LABELING A PARASITIC WASP, MICROPLITIS-CROCEIPES (HYMENOPTERA, BRACONIDAE), WITH TRACE-ELEMENTS FOR MARK RECAPTURE STUDIES

Microplitis croceipes (Cresson), a parasitoid of larvae of Heliothis spp., was labeled by rearing it in host larvae that were fed diet containing 1,000-2,000 parts per million of one or more of four trace elements: cesium (Cs), dysprosium (Dy), rubidium (Rb), or strontium (Sr). Atomic absorption spectrophotometry was used for the analysis of the labels. Cs and Dy concentrations in Cs-labeled and Dy-labeled parasitoids overlapped those found in parasitoids reared on unlabeled diet. Although the amounts of Rb and Sr in labeled parasitoids declined after they emerged as adults and ceased to be exposed to a trace element source, parasitoids labeled with these elements were distinguishable from field-collected, unlabeled insects up to 20 d after adults emerged. Although development time of males and females and adult longevity of females differed between unlabeled and labeled parasitoids, the differences were small and the direction of the differences reversed between experiments, suggesting that the trace elements had little effect on development time or adult longevity.