UC Irvine

Antennae are crucial sensory organs that can act as mechanosensors. Their sensory morphology can influence the information transmitted to sensory organs. High-speed video was used to record cricket antennae movements through controlled single deflections and driven oscillations induced by a shaker table. Image analysis tools such as MaxTRAQ, ImageJ, and Canvas X were employed for morphological measurements, video digitization, and image processing. Numerical and analytical modeling, including Finite Element Modeling (FEM) using MATLAB (e.g., Elastica2D), estimated mechanical properties like EI gradient and damping ratio from observed oscillatory and bending behaviors of antennae deflections. Antennae return rapidly from deflection, minimizing oscillations akin to critical damping, which is crucial for reducing noise to mechanosensors like Johnston's organ at the scape-pedicel interface. Experimental deflections of cricket antennae revealed rapid return with minimal oscillation, optimizing response speed without excessive noise. Antennae bend such that the sharpest bend is closest to obstacles, facilitating obstacle localization or distance measurement. Modeling antennae as bending cantilever beams showed a proximal-to-distal decline in flexural rigidity, matching their tapered structure. This taper-induced flexibility protects antennae from breakage during deflection, which is crucial during high-speed movements to prevent collision-related breakage.Along with how damping can influence sensory feedback of the antennae, I studied Böhm's bristles in Acheta domesticus, which are specialized sensory structures found at the base of the antennae in most insects. These bristles are located near the joints where the antennae connect to the head and are thought to bend as these joints move, providing information about the angles and positions of the antennae. Scanning electron microscopy (SEM) showed two distinct groups of Böhm's bristles on both the top and bottom of the scape, as well as two additional groups on the sides of the pedicel. Our study found that these bristles bend when the antenna joints are fully extended, meaning they are perfectly positioned to give feedback within the range of joint movement. This arrangement may help us understand the precision and resolution of sensory input about joint movements, offering new insights into how insects sense and react to their environment through antennae movements. Course-based research projects offer valuable benefits to both undergraduate students and instructors, particularly in generating pilot data for research grant proposals or publications. However, it's important to recognize that data collected by students can be susceptible to confirmation bias, where preconceived expectations influence interpretation. An examination of student-collected data in a lab course revealed variations in measurements based on the hypothesis being tested, indicating the presence of confirmation bias. To mitigate this issue, various strategies can be implemented, such as utilizing anonymous studies and openly addressing confirmation bias among students.