Eating the evidence? Manduca sexta larvae can not disrupt specific jasmonate induction in Nicotiana attenuata by rapid consumption

As feeding by the tobacco specialist Manduca sexta L. is known to result in significantly higher jasmonate (JA) concentrations in Nicotiana plants tha n do mechanical simulations of the larval damage, we investigated whether M . sexta, which is known to rapidly consume large quantities of leaf materia l, can impair this "recognition" response by consuming the leaf tissue befo re it can respond with amplified JA levels. We report that oral secretions (OS) from M. sexta, but not from the cabbage specialist Pieris rapae, ampli fied the wound-induced JA response of Nicotiana attenuata Torr. Ex Wats., r egardless of larval diet, instar and molting stage, and were still active a fter boiling and when diluted to 1/1000. The largest JA response occurred w ithin 40 min in tissues adjacent to the OS application site. When 3 mm of l eaf tissue immediately adjacent to the OS application site was excised with in 40 s, the signal that elicits JA amplification was found to travel rapid ly into the leaf, beyond the mandibular reach of the larvae. We conclude th at M. sexta is not able to consume the evidence of feeding activity.