Abstract: 【Aim】 This study aims to understand the relationship between insect infestation and seed production and seed size of Quercus glandulifera and Quercus aliena var. acuteserrata . 【Methods】 The seed production of Q. glandulifera and Q. aliena  var. acuteserrata and insect infestation characteristics on their seeds in Foping National Natural Reserve, Qinling Mountains were investigated in 2011 and 2012. 【Results】 The seed rain density and seed production of Q. glandulifera and Q. aliena  var. acuteserrata were obviously different between 2011 and 2012. The seed rain density and seed production of Q. glanduliferain 2011 were 145.76±24.56 nuts/m² and 74.97±11.56 nuts/m², respectively, which were significantly higher than those in 2012 (64.09±9.61 nuts/m² and 34.30±3.51 nuts/m², respectively). The seed rain density and seed production of Q. aliena  var. acuteserrata  in 2011 were 238.88±43.97 nuts/m² and 117.34±18.76 nuts/m², respectively, which were also significantly higher than those in 2012 (112.00±19.20 nuts/m² and 55.96±19.20 nuts/m², respectively). The proportions of intact seeds of Q. glandulifera and Q. aliena  var. acuteserrata in 2011 were 49.73% and 50.73%, respectively, which were significantly higher than those in 2012 (38.69% and 44.28%, respectively). The proportions of insect-infested seeds of Q. glandulifera and Q. aliena  var. acuteserrata  in 2011 were 28.05% and 19.31%, respectively, which were lower than those in 2012 (39.77% and 26.63%, respectively), but the difference was not significant between 2011 and 2012. The seed size of the two insect-infested seed species was significantly larger than that of their intact seeds in 2011 and 2012. There were significant correlations between the number of insect larvae infesting seeds and seed size of Q. glandulifera and Q. aliena  var. acuteserrata  in 2011, but the correlations were not significant in 2012. 【Conclusion】 Our study demonstrated that there is a certain relationship between the insect infestation rate and the seed production of Q. glandulifera and Q. aliena  var. acuteserrata in the lower seed production year, i.e., the insect infestation rate of seeds has a rising trend in the lower seed production year, and vice versa. Insects prefer to larger seeds of the two oaks for oviposition, and there is also a certain relationship between the number of insect larvae infesting seeds and the seed size, i.e., larger infested seeds contain more larvae.

Key words: Quercus glandulifera, Quercus aliena , var. acuteserrata, seed production, seed size, insect infestation