The initial tolerance to sub-lethal Cd exposure is the same among ten naïve pond populations of Daphnia magna, but their micro-evolutionary potential to develop resistance is very different

摘要: Abstract Genetic variation complicates predictions of both the initial tolerance and long-term (micro-evolutionary) response natural Daphnia populations to chemical stressors from results standard single-clone laboratory ecotoxicity tests. In order investigate possible solutions this problem, we aimed compare sub-lethal Cd 10 naive pond magna as well their evolutionary potential develop increased resistance. We did so by measuring reproductive performance 120 clones, i.e. 12 clones hatched recent dormant egg bank each populations, in absence (Cd-free control) presence 4.4 μg Cd/L. show that , defined individuals first generation exposed relative a Cd-free control was not significantly different among studied averaged 0.82 ± 0.04 over these populations. Moreover, populations’ tolerances were also mean 0.87 ± 0.08 at 4.0 μg Cd/L measured for group 7 often-used collected range European testing laboratories. This indicates can be relatively accurately predicted test data only handful clones. then used estimates broad-sense heritability ( H 2 ) – based on same dataset proxy capacities evolutionarily respond terms development resistance which is here increase with time frequency higher population (accompanied an Cd-tolerance above tolerance). estimated values cover almost entire theoretically range, ranging zero (for five populations) between 0.48 0.81 other populations). that, unlike Cd, (long-term) micro-evolutionary may very Therefore, conclude it difficult predict unstudied stress sample It therefore suggested new methods forecasting responses should explored, such predictive models combination population-genomic time-series data.