ABSTRACT
We investigated the sensitivity of resting eggs of the cladoceran Moina macrocopa to the effect of ionizing radiation during the reactivation of the eggs. The study showed that the resting eggs during reactivation are more vulnerable to irradiation than the resting eggs in a stage of deep dormancy. The decrease in the efficiency of egg reactivation was observed at high doses, the growth rate of juveniles, fecundity, and the number of produced clutches by females strongly decreased when resting eggs at the reactivation stage absorbed doses of 64 Gy and higher.
Subject(s)
Cladocera/growth & development , Eggs/radiation effects , Gamma Rays , Radiation Tolerance , AnimalsABSTRACT
We investigated the effects of γ-irradiation on the survival of resting eggs of the cladoceran Moina macrocopa and on the parameters of the life cycle of neonates hatched from the irradiated eggs. It was shown that γ-irradiation in a wide range of doses (from the background level to 100 Gy) had no effect on survival of eggs and mortality of neonates hatched from the irradiated eggs. However, exceeding the absorbed dose of 40 Gy sharply decreased the reproductive potential of the neonates hatched from irradiated eggs.
Subject(s)
Crustacea/radiation effects , Gamma Rays , Life Cycle Stages/radiation effects , Ovum/radiation effects , Animals , Crustacea/growth & developmentSubject(s)
Crustacea/physiology , Demography , Ecosystem , Fresh Water , Population Dynamics , AnimalsABSTRACT
Three levels of chemical communications involved plankton Crustacea are considered: 1) Influence of zooplankton excretion on phytoplankton; 2) Influence of zooplankton excretion on the individuals of the same or other species of the same trophic level; 3) Influence of chemical cues released by predatory zooplankton and fish on herbivorous zooplankton. The data on the influence of excreted cues on some physiological (growth, reproduction, feeding, etc.) and behavioural (vertical and horizontal migrations) characters of planktonic crustaceans are presented. Ecological role and chemistry cues responsible for the interactions of different trophic levels can be different. It is considered that chemical communications in aquatic ecosystems can be provided with: 1) Species-specific cues that strictly influence particular biological functions (communication system of feromone type); 2) Non-specific cues that strictly influence particular functions (system of regulator, that act at the whole ecosystem as the hormonal system of an organism). 3) Non-specific substances with broad (non-specidic) influence--toxic substances of "biocondition substances" according to classification of Novikov and Kharlamova (2000).
