Researches On The Host Selection Behavior Of Dastarcus Helophoroides(Fairmaire), A Parasitoid Of Monochamus Alternates(Hope)

Herbivorous insect predators in search of host process, volatile compounds play an important role in the information. Dastarcus helophoroides is an important natural enemy of Monochamus alternatus, it is distributed throughout most Provinces in China and there is a strong ecological adaptability. Based on chemical ecological methods, author used volatile compounds from larva frass (LF) and wood with larval tunnels (WLT) of M alternatus to study their attractiveness to a natural enemy-D. helophoroides, in order to make use of this natural enemy to biological control of M. alternatus.There are three aspects to introduction.1. By using Y-tube olfactometer, we studied the response of D. helophoroides adult towards different odor sources from host (M. alternatus (Hope)) and host tree (Pinus tabuleaformis) were tested in either no-choice or two-way choice tests,such as larva frass (LF)、.wood with larval tunnels (WLT)%bark with larval tunnels (BLT)、Host larvae、 uninfested wood and uninfested bark。The results showed that, the volatiles from the WLT and LF show significant attractiveness to adults of D. helophoroides (wild populations F1and experimental population) when compared with blank air. Bark with host larval tunnels, host larvae, uninfested bark and uninfested wood have no attractiveness to D. helophoroides. Comparison of different odor sources between wild populations F1and experimental population of D.helophoroides adult Compared LF with WLT, adults of D. helophoroides show no significant difference towards them, but there are more adults attracted by LF.2. The volatiles from LF with WLT were analyzed by SPME-GC-MS and the results showed that the main volatile substances were terpines. Seven main monoterpines were a-Pinene, β-Pinene, β-Mycrene, Limonen,a-Phellandrene, Camphene ande3-Carene. The percentage of the each monoterpines were different between LF with WLT.,3-Carene only detected in WLT. Camphene only detected in LF.3.By Y-tube olfactometer, we studied the behavioral response of D. helophoroides adult towards a-pinene,(ls)-(-)-a-pinene,(+)-p-pinene,(-)-β-pinene,(+)-3-carene, DL-limonene, S-(-)-limonene, R-(+)-limonene, p-Mycrene. The results showed that a-pinene and R-(+)-limonene could signicantly attract adults of D. helophoroides (wild populations F1) Other monoterpines showed no attractiveness to D. helophoroides (wild populations F1).a-pinene,(+)-β-pineneand and R-(+)-limonene could signicantly attract adults of D. helophoroides (experimental population). Other monoterpines showed no attractiveness to D. helophoroides (experimental population)...