【目的】 松树蜂Sirex noctilio Fabricius是国际重大林业检疫性害虫，新渡户树蜂Sirex nitobei Matsumura是我国土著种，分布广泛；两者在我国局部地区共同危害樟子松Pinus sylvestris var. mongolica Litv。本文根据种群生态位的相关理论对两种害虫在樟子松人工林内的危害情况、空间分布格局及时间和空间生态位进行研究，探讨外来入侵种与土著种的种间关系，以期指导外来有害生物的防治工作。【方法】 林间踏查选择10块样地，连续2年进行每木检尺，采用分布型指数法判断两种树蜂的种群空间分布格局。记录两种树蜂羽化期和羽化数量，统计羽化孔相对位置，定量描述两者种群之间的共存机制。 【结果】 两种树蜂在林间为聚集分布，主要受害木的胸径集中在16.00~18.00 cm；松树蜂羽化期集中于6月底至9月初，新渡户树蜂于8月底至9月底，初步推断在研究林分中，松树蜂的当年侵入时间早于新渡户树蜂；松树蜂的雌雄性比为0.604，新渡户树蜂的雌雄性比为0.174；两种害虫的空间生态位较分离。 【结论】 松树蜂在内蒙古通辽市金宝屯林场属于定殖初期，与土著种新渡户树蜂共同危害樟子松，两者在林间的可利用资源丰富且虫口密度较低，导致空间生态位分离，初步推测不存在强烈的竞争关系；且各项空间分布型指标符合聚集分布。

 [Objectives]  Sirex noctilio Fabricius, an invasive species, is a major international forest quarantine pest that mainly damages Pinus sylvestris var. mongolica Litv in some parts of China. S. nitobei Matsumura is an indigenous species that is widely distributed in China. The spatial distribution patterns, and temporal and spatial niches of these species in P. sylvestris var. mongolica forests were investigated according to the population niche theory with the aim of identifying competitive and symbiotic relationships between these species that can guide the prevention and control of S. noctilio. [Methods]  Ten sample plots were selected through field investigations in Jinbaotun forest farm, Inner Mongolia, Tongliao City, and population distribution indices were used to analyze the spatial distribution patterns of both species in these plots over two consecutive years. Damaged pines were randomly selected and felled. Adult molting periods and quantity were noted, eclosion holes were marked using sulfuric acid paper to count the preferred eclosion sites of each species, and the coexistence mechanism of the two species was quantitatively described. [Results]  Both species had a clustered distribution. The DBH of damaged trees ranged from 16 cm to 18 cm. The adult molting period of S. noctilio was from the end of June to the beginning of September, whereas that of S. nitobei was from the end of August to the end of September. We were able to deduce that the infesting period of S. noctilio occurs earlier than that of S. nitobei in our study area. The sex (female: male) ratio of S. noctilio was 0.604 whereas that of S. nitobei was 0.174. The niches of each species differed. [Conclusion]  S. noctilio and S. nitobei had relatively abundant resources and lower than average population densities, causing the spatial niche of each species to diverge. We suspect that competition between these species is relatively low in the early stage of colonization by S. noctilio. Aggregation indices indicate that both species have an aggregated distribution.