Interadaptation Between Eristalini Species (Diptera:Syrphidae) And Their Visiting Flowers On South Slope Of Qinling Mountains

The characteristics of plant growing and the living habits of insect often lead to the complex and diverse interadaptation relationships using each other as a natural selection condition in evolution.In this paper,the flower-visiting Eristalini species distributed on south slope of Qinling Mountains as the research object,the interadaptation between Eristalini species and their visiting flowers were carried out including the Eristalini species diversity,the trendency of color of the Eristalini species visiting flowers,Eristalini species' sensillum ultrastructure on the antennal and proboscis(the type,quantity and distribution of sensillum)by means of scanning electron microscope,and the floral features(flower inflorescence,color and corolla shape).The results of this research provided a theoretical support for the protection and reasonable development of flower-visiting Syrphidae species and flowering plants on south slope of Qinling Mountains,and it also given the basic information in comprehensive studying the cooperative coevolution between Syrphidae and flowering plants by the characteristics of interadaptation between Eristalini species and flowering plants.Meanwhile,it can accumulate some basic data for further exploring the formation and maintenance biological diversity.The main results of this research were as following:(1)The investigation about the diversity of Syrphidae was carried on at 6 various habitats located in Liuba,Yangxian,Foping and Ningshan counties on south slope of Qinling Mountains.As a result,there were 48 genera and 113 species in two subfamilies and 12 tirbes with 1,546 specimens,of which 6 genera and 12 specieswere included in the tribe Eristalini with 572 specimens.With the Eristalini specimens deposited in Qinba Biological Museum of Shaanxi University of Technology and relevant literatures,there were 7 genera and 23 species of Eristalini distributed on south slope of Qinling Mountains.(2)A new species of Cerioidini,Ceriana flavivittatus sp.nov.is somewhat similar to Ceriana anceps(Seguy,1948)and the significant difference is that their scutellumsare are both black,but the former transversely places small and triangular yellow patches before transverse suture on the mesonotum,which connect with longitudinal yellow patches on the back-end of anepisternum and yellow patches on the posterodorsal angle of katepimeron.the latter are all black on the mesonotum and pleuron,and only postpronotal lobes are yellow.(3)Analysis of species diversity shows that the Huayang town in Yangxian County about the Shannon–wiener,Pielou,Simpson and Margalef of flower-visiting Eristalini species in the following six habitats was the highest,which means the largest amount of information closely associated with the local complex habitat and the types of flowering plants.The similarity and cluster analysis also showed that Liuhou town in Liuba County and Zibaishan Mountains as a category for flower-visiting Eristalini species,the Huayang town in Yangxian County,Liangfengya protection station in Foping nature reserve,Xunyangba forest region and Pingheliang nature reserve in Ningshan County as the other category,as well as Huoshaodian town in Liuba County and Tiantaishan forest park in Hanzhong as the third category.(4)The results of the investigation about flowering plants visited by flower-visiting Syrphidae showed that there were 37 families,109 genera and 134 species,in which there were 31 families,80 genera and 96 species mainly including Compositae,Liliaceae,Umbelliferae,and Rosaceae visited by flower-visiting Eristalini species.Eristalis tenax,which visited 28 families 69 genera and 80 species of flowering plants,is the most important pollination Eristalini species on south slope of Qinling Mountains.E.cerealis is followed,which visited 19 families,42 genera and 47 species.(5)Analysis of the floral features of flowering plants visited by Eristalini species showed that flower-visiting Eristalini species perfered to visit the white and yellow flowers.Flower inflorescence include umbrellas,racemes,heads,panicles and solitary flower,and Corolla is mainly radiation symmetry,and most of choripetalous flowers are visiting and corolla shape has bell shape,tubular and tube shape and so on.(6)The result of Color Disk Trap experiment to research the trendency of color of the Eristalini species visiting flowers showed that Eristalini species were attracted by these yellow color plates,and indicated a strong tendency towards yellow.(7)The antennae and proboscis of flower-visiting Eristalini species have eight different sensillum,Sensilla trichodea(?,?,?),Sensilla basiconica,Sensilla chaetica(?,?),Microtrichia,Sensilla coeloconica and Sensory pit.The first seven sensillum are not significant differentiated in distribution in the intra-species and inter-species,and differentiated in the morphology of the sensilla including the length and base diameter.There are lots of sensilla trichodea ?,Sensilla basiconica,Sensilla chaetica ? and Microtrichia,and few sensilla trichodea(?,?),Sensilla chaetica ? and Sensilla coeloconica.Sensory pits are distributed in the antennal flagellama,there are no differences in distribution in the intra-species,and differentiated in the inter-species.There are more Sensory pits in the ventral and less in the dorsal of antennal flagellam.In the study,it is firstly found that the male of Mallota viridiflavescentis,M.semenovi and E.Maculabdomnis,the male and female of Helophilus virgatus,E.tenax and Lathyrophthalmus viridis have sensilla coeloconica on all of the three parts,the flagellam,arista and labella,and also found the male of L.tarsalis and E.maculabdomnis,and the male and female of Phytomia zonata have sensilla coeloconica on the inside of hypopharynx at the first time.