Influence of reproduction on variability of life history parameters in Artemia salina (Crustacea, Anostraca)

摘要

The variability of growth and reproduction parameters in bisexual and parthenogenetic families (groups of specimens emerged from separate broods) of the brine shrimp Anemia salina was determined experimentally. Transition from parthenogenesis to bisexual reproduction shortens the juvenile period and lifespan of females, reduces the proportion of broods and the total fecundity per life history, and raises the number of nauplii in the total fecundity. The size of mature females and the number of sexproducts in their first brood do not differ significantly. The dispersion of all the parameters, except for body size, is higher in bisexual females. In parthenogenetic and bisexual females, the size of a specimen is the most stable parameter, whereas the number of broods and total fecundity per life history are the most variable. The duration of stages of ontogenesis and the number of sex products in the first brood are characterized by an intermediate level of variability. Acceleration of maturation does not affect the duration of life history of females, their body size, and the number of sex products in the first brood, but increases the number of broods and total fecundity per life history, which contradicts the concept of the "cost of reproduction." The variability of life history parameters and the presence of alternative reproductive modes make populations of A. salina more stable, especially in the unstable and unpredictable conditions of ultrahaline reservoirs. Innate speed of rise in the abundance of a population is similar in families with parthenogenetic and bisexual reproductive modes. However, bisexual reproduction guarantees the current functioning of a population, and parthenogenesis, its future survival.