We’ve all heard the saying beauty is only skin deep – but is that such a bad thing?
While it may or may not be true for people, in truth much of the natural world relies on relatively thin outer coverings for a variety of applications, from attracting a mate to surviving an encounter with a predator.
Some of our favorite foods, like apples and oranges, use outer skins or peels chock full of phytochemicals to help keep pests and diseases at bay.
Most insects are encased with exoskeletons made of chitin, allowing them to withstand an impressive amount of damage and retain moisture. Interestingly enough, some insects with particularly tough exoskeletons can’t make it on their own.
Some beetles rely on symbiotic bacteria or other microbes to help provide exoskeletal building blocks, for example, and if they find themselves without this microscopic help the strength of their exoskeletons suffers accordingly.
While butterflies don’t sport impermeable suits of chitinous armor, they use thin outer layers on their wings in order to blend into, or stand out from, their environment. These layers can be as thin as a single cell, and are able to quickly detach in the event of a scuffle, leaving attackers chewing on a mouthful of scales while the butterfly slips away.
Some outer coverings can be more insidious – hospitals worldwide are involved in a constant battle against harmful pathogens and the protective layers they use to protect themselves and spread.
Known as biofilms, these layers can shelter pathogens on dry and otherwise challenging surfaces.
Under the sea, sponges and other immobile creatures rely on thin coatings to help protect them from being covered in barnacles and other hitchhikers. Inspiration from these organisms has led to an array of “environmentally friendlier” protective applications for boats and other man-made aquatic constructions.
The outer coverings of insects are often varied in shape and function.
Most social bees and wasps, for example, exude scents from certain areas of their exoskeletons that can help give their nestmates a hint into what they’re doing.
Honey bees have been found to change scent rapidly as they age. This makes it easier for busy workers to quickly identify young bees who may need help eating or getting around. At the entrance, guard bees give those seeking access into the hive a quick sniff at the door, and are much more lenient with letting juvenile bees through.
Social wasps “read” the outer layers of other wasps to identify nestmates, and can remember the information they glean to help ward off future intrusions. Invaders of social insect nests usually rely on either mimicking the natural ‘smells’ found on the outside of their intended victim, or covering themselves in other substances that help them become undetectable. Even though many of these outer coverings are relatively thin, they are able to completely change the way an organism reacts with the world around it.
Scientists in multiple fields have naturally taken notice of the subtle power behind an outer coating.
Many modern health centers rely on thin but powerful antimicrobial coatings in some capacity, either on surfaces directly or inside of air purifiers.
These coatings often rely on zinc, titanium and silver compounds as active ingredients, and can reduce disease spread while also being relatively environmentally friendly when disposed of properly. In the field of agriculture, scientists at Lincoln University in New Zealand are currently developing coatings made of fatty acids and complex carbohydrates that can help make fruit like cherries too slippery for fruit flies and other pests to properly lay their eggs.
Developing similar techniques could perhaps help curb our reliance on more environmentally impactful chemicals.
Brannen Basham and his wife, Jill Jacobs, operate Spriggly’s Beescaping, a business dedicated to the preservation of pollinators. He can be reached at firstname.lastname@example.org.