Multimodal signal detection in ants: Evidence for lateralization in antennal electrophysiological responses.

Social insects rely on multimodal communication systems to coordinate both individual and colony-level responses, yet the sensory foundations underlying the perception of combined signal components remain poorly understood. In ants, alarm communication often integrates chemical and vibroacoustic cues, but how these modalities are detected and processed by individual workers is still largely unexplored. In this study, we investigated the peripheral detection of multimodal alarm signals in Myrmica scabrinodis, examining how workers detect concurrent alarm pheromones and stridulations. Our electrophysiological recordings revealed that chemical cues are primarily detected through the antennae, which showed robust responses to pheromones but no detectable sensitivity to vibroacoustic stimuli. Leg recordings provided no conclusive evidence of chemical or vibroacoustic detection, although inconsistent responses to vibroacoustic stimuli in the left hindlegs suggest a potential mechanosensory role that requires further investigation. Chemical and vibroacoustic stimuli are probably detected independently at the peripheral level, likely converging only within central processing pathways in the brain. Moreover, we found evidence of lateralization in sensory detection: the right antenna exhibited greater sensitivity to alarm pheromones than the left, suggesting a left-right bias associated with population-level lateralization previously described in other social insects. Such asymmetries may contribute to enhanced group coordination by imposing consistent physiological biases on signal detection. Taken together, our results provide new insights into the specialization and lateralization of sensory structures involved in ant alarm communication, offering a foundation for further investigation into the neural mechanisms underlying multimodal signal integration in social insects.