Ontogenic changes in cardiac function in crustaceans

Abstract

Ontogenic changes in cardiac function were studied in four different species of crustaceans; the water flea Daphnia magna (“wild-type” and clone), the amphipod Gammarus duebeni, the lobster Nephrops norvegicus and the brine shrimp Artemia franciscana. The pattern of cardiac function, from its first appearance through to sexual maturity, was similar in each of the species examined: the main differences were differences in the timing of key events. Cardiac function commenced immediately prior to hatching in both N. norvegicus and G. duebeni and rose to a peak sometime after hatching. In D. magna and A. franciscana, however, commencement of cardiac function was post-hatch. The variation in heart rate encountered in cloned D. magna was similar to comparable data for “wild-type.” The relationship between heart rate and body weight for each species was biphasic and could not simply be described by a single power function. After the peak in heart rate observed for each species, heart rate became weight specific although the exact nature of the relationship was different between species with tubular hearts and those with globular hearts.