Female wolverine ( Gulo gulo) reproduction: reproductive costs and winter food availability

• Published in: Canadian Journal of Zoology
• Main Author: Persson, Jens
• Format: Article in Journal/Newspaper
• Language: English
• Published: Canadian Science Publishing 2005
• Subjects: Gulo gulo
• Online Access: http://dx.doi.org/10.1139/z05-143; http://www.nrcresearchpress.com/doi/pdf/10.1139/z05-143

An individual has only a given amount of resources, and therefore an increase in one demographic trait results in a trade-off that necessitates a decrease in a different demographic trait. In general, the main factor determining an individual mammal's reproductive investment is food supply. This study addresses how female wolverine (Gulo gulo (L., 1758)) reproduction is limited. I tested two complementary hypotheses: (1) current reproduction is affected by the costs of reproduction in the preceding year and (2) current reproduction is affected by food availability in the current winter. I addressed the first hypothesis by comparing reproductive rates of females in relation to their reproductive effort in the preceding year. I experimentally tested the second hypothesis by comparing reproductive rates of food-supplemented females versus non-supplemented females. Reproduction incurred costs on female wolverines that affected future reproduction, and reproductive costs appeared to be related to the duration of parental care. Reproduction was higher for food-supplemented females than for non-supplemented females, even though all food-supplemented females had reproduced the preceding year. This study suggests that reproduction is limited by winter food availability and that additional food can compensate for reproductive costs. Thus, I suggest that female wolverine reproduction is determined by their condition in winter, which is a result of the combined effect of reproductive costs and winter food availability.