North Luo River Syrphidae Division (syrphidae) Insects

The North Luo River Basin located in the Loess Plateau of the Northern Shaanxi,is the most serious soil and water loss in the word.In recent years,the effectiveness of returning farmland to forest or grassland of this area was great.So investigation of the insect species diversity,and rational developing and utilizing biological resources in this area,was important to promote the coordinated development of regional economy.This study is based on the project of "the researching of ecological construction animal species variety,quantity and dynamics in the North Luo River Basin".The hoverfly belong to Syrphidae which belong to Diptera.So far it has documented about 6 000 species(200 genera).In nature,the results from the present investigation suggest that the more important pollinating insects are Syrphidae,followed by the bees.The seed yield pollinated by Syrphidae is almost 3 times as large as the control.At the same time,the Syrphidae has importance in bionics,biological control and other aspects.Diversity of hoverfly community in North Luo River Basin is investigated using Fauna, species-abundance model,diversity index and clustering and so on in this paper.This research provides the basic information for Biodiversity Conservation and ecological environment protection of the North Luo River Basin for sustainable development.This experiment has collected 2 575 Syrphidae specimens,which belong to 2 subfamilies 11 tribes 29 genera 52 species.4 new species:Chrysotixum luohensis Huo,sp.nov.;Sphaerophoria sp. nov.;Monoceromyia Huo,sp.nov.;Pipiza huanglingensis Huo,sp.nov.2 new recording species in China:Platycheirus pennipes((?)hara,1980);Eupeodes(Eupeodes) latilunulatus(Collin,1931)。7 new recording species in Shaanxi:Chrysotoxum cautum(Harris,1776);Paragus albifrons(Fallen, 1817);Dasysyrphus albostriatus(Fallen,1817);Eupeodes(Eupeodes) latifasciatus(Macquart, 1829);Sphaerophoria rueppelli(Wiedemann,1830);Mallota sogdiana(Stackelberg,1950); Pipizella antennata(Violovitsh,1981)。There are 52 species recorded from the North Luo River Basin located in the Loess Plateau of the Northern Shaanxi.The sub-worldwide and the worldwide separately are 20.690%and 31.034% of the total.The multi-region distributing genera are the predominant composition of the hoverflies fauna in the region(48.276%of the total).On species composition,the Syrphidae insect species in both the Palaearctic and Oriental region are the predominant composition of the hoverflies fauna,and the Palaearctic region followed.At our country's 7 major zoogeographical sub-areas,in the central China and northern China are 32 species(61.538%of the total),in both Mongolia-Xinjiang Region and northern China are 30 species(57.692%of the total),in both the northeast China and northern China are 24 species (46.154%of the total).We analysed the Diversity indices using the Shannon-Wiener diversity index,the Margalef abundance index,the Pielou uniformity index,and the Simpson dominance index in different month,different location and different habitat.The variational trend of diversity index in different months is the following:Shannon-Wiener is September＞June＞August＞May.Margalef is August＞June＞September＞May.Pielou is June＞September＞May＞August.Simpson is May＞August＞September＞June.The variational trend of diversity index in different sites is the following:Wuqi County in the Simpson dominance index is lowest,but Ganquan County in the Shannon-Wiener diversity index and the Pielou uniformity index all are highest,and Huangling County in the Margalef abundance index is highest.The variational trend of diversity index in different habitats is the following:grassland in Shannon-Wiener diversity index and Margalef abundance index is highest.But woodland in the Pielou uniformity index and the Simpson dominance index are highest.The species-abundance models of different month,site and habitat all match baxically to Preston's lognormal distribution.This distribution has been hoped to appear in many communities.The clustering results of different months show that similarity of May and June is the highest; The clustering results of different sites show that similarity of Wuqi and Zhidan is the highest, Luochuan and Huangling is the higher,Fuxian closes to Luochuan and Huangling;The clustering results of different habitats show that similarity of grassland and woodland is the highest,another habitats are fewer.The results of PCA to climate and the hoverfly of different locations show the cumulative percent of three principal components of climate reach 94.459%,the cumulative percent of four principal components of hoverfly reach 88.872%,which also occupy vast information's and may represented the characteristics of the whole community.The results of stepwise regression to climate factors and hoverfly community show:The climate factors affecting the species and numbers of hoverfly are the highest temperature utter mostly,the highest precipitation of May to September,the lowest precipitation of May to September,and accumulated temperature of exceed or equal to 10℃and time without frost et al.