Insects depend on their adhesive footpads to help them skitter along leaves, logs and the sides of your picnic basket. Now, a study reveals just how beetles keep their feet clean and ready to cling.

The research, reported on Nov. 9 in the journal Proceedings of the Royal Society B, finds that it's a decrease in friction that tells beetles to groom their dirty feet.
Though the study was undertaken in the spirit of curiosity, said lead researcher Stanislav Gorb of Christian Albrecht University of Kiel in Germany, the findings could have implications for robot designers or engineers looking for novel ways to measure contamination.
Beetle feet are covered with miniscule hairs called setae.
These setae produce fluid that isn't sticky but helps increase the molecular attraction between the beetle's foot and a surface, much in the same way that a wet scrap of paper will stick to glass.
Many plants make it their business to disrupt insect setae by excreting tiny wax crystals that dirty the bugs' feet. For example, Gorb told LiveScience, carnivorous pitcher plants secrete wax so insects walking along inside them will slip, fall and get trapped for digestion.
Beetles have special comb-like organs on their legs that they use to clean their feet when they get contaminated. The question, Gorb said, was how the bugs know their feet are dirty.
Animals have all sorts of sensors, like the touch receptors in human fingers that gather information about tactile sensations, or the receptors in skin that respond to pressure. What the beetles have in their feet was a mystery. So Gorb and his colleagues wrangled six leaf beetles onto aluminum-and-silicon surfaces nano-engineered to have different levels of roughness. First, they anesthetized the beetles with carbon dioxide.
Next, they used a heating tool to place a drop of molten beeswax onto each beetle's back, affixing a human hair to each exoskeleton.
When the beetles woke up, the researchers attached the hair to a device used to measure force.
(Source: LiveScience.com)