Limnetica 38

Some Moina species are predominantly found in large ponds and lakes while others are restricted to temporary pools or estuaries. The life history strategies and resistance to starvation of different species of Moina depend on their habitat. We compared the demography and starvation resistance in three species of the genus: Moina macrocopa (isolated from a reservoir), M. cf. micrura (from a small lake) and M. cf. wierzejskii (from a temporary pool). Population growth of the three Moina species was followed for 15 days using Chlorella vulgaris at a density of 1 x 106 cells/ml. Daily the females, males and ephippia produced by each cladoceran species were enumerated and transferred to a fresh test medium. We also tested the differences in resistance to starvation of the adults and the neonates by comparing the days until all the unfed individuals had died. Population growth curves of Moina macrocopa, M. cf. micrura and M. cf. wierzejskii showed significantly different trends. Moina macrocopa had higher peak densities (5-6 ind/ml) and higher population growth rates (0.33 per day) than the other two species. However, M. cf. wierzejskii had higher production of both, males and ephippia (0.3-0.4 ind/ ml and 0.7-0.8 ind/ml, respectively) than the rest. Regardless of the species, neonates were less resistant to starvation than adults. We discuss here adaptations of the life history strategies of these taxa in relation to their habitat.