Earwax is both slippery and sticky—this weird combo might lead to safer insect repellents

Scientists examined the unique properties of earwax as they observed ants interacting with earwax of different characteristics. The mystery surrounding earwax dates back to ancient times, with people debating whether to remove it or not. The general medical consensus is that ears self-clean, and earwax offers benefits such as ear canal lubrication, infection prevention, and debris trapping.

Impacted earwax affects about 20% of Americans annually, resulting in 12 million patient visits each year. Insects, primarily children's foreign objects, often become lodged in ears. While rare, insects in the ear have prompted physicians to consider whether earwax acts as a natural insect repellent. The question of how earwax accomplishes this task led researchers, including Ph.D. student David Ancalle, to conduct experiments with earwax and insects.

Using earwax from deceased mammals and friends, they determined that earwax can indeed repel insects without resorting to harmful chemicals. Experiments with ants on coated glass slides revealed that earwax's dual nature makes it an effective anti-stick material. Smooth earwax is almost impossible for ants to climb, while rough earwax presents a challenge but allows for progress.

The researchers concluded that earwax has anti-stick properties when interacting with insects' feet. Further investigations involved ants crawling through earwax-coated tunnels, similar in size to a human ear canal. Ants became coated in earwax, grooming furiously to remove as much as possible even after several minutes. The unique properties of earwax, such as its lipids, thinning upon deformation, and microscopic holes, contribute to its paradoxical slipperiness and stickiness.

These characteristics set earwax apart from conventional pest control methods, offering a bio-friendly alternative inspired by nature.