Habe Shunya, Matsuyama Shigeru, Kanzaki Natsumi, Hamaguchi Keiko, Ozaki Mamiko, Akino Toshiharu
Applied Entomology Laboratory, Kyoto Institute of Technology, 1, Saga-ippongi-cho, Kyoto, 616-8354, Japan.
Graduate School of Life and Environmental Sciences, University of Tsukuba, 1-1-1, Tennoudai, Tsukuba, 305-8572, Japan.
J Chem Ecol. 2024 Dec;50(12):884-893. doi: 10.1007/s10886-024-01548-0. Epub 2024 Sep 21.
The nuptial flight of ants usually occurs during certain periods of the year. Alate females and males fly out of their nests to mate simultaneously. In the genus Camponotus, sex-specific chemicals are deposited in the male head; however, their roles in nuptial flight have not yet been clarified. This study aimed to elucidate the functions of male-specific chemicals in the Japanese carpenter ant Camponotus japonicus. First, we identified three chemicals characteristic to the male - methyl salicylate (MS), methyl 6-methylsalicylate (MMS), and methyl anthranilate (MA) - all of which triggered electroantennogram (EAG) responses in both alate males and females. As the relative content of MS was insufficient for GC comparison, we investigated the quantitative changes of MMS and MA in the male head capsules before and after flight under laboratory conditions. The amounts of both compounds were significantly reduced after flight, which suggested that males secrete them during flight. Thereafter, a field trap experiment was conducted in three fields of the Kyoto Prefecture, Japan, during the nuptial flight season in 2021 using MMS and MA as baits. The number of captured alate males was significantly higher than that of the females, suggesting that these compounds primarily attracted males rather than females. Considering the field conditions, if the local concentration of these chemicals is increased by male aggregation, females may be attracted as they also showed EAG responses. Our findings represent a first step toward understanding chemically mediated male lek formation during the process of male aggregation syndrome in this species.
蚂蚁的婚飞通常发生在一年中的特定时期。有翅雌蚁和雄蚁会同时飞出巢穴进行交配。在弓背蚁属中，雄性特异性化学物质沉积在雄蚁头部；然而，它们在婚飞中的作用尚未明确。本研究旨在阐明日本木工蚁（日本弓背蚁）中雄性特异性化学物质的功能。首先，我们鉴定出了三种雄性特有的化学物质——水杨酸甲酯（MS）、6 - 甲基水杨酸甲酯（MMS）和邻氨基苯甲酸甲酯（MA）——所有这些物质都能引发有翅雄蚁和雌蚁的触角电图（EAG）反应。由于MS的相对含量不足以进行气相色谱比较，我们在实验室条件下研究了飞行前后雄蚁头部胶囊中MMS和MA的定量变化。飞行后这两种化合物的含量均显著降低，这表明雄蚁在飞行过程中会分泌它们。此后，在2021年婚飞季节，于日本京都府的三个田野中进行了田间诱捕实验，使用MMS和MA作为诱饵。捕获的有翅雄蚁数量显著高于雌蚁，这表明这些化合物主要吸引雄蚁而非雌蚁。考虑到田间条件，如果这些化学物质的局部浓度因雄蚁聚集而增加，雌蚁可能会被吸引，因为它们也表现出了EAG反应。我们的研究结果是朝着理解该物种雄性聚集综合征过程中化学介导的雄性求偶场形成迈出的第一步。
