Evol Ecol Res 20: 247-263 (2019)     Full PDF if your library subscribes.

Trajectory and rate of change in female life-history traits following colonization of a freshwater, lacustrine environment by oceanic Threespine stickleback

John A. Baker1, David C. Heins2 and Jordan E. Baum2,3

1Department of Biology, Clark University, Worcester, Massachusetts, USA, 2Department of Ecology and Evolutionary Biology, Tulane University, New Orleans, Louisiana, USA and  3New York Presbyterian Hospital-Weill Cornell Medicine, Department of Pathology and Laboratory Medicine, New York, USA

Correspondence: J.A. Baker, Department of Biology, Clark University, 915 Main Street, Worcester, MA 01610, USA. email: JBaker@Clarku.edu


Question: What is the trajectory of change of female life-history traits following colonization of a freshwater lake by oceanic Threespine stickleback?

Hypotheses: Based on comparative studies of many freshwater populations, we predict that (1) reproductive effort and clutch size will be reduced from the ancestral condition, and (2) the breeding pool of females will change to include greater percentages of younger breeders. The trajectory of change in egg size cannot be predicted from current knowledge.

Organism and field site: Threespine stickleback (Gasterosteus aculeatus). Loberg Lake, south-central Alaska, was poisoned in 1982 to remove all fish, and then restocked by the Alaska Department of Fish and Game with trout only; the lake was apparently naturally recolonized by anadromous stickleback between 1983 and 1989.

Methods: Annual small-mesh trap collections between 1992 and 2015, and trap collections of the presumed ancestral stock in a nearby stream, the latter providing the starting point for evolutionary trajectory calculations. Our study encompassed an estimated 21 generations.

Conclusions: Reproductive effort and clutch size (both standardized for female body size) declined as predicted, by 28% and 41% from the ancestral values, respectively. Although the overall downward trend in both traits was substantial and rapid, a strong cyclical pattern was also present. Female breeding age also declined as predicted, with age-1 breeders becoming more prevalent in the lake. Egg size did not change appreciably.

Keywords: clutch size, egg size, freshwater invasion, Gasterosteus aculeatus, rapid evolution, reproductive effort.

IF you are connected using the IP of a subscribing institution (library, laboratory, etc.)
or through its VPN.


        © 2019 John A. Baker. All EER articles are copyrighted by their authors. All authors endorse, permit and license Evolutionary Ecology Ltd. to grant its subscribing institutions/libraries the copying privileges specified below without additional consideration or payment to them or to Evolutionary Ecology, Ltd. These endorsements, in writing, are on file in the office of Evolutionary Ecology, Ltd. Consult authors for permission to use any portion of their work in derivative works, compilations or to distribute their work in any commercial manner.

       Subscribing institutions/libraries may grant individuals the privilege of making a single copy of an EER article for non-commercial educational or non-commercial research purposes. Subscribing institutions/libraries may also use articles for non-commercial educational purposes by making any number of copies for course packs or course reserve collections. Subscribing institutions/libraries may also loan single copies of articles to non-commercial libraries for educational purposes.

       All copies of abstracts and articles must preserve their copyright notice without modification.