Although she was a high soprano , she performed , and recorded , both the trousers roles of the Composer in Strauss 's Ariadne auf Naxos and Octavian in Der Rosenkavalier . Although she was a high soprano , she performed , and recorded , both the trousers roles of the Composer and Octavian on Richard Strauss 's Ariadne auf Naxos and Der Rosenkavalier , respectively .