Light exposure induces compensatory shelter tube construction in termites

Many social insects build protective structures as first-line defences against environmental stressors and predators. This collective behaviour is regulated by various environmental cues through self-organized processes Although several factors such as humidity and tactile cues have been explored, it remains unclear whether light, a strong indicator of environmental exposure, can directly mediate collective construction. Termites are cryptic insects that constrain their activities within dark, enclosed environments, and many species build shelter tubes when exposed to open space, making them an ideal system to address this question. In this study, we examined shelter tube construction in the Formosan subterranean termite, Coptotermes formosanus, under light and dark conditions. We show that termite groups exposed to light increased construction activity, building shelter tubes faster and displacing more soil in open areas while consuming less food than those maintained in darkness. The results demonstrate that light acts as an aversive cue that accelerates protective construction, triggering termites to prioritize environmental buffering over food exploitation. Our findings reveal an empirical link between photosensory perception and collective construction, and highlight how sensory cues modulate task allocation and adaptive collective behaviour in social systems.