Natural selection by predators on the defensive apparatus of the three-spined stickleback, Gasterosteus aculeatus L.

摘要: Three-spined sticklebacks (Gasterosteus aculeatus L.) can receive considerable protection against predators from characteristic dorsal and pelvic spines. The size structure of this defensive apparatus were examined in marine freshwater populations located throughout the European distribution species exposed to differing predatory levels predation pressure. Marine appear experience greatest pressure have largest apparatus. Predation appears decline towards both northern southern distributional extremes Gasterosteus, a result attributable differential distributions major piscine predators, especially pike perch; pattern produces arched clines morphometrics structures. Local differences central latitudes also be attributed site-specific Evidence is given for hereditary environmental determination varia...