Industrial pollution affects behaviour of the leafmining moth Stigmella lapponica

Abstract

AbstractWe explored the impacts of industrial air pollution on the behaviour of the leafmining moth Stigmella lapponica (Wocke) (Lepidoptera: Nepticulidae) by comparing the characteristics of larval gallery mines in mountain birch [Betula pubescens ssp. czerepanovii (Orlova) Hämet‐Ahti (Betulaceae)] leaves collected from unpolluted forests and from heavily polluted industrial barrens surrounding the copper‐nickel smelter in Monchegorsk in north‐western Russia. Population density of S. lapponica, survival of larvae, length of the completed mine, and width of its terminal part did not differ between polluted and unpolluted sites. Females in unpolluted sites only rarely (16%) oviposited on the apical half of the leaf and the larval mortality in mines that started in the apical part of the leaf was 83%. A significantly larger (38%) proportion of mines started in the apical half of the leaves in polluted sites, and the larval mortality in these mines was only 45%. The between‐habitat difference in the choice of the oviposition sites by S. lapponica is the first demonstration of the adaptive plasticity of oviposition behaviour in a leafmining insect. This difference was not explained by specific leaf weight which did not vary within leaves. Larvae mining in polluted leaves extended 25% farther between turns, and the galleries turned more sharply than in unpolluted leaves. This result confirms the abilities of leafmining larvae to evaluate the quality of the ingested food and adjust their behaviour accordingly. Thus, pollution modifies both the preference of S. lapponica females for oviposition sites within a birch leaf and the behaviour of S. lapponica larvae mining these leaves. This is one of the first records of changes in insect behaviour in natural environment disturbed by industrial pollution.