Monday, June 4, 2007 - 1:15 PM
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Dietary cadmium dynamics and detoxification capacity in predatory stoneflies: Physiological and phylogenetic comparisons

Caitrin A. Martin and David B. Buchwalter, Ph.D. Environmental and Molecular Toxicology, North Carolina State University, Raleigh, NC 27606

It has become increasingly evident that diet plays a major role in the bioaccumulation of metals in aquatic invertebrates. A major challenge associated with understanding metal dynamics in stream insects lies in their incredible diversity. This study was designed to determine if closely related species share physiological characteristics such as Cd assimilation efficiency from food, efflux, and subcellular compartmentalization. These comparisons were made among 7 stonefly (Plecoptera)species, (5 perlids, 2 perlodids) fed 109Cd contaminated prey (Lumbriculus variegates).  This study indicates that diet is indeed an important route of Cd exposure in predatory stoneflies. Cadmium distributions in the perlodid species show that a greater percentage of Cd exists in the detoxified (e.g. associated with metallothionein and MT –like proteins) compartment, indicating that perlodids have a greater capacity for detoxifying metal body burdens than perlid stoneflies and are therefore less susceptible to metal insult.  There are some similarities among related taxa, however, physiological processes such as metal uptake and efflux appear to vary within families, suggesting that predictions about species sensitivity based on experiments done at higher taxonomic levels may be erroneous.

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