Influences of different damaged pines on growth and development of pine caterpillar larvae

Pine caterpillar(Dendrolimus punctatus tabulaeformis) larvae were fed with damaged pine needles of different degrees to evaluate the effects of pine needles on the growth and development of them.The results showed that the nutritional index of the larvae declined.Especially,the least amount of food ingested and voided feces,least nutritional index,slower development,lightest pupae and more mortality were found in those pine caterpillar larvae fed with pine needles of 50 % damaged.The damaged pine needles significantly influenced the population dynamics of pine caterpillar.The nutritional indexes of larvae fed with 25 % and 75 % damaged pine needles were similar.And the nutritional index of the dark morph was higher than that of the tint one,and its mortality was lower than that of the tint morph.However,this phenomenon was reversed at the later stage of taking pine needles of 50 % damaged.