Ultrastructure Of Antennal Sensilla From Parasitoid Fopius Arisanus And Its Responses To Semiochemicals From Bactrocera Dorsalis Eggs Surface

Ultrastructure of antennal sensilla from Fopius arisanus （Sonan） was studied inthis paper. The hexane extracts of Bactrocera dorsalis （Hendel）eggs’ surface wereanalyzed by Gas Chromatography/Mass Spectrometry（GC-MS）. Among them, ninekinds of chemical were chosed to research the EAG and behavior responses of F.arisanus.1. The antennal sensory sensilla of the parasitoid, F. arisanus were observed withscanning electron microscopy. Totally, six distinct types of sense receptors wereobserved, including sensilla trichodea and sensilla basiconica with two kindsrespectively, Bohm’s bristles, sensilla placodea, sensilla squamiformia and sensillacoeloconica. The morphology and structure of these sensilla were compared with thatfound in other braconid wasps. Their possible functions are discussed in light ofpreviously published literature.2. Volatile chemicals from the eggs of B. dorsalis influence the host-seekingbehavior of F. arisanus. In order to indentify the main component of volatilechemicals, the hexane extracts collected from the surface of B. dorsalis eggs wereanalyzed by GC-MS. After searching the GC-MS database and comparison withstandard mass spectra,12components from eggs’ surface were indentified. Also thecontent of these chemicals was determined by the aera normalizing method. Theprincipal components of hexane extracts were straight saturated hydrocarbons rangingfrom C-12to C-25with some alcohols and aliphatic acid ramifications.3. With the increasing concentration of9kinds of chemical, the EAG value of F.arisanus to tetradecanol declined gradually in contract to the ascending EAG valuesof heneicosane and tetracosane. When the volume of solution concentration reached10^-4, the EAG response of F. arisanus to hexadecanol arrived the highest value in itsfive diluted times. Similarly, the volumes of ethyl tetradecanoate, dodecane, docosane,tricosane and pentacosane were10^-4,10^-3,10^-4,10^-3and10^-5relatively with their highestvalues. There were significant variation between female and male when stimulantswere tricosane, dodecane and tetracosane. 4. The behavior responses of F. arisanus to9kinds of chemical were identifiedwith the EAG response on the whole. Except tricosane, dodecane and tetracosane,there was also a kind of chemical （ethyl tetradecanoate） that could cause significantvariation between female and male.