Its chief food is haws , the fruit of the hawthorn tree .
Adults can overwinter on a diet of leaves , and individuals can be found on many potential food plants , including pedunculate oak , sessile oak and whitebeam .
Its chief food is haws , the fruit of the hawthorn tree , but adults can overwinter on a diet of leaves , and individuals can be found on many potential food plants , including pedunculate oak , sessile oak and whitebeam .