The Asian longhorned beetle Anoplophora glabripennis is a wood-boring beetle that,upon severe outbreaks,causes great damage in the artificial shelter-forest of the Three-Northern Areas.The great spotted woodpecker Picoides major is one of the natural predators of A.glabripennis.P.major is also a common species in Wulate Qianqi of the Inner Mongolia Autonomous Region and is widely distributed in the artificial shelter-forest.The wood-boring beetle is an important food source of P.major,especially during the winter.Despite the potential of P.major to control A.glabripennis populations,surprisingly little is known about their predator-prey interactions.This information is essential to predicting the efficacy of P.major as a control agent to A.glabripennis.Therefore,it is important to study how the predator responds to changes in prey density.From 2006 to 2008,fifteen study plots were selected,and the predation of P.major on A.glabripennis was examined with sample plot and trace investigation,the latter being in the field.The results showed that the function response of P.major to A.glabripennis was Holling Ⅲ,with a non-linear regression equation.The increase in predation capacity correlated with the increase in A.glabripennis density,within a certain density range.As the density of A.glabripennis increased,the predatory capability had a positive acceleration phase,then a negative acceleration phase,and finally a saturation state.Likewise,as the density of A.glabripennis increased,the predation rate initially increased,peaked,and was reduced in the end,with a non-linear regression equation.The results indicated that the numerical response was a positive reaction to density.In other words,the population density of P.major increased as the density of A.glabripennis increased.
