Ulstrastructure Of Antennal Sensilla Of Two Main Chinese White Pine Bark Beetles In Qingling Mountains

Dendroctonus armandi Tsai et Li (Coleoptera: Scolytidae) and Ips acuminatusGyllenhal (Coleoptera: Scolytidae), two main invasive bark bettles of Chinese white pine(Pinus armandi Franch), are highly dependent on its olfactory system, especially the antennalsensilla, for activities such as host seeking, mating, oviposition and population aggregation.They threatened the safe of forest ecosystem of our country seriously and caused a loss to oureconomic. This research aimed at observing their antennal sensilla distribution andultrastructure in order to reveal their o invasion and proliferation mechanism.In this research, scanning electron microscopy is used to observe the sensilla on the adultIps acuminatus and the different phases D. armandi. We found the following results:(1) There were not obvious differences between structure and morphology of male andfemale adult I. acuminatus. Six types of sensilla identified on the antennas of both female andmale were: sensilla trichodea (ST Ⅰ and ST Ⅱ), zigzag sensilla, sensilla chaeticum,bud-shaped sensilla, sensilla basiconica and fluted sensillum. Sensilla triehodea was thedominant type，which occupied about83%, and zigzag sensilla distributed on all parts ofantennae. Among all parts of antennae, majority of sensilla spreaded on the club of theantennae and occupied92.3%, while the funicle is3.4%.(2) The antenna of the larve D. armandi were undeveloped. The surface were equippedwith two types of sensilla, sensilla basiconica (SBⅠ, SBⅡand SBⅢ), sensilla styloconica.(3)The antenne of the early pupal D. armandi consisted of scape, funicle and club. Threearcuate zones with many unsharp basiconica protuberances on the surface located on the twosides of the club and two bands were in the middle part. There were abundant basiconicaprotuberances on the posterior surface of the club edge.(4) The antenne of the early pupal D. armandi was similar to the early pupa, but therewere three bands in the middle part. Lots of sharp-top basiconica protuberances were on thesurface of the arcuate zones and the posterior surface of the club edge(5) Ten types of sensilla were identified on the adult D. armandi antenne: sensillatrichodea (STⅠ, STⅡ, STⅢ, STⅣ and STⅤ), sensilla basiconica, zigzag sensilla, sensillafurcatea (SFⅠ, SFⅡ and SFⅢ), sensilla styloconica, fluted sensillum, sensilla chaeticum, sensilla campaniformia, bud-shaped sensilla, b hm bristle (BBⅠ，BBⅡand BBⅢ). Majorityof sensilla spreaded on the club, zigzag sensilla distributed on all parts of antennae, while thesensilla trichodea, sensilla styloconica, sensilla campaniformia and fluted sensillum justlocated on the club, sensilla furcatea just found on the base of the scape.Comparison of the pupal and adult D. armandi, we inferred the various sensilla on theclub might be differentiated from sensilla basiconica, and the sensilla on the posterior surfaceof the club edge growth the earliest, and the side rowed earlier than the middle part.