Rapid genetic erosion in pollutant-exposed experimental chironomid populations.
Few studies have evaluated how effectively environmental contamination may reduce genetic diversity of a population. Here, we chose a laboratory approach in order to test if tributyltin (TBT) exposure at environmentally relevant concentrations leads to reduced genetic variation in the midge Chironomus riparius. Two TBT-exposed and two unexposed experimental populations were reared simultaneously in the laboratory for 12 generations. We recorded several life-history traits in each generation and monitored genetic variation over time using five variable microsatellite markers. TBT-exposed strains showed increased larval mortality (treatments: 43.8%; controls: 27.8%), slightly reduced reproductive output, and delayed larval development. Reduction of genetic variation was strongest and only significant in the TBT-exposed strains (treatments: -45.9%, controls: -24.4% of initial heterozygosity) after 12 generations. Our findings document that chemical pollution may lead to a rapid decrease in genetic diversity, which has important implications for conservation strategies and ecological management in polluted environments.
Nowak
Carsten
C
Abteilung Okologie und Evolution, Institut für Okologie, Evolution und Diversität, J. W. Goethe-Universität Frankfurt am Main, Siesmayerstrasse 70, 60054 Frankfurt am Main, Germany.
Vogt
Christian
C
Pfenninger
Markus
M
Schwenk
Klaus
K
Oehlmann
Jörg
J
Streit
Bruno
B
Oetken
Matthias
M
D000818:Animals; D002683:Chironomidae / Q000187:drug effects* / Q000235:genetics / Q000502:physiology; D004463:Ecology / Q000379:methods; D004785:Environmental Pollutants / Q000633:toxicity*; D014644:Genetic Variation; D008018:Life Cycle Stages; D018895:Microsatellite Repeats; D018675:Toxicity Tests; D014220:Trialkyltin Compounds / Q000633:toxicity*
D004785:Environmental Pollutants; D014220:Trialkyltin Compounds; C011559:tributyltin