Effects of dynamic variety of plant community on insect diversity in litchi orchard

Vegetation diversity is the basic of the diversity of natural enemies in orchard ecosystem.In this study,species and quantity of herbaceous plants of the Lianzhoulu Litchi Orchard were investigated in Heng County,Guangxi.Vegetation diversity in the orchard and its changing laws were studied by analyzing 4 characteristic indexes(species richness index;species diversity index;species evenness index;dominant concentration index).At the same time,the species and quantity of insects dwelling in the orchard were researched,the same 4 characteristic indexes of insect community were also calculated.The results showed that species diversity indexes,species evenness indexes and dominant concentration indexes of orchard vegetation were 0.842-1.370,0.445-0.659 and 0.326-0.518 during April to September respectively.Peak values of diversity indexes of the vegetation appeared simultaneously with that of the insects,both in May to June.A narrow range fluctuation of vegetation diversity indexes caused a large range alteration of the insect diversity indexes,suggesting that the vegetation diversity of orchard markedly worked on the structure and the components of the dwelling insects.There were a closed correlation between vegetation diversity and insect diversity.