LATITUDINAL DIFFERENTIATION IN EMBRYONIC DURATION, EGG SIZE, AND NEWBORN SURVIVAL IN A HARPACTICOID COPEPOD

Abstract

We demonstrate significant genetically based differentiation in embryonic duration (h), egg size (µm3), and newborn survival (number/h) in the harpacticoid copepod, Scottolana canadensis (Crustacea), taken from a broad range of latitudes (°N) and reared in the laboratory for several generations under the same conditions. Egg development times of the northern-derived (ME) individuals were significantly longer at all test temperatures, and thus did not demonstrate compensation at low temperature. Maine development times may be due to the larger egg size.