Critique of some practices in life-history studies, with special reference to harpacticoid copepods

Abstract

Published studies on the demography and reproductive strategies of harpacticoid copepods are examined critically. At the technical level, the popular approximation r ≈ In R0/Tc is shown to be inappropriate as an estimate of the intrinsic rate of increase of harpacticoids. It leads to a systematic underestimation, by 8-29%, for life histories typical of fast-breeding species. Various ad hoc variants of r and R0 calculations occurring in the literature are also criticized. .At the conceptual level, a more discriminating approach to life-history characteristics is necessary; this applies both to the assessment of their 'strategic' significance, and to their diagnostic power with regard to the various 'strategies'. Special attention is given to the non-equivalence of parity and voltinism. Recommendations that should promote the construction of a more rigorous cognitive framework are included.