The Wasp as Terrestrial Indicator of Environmental Metal Composition: Evidence from Zimbabwe.

We explored metal concentrations in wasps from four sites near Harare, Zimbabwe, on a 106 km west-east transect. We found elevated concentrations at two presumed-polluted sites (a platinum mine, and a known polluted lake) located near a metal-enriched geological feature (The Great Dyke). A site in urban Harare and a nature reserve served as reference. Only wasps from the two presumed-polluted sites had quantifiable Pt. For Cr, Ni, Mg, Se, Fe, Mn, and V we report the highest concentrations in wasps yet published. Wasps from the presumed-polluted sites had significantly higher concentrations of most metals when compared with wasps from the reference sites, suggesting pollution as a source. Geology, however, differ between the sites. It is probable therefore, that both geology and pollution contributed towards the differences in metal concentrations. Due to its long and narrow dimensions (550 km long and 4 - 11 km wide), the Great Dyke offers opportunities for comparative studies. Since wasps form a complex part of the food web and ecology, studies on the transfer of metals to wasps' predators are needed, especially given that some birds specialize in feeding on hymenopterans. The rich diversity of wasps (more than 145 000 species worldwide) occupying multiple different trophic levels, are good indicators, and has a rich potential to join other invertebrates as terrestrial indicators. This article is protected by copyright. All rights reserved.