Energy budgets of latitudinally separated Scottolana canadensis (Copepoda: Harpacticoida)

Abstract

We tested the hypothesis that evolution in a local population shifts individual metabolic properties to maximize energy budgets under the prevailing temperature regime. We measured scope for growth [ng C( µ g dry mass) −1 h −1 ] in latitudinally separated adult females of Scottolanacanadensis (Willey) and used common‐rearing techniques to assess the degree of genetic differentiation. Florida (low latitude) females were at an energetic disadvantage at 15°C, but Maine (high latitude) females were not always disadvantaged at 25° or 28°C. At high test temperatures, Maine females had higher oxygen consumption rates [n1 O 2 ( µ g dry mass) −1 h −1 ] than those from Maryland (middle latitude) or Florida. The higher cost of respiration of the Maine individuals was offset bygrazing rates [cells ( µ g dry mass) −1 h −1 ] on the algae Isochrysis galbana (ISO) comparable or higher than Maryland or Florida.