Comparison On The Characteristics Of Insect Communities In Zenia Insignis Chun Forest Between Fujian Introducing Regions And Other Regions

Zenia insignis is native to Guangxi and it has been introduced to the forests of Northwest Fujian. Based on field investigation, the species and the number of insect community in Zenia insignis from Fujian, Guangxi and other introducing regions were counted, and analyses were conducted on the insect community structure.The differences of the insect community structure were compared among Fujian, original and other introducing regions.Reasons for the change of insect community structure were analysed by investing the understory vegetation of Zenia insignis. The main results are as follows:(1)The insect community structure of Zenia insignis in Fujian. In Longyan, Colepterawas the major order and Curculionidae,Oedipodidae and Chrysomelidae werethe dominant groupsin canopy. Orthopterawas the major order and Oedipodidae,Culicidae and Formicidae were the dominant groups in understory. In Shunchuang, Homopterawas the main order and Cicadellidae was the dominant group in canopy. Orthoptera was the main order and Cicadellidae, Tettigoniidae and Oedipodidae were the dominant groups in understory. In both canopy and understory of Zenia insignis in Northwest Fujian, the families, species and individuals of phytophagous functional groupshad the largest proportion and those of parasiticfunctional groups had the least proportion. The species and individuals of phytophagous functional groups account for the highest proportion from March to October. The richness, diversity and evenness of insect community in canopy were less than those in understory, but the dominant concentration index of insect community in canopy was higher than those in understory. The richness and diversity of herbivorous insects were all the highest in both canopy and understory. In Longyan, S/N and S1/S2 of insect community in canopy were higher than those in understory, but N1/N2 of insect community in canopy was less than those in understory. In Shunchuang, S/N and S1/S2and N1/N2 of insect community in canopywere significantly higher than those in understory. The dynamic trend of phytophagous functional groups comes closest to the group population in both canopy and understory. The trend of richness,richness index and the diversity were very close in canopy. But the trend of dominance concentration index and evenness index were opposite.(2)The comparison of insect groups in Zenia insignis between Fujian and original regions. In Dachi, Longyan, Orthoptera was the major order in both canopy and understory. In Yanshan, Guangxi, Lepidopterawas the major order in canopy and in understory was Hemiptera. In Langneitun, Guangxi, Dipterawas the main order in canopy and in understory was Orthoptera. Form the comparison between canopy and understory, the families, species and individuals of phytophagous functional group had the highest percentage in both Fujian and Guangxi.The proportion of phytophagousspecies in canopy was higher in Dacchi and Langneitun. In Yanshan, the canopy had as much species as the understory.The proportion of phytophagous individuals in canopy was higher in Dachi, but in Guangxi, that in understory was higher. In Dachi, Longyan and Langneitun, Guangxi, insect groups in understory had more species, its distribution was more uniform and its diversity was higher. In Yanshan, Guangxi, the species in canopy was less than that in understory, but its distribution was more uniform and its diversity was higher. Form the comparisons among different sample plots, in canopy, the richness index and diversity index of group population were relatively lower in Dachi. The richness index and evenness indexof group population were higher and the dominance concentrate index was lowerin Yanshan.The richness index of group population was higher in Langneitun, but the evenness index was lower and dominance concentrate index was high. From the relative stability, S/N of insect community in canopy in Yanshan,Guangxi was highest. S1/S2 and N,/N2 of insect community in canopy in Langneitun,Guangxiwere highest.S/N、S1/S2 ofinsect community in understory in Langneitun was highest. N1/N2 of insect community in understory in Dachi, Longyan was highest.(3)The comparison of insect groups in Zenia insignis between Fujian and other introducing regions. In Dachi, Longyan, Orthoptera was the major order in both canopy and understory. In Tielong, Guangdong, Lepidoptera was the main order in canopy and in understory was Diptera. In Tuojiang, Hunan, Hemiptera was the main order in canopy and in understory was Orthoptera. In Dayu,Hunan, Coleoptera was the major order in canopy and in understory was Diptera.Form the comparison between canopy and understory, the families, species and individuals of phytophagous functional groups had higher percentage in Fujian, Guangdong and Hunan.(Only in Dayu,Hunan, predatory insects was slightly higher than phytophagous insects.) The percentage of phytophagous insects species in canopy was higher than that in understory in Dachi, but the situation was opposite in Guangdong and Hunan. The percentage of phytophagous individuals in canopy was higher than that in understory in Dachi and Tuojiang, Hunan, but the situation was opposite inTielong. In Dachi, Guangdong and Hunan,the species of insects in canopy was less than that in understory and it was unevenly distributed. Form the comparisons among different sample plots, in canopy, the richness index and diversity index of group population were the highest and the dominance index of it was the lowest in Tielong,Guangdong. The richness index of group population was the lowest in Dachi, Longyan, but the evenness index of it was the highest. The diversity index and evenness index of group population were the lowest in Tuojiang, Hunan, and the dominance concentrate index of it was the highest. From the relative stability, S/N and S1/S2 of insect group in canopy was higher in Tielong, Guangdong. Ni/N2 of insect group in canopy were highest in Dayu, Hunan. S/N, S1/S2 and N1/N2 of insect group in understory was highest in Dayu, Hunan.(4)Relationship between plant community and insect community in Zenia insignis forest.The vegetation composition in understory had great difference among Fujian, Guangxi, Guangdong and Hunan. Compares with original and other introducing regions, the richness index, diversity index and evenness index of plant community in understory were all the highest and the dominance index of it was the lowest in Dachi,Longyan. The difference of plant community was probably the reason of the difference of insect community.