Foote Nathaniel E, Foote Gabriel G, Comai Nathan, Ibarra Caballero Jorge R, Stewart Jane E, Ambrose Anthony R, Baxter Wendy L, Davis Thomas S
Forest & Rangeland Stewardship, Warner College of Natural Resources, Colorado State University, Fort Collins, CO, USA.
Department of Entomology and Nematology, University of California, Davis, Davis, CA, USA.
Environ Entomol. 2024 Dec 16;53(6):1183-1196. doi: 10.1093/ee/nvae089.
Here, we describe patterns of reproduction and flight phenology of putative Phloeosinus punctatus in giant sequoia groves and compare morphology and genotypes of beetles from sympatric giant sequoia (Sequoiadendron giganteum) and California incense-cedar (Calocedrus decurrens). Surveys conducted in 2022 revealed that numerous branches fall from giant sequoia crowns (on average ~30 branches/tree), with 20%-50% of trees per site shedding branches, depositing breeding material for beetles on the forest floor that subsequently becomes colonized. When noninfested branches cut from mature giant sequoias were placed at the ground surface, they were colonized by P. punctatus and produced an average of 28 beetles/kg branch. Climbing and examination of sequoia crowns in 2023 showed that 75% of mature trees across 11 groves showed evidence of adult beetle entrance holes in their crowns. In 2021, tests with sticky traps showed that beetles alighted on fallen branches from 20th May to 20th August (peak landing: 2nd July); a logistic model developed from emergence data in 2021 and 2022 predicts the emergence of F1 offspring from branches between 10th July and 1st September (peak emergence: 8th August). Beetles emerging from giant sequoia preferred to settle on giant sequoia, did not reproduce in incense-cedar, and diverged morphologically from beetles emerging from incense-cedar. However, phylogenetic analysis of three genes (28S, CAD, and COI) revealed no clear pattern of sequence divergence, suggesting a single species (P. punctatus) that colonizes both hosts, though cryptic speciation may not be detectable with standard barcoding genes. Ecological and potential management implications are discussed.
在此，我们描述了巨杉林中疑似点刻材小蠹（Phloeosinus punctatus）的繁殖模式和飞行物候，并比较了同域分布的巨杉（Sequoiadendron giganteum）和加州翠柏（Calocedrus decurrens）上甲虫的形态和基因型。2022年进行的调查显示，大量树枝从巨杉树冠掉落（平均每棵树约30根树枝），每个地点20%-50%的树木有树枝掉落，在森林地面上为甲虫沉积了繁殖材料，随后这些材料被定殖。当从成熟巨杉上砍下未受侵染的树枝放置在地面时，它们被点刻材小蠹定殖，平均每千克树枝产生28只甲虫。2023年对巨杉树冠的攀爬和检查表明，11个树林中75%的成熟树木树冠上有成年甲虫进入孔的迹象。2021年，使用粘性诱捕器进行的测试表明，甲虫在5月20日至8月20日降落在掉落的树枝上（降落高峰：7月2日）；根据2021年和2022年的羽化数据建立 的逻辑模型预测，F1代后代在7月10日至9月1日之间从树枝上羽化（羽化高峰：8月8日）。从巨杉羽化出的甲虫更喜欢在巨杉上定居，不在加州翠柏上繁殖，并且在形态上与从加州翠柏羽化出的甲虫不同。然而，对三个基因（28S、CAD和COI）的系统发育分析没有揭示出明显的序列分歧模式，这表明存在一个定殖于两种寄主的单一物种（点刻材小蠹），尽管使用标准条形码基因可能无法检测到隐秘物种形成。本文还讨论了其生态和潜在管理意义。
