Find in Library

<i>Sirex noctilio</i>, a European woodwasp, occasionally shares resources with the native <i>S. nitobei</i> and other colonizers in northeast China. The impact of its coexistence on individual species remains unclear. Random sampling was conducted to assess the patterns and extent of insect co-colonization across various spatial scales. Additionally, we analyzed wood sections to determine the density, adult size, and distribution of the two <i>Sirex</i> species. Spatial scales revealed negative associations (<i>Asemum striatum</i> and <i>Phaenops</i> sp.) and neutral ones (<i>Ips acuminatus</i>) between woodwasps and other co-colonizers. Clustering of woodwasps and <i>Phaenops</i> sp. occurred at a small scale (0–7.3 m). Regression analysis showed a positive correlation between the chance of woodwasp attacks and past attacks on the same host, with little impact from other colonization factors. The distribution and body size of <i>S. noctilio</i> within the tree appeared unaffected by <i>S. nitobei</i>’s presence. In the presence of <i>S. noctilio</i>, <i>S. nitobei</i> tended to lay eggs in damaged sections. At the stand level, the overall impact of <i>S. noctilio</i> on <i>S. nitobei</i> population density is likely positive because <i>S. nitobei</i> prefer weaker trees, a preference potentially influenced by initial attacks from <i>S. noctilio</i> on healthier hosts.