Selective Soil Organic Matter Consumption by Larvae of Adoryphorus couloni (Burmeister) (Coleoptera: Scarabaeidae)

Analysis of the gut contents of third-instar larvae of the redheaded pasture cockchafer Adoryphorzcs couloni indicates that they feed preferentially on organic matter in soil under perennial ryegrass pastures, rather than simply consuming the bulk soil indiscriminantly. Larvae sequester carbonaceous material at 2-4 times its concentration in the external soil environment. This was confirmed by confining larvae in artificial soils with various proportions of organic matter, with the degree of assimilation depending on the size of the food particles. Better management of the organic matter in the root zone of pastures may hold a key to the management of this pest.