Graduate School of Agriculture, Hokkaido University, Kita 9 Nishi 9, Kita-ku, Sapporo, 0608589, Japan.
Key Laboratory of Agrometeorology of Jiangsu Province, Department of Ecology, School of Applied Meteorology, Nanjing University of Information Science & Technology (NUIST), Nanjing, 210044, People's Republic of China.
Environ Res. 2022 Mar;204(Pt A):111996. doi: 10.1016/j.envres.2021.111996. Epub 2021 Sep 1.
Behavior of insects, such as pollination and grazing, is usually determined by biogenic volatile organic compounds (BVOCs). However, particularly in O-polluted urban forests, the BVOCs-based plant-insect communication can be disrupted by the reaction of O with leaf-emitted BVOCs, such as between Japanese white birch (Betula platyphylla var. japonica) and a leaf beetle (Agelastica coerulea). To understand plant-insect communication in O-polluted environments, it is necessary to identify chemical species of BVOCs that contribute to attractiveness toward insects but are diminished by elevated O. In this study, we conducted olfactory response tests and gas chromatography mass spectrometry (GC-MS) analyses to clarify whether there is a similarity of BVOC components among Betulaceae host trees that can explain the attraction of the stenophagous insect A. coerulea. The olfactory response tests indicated that Betulaceae host trees attract A. coerulea via leaf-emitted BVOCs, while there was no preference of the leaf beetles to non-host trees (Sorbus commixta and Morus bombycis). However, GC-MS analyses indicated that the composition of BVOC blends considerably differed among Betulaceae host trees, although alders (Alnus hirsuta and A. japonica) had a similar composition of BVOC blend in each season (June and September) during which the adult leaf beetle is active. A distinct characteristic of the emission from B. platyphylla was that 2-carene and limonene, which are O-reactive species, were emitted with a high monoterpene ratio irrespective of the season. Thus, these volatiles and the blend could be expected to lead the disrupted communication found between B. platyphylla and A. coerulea under elevated O in previous field studies. In addition, our results indicated that A. coerulea is attracted to more than one blend within Betulaceae host trees, suggesting that grazing damages can be affected by different host preferences and O reactivity with specific BVOCs in the field. BVOCs-based plant-insect interactions should be further studied in multi-species communities to better understand plant-insect communication in O-polluted environments.
昆虫的行为，如传粉和取食，通常由生物源挥发性有机化合物（BVOCs）决定。然而，特别是在 O 污染的城市森林中，植物与昆虫之间基于 BVOCs 的通讯可能会被 O 与叶片排放的 BVOCs 之间的反应所破坏，如日本白桦（Betula platyphylla var. japonica）与叶甲（Agelastica coerulea）之间的反应。为了了解 O 污染环境中的植物-昆虫通讯，有必要确定对昆虫有吸引力但因 O 升高而减少的 BVOC 化学物质种类。在这项研究中，我们进行了嗅觉反应测试和气相色谱质谱（GC-MS）分析，以阐明能否用桦木科寄主树木中 BVOC 成分的相似性来解释专食性昆虫 A. coerulea 的吸引力。嗅觉反应测试表明，桦木科寄主树木通过叶片排放的 BVOCs 吸引 A. coerulea，而叶甲对非寄主树木（水曲柳和桑树）没有偏好。然而，GC-MS 分析表明，尽管在成虫叶甲活跃的 6 月和 9 月这两个季节，桤木（Alnus hirsuta 和 A. japonica）的 BVOC 混合物组成相似，但桦木科寄主树木的 BVOC 混合物组成差异很大。B. platyphylla 排放物的一个显著特征是，2-蒈烯和柠檬烯，这两种 O 反应性物质，在无论哪个季节，都会以较高的单萜比释放。因此，这些挥发性物质和混合物可能会导致在之前的野外研究中，在升高的 O 条件下，B. platyphylla 和 A. coerulea 之间发现的通讯中断。此外，我们的结果表明，A. coerulea 会被桦木科寄主树木中的多种混合物吸引，这表明在野外，取食损害可能会受到不同寄主偏好和 O 与特定 BVOCs 反应的影响。应该在多物种群落中进一步研究基于 BVOCs 的植物-昆虫相互作用，以更好地理解 O 污染环境中的植物-昆虫通讯。
