Sekiwa Ryoko, Ibuki Tatsuya, Shigaki Shunsuke
Department of Electronics and Bioinformatics, Meiji University, Kawasaki, Japan.
Principles of Informatics Research Division, National Institute of Informatics, Tokyo, Japan.
Front Robot AI. 2025 Jun 2;12:1602867. doi: 10.3389/frobt.2025.1602867. eCollection 2025.
This study aims to develop a robotic system that autonomously tracks insects during free walking to elucidate the relationship between olfactory sensory stimuli and behavioral changes in insects. The adaptability of organisms is defined by their ability to select appropriate behaviors based on sensory inputs in response to environmental changes, a capacity that insects exhibit through efficient adaptive behaviors despite their limited nervous systems. Consequently, new measurement techniques are needed to investigate the neuroethological processes in insects. Traditional behavioral observations of insects have been conducted using free-walking experiments and treadmill techniques; however, these methods face limitations in accurately measuring sensory stimuli and analyzing the factors contributing to detailed behavioral changes. In this study, a robotic system is employed to track free-walking insects while simultaneously recording electroantennogram (EAG) responses at the location of the antenna of the insect during movement, thus enabling the measurement of the relationship between olfactory reception and behavioral change. In this research, we focus on a male silk moth as the target insect and measure its odor source localization behavior. The system comprises a high-speed camera to estimate the movement direction of the insect, a drive system, and instrumentation amplifiers to measure physiological responses. The robot tracks the insect with an error margin of less than 5 mm, recording the EAG responses associated with the olfactory reception during this process. An analysis of the relationship between EAG responses and behavior revealed that the silk moth exhibits a significant amplitude in its EAG responses during the initial odor source localization stage. This suggests that the moth does not necessarily move toward the strongest odor. Further information-theoretic analysis revealed that the moth might be moving in the direction most likely to lead to odor detection, depending on the timing of its olfactory reception. This approach allows for a more natural measurement of the connection between olfactory sensory stimuli and behavior during odor source localization. The study findings are expected to deepen our understanding of the adaptive behaviors of insects.
本研究旨在开发一种机器人系统，该系统能够在昆虫自由行走时自主跟踪它们，以阐明嗅觉感官刺激与昆虫行为变化之间的关系。生物体的适应性是由它们根据感官输入选择适当行为以应对环境变化的能力来定义的，尽管昆虫的神经系统有限，但它们通过高效的适应性行为展现出了这种能力。因此，需要新的测量技术来研究昆虫的神经行为学过程。传统的昆虫行为观察是通过自由行走实验和跑步机技术进行的；然而，这些方法在准确测量感官刺激和分析导致详细行为变化的因素方面存在局限性。在本研究中，采用了一种机器人系统来跟踪自由行走的昆虫，同时在昆虫移动过程中记录其触角位置的触角电图（EAG）反应，从而能够测量嗅觉接收与行为变化之间的关系。在这项研究中，我们将雄性家蚕作为目标昆虫，并测量其气味源定位行为。该系统包括一个用于估计昆虫运动方向的高速摄像机、一个驱动系统以及用于测量生理反应的仪器放大器。该机器人跟踪昆虫时的误差幅度小于5毫米，并在此过程中记录与嗅觉接收相关的EAG反应。对EAG反应与行为之间关系的分析表明，家蚕在初始气味源定位阶段其EAG反应具有显著的幅度。这表明家蚕不一定朝着气味最强的方向移动。进一步的信息论分析表明，根据其嗅觉接收的时机，家蚕可能朝着最有可能检测到气味的方向移动。这种方法能够更自然地测量气味源定位过程中嗅觉感官刺激与行为之间的联系。预计该研究结果将加深我们对昆虫适应性行为的理解。
