Abstract

Global warming disrupts freshwater ecosystems, affecting the movement of vagile aquatic insects and their Functional Feeding Groups (FFGs), key to nutrient cycling and energy flow. This study hypothesized that predators would be less sensitive to thermal stress than collectors, scrapers, and shredders, leading to minimal movement changes. Using a cost-effective video-tracking system, we analyzed four movement variables under three levels of thermal stress. Results showed varied FFG responses, particularly under transitional heated-water conditions. Collector-filterers and shredders exhibited significant changes in total path length and movement tortuosity, while speed-related variables remained largely unaffected. Strong correlations were observed, except among gatherers under the highest temperature. The experiment suggests that warming may constrain point-to-point movement, with distance-related variables proving the most reliable indicators of sensitivity. Collectors, scrapers, and shredders showed greater distance reductions than speed changes, highlighting critical functional and trophic shifts in microhabitat dynamics under global warming.