Inherited interpopulation differences in size at first reproduction in threespine stickleback, gasterosteus aculeatus L.

Abstract

Minimum female size at first reproduction is examined in 25 lacustrine populations of sticklebacks (G. aculeatus). Field and laboratory data indicate that interpopulation differences in minimum size at first reproduction are inherited and probably represent local adaptations. Some possible selective factors are examined and predation by trout is suggested as a mechanism selecting for extremes (either small or large) sizes at first reproduction. © 1977, The Genetical Society of Great Britain. All rights reserved.