Energetic Values in Interstitial Isopods and Amphipods from Sandy Beaches as a Function of Body Size and Season (Western Mediterranean)

Abstract

Modern ecological literature includes a large number of studies dealing with energy flow, aiming at a better understanding of the functioning of ecosystems, and of the interactions between different ecosystems. In this field, only the South African sandy beaches (Dye, 1981 ; Griffiths, 1981 ; Koop et al., 1982 ; MacLachlan et al., 1981) and the Indian beaches (Wafar et al. 1980) have been taken into account. Some isolated data exist in Europe (Lasserre, 1980 ; Lasserre and Renaud-Mornant, 1971). As reproduction cycles and population dynamics of interstitial isopods and amphipods of Mediterranean sandy beaches are well known, such studies can be carried out. In order to establish the energetic budget of these crustaceans, and within the framework of a study of energy flow in these animals, calorimetic mesures provide an element contributing to the definition of the potential energy fraction that they represent for conceivable predators, and of their nutritive value. The present study deals with three interstitial crustaceans : the isopods Angeliera phreaticola and Microcharon marinus, and the amphipod Bogidielia chappuisi ; all live in the sandy beaches of the Roussillon coast (France, Western Mediterranea).