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

Abstract

Nickel and copper concentrations in birch leaf tissues, in leafmining larvae of Eriocrania semipurpurella, and in larval faeces were measured in leaf-specific samples collected at five sites along a strong pollution gradient in the Kola peninsula, northwest Russia. Metal concentrations at the most polluted 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 among the individual trees within a site; the latter may have resulted from the 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 concentrations in larvae were 4.76 and those in frass 3.04 times as high as in the leaf parenchyma. Last instar larvae contained 5–10% of nickel 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-specific larval weight and feeding efficiency decreased with an increase in foliar concentrations of both metals. Within-site variation in larval weight was independent of metal concentrations in larval bodies; feeding efficiency correlated with Cu concentrations in the larvae, while Ni had no effect on this character. ©