Study On The Composition And Diversity Of Insects In Yanqing District Of Beijing

Yanqing District is an important ecological barrier in Beijing and has abundant insect resources.To explore the insect biodiversity in this area,a comprehensive insect survey was carried out in the area during 2017?2018,collecting 25 885 insects,making 5013 dried specimens.The survey of.insect biodiversity were completed basically.The results of the survey are as follows:1.Composition and diversity characteristics of insect communities in Yanqing District,BeijingAccording to the collected specimens,a total of 379 species were identified,composed by 127 families in 15 orders.The five orders with the largest number of insects collected in Yanqing District were Diptera,Hemiptera,Lepidoptera,Hymenoptera,and Orthoptera;the five orders with the largest number of insect families collected were Coleoptera,Lepidoptera,Hemiptera,Diptera,Hymenoptera.Among them,the largest insect familiy collected were Coleoptera and Lepidoptera;the largest insect amount collected was Diptera.Analysis of insect diversity in different areas of Yanqing District in Beijing shows that the five areas with the biggest number of insect species collected were areas No.7(Baihebao Reservoir),No.3(Baili Mountain Scenic Area),No.14(near Erlou),No.25(Song Mountain),and No.1.The areas collected biggest insect amount were No.3(Baili Mountain Scenic Area),No.20(near Dayushu Town),No.7(Baihebao Reservoir)and No.22(near Xiaying Town).The areas with the lowest Shannon diversity indexes were No.17(near Huyu)and No.20(near Dayushu Town).In general,the difference of the Shannon diversity indexs in Yanqing District was relatively lower.The Shannon diversity indexs in the mountains such as east,north,northwest of Yanqing District,were relatively higher and more similar.The insect diversity indexs in the urban gathering area of Yanqing District were lower.The grid with the highest dominance index was No.20(near Dayushu Town);the grid with the smallest dominance index was No.7(Baihebao Reservoir).Generally,the distribution of the Margalef richness index in different areas of Yanqing District ranges from 3.203 to 16.935,and the distribution was relatively uniform.In the overall area of Yanqing District,the insect abundance was decreased from northwest to southeast.The insect evenness indexs were higher than 0.50 in most area.The insect evenness indexs in Yanqing District were remained at a higher level and the difference among total district was small,revealed that the insect distribution in Yanqing District was relatively uniform.The relative stability indexs of insect communities in different regions were between 0.020 and 0.145,and relative stability indexs less than 0.050 were No.3(Baili Mountain Scenic Area),No.10(Zhenzhuquan Town),No.12(near Baibogou),No.16(near Dazhuangke Town),No.17(near Huyu),No.20(near Dayushu Town).2.Investigation of insect diversity in different habitats in Yanqing District,BeijingThe survey results of insect diversity in five ecological types(ie wetland,Plantation,forests,Grassland-shrubs and Cropland)in Yanqing District of Beijing showed that the amount of individual insects in different habitats was wetland>Cropland>Grassland-shrub>Forest>Plantation;the amount of insect families is Cropland>wetland>forest>Grassland-shrub>Plantation.Insect richness index is in order of Wetland>Plantation>Forest>Grassland-shrub>Cropland,and evenness index is Wetland=Forest>Grassland-shrub>Plantation>Cropland.In addition,the Sannon diversity index was significant different among different habitats(P<0.01),and the order of H' value was Wetland>Forest>Plantation>Grassland-shrub>Cropland(P<0.01).Insect dominance index was also significant different among different habitats(P<0.01),the order were Wetland>Forest>Plantation>Grassland-shrub>Cropland.On the other hand,the Jaccard community similarity of the five habitats were all higher than 0.5 and lower than 0.75,which was moderately similar.The results also showed that insects have a tendency to choose different habitats.The insect species in areas such as wetlands and forests with fewer human disturbances and smaller human impacts were abundance,and the insect biodiversity was stable.When protect the insect diversity in Yanqing,we should protect that of wetlands and forest areas at first.3.Comparison of different insect collection methods in Zhenzhuquan Township,Yanqing District,BeijingIn 2018,the insect collection experiment was carried out in Zhenzhuquan Township,Yanqing District,Beijing.Using standard insect collection methods,the four insect collection methods of Line transect,Malaise trap,Light trap and Pitfall Trap(mixture of sweet and sour liquid)were compared.A total of 3996 insects which belonged to 12 orders and 87 families were collected.Among them,Lepidoptera had the largest insect species number,followed by Hemiptera and Coleoptera.Hymenoptera has the largest amount,followed by Diptera and Lepidoptera.A total of 72 species of 61 families were collected by Line transect,95 species of 45 families were collected by the light trap method,41 species of 39 families were collected by the Malaise trap,and 25 species of 14 families were collected by Pitfall Trap.There were significant differences among the amount of insect species collected in different habitats by different methods(P<0.01).Among the different collection methods,the similarity of the insects collected by the Malaise trap and the Line transect was moderately dissimilar(q=0.436),and the other methods were very dissimilar.More insects species can be collected by adopt different collection methods.Due to the Malaise trap was very convenient for collected insects and saved manpower,it was considered to be the best collection method in this survey,if it just allowed using single method.Moreover,the effect of Line transect was most stable.Though the light trap method has good collection effect,the application was complicated.Compared with other methods,the sweet and sour liquid trap method can neither collect a large number of insects nor specific species of insects.If there were no special demand,researchers can consider reducing or abandoning the the sweet and sour liquid trap method in large-scale investigations.