PARENT SESSION
Contributed Oral Session 126: Mammal Ecology: Management, Reproduction, and Food Webs
Thursday, August 11, 8:00 AM - 11:30 AM, Meeting Room 524 C, Level 5, Palais des congrès de Montréal
How much worth is indirect fitness? A test using the yellow-bellied marmot.
Oli, Madan1, Armitage, Kenneth2, 1 Department of Wildlife Ecology and Conservation, Gainesville, FL, USA2 Department of Ecology and Evolutionary Biology, Lawrence, KS, USA
ABSTRACT- Organisms may gain fitness directly through their own reproduction (direct fitness), or indirectly through reproduction of relatives (indirect fitness) with whom they share genes. Indirect fitness has been suggested to be an important component of inclusive fitness, but the contribution of indirect fitness to an organism's inclusive fitness has rarely been empirically evaluated. Using 40 yrs of life-history data and the concept of individual fitness, we estimated direct and indirect components of fitness of female yellow-bellied marmots (Marmota flaviventris). We found that the contribution of indirect fitness to total fitness of most female yellow-bellied marmots was rather insubstantial. Females that lived past the reproductive age (2yr) but did not reproduce themselves had significantly lower total fitness compared to females that reproduced. The relative contribution of indirect fitness to total fitness of females that realized reproduction was substantially lower than that of the direct fitness. These results suggest that, at least in female yellow-bellied marmots, forgoing reproduction in the hope of gaining indirect fitness is a bad idea, and that individuals typically act to increase their direct, rather than indirect, fitness. Thus, "dying to save a kin" may be an evolutionary suicide in yellow-bellied marmots and many other species of mammals.
Key words: fitness, direct fitness, indirect fitness, Yellow-bellied marmot