Life history timing, but not body size, of Mysis salemaai (Crustacea: Mysida) conserved across a trophic gradient at its southern distribution
文摘
The mysid shrimp Mysis salemaai is a key component of many lake food webs. However, despite its strong declines in some systems, information on its life history is rudimental. We explored variation in life history patterns of M. salemaai and how this varies with key environmental gradients at the southern range of its distribution. We found that body mass of reproductive females and individual larvae varied among lakes and increased with phosphorus concentrations, whereas growth rates were associated positively with temperature. However, even across strongly contrasting nutrient conditions, M. salemaai had invariant life history timing with a single, synchronised winter recruitment followed by parent mortality. This contrasts with variable reproductive timing of the species reported across the Baltic Sea, probably owing to differences in ambient conditions or genotypes. The highly variable body size at maturity likely facilitates matching of reproduction with seasonal pulses of planktonic food across a broad range of growing conditions. We conclude that current population declines of M. salemaai warrant further investigations into the temporal plasticity of environmental matching.KeywordsLakesTotal phosphorusReproductionPopulation structureGrowth rateBody mass