Impact of apple orchard management strategies on earthworm (Allolobophora chlorotica) energy reserves

Abstract

To assess the effects of agricultural management strategies on earthworm energy reserves (glycogen and lipids), 16 apple orchards under different strategies (organic, Integrated Pest Management (IPM), conventional and abandoned) were selected. Soil samples and 10 adults of the most common earthworm species (Allolobophora chlorotica) were sampled in each orchard. The glycogen and lipid concentrations in the earthworms did not correlate with any soil characteristics and no significant differences in earthworm weight were observed between strategies. However, significantly lower glycogen and lipid concentrations were found in earthworms inhabiting conventional orchards, with a decrease of 45 and 63% compared to organic and abandoned orchards respectively. Earthworms from IPM orchards had intermediate values. This suggests that pesticide usage leads to the observed decrease of energy reserves in A. chlorotica. Thus the reduced insecticide use in IPM compared to conventional strategies, albeit significant, appears to be too small to result in pronounced effects on energy reserves in this earthworm species.