The 2005 ESA Annual Meeting and Exhibition
December 15-18, 2005
Ft. Lauderdale, FL

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Friday, December 16, 2005 - 8:42 AM
0439

Stable isotope marking with 44Ca: A new technique to study parasitism in the field

Heike Wanner, heike.wanner@ipw.agrl.ethz.ch1, Hainan Gu1, Bodo Hattendorf2, Detlef Günther2, and Silvia Dorn1. (1) ETH (Swiss Federal Institute of Technology), Institute of Plant Sciences/Applied Entomology, LFO, Zürich, Switzerland, (2) ETH (Swiss Federal Institute of Technology), Laboratory of Inorganic Chemistry, HCI, Zürich, Switzerland

A new internal marking technique using the rare stable isotope 44Ca was developed for the gregarious endoparasitoid Cotesia glomerata, which parasitizes Pieris brassicae larvae. The isotope was enriched in parasitoids through the food chain, i.e. 44Ca was enriched in plants and transferred to the parasitoids via their host larvae feeding on the enriched plants. Adult female parasitoids could then transfer the 44Ca marker through oviposition to a new generation of host larvae. Enrichment of 44Ca is traced by analysis of individuals using inductively coupled plasma mass spectrometry (ICPMS) with a dynamic reaction cell (DRC). This new marking technique with 44Ca was shown to be applicable under greenhouse and field conditions to trace dispersal of the parasitoid and parasitism in mark-release studies.



Species 1: Hymenoptera Braconidae Cotesia glomerata
Species 2: Lepidoptera Pieridae Pieris brassicae
Keywords: Parasitism, Stable isotopes