Offensive leaf and apical bud clipping by Temnaspis japonica suppresses the ash tree damage response and protects oviposited immatures

Temnaspis japonica (Coloeoptera, Megalopodidae) female cuts off almost all the leaves and the apical bud of the stem into which she oviposites. Larva hatches inside the stem without leaves and apical bud, and infests the pith of stem as stem borer. In order to reveal the adaptive significance of the leaf clipping behavior by female, we conducted field experiment with four treatments including artificial egg insertion into stem and leaf clipping: Treatment 1, artificial egg insertion into stem and artificial leaf and apical bud clipping; 2, artificial egg insertion into stem without leaf and apical bud clipping; 3, artificial egg insertion into stem with leaf and apical bud clipping by T. japonica; 4 (insect oviposition), oviposition into stem and leaf and apical bud clipping by T. japonica. Survival rates of immatures were compared 6 weeks after treatment. Also, stem thickening caused by egg-insertion was checked to examine the relationship among thickening degree, immature survival, and treatment. Thickening degree was divided into four categories: 0, no thickening; 1, a little thickening; 2, moderate thickening; and 3, heavy thickening.