Study On The Diversity Of Insect Species In The Northern Luo River Basin

Insect is the biggest class group of the animality, regardless of being individual quantity, the biomass, the number of species and genes, they hold the very important status in the biodiversity. The relationship between insect and humanity are close and complex, some insects create the grave disaster to the humanity, some kinds have provided the rich resources to the humanity. Finds out the present situations of insect species diversity comprehensively has the very vital practical significance to protect and using the insect diversity resources continually and the human society economic development.The Northern Luo river basin is situated at loess plateau of the Northern Shannxi, which is one of the most serious soil erosion areas in our country. In recent years, the effect of Grain for Green Program in this area is tremendous. It is significant to promote the regional economies coordinated development that research on insect species diversity and develop and use the Northern Luo river basin living resources reasonably. Take"The Study of animal population, species, quantity and dynamic state about the ecological construction in the Northern Luo river basin"the project as a platform, the diversity of insect in the Northern Luo river basin was investigated and studied during May to September in 2007. In the first part of this thesis, the insect quantitites, species- abundance in the Northern Luo river basin was anlysised in the taxonomic category of order and family. In the second part, the Coccinellidae is taken as the representative species and its quantities, species-abundance, diversity indices and the similar cluster was analysised.1. The investigation result: the thesis preliminary reported the insect resources in the Northern Luo river basin. This investigation has collects 14004 insect specimen, in which 11730 has identified and subject to 13 orders 91 families and 305 species, 2274 insect specimen has not identified.2. The results of analysis about insect species abundance: the quantity of Coleoptera is 5497, accounting for 39.25 percent; Lepidoptera is 4244, accounting for 30.31 percent; Orthoptera is 2299, accounting for 16.42 percent; the proportion of other orders less than 5%. Insect abundance in different months: June & July > August > September > May, it shows that the behavior of insect most frequently is in June & July, followed over time, the number of insects are gradually reduce. Insect abundance in different sites: Fuxian > Ganquan > Wuqi > Luochuan = Zhidan > Huangling, it shows that the insect abundance is relatively more large in the middle reaches of the Northern Luo River basin. Insect abundance in different altitudes: 900-1000m > 800-900m > 1000-1100m > 700-800m > 1100-1200m > above 1200m, it shows that insects distributed between altitudes 800m to 1000m mostly and the insect abundance is decreasing with increased altitude above 1000m. Insect abundance in different ecotypes: shrub-floodplain > grassland > woodland > farmland, it shows that shrub-floodplain and grassland are more suitable ecotypes for insect living.3. The investigation result about Coccinellidae: the investigation and study has collects 525 Coccinellidae specimen, subject to 12 genera and 15 species, in which 10 genera only include 1 spieces each.4. Speices-abundance of Coccinellidae: (1) The quantity, abundance are more than 10 species are in May to July; 7 species in August; only 5 species in September at least. The dominant species are Coccinella septempunctata L., Henosepilachna vigintioctoma- culata M. and Harmonia axyridis P. that constitute a high proportion in each month and site. (2) In addition, Hippodamia variegata G. and Coccinula quatuordecimpustulata L. are dispersed species. (3) The dominant species between altitudes 700-900 m , 900-1100 m and1100-above1100m respectively is Coccinella septempunctata L., Harmonia axyridis P. and Hippodamia variegata G.. The distribution of species-abundance is more uniform above altitude 1100m. And Hippodamia variegata G. and Coccinula quatuordecimpustulata L. are mainly distributed above 1100 m. (4) Coccinella septempunctata L. is the widespread dominant species in the entire study area. (5) Combination with the species-abundance model of different months, sites, altitudes and ecotypes, the analysis results were objectively reflected that the Cocdingllidae's distributing characteristics and laws in the studied area.5. The results of Coccinellidae diversity indices analysis: the variational trend of diversity indices in different months: H' and Dm is May >June-July>August > September ; Jsw is September> August> May> June-July;λis September > August> June-July> May; PIE is May > June-July > August > September. The variational trend of diversity indices in different sites: H' is Wuqi > Huangling > Zhidan > Fuxian > Luochuan > Ganquan; Dm is Zhidan > Huangling > Wuqi > Luochuan> Ganquan> Fuxian; Jsw is Wuqi > Huangling > Fuxian > Luochuan > Ganquan > Zhidan;λis Luochuan > Ganquan> Zhidan> Fuxian> Huangling> Wuqi, is contrary to PIE. Above the altitude of 1100m, H' and Jsw and PIE is the maximum, butλis the minimum; Dm is the maximum between the altitude of 900-1100m. The variational trend of diversity indices in different ecotypes, H' is shrub-floodplain > grassland > woodland > farmland; Dm is grassland > woodland> shrub-floodplain > farmland; Jsw is farmland > shrub-floodplain > grassland > woodlands.λis woodland > farmland > grassland > shrub-floodplain, and PIE is contrary toλ.6. The results of Coccinellidae similarity indices clusting analysis: the similarity of August and September is the highest, followed by May and June-July is also higher. In regard to the site, The similarity of Ganquan and Fuxian is the highest; Wuqi and Zhidan, Ganquan and Luochuan is also higher; followed by Huangling and Luochuan. By comparison of different ecotypes, the similarity of farmland and shrub-floodplain is the highest.