EXCRETION OF CADMIUM DURING MOLTING AND METAMORPHOSIS IN TENEBRIO-MOLITOR (COLEOPTERA, TENEBRIONIDAE)

The effects of moulting between instars and metamorphosis on the conte nts of Cd were studied in T, molitor larvae both by following the radi oactive tracer Cd-109 ingested on one occasion and by analysing Cd con centration in larvae and newly hatched adults with a continuous intake of Cd, Larvae were given Cd-109 in one meal, Contents of Cd-109 were then determined periodically throughout the larval stage and in newly hatched adults, Moulting lowered the Cd-109 contents, but to a smaller degree compared with metamorphosis, The rate of reduction during thes e processes decreased with time elapsed since ingestion of Cd-109 and moulting or metamorphosis, At metamorphosis, the loss of Cd-109 took p lace almost entirely at the pupation. With a continuous intake of Cd, concentrations ire T. molitor were correlated to those in their food, Newly hatched adults had lower Cd concentrations than the correspondin g larvae, when Cd concentrations in food were high.