Abstract.1The larvae of the chequered skipper butterflyCarterocephalus palaemonnotch the blades of purple moor‐grassMolinia caeruleabefore feeding.2The nutrient concentrations above and below these notches were measured and the nutrient concentrations of undamaged blades of the host plant.3Nutrient concentrations above the notches remained similar to undamaged blades for a short period, whilst concentrations below declined, especially nitrogen, calcium and magnesium.4The feeding behaviour ofC.palaemonlarvae is discussed in relation to declining levels of nutrients in the food plant over the larval season and to other possible reasons for this behaviour, such as avoidance of host defences initiated in response to attac