Klingenberg Matthew D, Björklund Niklas, Aukema Brian H
Ecosystem Science and Management Program, University of Northern British Columbia, Prince George, BC, Canada.
Environ Entomol. 2010 Jun;39(3):898-906. doi: 10.1603/EN08269.
Hylobius warreni Wood, also known as the Warren root collar weevil, is a flightless insect that feeds on conifers throughout the boreal forests of Canada. Mature trees typically can withstand feeding, but larval feeding around the root collar may cause mortality to young trees. Recently, a large outbreak of mountain pine beetle (Dendroctonus ponderosae Hopkins) has killed a high proportion of mature lodgepole pine (Pinus contorta Douglas variety latifolia) across British Columbia, Canada. This raises concerns that adult weevils may migrate from mature forests with reduced host pools into adjacent young forests that had been salvaged and replanted. To study movement of these walking weevils in different habitat types, we constructed three research plots consisting of various combinations of live-, dead-, and mixed (i.e., live and dead)-tree habitats. We observed dispersal patterns of individually labeled insects using a novel insect trap attached to the base of trees. Approximately 35% of insects were recaptured over 1 mo. Weevils were least likely to be recaptured proximate to the release location when released in a habitat with dead trees. Movement rates therein were almost double the rates of insects moving through live- or mixed-tree habitats. Our findings support the hypothesis that H. warreni may disperse out of habitats with dead trees into areas with higher proportions of green trees. Our findings are discussed in the context of habitat discrimination and potential increases in herbivory by H. warreni in western Canada given salvage harvesting activities after outbreaks of mountain pine beetle.
沃伦氏长小蠹（Hylobius warreni Wood），也被称为沃伦根颈象甲，是一种不会飞的昆虫，以加拿大北方森林中的针叶树为食。成熟树木通常能够承受其取食，但幼虫在根颈周围取食可能会导致幼树死亡。最近，一场大规模的山松甲虫（Dendroctonus ponderosae Hopkins）疫情导致加拿大不列颠哥伦比亚省的大部分成熟黑松（Pinus contorta Douglas variety latifolia）死亡。这引发了人们的担忧，即成年象甲可能会从寄主数量减少的成熟森林迁移到邻近经过采伐和重新种植的幼林。为了研究这些步行象甲在不同栖息地类型中的移动情况，我们构建了三个研究样地，它们由活树、死树和混合（即活树和死树混合）树栖息地的各种组合构成。我们使用一种附着在树基部的新型昆虫诱捕器观察个体标记昆虫的扩散模式。在1个月内大约35%的昆虫被重新捕获。当在有死树的栖息地释放时，象甲在释放地点附近被重新捕获的可能性最小。其移动速度几乎是在活树或混合树栖息地中移动昆虫速度的两倍。我们的研究结果支持这样的假设，即沃伦氏长小蠹可能会从有死树的栖息地扩散到绿树比例更高的区域。我们在栖息地辨别以及考虑到山松甲虫疫情后加拿大西部进行的采伐活动，沃伦氏长小蠹食草量可能增加的背景下讨论了我们的研究结果。
