槲栎种子雨进程中昆虫的捕食特征

为了了解昆虫捕食与槲栎Quercus aliena种子大小和产量的关系以及在栎林更新中的作用，于2008和2009年秋季，分别在暖温带伏牛山系天池山国家森林公园内研究了两个年度槲栎的种子雨过程及昆虫捕食特征。结果表明：（1）种子雨过程从8月中下旬到9月底约经历40 d，存在高峰期且时段较明显，高峰期下落种子量分别占全部种子雨量的78.13%（2008年）和75.91%（2009年）；（2）槲栎的种子雨强度年间存在较大差异，2008年明显小于2009年（两年分别为31.75±16.65粒/m²和51.92±29.26粒/m²），但2009年的橡子明显比2008年小（两年分别为1.94±0.61 cm³和2.46±0.57 cm³）；（3）种子雨构成比例在两个年份间存在差异，完好种子的量分别为59.05%（2008年）和36.12%（2009年），虫蛀率在大量结实的2009年显著提高；（4）虫蛀橡子（2.29±0.42 cm³）显著大于完整橡子（1.59±0.32 cm³），且虫蛀种子中所含虫卵数与种子大小显著正相关，昆虫有选择大种子产卵寄生的偏好。本研究的结果说明，昆虫对槲栎大种子有寄生选择偏好;大部分槲栎种子遭遇象甲虫蛀而降低生命活力，这可能是影响槲栎林更新的主要因素之一。

Insect acorn predation over the seed rain of Quercus aliena

Insect seed predation and its relationships with seed rain of Quercus aliena were investigated in Tianchi Mountain National Forest Park of Funiu Mountain in Luoyang, a warm temperate forest, from August to September in 2008 and 2009. The results indicated that the duration of seed rain of Q. aliena lasted from middle August to late September. The seed amount at the peak acounted for 78.13% and 75.91% of all seeds in 2008 and 2009, respectively. The seed rain density of Q. aliena was 31.75±16.65 and 51.92±29.26 nuts/m² in 2008 and 2009, respectively. Seed size in 2009 (1.94±0.61 cm³) was significantly smaller than that in 2008 (2.46±0.57 cm³）. The proportion of intact seeds in 2008 and 2009 was 59.05% and 36.12% respectively, and the proportion of the insect-infested seeds was increased significantly in 2009. We also found that the number of weevil eggs and larvae in each insect-infested acorn was significantly correlated with acorn size, and the infested acorns （2.29±0.42 cm³ in size） were much larger than the sound ones （1.59±0.32 cm³ in size）, indicating the preference of weevils to larger acorns for oviposition. The results suggest that weevils prefer larger acorns for oviposition, and the higher proportion of weevil-infested acorns may be one of the main causes of decline in seedling establishment of Q. aliena.