Energy Metabolism in Postlarval Ontogenesis of Planorbarius corneus (Planorbidae, Gastropoda)

Abstract

The change in the rate and mass-specific rate of oxygen consumption was studied during individual ontogenesis of nine Planorbarius corneus individuals starting from 3 weeks after hatching until the death of animals. It is shown that, at the initial stages of development, the mass-specific rate of oxygen consumption increases, reaching a maximum at 3–7 weeks after hatching. The rate of oxygen consumption then permanently increases, and the mass-specific rate of oxygen consumption permanently decreases. The dependences of mass-specific rate of oxygen consumption (q) on the age (t) for individual P. corneus can be described by the equation q_st/(1 – exp(–k (t + t₀))). The values ​​of the coefficients of this equation for different specimens do not differ significantly and are, on average, k = 0.134 ± 0.016 weeks^–1; q_st = 0.117 ± 0.006 mL O₂/(h g). The dependence of the rate of oxygen consumption (Q, mL O₂/h) on body weight (M, g) in individual development is well described by allometric equations, the power coefficients of which vary from 0.647 to 0.944 and significantly differ from each other (p < 0.001). Nevertheless, the data for all mollusks can be described by the united equation Q = 0.061 M^0.795. The power coefficient of this equation does not significantly differ from the Hemmingsen constant 0.75.