reflect substantial measured by success.