INTERPOPULATION DIFFERENCES IN ACUTE RESPONSE OF BROTIA-HAINANENSIS (GASTROPODA, PROSOBRANCHIA) TO CADMIUM - GENETIC OR ENVIRONMENTAL VARIANCE

Adolescent Brotia hainanensis collected from two separate sites along the same river showed markedly different acute responses to cadmium ev en after laboratory acclimation for one week. Similar interpopulation differences persisted in the F-1 juveniles (<two-day old) which were d escendants of laboratory-cultured snails. Although these results could imply that the inter-site differences in cadmium tolerance for the tw o populations may have a genetic basis, these differences in metal tol erance in the F-1 juveniles disappeared after the juveniles had been c ultured under identical laboratory conditions for one week. Quantitati ve genetical analyses revealed that variance of initial shell length a nd survival time of F-1 juveniles exposed to 10 mg/litre cadmium was s ignificantly smaller for juveniles that were offspring of the same fem ale as compared with animals that were descendants of different female s. Moreover, the survival time was positively, correlated with the ini tial size of the juveniles. Common environmental and maternal effects have an overwhelming influence on cadmium tolerance in these ovovivipa rous snails. Copyright (C) 1996 Elsevier Science Ltd.