Defensive odor emission from larvae of two sawfly species,Pristiphora erichsonii andP. wesmaeli

The emission of species-specific odors byPristiphora erichsonii andP. wesmaeli is accompanied by a characteristic defensive behavior called "snap bending." When the larvae are disturbed, blends of volatile compounds are emitted from ventral glands. The odor ofP. erichsonii, a colonial species, is composed of bornyl acetate, borneol,trans-pinocarveol, myrtenol, benzaldehyde, and tetradecyl, hexadecyl, and octadecyl acetates, whereas that of the solitaryP. wesmaeli is composed of 3-carene-10-al, linalool, myrtenal, and benzaldehyde. The role of these compounds in the defensive behavior of the larvae is discussed.