北方草地牛粪中金龟子的多样性

The diversity of scarab beetles in grassland cattle dung from North China

2006年5—9月,在内蒙古鄂温克族自治旗(典型草原)、内蒙古科尔沁左翼后旗(沙地草原)和吉林省长岭县(草甸草原)3种放牧草地中,采用陷阱法和野外牛粪解剖手捡法采集牛粪中的金龟子,共采集金龟子75981头,分属9科43种。对其进行多样性分析,结果表明:长岭和鄂温克族自治旗牛粪生境中的优势种均是黄缘蜉金龟Aphodius sublimbatus(Motschulsky)(分别占各自生境捕获个体数的88.188%和93.547%),科尔沁左翼后旗的优势种为双顶嗡蜣螂Onthophagus bivertex Heyden(67.067%)、小蜉金龟Aphodius pusillus(Herbst)(14.524%)和独角凯蜣螂Caccobius unicornis(Fabricius)(10.264%)。科尔沁左翼后旗牛粪中金龟子的Simpson指数、Shannon-Wiener指数和均匀度指数在3种草地中均最高,长岭次之,鄂温克族自治旗最低。3种草地牛粪中金龟子的物种数与其丰富度相一致:长岭>科尔沁左翼后旗>鄂温克族自治旗。Sorenson群落相似性系数在0.458—0.578之间。

Abstract： Scarab beetles in grassland cattle dung were collected through pitfall traps and dissecting cattle dung in Ewenke Autonomous County （typical steppe）, Horqin Left Back Banner （sand steppe） in Inner Mongolia, and Changling County （meadow steppe） in Jilin Province in May-September 2006. Species composition, diversity, and similarity of the scarab communities were analyzed. The pitfall trap method was as follows： A plastic bucket was buried in the experimental plot with the top of the bucket at ground level. The bucket contained a solution of 70% alcohol, and there was an iron wire frame covered with mesh. A nylon bag with 1 kg of fresh cattle dung was placed on the iron wire frame. After 3 days, the scarab beetles in the bucket were collected. This procedure was conducted monthly, for 3 successive days, and there were six repetitions in each experimental region. The method for dissecting cattle dung was as follows： select cattle dungs and collect the scarabs in the dung and a 10cm layer of soil under the dung. At least 200 cattle dungs were dissected every month in each experimental region. A total of 75 981 scarabs were captured, belonging to 4~ species and 9 families, in which there were 19 species of the family Aphodiidae, 9 species of the family Scarabaeidae, 6 species of the family Melolonthidae, 2 species of the family Trogidae, 2 species of the family Geotrupidae, 2 species of the family Rutelidae, and each of the families Ochodaeidae, Cetoniidae and Dynastidae had 1 species. There were 10 mutual species among the threeexperimental regions： Onthophagus bivertex Heyden, O. gibbulus （Pallas）, Aphodius breviusculus （Motschulsky）, A haemorrhoidalis （Linnaeus）, A. impunctatus Waterhouse, A. naraensis Nakane, A. pusillus （Herbst）, A. rectus Motschulsky, A. sublimbatus （ Motschulsky ）, Autonomous County, the dominant species was and Proagopertha lucidula Faldermann. In Changling and Ewenke Aphodius sublimbatus （Motschulsky） （88. 188% and 93. 547% respectively）. In Horqin Left Back Banner, the dominant species were Onthophagus bivertex Heyden （67. 067% ）, Aphodius pusillus （ Herbst ） （ 14. 524% ） and Caccobius unicornis （ Fabricius ） （ 10. 264% ）. The diversity analysis demonstrated that the Simpson Index, Shannon-Wiener Index and Pielou Index of the scarab community were highest in Horqin Left Back Banner and lowest in Ewenke Autonomous County. Species numbers of scarabs were in accordance with its richness in cattle dung in different regions. Changling County had the highest richness index, followed by Horqin Left Back Banner and Ewenke Autonomous County. The similarity index and Horqin Left Back Banner was moderately similar at 0. 578. of scarab communities between Ewenke Autonomous County The similarity index of scarab communities between Ewenke Autonomous County and Changling County was moderately similar at 0. 553. The similarity index of scarab communities between Changling County and Horqin Left Back Banner was moderately dissimilar at 0. 458. There were significant differences in the nunlber of scarabs in different regions. Our analysis suggests that four factors result in the differences in diversity of scarab communities in the three experimental regions ： （ 1 ） Large-scale climatic factors dominate the primary composition of scarab communities; （2） The altitude and latitude of the experimental regions impact the number of families and species of scarabs; （3） Vegetation types impact the diversity and evenness of scarab communities; （4） Grazing pressures impact individual numbers of scarab communities.