Size Polymorphism and Fluctuating Asymmetry of Artemia (Branchiopoda: Anostraca) Populations from the Crimea

Abstract

Fluctuating asymmetry (FA) of animals as a measure of ontogenetic stability is widely used in environmental bioindication. Environmental stress leads to increased levels of FA within populations. Artemia (Anostraca) is among the most primitive and ancient groups of crustaceans, inhabiting hypersaline waters worldwide. Despite of this there are only few studies on FA in Artemia populations, showing opposite results. To assess FA we used length of the first antenna and number of furcal setae on left and right sides. In 2004–2013 the samples were collected from 10 hypersaline lakes in Crimea. Two size groups presented in the studied lakes; diploids constitute a small size group, and polyploids – a larger one. Average length in both groups significantly correlated with salinity. No one directed influence of salinity on FA was found. Manifestation of FA was different in small and large size groups. Changes in salinity can explain not more than 40–55 % of FA variability for studied traits. Parthenogenetic populations of Artemia in Crimean lakes have differences in FA manifestation, which may be explained by differences in water salinity, genetic architecture, and selective pressure against individuals with highest FA. We cannot explain the observed FA differences in studied Artemia populations

Keywords

• developmental instability
• genetic differences
• ploidy
• salinity
• selective pressure