Variation in the mineral composition of eggs of the snail, Helix aspersa between populations exposed to different levels of metal contamination.

摘要: The eggs of terrestrial gastropods represent a major investment resources by the parent, not least in provision essential metals. In this experiment 11 populations Helix aspersa were collected from habitats with different histories lead exposure and allowed to reproduce laboratory. After 4 months on low metal diet, five four-egg samples taken single clutch each population analysed for their content. Within-clutch between variation measured. No Pb or Cd was detected any eggs. Both trace metals show considerable within same clutch. Cu levels consistent across while egg Zn closely correlated soil Zn. Median Ca Mg little relation concentrations. However, declines populations. While content appears be regulated, an interaction parental tissues may mediate supply