Phenotypic plasticity in reproductive and somatic efforts of female Columbian ground squirrels

We examined a 27-year dataset of life-history traits on these long-living (8 –10 years), hibernating, montane-living mammals. Environmental variation was estimated from two important traits of mothers, their relative timing of breeding and spring maternal body mass (initial “capital” for use in subsequent reproduction). Results from 183 known-aged mothers and 508 litte rs revealed considerable variation in the relative timing of breeding, initial maternal mass, and reproductive and somatic efforts, as well as significant variation among ages and years. Results from 125 mothers that reproduced more than once (and 450 litters) revealed significant plasticity of repr oductive and somatic efforts with respect to relative timing of breeding and spring maternal mass. A within-subject centering statistical approach showed that phenotypically plastic reproductive and somatic efforts were due to variation within individuals, but were not always reflected by the patter n of responses among individuals in the population. The plastic responses of different mothers appeared to be similar in strength.
Source: Canadian Journal of Zoology - Category: Zoology Authors: Source Type: research