The rainfall with the mortality of the first instar nymphy have the significant correlation (at the 0.01 level), which is the key factor of the fist instar nymphy population.

• 林间虫口密度与降水量呈极显著负相关，降水量对初孵若虫的死亡率呈极显著相关，是影响初孵若虫种群的关键因子。