Quantifying neuropeptide-induced organ contractions in Bombyx mori using a Python-based analysis tool – InsectMotion

InsectMotion is a Python-based software tool designed for the post hoc analysis of video recordings that capture movements or muscle contractions in insects and other invertebrates. It provides a simple, fast and automated approach for semi-quantitative assessment of motion by measuring the “pixel activity” expressed by changes in pixel intensity or color. Unlike many existing approaches, it does not require specialized equipment, chemical reagents, or expensive software. The application distinguishes active and inactive pixels within selected regions of interest (ROI) and measure their changing activity over a pre-set time. InsectMotion offers two analysis modes: Graphical Analysis (GA), and Pixel Activity Analysis (PAA), both adaptable to various experiments. GA generates a graphical illustration of pixel activity (in selected ROIs) over time together with numerical data from the measurement. PAA produces binary Portable Network Graphic (PNG) images highlighting the active clusters of pixels in the video. As a follow-up to Čižmár et al. (2019), which identified calcitonin-like diuretic hormone (CT-DH) and myoinhibitory peptides (MIPs) as regulators of male accessory glands and gonoducts in Bombyx mori , we used InsectMotion to quantify neuropeptide-induced contractions in multiple silkworm organs. Developed and validated in B. mori , InsectMotion also performs reliably in other small arthropods, demonstrating broad applicability for quantitative motion analysis. By lowering the technical barrier for contraction-based assays, InsectMotion supports more accessible phenotypic studies in neurobiology and physiology.