Sirex noctilio host searching behavior: use of reliable infochemicals emitted by fungal symbiont

FERNANDEZ AJO, AA; MARTINEZ, A; VILLACIDE, JM; CORLEY, JC

Salt Lake City

Congreso; IUFRO 2014; 2014

IUFRO

The woodwasp Sirex noctilio is considered a major pest of pine plantations worldwide. Female wasps establish a symbiosis with the basidiomycete Amylostereum areolatum. Arthrospores of the fungus, carried in special sacs, are deposited into living trees at the moment of oviposition. Fungal growth within the wood is fundamental for larval nutrition. Previous studies have established a strong spatial aggregation of S. noctilio attack, with females favoring previously attacked trees since multiple fungal insertions help weakening the tree and increase larval survival. Therefore we hypothesize that host-searching females will rely on fungal volatiles (in addition to pine infochemicals) since they will be a reliable indication of host suitability. We investigated the volatile emissions of fungal growth and used electrophysiological and behavioral assays to establish the relevance of these volatile compounds in the context of female host searching behavior. We suggest that some of the fungal volatiles are used as cues during the host searching process, and their potential use in pest monitoring programs is discussed.