Beato Magalí, Usseglio Virginia Lara, Gergolet Díaz Donald, Zunino María Paula, Merlo Carolina
Universidad Nacional de Córdoba (UNC), Facultad de Ciencias Exactas, Físicas y Naturales (FCEFyN), Cátedra de Química Orgánica, Av. Vélez Sarsfield 1611, Córdoba, X5016GCA, Argentina.
Instituto Multidisciplinario de Biología Vegetal (IMBiV-CONICET-UNC), Av. Vélez Sarsfield 1611, Córdoba, X5016GCA, Argentina.
J Chem Ecol. 2025 Sep 18;51(5):94. doi: 10.1007/s10886-025-01643-w.
Microbial volatile organic compounds (VOCs) are key modulators of insect behavior. These low molecular weight compounds influence ecological interactions and hold potential as sustainable agents in pest control. Sitophilus zeamais, a major pest of stored maize worldwide, causes significant post-harvest losses. While fungal VOCs have been studied in grain storage systems, bacterial-insect interactions remain poorly understood. This study evaluated the effects of VOCs emitted by four Enterococcus strains isolated from maize grains on the behavior and mortality of S. zeamais. Maize grains were inoculated with bacterial cultures, and VOCs were identified using gas chromatography-mass spectrometry. Behavioral responses were assessed in a two-choice olfactometer using both bacterial blends and individual pure compounds at varying concentrations. Additional assays included fumigation tests for toxicity and evaluation of oviposition behavior through egg staining in treated grains. Results showed that bacterial VOCs significantly affected the behavior and survival of S. zeamais, supporting their bioactive potential and involvement in interspecific interactions. Acetoin, acetic acid, and diacetyl were identified as the predominant volatiles. Among them, acetic acid acted as a repellent while also stimulating oviposition, acetoin functioned as an attractant, and diacetyl stood out for its toxicity, with effects observed even at low concentrations. These findings highlight the ecological relevance of bacterial volatiles in modulating insect behavior in stored grain systems and contribute to a broader understanding of the chemically mediated interactions between microorganisms and insects in confined environments.
微生物挥发性有机化合物（VOCs）是昆虫行为的关键调节因子。这些低分子量化合物影响生态相互作用，并有望成为害虫防治的可持续药剂。玉米象是全球储存玉米的主要害虫，会造成重大的收获后损失。虽然在粮食储存系统中已经对真菌VOCs进行了研究，但细菌与昆虫之间的相互作用仍知之甚少。本研究评估了从玉米籽粒中分离出的四种肠球菌菌株释放的VOCs对玉米象行为和死亡率的影响。将细菌培养物接种到玉米籽粒上，并用气相色谱 - 质谱法鉴定VOCs。使用细菌混合物和不同浓度的单一纯化合物在双选嗅觉仪中评估行为反应。其他试验包括毒性熏蒸试验以及通过对处理过的籽粒进行卵染色来评估产卵行为。结果表明，细菌VOCs显著影响玉米象的行为和存活，证明了它们的生物活性潜力以及在种间相互作用中的作用。3 - 羟基 - 2 - 丁酮、乙酸和双乙酰被鉴定为主要挥发物。其中，乙酸起到驱避作用，同时也刺激产卵，3 - 羟基 - 2 - 丁酮起到吸引作用，双乙酰因其毒性而突出，即使在低浓度下也能观察到其效果。这些发现突出了细菌挥发物在调节储存谷物系统中昆虫行为方面的生态相关性，并有助于更广泛地理解在封闭环境中微生物与昆虫之间的化学介导相互作用。
