Caste-specific origins of Lévy-like movement in social termites reveal social modulation of scaling laws

Lévy walks, the scale-free movement patterns emerging across taxa, are thought to reflect optimal search strategies shaped by intrinsic physiology or environmental constraints. Yet how social organization modulates the emergence of Lévy-like movements remains unclear. Here we combine high-resolution tracking and agent-based modelling to compare the movement of queens and workers of the termite Reticulitermes labralis under varying group densities. Both castes displayed step-length distributions consistent with truncated power laws, but their scaling exponents diverged: workers maintained Lévy-like movement across densities, whereas queens tended to shift toward Brownian-like movement in high-density groups. Behavioral kinematics paralleled these patterns: workers moved faster, turned less frequently, and explored larger spatial areas, while queens showed slower, more confined trajectories; turning frequency was positively associated with the scaling exponent, linking local reorientation to heavy-tailed step lengths. Simulations revealed that caste-specific turning dynamics and encounter-driven modulation could reproduce the empirical divergence, mechanistically linking the effects of caste-specific traits and social contacts on the formation of differences in Lévy-like movement patterns. Functional tests further showed that swapping scaling exponents between castes reduced encounter efficiency and movement performance-especially for workers, indicating adaptive tuning of Lévy parameters to social role. These finding reveal that Lévy-like movements in social insects arise from the interplay between intrinsic behavioral roles and extrinsic crowding, providing a framework for how division of labour and spatial interactions shape the evolution of movement behaviour.