MP8 Metals in the Environment: Dietary concerns in Aquatic Systems
Monday, 14 November 2005: 8:00 AM - 5:30 PM in Exhibit Hall

(DUM-1117-222567) Metal transfer from prey to the aquatic insect Sialis.

Dumas, J.¹, Hare, L.¹, ¹ INRS-ETE, Québec, Québec, Canada

ABSTRACT- Larvae of the alderfly Sialis take up metals mainly from their prey. Metals present in prey are likely to be more or less available to this predator depending on how they are bound within prey cells; thus metals in the cytosol are thought to be more readily assimilated than are those in particulate fractions such as granules. To verify this hypothesis, we exposed various types of prey to sediments spiked with nickel (⁶³Ni) and thallium (²⁰⁴Tl). Some prey were sacrificed to determine the subcellular compartmentalization of Ni and Tl, whereas others were given to Sialis as food. Our results suggest that metal assimilation by Sialis depends on the forms in which metals are present in its prey. We conclude that predictions of metal concentrations in aquatic predators could be improved by considering both the composition of the predator's diet and the cellular distribution in various prey types.

Key words: trophic transfer, assimilation efficiency, nickel, thallium