# Usage of a Sensory-Motor Intervention System for Understanding the Adaptive Behavior of Insets
## 4 Virtual Reality System for an Insect  
The virtual reality system for an insect can induce the illusion that the insect is moving in a real environment by connecting a behavior measurement device that can provide multisensory stimuli to a virtual space constructed on a computer, as shown in Figure 4A. [PERSON] et al. [67] focused on the female localization behavior of an adult male silk moth and investigated the integration of multisensory stimuli during localization behavior. This VR is designed based on the tethered measurement system [68], and a multisensory stimulator is installed around the behavioral measurement system. During the experiment, three types of multisensory stimuli were provided: odor, wind, and vision. The odor stimulator provided an odor by spraying air containing sex pheromones onto the right and left antennae on the head of the silk moth at an arbitrary time. The timing of odor spraying was controlled by opening and closing the solenoid valve. Visual stimuli were provided using LED arrays surrounding the silk moth. The presentation direction of the stripe pattern generated by the LED array is controlled according to the rotation direction of the silk moth because it modifies its behavior by the optical flow [69]. The wind direction stimuli were presented using a push-pull airflow generator called a local exhaust system. The airflow generator was attached to a hollow servomotor, which was controlled according to the heading angle of the silk moth to send air from an arbitrary direction. The odor distribution in the virtual space was generated by recording the diffusion of odor (smoke) from the odor source in advance using airflow visualization technology and playing it back randomly in the virtual space. Smoke emitted from the odor source was diffused into the space at a frequency of 1 Hz (Duration: 0.2 s, Interval: 0.8 s) and a wind speed of approximately 0.6 m/s from behind the odor source. This allowed us to represent in the virtual space a phenomenon similar to the diffusion of odors in a real environment. The presentation timing of each sensory stimulus was linked to the environmental information detected by the agent (virtual insect) in the virtual space, as shown in Figure 4A. The behavioral changes induced by multisensory stimuli are reflected in the amount of movement of the agent in a virtual space. This closed-loop system enabled us to measure the relationship between multisensory stimuli and behavioral changes comprehensively. The multisensory stimuli were presented in the behavioral experiment as shown in Figure 4B. Figure 4B (left and right) shows the differences in the number of sensory stimuli presented, with the left condition presenting \(\leq\)2 sensory stimuli and the right condition presenting 3 sensory stimuli. In Figure 4B, \"\(\times\)\" indicates the condition in which no sensory stimuli are presented, \"\(\bigcirc\)\" indicates that the direction of the sensory stimulus detected by the agent in the virtual space are similar to the direction actually presented to the silk moth, and \"\(\bullet\)\" indicates that the direction of detection and the direction of stimulus presentation to the silk moth is reversed. For example, the wind stimulus provided to the silk moth in Cond. ii was from the rear, even though the agent received wind from the front. An odor (a sex pheromone) is an essential sensory stimulus that excites localization behavior; therefore, it was provided under all conditions. The odor stimulus was provided to the left and right antennae of the silk moth according to the sensor responses on the left and right sides of the agent. The agent in the virtual space began its search from a position 300 mm downwind of the odor source. Localization was considered successful if the agent could reach the odor source within the time limit. In this experiment, we set the time limit to 5 min, which was long enough because it was unclear what kind of behavioral changes would occur when sensory information was manipulated.