Sawfly egg deposition extends the insect life cycle and alters hormone and volatile emission profiles

Introduction Insect oviposition can enhance plant defenses and decrease quality in response to future feeding damage by hatched larvae. Induced resistance triggered egg deposition its negative effect on insect herbivore performance is known for several annual plants but has been much less studied woody perennials, such as species of the Salicaceae. Here we willow Salix babylonica specialist sawfly Nematus oligospilus impact performance. Methods We measured larval pupa formation evaluated influence phytohormones volatile emission profile. Results showed that reduced neonate growth increased proportion prepupae delayed their transition pupae, thus extending length cocoon phase. Oviposited willows jasmonic acid levels changed profile through enhanced concentrations terpenoids, ( E/E )-α-farnesene, (Z)- E )-β-ocimene. Volatile profiles were characteristic each type (oviposition vs. feeding), no priming was found. Discussion demonstrated could perceive per se a primary factor activating defense signaling via pathway. This induced ultimately determined changes pupation dynamics may affect whole population cycle.