Repository logo

Fitness consequences of peak reproductive effort in a resource pulse system

Faculty Advisor




iteroparous species, North American red squirrels, environmental conditions, reproductive output, boreal ecology, evolutionary ecology, evolutionary theory, physiological state, individual quality, exploration tendency

Abstract (summary)

The age trajectory of reproductive performance of many iteroparous species features an early - life increase in performance followed by a late - life senescent decline. The largest contribution of lifetime reproductive success is therefore gained at the age at which reproductive performance peaks. Using long term data on North American red squirrels we show that the environmental conditions individuals encountered could cause variation among individuals in the “height” and timing of this peak, contributing to life history variation and fitness in this population that experiences irregular resource pulses. As expected, high peak effort was positively associated with lifetime reproductive output up to a high level of annual effort. Furthermore, individuals that matched their peak reproductive effort to an anticipated resource pulse gained substantial fitness benefits through recruiting more offspring over their lifetime. Individual variation in peak reproductive effort thus has strong potential to shape life history evolution by facilitating adaptation to fluctuating environments.

Publication Information

Hamalainen, A., McAdam, A. G., Dantzer, B., Lane, J. E., Haines, J. A., Humphries, M. M., Boutin, S. (2017). Fitness consequences of peak reproductive effort in a resource pulse system. Scientific Reports 7:9335. DOI: 10.1038/s41598-017-09724-x


Item Type





Attribution (CC BY)