Metal Concentrations of Insects Associated With the South Africa Ni Hyperaccumulator Berkheya coddii (Asterceae)

Document Type

Article

Publication Date

4-1-2006

Department

Biological Sciences

School

Biological, Environmental, and Earth Sciences

Abstract

The high levels of some metals in metal hyperaccumulator plants may be transferred to insect associates. We surveyed insects collected from the South African Ni hyperaccumulator Berkheya coddii to document whole‐body metal concentrations (Co, Cr, Cu, Mg, Mn, Ni, Pb, Zn). We also documented the concentrations of these metals in leaves, stems and inflorescences, finding extremely elevated levels of Ni (4 700–16 000 ∞g/g) and high values (5–34 ∞g/g) for Co, Cr, and Pb. Of 26 insect morphotypes collected from B. coddii, seven heteropterans, one coleopteran, and one orthopteran contained relatively high concentrations of Ni (> 500 ∞g/g). The large number of high‐Ni heteropterans adds to discoveries of others (from California USA and New Caledonia) and suggests that members of this insect order may be particularly Ni tolerant. Nymphs of the orthopteran (Stenoscepa) contained 3 500 ∞g Ni/g, the greatest Ni concentration yet reported for an insect. We also found two beetles with elevated levels of Mg (> 2 800 ∞g/g), one beetle with elevated Cu (> 70 ∞g/g) and one heteropteran with an elevated level of Mn (> 200 ∞g/g). Our results show that insects feeding on a Ni hyperaccumulator can mobilize Ni into food webs, although we found no evidence of Ni biomagnification in either herbivore or carnivore insect taxa. We also conclude that some insects associated with hyperaccumulators can contain Ni levels that are high enough to be toxic to vertebrates.

Publication Title

Insect Science

Volume

13

Issue

2

First Page

85

Last Page

102

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