Emission and localization site of pheromones in Ambrosia beetle Megaplatypus mutatus attacking three host species.

P. GATTI LIGUORI, P.GONZALEZ AUDINO, E. ZERBA

Neuchatel, Switzerland

Congreso; 25th ISCE Annual Meeting; 2009

Megaplatypus mutatus, an Ambrosia beetle (Platypodidae) native to South America, is a main forest pest that attacks live standing trees, affecting commercial poplar and broadleaf plantations. Attack is initiated by pioneer males selecting a host tree to build a short nuptial gallery, from which they attract females using a sexual pheromone composed mainly by (+) 6-methyl-5-hepten-2-ol ((+)-sulcatol) and 6-methyl-5-hepten-2-one (sulcatone). Recently 3-pentanol was found in the chemical analyses of volatiles using an SPME coating specific for low molecular weight alcohols and ketones. Although identified in a small percentage of samples, walking behavioral bioassays with video image analysis showed that at the doses tested, 3-pentanol elicited an attractive response from females. In the present study, we determined the sites of production of the pheromones within males and the temporal pattern of pheromone emission during gallery initiation and establishment. (+) Sulcatol, sulcatone and 3-pentanol were found only in proctodeum. Sulcatol and 3-pentanol production was detected 1-2 days after gallery initiation with maximal production between 5-12 days. Sulcatone production was noted during the same period although only in trace quantities. We collected male volatile emissions during the hours of peak flight by using a specific polar microextraction phase and the extract was analyzed by GC-MS. (+) Sulcatol and sulcatone were noted in pheromone emissions from males on three different host species, between 2-12 days post gallery initiation until day 51; sulcatone always in lower amounts. The temporal patterns of sulcatol sulcatone and 3-pentanol within male M. mutatus proctodeum correspond to the temporal patterns of emission.