Complex relationship between tunneling patterns and individual behaviors in termites

<p>The nests built by social insects are complex group-level structures that emerge from interactions among individuals following simple behavioral rules. Nest patterns vary among species, and the theory of complex systems predicts that there is no simple one-to-one relationship between variations in collective patterns and variation in individual behaviors. Therefore, a species-by-sp<span>ecies comparison of the actual building process is essential to understand the mechanism producing diverse nest patterns. </span><span><span>Here we compare tunnel formation of three termite species, and reveal two mechanisms producing interspecific variation: in one, a common behavioral rule yields distinct patterns via parameter-tuning; in the other, distinct rules produce similar patterns. </span></span><span>We found that two related species </span><span><span>transport sand in the same way using mandibles</span></span><span> but build tunnels with different degree of branching. The variation arises from different probabilities of choosing between two behavioral options at crowded tunnel faces: excavating the sidewall to make a new branch or waiting for clearance to extend the current tunnel. We further discovered that a third species independently evolved low-branched patterns using different building rules; namely a bucket-brigade that can excavate a crowded tunnel</span><span><span>. Our findings emphasize the importance of direct comparative study of collective behaviors at both individual- and group-levels</span></span><span>. </span></p>