Research On The Insect Diversity In The Area Of Red Imported Fire Ant(Solenopsis Invicta)

Solenopsis invicta Buren is a kind of invasive insect which has an advantage of population competition and an astonishing reproduction rate. S. invicta epidemic situation has taken place in our country such as Guangdong, Hunan, Guangxi, etc since 2004. In order to discuss the influence of S. invicta on the local insect diversity for further understanding the harm brought by it, to provide certain theoretical support for the control of S. invicta and the risk assessment of its invasion, the insect diversity in the area of imported S. invicta was investegated and studied in Luorong town, Liuzhou City, Guangxi from July, 2006 to July, 2007. The main experimental results were as follows:1. In one year's field survey and collection, 7950 adult species were found in the 208 captured specimens, belonging to 10 orders, 65 families. Hemiptera accounted for a considerable proportion in the captured specimens, it was 30.327%, Coleoptera, Orthoptera, Diptera, Homoptera, Hymenoptera were second, accounting for 21.862%, 16.742%, 10.704%, 10.478%, 6.403% respectively. Coleoptera accounted for a considerable proportion in the number of species, it was 30.288%, Hymenoptera, Hemiptera, Diptera, Orthoptera, Homoptera were second, accounting for 21.154%, 15.865%, 12.981%, 10.577%, 3.846% respectively. Chrysomeloidea was the main group in the composition of Coleopteran, Coreidae, Lygaeidae, Pentatomidae were the main groups in Hemiptera, Acridoidea was the main group in Orthoptera, Fulgoroidea, Cicadelloidea, Cercopoidea were the main groups in Homoptera.2. Comparison between two blocks of sample plots. The number of insect species and the number of insect individuals were 349 and 1876 respectively in sample plotâ… . The number of insect species and the number of insect individuals were 288 and 1497 respectively in sample plotâ…¡. Plotâ… was a little more than plotâ…¡either in the number of insect species or the number of insect individuals.Diversity analysis of two plots showed that plotâ… was higher than plotâ…¡in dMa richness index, H' diversity index, Devenness index J and D diversity index in almost one year.By T-test of the diversity index, it was obtained that there was no significant difference between two blocks of sample plots in dMa richness index,H' diversity index, Devenness index J and D diversity index.From the view of the survey of sample plots, the quantity of S. invicta of sample plotâ… was less than plotâ…¡, and the density of ant nests of plotâ… was also lower than plotâ…¡. It could be seen that the quantity of S. invicta and the density of ant nests had certain influence to the numbers of insect species, the individuals and diversity index of insects around them, but this difference was not significant.3. Comparing the sample plots of treatment groupâ… and control groupâ…¢, treatment groupâ…¡and controlâ…£, it could be seen that the control group was more than the treatment group either in insect species or individuals. Diversity analysis of two plots showed that the control group was higher than the treatment group in dMa richness index, H' diversity index, Devenness index J and D diversity index in almost one year. By T-test of the diversity index,it was obtained that there was significant difference between two blocks of sample plots in dMa richness index, H' diversity index, but there was no significant difference in Devenness index J and D diversity index.The numbers of species and individuals of insect communities around the sample plots invaded by S. invicta was significantly less than the numbers of no invasion by S. invicta. The invasion caused by S. invicta had an influence to the diversity of insect communities around them,and this influence manifested significant difference.4. The data of four sample plots from April, 2007 to July, 2007 was analyzed. Single factor variance analysis for dMa, H', J, D diversity index of four sample plots showed that there was significant difference in dMa richness index between plotâ… and plotâ…¢, plotâ…¡and plotâ…£. There was significant difference between plotâ…¡and plotâ…£in H ' diversity index. dMa index, H' index, J index and D index of control group plots were high, it indicated that the insect communities of them were relatively stable. On the contrary, dMa index, H' index, J index and D index of treatment group plots were low,it indicated that the insect communities of them were unstable.Similarity index and cluster analysis of insect communities of four sample plots showed that similarity coefficients of plotâ… and plotâ…¡were the maximal, which was 0.815533, and that similarity coefficients of plotâ…¡and plotâ…£were the least, which was 0.5. The sample plots of S. invicta were clustered together, and the sample plots without S. invicta were clustered together, which were richer in insect diversity.By principal components analysis of dMa, H', J, D indexes, the principal component scores of diversity index information of various kinds of sample plots were obtained. Concrete sorting was as follows: Plotâ…¢>Plotâ…£>Plotâ… >Plotâ…¡.It could be obtained that the invasion of S. invicta,the quantity of S. invicta and the density of ant nests had influence to the insect communities around them.