Food preferences and feeding rates of Armadillidium vulgare were measured with leaf litter from nine species of plant from a grassland heath. Litter from dicotyledonous plants was significantly preferred to that from monocotyledonous and bryophyte species but preferences for monocotyledonous litter increased as this decayed.For a given state of decay consumption and absorption rates were highest for dicotyledonous foods. Decayed monocotyledonous foods were consumed and absorbed at a greater rate than standing dead foods. The decayed dicotyledonous material was also consumed more rapidly than the standing dead food but the absorption rate was not significantly different because the decayed food was absorbed less efficiently.It is suggested that A. vulgare maintains high absorption rates on some low quality foods by increasing consumption rate but that its ability to do this depends upon which defences were used by the plants when alive.