Davis T S, Hofstetter R W
Southwest Forest Science Complex, Northern Arizona University, School of Forestry, 110 East Pine Knoll Dr., Flagstaff, AZ 86011, USA.
Environ Entomol. 2009 Jun;38(3):639-50. doi: 10.1603/022.038.0315.
Interspecific interactions among tree-killing bark beetle species may have ecologically important consequences on beetle population dynamics. Using two tree-killing beetle species (Dendroctonus brevicomis and D. frontalis), we performed observational and experimental studies to verify cross-attraction and co-colonization under field conditions in northern Arizona and test the effects of gallery density and species ratio on response variables of average gallery length, offspring size (progeny fitness), and offspring production per centimeter gallery (fecundity). Our results show that both D. frontalis and D. brevicomis aggregate to pheromones synthesized de novo by D. brevicomis under field conditions and that galleries of both D. brevicomis and D. frontalis occurred together in the same region of a single host tree with significant frequency. In experimental manipulations of species ratios, the presence of conspecific beetles in the gallery environment strongly mediated fecundity, but D. frontalis was the only species that suffered negative impacts from the presence of heterospecific beetles in the gallery environment. Interactions did not result in any apparent fitness effects for progeny of either species, which suggests that multispecies aggregations and co-colonization may be a dominant ecological strategy in the region and result in niche sharing.
杀死树木的树皮甲虫物种之间的种间相互作用可能会对甲虫种群动态产生重要的生态影响。我们使用两种杀死树木的甲虫物种（西部松大小蠹和南方松大小蠹），在亚利桑那州北部的野外条件下进行了观察和实验研究，以验证交叉吸引和共同定殖情况，并测试虫道密度和物种比例对平均虫道长度、后代大小（后代适合度）以及每厘米虫道后代产量（繁殖力）等响应变量的影响。我们的结果表明，在野外条件下，南方松大小蠹和西部松大小蠹都会聚集到由西部松大小蠹新合成的信息素周围，并且南方松大小蠹和西部松大小蠹的虫道在同一寄主树的同一区域频繁共同出现。在物种比例的实验操作中，虫道环境中同种甲虫的存在强烈影响繁殖力，但南方松大小蠹是唯一在虫道环境中受到异种甲虫存在负面影响的物种。种间相互作用并未对任何一个物种的后代产生明显的适合度影响，这表明多物种聚集和共同定殖可能是该地区的一种主要生态策略，并导致生态位共享。
