COMPARATIVE EXPERIMENTS ON HEARTBEATS OF UNRESTRAINED DECAPODE CRUSTACEANS (ASTACUS FLUVIATILIS FAB ASTACUS LEPTODACTYLUS ESCHSCHOLZ AND CAMBARUS AFFINIS SAY)

The temperature influence on the heartbeats of unrestrained Astacus fluviatilis, Astacus leptodactylus, and Cambarus affinis has been studied by means of aspiration electrodes. This method allows a complete and long termed registration of the heartbeats. The rule of van t'Hoff has been proved for the heartbeat frequencies of Astacus fluviatilis between 0 and 26° C, of Astacus leptodactylus between 0 and 28° C, and of Cambarus affinis from 0-30° C. Lethal temperatures have been found at about 28° C, 34° C, and 37° C respectively, the Q10 was measured as 1.7, 1.9, and 1.8 respectively. Warm adapted specimen show a significant higher frequency at higher temperatures than cold adapted ones. Young individuals of little weight (2.5 g) have been found to posses a marked higher frequency than the heavier adult animals (90 g). © 1969 Springer-Verlag.