Uptake and excretion of nickel and copper by leaf-mining larvae of Eriocrania semipurpurella (Lepidoptera : Eriocraniidae) feeding on contaminated birch foliage

Nickel and copper concentrations in birch leaf tissues, in leafmining larva e of Eriocrania semipurella, and in larval faeces were measured in leaf-spe cific samples collected at five sites along a strong pollution gradient in the Kola peninsula, northwest Russia. Metal concentrations at the most poll uted site were 3-6 (Cu) to 6-14 (Ni) times as high as at the reference site . We found variation in metal concentrations among study sites, but not amo ng the individual trees within a site; the latter may have resulted from th e large variation associated with individual samples. Approximately 48% of total foliar Ni and 35% of Cu was deposited in the leaf parenchyma and was thus available for the leafminer. Ni concentrations in larval bodies were 0 .84 and in larval frass 1.30 times as high as in the leaf parenchyma. Cu co ncentrations in larvae were 4.76 and those in frass 3.04 times as high as i n the leaf parenchyma. Last instar larvae contained 5-10% of nicker and 20- 50% of copper which they may have consumed with the leaf parenchyma during their lifetime, as estimated from the mine size and metal concentration in the parenchyma. Site-specifrc larval weight and feeding efficiency decrease d with an increase in foliar concentrations of both metals. Within-site var iation in larval weight was independent of metal concentrations in larval b odies; feeding efficiency correlated with Cu concentrations in the larvae, while Ni had no effect on this character. (C) 2000 Published by Elsevier Sc ience Ltd. All rights reserved.