The effect of food concentration on the growth rate, fecundity and the change of the reproductive mode of Moina brachiata (Crustacea: Cladocera) single females
Tatiana Stanislavovna Lopatina, Egor Sergeevich Zadereev
Abstract
The study addresses the effect of food availability on the specific somatic growth rate, fecundity and diapause induction in a cladoceran Moina brachiata. The optimal food concentration of 400 thousand cells/ml was defined for the growth and asexual reproduction of individually cultivated M. brachiata females. Being optimal for parthenogenesis, this food concentration does not limit the specific somatic growth rate and fecundity of this species. The trophic conditions inducing a change of the reproductive mode have been determined for the first time for the M. brachiata. In addition, the effect of food concentration under which the maternal generation was kept on the ability of their progeny to produce resting eggs was studied: the number of females that had changed their reproduction mode tended to decrease with an increase in food concentration provided to the maternal and offspring generations. It was demonstrated that, of the two species of cladocerans coexisting in the same biotopes, M. brachiata is more demanding of food conditions than M. macrocopa: a change of the reproductive mode and the limiting effect of food concentration on the specific somatic growth rate in M. brachiata females are observed under a food concentration four times as great as that for M. macrocopa females. A model of coexistence in natural water bodies of two cladoceran species, M. macrocopa and M. brachiata, was developed.