Meeting Abstract
Biological adhesive systems like those of the gecko and marine mussel have fascinated scientists for centuries, however other biological adhesive systems have received less attention. In particular, insects, especially flightless insects like ants, are far less studied despite their reliance on adhesion to move and interact with their complex environment. Furthermore, arboreal ants such as Cephalotes atratus, rely on adhesion to exploit canopy resources 30m above ground, where a fall from this height can be costly. In this study we investigated how relevant environmental conditions, such as substrate roughness and structure, affect adhesive and locomotor performance of this dominant canopy-dwelling species. Using laboratory studies we found that shear adhesion, normal adhesion and running velocity are all significantly impacted by variation in substrate roughness. Interestingly, static adhesion (normal and shear) was higher on rough substrates but running velocity was consistent across a variety of substrate roughness sizes, except smooth glass. This suggests that clinging to substrates with variable surface roughness is more difficult than running across them. These results were further confirmed on natural substrates like leaves, bark and vines typically found in their native habitat, and in field-based studies on Barro Colorado Island, Panama. Collectively, the results of this study support the hypothesis that life in the forest canopy poses specific selection pressures for wingless arboreal insects like ants.
