Meeting Abstract
Wingless ants foraging in the tropical rainforest canopy must cling and run along substrates such as leaves, vines and bark. However, tree crowns offer little protection from sun, wind, and rain, creating a complex and challenging environment for the tiny adhesive pads of an ant. Here we explore how two common environmental features of the tropical canopy, substrate wettability (hydrophobicity) and rain, affect the static and dynamic adhesive performance of a common tropical canopy ant (Cephalotes atratus). We found that C. atratus workers exhibit higher shear and normal adhesion on intermediately wetting substrates. The addition of surface water droplets (resembling rain) did not affect normal adhesion, but shear adhesion was reduced. Running speed was lower on all wet substrates. Finally, we investigated adhesion to a less controlled but more ecologically relevant substrate: wood. We found that normal and shear adhesion differed among dry, misted and water-soaked wood, and generally reduced running speed. Here we provide the first quantitative assessment of tropical canopy ant adhesive performance across conditions that approximate those encountered in the canopy.
