Host Location Of Trissolcus Japonicus By Utilizing The Infochemicals Released By Halymorpha Halys

Halyomorpha halys(St?l)(Hemiptera: Pentatomidae) is an important pest on the fruits trees and vegetables. Trissolcus japonicus(Ashme ad)(Hyme noptera: Scelionidae) is a dominant e gg parasitoid of H. halys in China. The host selection behavior of parasitoids has been se parated into various steps, including host habitat location, potential host location, host location, host recognition, host discrimination, and host acceptance, during which semiochemicals play an important role. In our present study, Y-olfactometer was used to conduct behavioral bioassays to test the olfactory response of T. japonicus to host pest and its specific volatile chemicals. Ante nnal sensilla of T. japonicus were observed by scanning electron microscopy(SEM). Electrophysiological activity compounds released by H. halys egg masses and adult bodies were identified by GC-EAD combine d with GC-MS measures. The purpose of our study is to explore evidences that T. japonicus can use the chemical defensive substance of H. halys as kariomone to locate host, which would provide theoretical basis for biological control of H.halys.1 The behavioral bioassay for host location of T. japonicusIn Y-olfactometer tests, T. japonicus females responded positively to H. halys eggs and virgin males, but did not respond to virgin female H. halys. T rissolcus japonicus femeals were strongly repelled by mated male and female bugs as well as host pe ach tree leaves. In addition, T. japonicus were attracted by n-tridecane but showed no preference to trans-2-decenal.2 The antennal sensilla of T. japonicusAbundace, size and distribution of antennal sensilla of T. japonicus were obeserved by SEM. It re ve aled se ve n morphologically different types of sensilla and one gland, including trichodea sensillum, basiconica sensillum, chaetica sensillum, groo ve d-peg sensillum, c ampaniformium sensillum, sickle-shapped sensillum, papillary se nsillum and peg gland. Se xual dimorphism in the ante nnae of T. japonicus males and female was also confirmed. Se x gland was o nly found on the 5t h male antenommere, while papillary sensillum was only found on the female ante nnae. Male antennae possessed a greater number of sickle-shapped sensilla than female ante nnae, suggesting their possible function in perception of mate-related volatile cues as well as host-related volate cues.3 The electrophysiology research for host location of T. japonicusWith the aid of GC-EAD and GC-MS, nonanal, 2-decenal and n-tridecane were identified as electrophysiology activity compounds extracted from H. halys and elicited electrophysiological response in female T. japonicus. Taking into consideration of Y- olfactometer test results, we conclude d that n-tridecane was used by T. japonicus to locate H. halys.