Dynamics of body mass and oxygen consumption in the ribbed newt Pleurodeles waltl ontogenesis: 1. Endotrophic development

Dynamics of body mass and oxygen consumption in the ontogeny of the Spanish ribbed newt (Pleurodeles waltl): 2. Larval stage

“…Previously we showed that during the larval period, when the source of nutrition for the Spanish ribbed newt larvae is their yolk reserves, there are also observed common trends in changes in the specific growth rate and oxygen consumption intensity (Vladimirova et al, 2010). Most likely, during the entire premetamorphic larval period, changes in the increase rate of the newt body mass can influence the oxygen consumption dynamics.…”

“…In the axolotl (Ambystoma mexicanum) and Spanish ribbed newt (Pleurodeles waltl), the rate of body mass increase during the early larval stage rises simultaneously with the oxygen consumption increase, a trend also observed during embryogenesis (Novikov, 2000;Vladimirova et al, 2003Vladimirova et al, , 2010. These changes in the oxygen consumption intensity and the specific growth rate remain when the axolotl switches to external food sources, but with a decrease as the main trend.…”

“…The coefficients of dependence (1) are different at different developmental stages. During the early larval period, as well as during embryogenesis, oxygen con sumption grows faster than mass, and the power coef ficient k exceeds one (Ozernyuk, Lelyanova, 1985;Ozernyuk, 2000;Vladimirova et al, 2003Vladimirova et al, , 2010. After the larva switches to external nutrition, the ratio between these coefficients changes; the value of the power coefficient k lies in the range between 0.78 and 1 in most studied amphibian species and does not change until metamorphosis (Funkhouser, Mills, 1969;Feder, 1982;Vladimirova et al, 2003).…”

“…During the early stages of development, when larvae receive only endotrophic nutrition, the intensity of oxygen consumption grows, and later, after larvae switch to external nutrition, it decreases (Fletcher, Myant, 1959;Ozernyuk, Lelyanova, 1985;Seymour, Loveridge, 1994;Vladimirova et al, 2000Vladimirova et al, , 2010Ozernyuk, 2000). During metamorphosis, oxy gen consumption in some species decreases or stays the same (Etkin, 1934;Fletcher, Myant, 1959;Funk houser, Mills, 1969;Feder, 1982;Hastings, Burggren, 1995;Beck, Congdon, 2003) and increases in others (Wills, 1936;Hopkins, Handford, 1943;Sivula et al, 1972;Schwartz et al, 1973;Koval'chuk, 1976;Orlof ske, Hopkins, 2009).…”