Effects on survival and reproduction of Porcellio dilatatus exposed to different Cd species.

The woodlouse Porcellio dilatatus (Crustacea) is a suitable model organism as a biological indicator for the toxic effects evaluation induced by pollutants exposure in the environment. In this study, the influence of cadmium (Cd) species on survival and reproduction of isopods was investigated. Survival, growth and reproductive parameters (time to pregnancy, pregnancy duration, pregnancy and abortion occurrence, number of juveniles per female and juvenile weight) were recorded after isopods were exposed to two species of Cd deployed in food: Cd(Cys)(2) and Cd(NO(3))(2). There was a difference between survival rates of exposed males and females to both Cd species but in the case of Cd(NO(3))(2) these differences were more accentuated, with females having higher survival rates. In the presence of both metal species a reduction in the number of pregnancies and pregnancy duration was observed, while in the case of Cd(Cys)(2) all pregnancies were inconclusive. The number of juveniles delivered per female fed with Cd(NO(3))(2) contaminated food was lower than in the control, whereas the juvenile weights were higher. To the best of our knowledge, the present study is the first toxicity test demonstrating that metal speciation affects reproduction in isopods. Cd(Cys)(2) showed to be the most toxic of the contaminants tested in this long term exposure and capable of jeopardizing the reproduction efforts of isopods.