Evaluation of respiration parameters in a few generations and clones of Simocephalus vetulus (Crustacea, Cladocera) under controlled conditions
2010
Elena, Forasacco | Dominique, Fontvieille
Cladocera use their thoracic filter limbs, animated by rhythmic and persistent movements, for food collecting and gas exchanges. Several researches have been performed on Daphnia magna in natural environments and in laboratory to identify the adaptations developed toward a decrease or a lack in oxygen. However, no experiment was performed on cladocerans living exclusively in littoral areas, which need efficient adaptations to survive an always changing environment especially regarding oxygen concentration. These changes require from organisms that they spend additional energy in order to satisfy their need in oxygen. The present laboratory experiments were based on a typical inhabitant of littoral areas, Simocephalus vetulus, and on individuals which came directly from natural environments. Respiration rate and NADH fluorescence in filter limb muscles, as a marker of tissue oxygenation, were analysed on 20 families distributed over five generations, all acclimated and cultured under constant food supply conditions. The results underlined differences among generations especially due to body dimensions, and consequently to filter dimensions. As opposed to our former hypothesis, small and young individuals appeared to be more active and thus display a more efficient respiration than big and old Simocephalus.
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