Life-stage-dependent sensitivity of the cyclopoid copepod Mesocyclops leuckarti to triphenyltin

► Mesocyclops leuckarti is a good laboratory species for ecotoxicity testing. ► Copepod nauplii are more sensitive to triphenyltin compared to other stages. ► Copepod nauplii have a lower threshold of effects compared to other stages. ► 48 h quantal endpoints may not be appropriate for toxicity tests with copepods. ► GUTS can be used to describe differences in sensitivity between life stages.