Insects provide examples of many cunning stratagems to cope with the challenges of living in a world
dominated by surface forces. Despite being the current masters of the land environment, they are at
constant risk of being entrapped in liquids, which they prevent by having waxy and hairy surfaces. The
problem is particularly acute in an enclosed space, such as a plant gall. Using secreted wax to efficiently
parcel and transport their own excrement, aphids were able to solve this problem 200 Myr ago. Here, we
report on the physical and physiological significance of this ingenious solution. The secreted powdery wax
has three distinct roles: (i) it is hydrophobic, (ii) it creates a microscopically rough inner gall surface made
of weakly compacted wax needles making the gall ultra-hydrophobic, and (iii) it coats the honeydew
droplets converting them into liquid marbles, that can be rapidly and efficiently moved.