Linking conception and weaning success with environmental variation and female body condition in a northern ungulate

• Published in: Journal of mammalogy Vol. 95; no. 2; pp. 311 - 327
• Main Authors: Simard, M. Anouk, Huot, Jean, de Bellefeuille, Sonia, Côté, Steeve D.
• Format: Journal Article
• Language: English
• Published: Oxford American Society of Mammalogists 01.04.2014; Allen Press Publishing Services; Oxford University Press
• Subjects: Age; Animal behavior; Animal reproduction; Autumn; Body condition; Body size; Climatic conditions; Conception; Costs; Deer; Environmental conditions; FEATURE ARTICLES; Females; fertility; habitat; Lactation; Litter size; Plant biomass; Population density; Principal components analysis; Reproduction; reproductive pause; Success; Weaning; Winter; Quebec; Anticosti Island
• ISSN: 0022-2372; 1545-1542; 1545-1542
• DOI: 10.1644/13-MAMM-A-036

Success or failure of any stage of reproduction is generally related to maternal characteristics and environmental influences. In addition, postreproductive body condition of females should be a function of effort allocated to reproduction. Using data on > 800 female white-tailed deer (Odocoileus virginianus) harvested during 4 years on Anticosti Island (Quebec, Canada), we investigated factors affecting reproductive status, from ovulation to weaning, and measured the resulting effect on female body condition. The probability of ovulation (single or double) increased with female age, but weaning success was unrelated to age. Female reproduction was determined by climatic conditions in each season and the availability of preferred habitat, but high density only affected young primiparous females. More specifically, snowy autumns decreased ovulation rate, dry springs disfavored the production of twins, and cold and snowy winters decreased weaning success. Habitat with high summer plant biomass favored both 1st ovulation and weaning success. We suggest that restricted forage conditions encountered during their 1st year of life selected for higher-quality females, that is, females with fewer reproductive pauses and higher weaning success. Reproductive effort generally decreased female body condition, which was lower in lactating than nonlactating females. We suggest that twin production occurred in higher-quality females because, although females conceiving twins had reduced fat reserves, they maintained larger body size and higher muscular mass than mothers of singletons. Our results demonstrate that females adjusted reproductive effort according to seasonal environmental conditions, probably to minimize the consequences of reproduction on body condition, a proxy of reproductive cost.