Effect of temperature on respiration of larval stages of Hyas araneus and H. coarctatus (Decapoda, Majidae)

Abstract

Larvae of the crustaceans Hyas araneus L. and H. coarctatus Leach were reared in the laboratory at 12°C; their respiration rates were measured at 3, 6, 9, 12, 15 and 18°C. For all stages of H. araneus and for the megalopa of H. coarctatus the increase in metabolic rates with increasing temperature could be described by Bglehrddek's equation; QZo values decreased in these cases with increasing temperature. In the zoeal stages of H. coarctatus the relation between respiration and temperature followed an exponential model, and the Qlo values remained constant (Zoea I) or increased (Zoea 11) with increasing temperature. At 3'C, equivalent stages of the 2 species had almost identical respiration rates (R, per individual); weight-specific metabolic rates (Q02) were higher in H. coarctatus. The rate of increase in R with increasing temperature was conspicuously lower in H. coarctatus than in H. araneus. At 18°C the former species had Rvalues 30% (Zoea I), 37 % (Zoea 11), and 16% (megalopa) below those in the latter species. Since there were similar differences in biomass (measured as dry weight, carbon, nitrogen, and hydrogen content) between corresponding stages of the 2 species, Q02 values became very similar at 18'C. The significance of the moult cycle and of adaptation is discussed in relation to the general results obtained from comparable investigations on crustacean larval metabolism.