Ayres Matthew P, Pena Rebeca, Lombardo Jeffrey A, Lombardero Maria J
Department of Biological Sciences, Dartmouth College, Hanover, New Hampshire, United States of America.
Departamento de Producción Vegetal, Universidad de Santiago, Lugo, Spain.
PLoS One. 2014 Mar 27;9(3):e90321. doi: 10.1371/journal.pone.0090321. eCollection 2014.
Accelerating introductions of forest insects challenge decision-makers who might or might not respond with surveillance programs, quarantines, eradication efforts, or biological control programs. Comparing ecological controls on indigenous vs. introduced populations could inform responses to new introductions. We studied the European woodwasp, Sirex noctilio, which is not a pest in its native forests, is a serious invasive pest in the southern hemisphere, and now has an uncertain future in North America after its introduction there. Indigenous populations of S. noctilio (in Galicia, Spain) resembled those in New York in that S. noctilio were largely restricted to suppressed trees that were also dying for other reasons, and still only some dying trees showed evidence of S. noctilio: 20-40% and 35-51% in Galicia and New York, respectively. In both areas, P. sylvestris (native to Europe) was the species most likely to have attacks in non-suppressed trees. P. resinosa, native to North America, does not appear dangerously susceptible to S. noctilio. P. radiata, which sustains high damage in the southern hemisphere, is apparently not innately susceptible because in Galicia it was less often used by native S. noctilio than either native pine (P. pinaster and P. sylvestris). Silvicultural practices in Galicia that maintain basal area at 25-40 m(2)/ha limit S. noctilio abundance. More than 25 species of other xylophagous insects feed on pine in Galicia, but co-occurrences with S. noctilio were infrequent, so strong interspecific competition seemed unlikely. Evidently, S. noctilio in northeastern North America will be more similar to indigenous populations in Europe, where it is not a pest, than to introduced populations in the southern hemisphere, where it is. However, S. noctilio populations could behave differently when they reach forests of the southeastern U.S., where tree species, soils, climate, ecology, management, and landscape configurations of pine stands are different.
森林昆虫的加速传入给决策者带来了挑战，他们可能会也可能不会通过监测计划、检疫措施、根除行动或生物防治计划做出应对。比较对本地种群和传入种群的生态控制可以为应对新传入的昆虫提供参考。我们研究了欧洲木蜂，即西松大小蠹，它在其原生森林中并非害虫，但在南半球却是严重的入侵害虫，在被引入北美后，其未来尚不确定。西松大小蠹的本地种群（在西班牙加利西亚）与纽约的种群相似之处在于，西松大小蠹主要局限于因其他原因而濒死的被抑制树木，而且仍然只有一些濒死树木有西松大小蠹侵害的迹象：在加利西亚和纽约分别为20% - 40%和35% - 51%。在这两个地区，欧洲赤松（原产于欧洲）是最有可能在未被抑制的树木上遭受侵害的树种。北美原产的树脂松似乎对西松大小蠹没有危险的易感性。辐射松在南半球遭受严重损害，但显然并非天生易感，因为在加利西亚，本地的西松大小蠹较少侵害它，而更常侵害本地松树（海岸松和欧洲赤松）。加利西亚维持林分断面积在25 - 40平方米/公顷的造林实践限制了西松大小蠹的数量。在加利西亚，有超过25种其他蛀木昆虫以松树为食，但与西松大小蠹同时出现的情况很少见，因此似乎不太可能存在强烈的种间竞争。显然，北美东北部的西松大小蠹种群与欧洲的本地种群（在欧洲它不是害虫）更为相似，而与南半球的传入种群（在南半球它是害虫）不同。然而，当西松大小蠹种群到达美国东南部的森林时，其行为可能会有所不同，因为那里的树种、土壤、气候、生态、管理以及松林的景观配置都不同。
