| The gall midge Jaapiella sp.(Diptera:Cecidomyiidae)is one of the most serious pests of the wolfberry,Lycium barbarum(Solanaceae)in northwest of China,which mainly damages the ovary and petals of the wolfberry flower buds,resulting in the malformation of buds and unable to bloom and bear fruit.Because the larvae and pupa are hidden in the flower buds and soils respectively,there is no effective method to control this pest.Therefore,the gall midge is known by farmers as "Goji cancer" in China.The gall midge is a typical phagocytic gall insect,and the adult has a short lifespan.Females emerge,generally mate once,and then search for the young buds of the wolfberry to oviposit.How do they quickly find a mate in their short life cycle,and accurately locate the young flower buds of L.barbarum,and then complete the reproductive tasks of copulation and spawning?What role do antennae play in mate selection and host orientation?At present,many questions are rarely reported and there is no clear answer.In this study,the reproductive biology,the effects of sex pheromones and host plant volatiles on adult mate selection and host location,and the ultrastructure of adult antennal sensillum of Jaapiella sp.were systematically studied,which provided scientific basis for the green and safe prevention and control of the pest.The main results were as follows:1.The reproductive biological characteristics of Jaapiella sp.were determined preliminarily.The way of Jaapiella sp.reproduction belonged to bisexual reproduction.Both male and female adults had multiple copulation habit,especially the male was more obvious.There was no obvious correlation between the presence of host plants and copulation behavior of Jaapiella sp.,but the age of day of the insect had a significant effect on copulation behavior.The 0-6 h of adults had the highest copulation frequency,which was the optimal age of copulation.The later stage of pupa was the initial development stage of the gall midge eggs,which had few mature eggs.Females emerge,generally mate once,and then search for the young buds of the wolfberry to oviposit.Their reproductive behavior was rapid and for a short time.The oviposition of female adults were very large.The effective spawning rate was about 88.32%.Therefore,the copulation and oviposition of most adults of the gall midges had been completed once they were found in fields,and these results would provided important guidance for determining the optimal control time for the pests in production.2.The source sex pheromone of Jaapiella sp.was preliminarily determined.Sex pheromone of Jaapiella sp.was produced by the females and could cause the males to produce significant tendency response.However,due to the extremely trace amount of the sex pheromone in Jaapiella sp.,no chemicals were detected by GC-MS,which were similar to the same functional groups as the active components of the sex pheromone in other gall midges.The results further proved that Jaapiella sp.had the characteristics of sexual reproduction,which would made it possible to control the gall midges with sex pheromone.3.The volatile components from the flower buds of L.barbarum and their attraction and avoidance to the females of Jaapiella sp.were preliminarily determined.Thirty seven compounds were identified from the volatiles of young and mature flower buds of L.barbarum.Among them,8 compounds could cause sustained antennal potential reaction in females.And 3-carene,camphene,terpinolene,and d-limonene had significant attraction to the female,and stimulated the females to produce significant anti-wind orientation or close to the odor source.And the females had a significant avoidance reaction for(+)-α-pinene.(Z)-3-hexen-1-ol,(Z)-3-hexenyl acetate and β-myrcene did not induce or avoid the females.Therefore,it was suggested that the female of Jaapiella sp.could accurately locate the flower buds of L.barbarum by using the variety of volatile compounds released from the flower buds of L.barbarum.4.The microstructure,types and distribution of antennal sensilla of Jaapiella sp.were defined.The antennae of both Jaapiella sp.male and female adults were moniliform,and had sexual dimorphism.The total length of male antennae was longer than that female.There were distinct internodes between falagellomeres of male antennae,with 10-16 falagellomeres,most of which were 15 segments.The number of falagellomeres of female antennae was 8-14,mostly 12 segments,and no obvious internodes.The variation of antennae segments of Jaapiella sp.in number mainly resulted from the fusion or constriction of the segments.There are four kinds of sensilla on the antennae were observed:sensilla chaetica,s.trichodea,s.coeloconica,and s.circumfila.Sensilla circumfila were are a special sensory type of Cecidomyiidae.In the male antennae,the types and number of the windward sensilla were more than that of the leeward,this allows the male to better sense information,especially sex pheromone.This study made a deep understanding of Jaapiella sp.according to the morphological and reproductive biological.The reproductive and biological characteristics of the adults and the ultrastructure of the antennal sensilla were clarified.The chemical communication function of semiochemicals in copulation and oviposition behavior of Jaapiella sp.was determined.These results provided scientific basis for green prevention and control of Jaapiella sp.. |
