Abstract
We tested the idea that leaf-cutting ants preferentially use one of their mandibles in the leading position when cutting leaves. We recorded the mandible position of both paint-marked and unmarked foragers from a laboratory colony of Acromyrmex echinatior during foraging bouts in two experiments 1 year apart (2012 and 2013). Both types of ants were ambidextrous in 2012, and so were unmarked ants in 2013. In contrast, marked ants in 2013 had a preference for leading with their right mandible. The individual laterality of these latter ants ranged from ambidexterity to about 70 % use of the preferred leading mandible. In 2013, we also estimated the cutting rate (length cut per second spent cutting) and harvesting rate (leaf area harvested per second spent cutting) of cutting events for marked foragers. Despite significant positive correlations between head size and both cutting and harvesting rates, the intensity of lateralization was better explained by cutting and harvesting rates than by head size. Specifically, the most lateralized foragers were the slowest and harvested the smallest leaf area per second. We interpret this association as evidence that lateralization was stronger for ants for which cutting was more challenging.