| Histia flabellicornis(Lepidoptera: Zygaenidaeis)is the major defoliator of Bischofia polycarpa.Their larvae feed on the leaves of B.polycarpa exclusively,and adults prefer to lay eggs on the leaves of B.polycarpa,which means it has a significant preference for this kind of host.Monophagous insects often use odorant cues released by the host during foraging and oviposition.They can recognize these special volitles through antennae or mouth which were covered by various sensilla.Therefore,Scanning electron microscope(SEM)was used to observe the ultrastructure of adults antennae and proboscis and larvae head,which might lay a foundation for studying the specific recognition mechanism of the pests.The main results are as follows:The antenna of the Histia flabellicornis adults is black and pectinate,consists of three parts: scape(Sc),pedicel(Pe)and flagellomeres(Fl).The average length of female antennae is 9.14±1.30 mm,and is 8.48±0.57 mm in male.There are six types antennal sensilla and 10 subtypes observed,including sensilla trichodea(ST-Ⅰ,ST-Ⅱ),sensilla chaetica(SCH-Ⅰ,SCH-Ⅱ),sensilla basiconica(SB-Ⅰ,SB-Ⅱ),sensilla squamiformia(SSQ),Sensilla auricillica(SAU)and Bǒhm bristles(BB-Ⅰ,BB-Ⅱ).Among them,only the length and basal diameter of SCH-II,the basal diameter of SB-I,SB-II and BB-II have significant gender differences.There are three types of sensilla found from adult proboscis :sensilla chaetica(SCH),sensilla basiconica(SB)and sensilla styloconica(SST).Only the length of SCH shows significant difference between two genders.The larva of H.flabellicornis is hypognathous with a chewing mouthpart which is composed of a pair of antennae,a piece of labrum and labium,a pair of mandible,maxilla,maxillary palpus,labial palpus and one spinneret and has six ocellus on each sides of gena.Few sensilla are distributed on larvae heads,only one sensilla trichodea(ST),one sensilla chaetica(SCH),one sensilla styloconica(SST)and two sensilla basiconica(SB)are found from the larvae antennae,ten pairs of sensilla chaetica(SCH)on the labrum,two sensilla trichodea(ST)on the mandible,one sensilla chaetica(SCH),thirteen sensilla bosiconica(SB),two sensilla styoconica(SST),one sensillum digitiformium(SD),one sensilla placodea(SPL)on the maxilla and maxillary palp,one sensilla styloconica(SST)and one sensilla chasetica(SCH)on the labial palp.The common sensilla types between adults and larvae are sensilla trichodea(ST),sensilla chasetica(SCH)and sensilla basiconica(SB).The specific sensilla types of adult antennae were sensilla squamiformia(SSQ),Sensilla auricillica(SAU)and and Bǒhm bristles(BB).Sensilla styoconica(SST),sensillum digitiformium(SD)and sensilla placodea(SPL)are only found in larvae heads.Study the morphological characteristics and distribution of different types sensilla in the adult and larva of H.flabellicornis could lay a morphological foundation for the research on olfactory and gustatory recognition mechanism of this monophagous insects. |
