We can soon thank butterfly tongues for better cancer treatments and vaccines
A closer look at the elaborate insects that have inspired engineers in countless ways.
For more than 130 million years, butterflies have graced our planet. For much of our own history we’ve enjoyed them, but never knew much about them. Over the past 10 years, that’s changed. Using high-tech tools, science has discovered hitherto undreamed of truths about these “flying flowers”—from how monarch butterflies migrate thousands of miles each fall to a mountain range in Mexico to how they create such stunning wing patterns. And some of these discoveries have even helped researchers find new ways to benefit people’s health.
Read more in The Language of Butterflies by Wendy Williams, published by Simon and Schuster on June 2, 2020.
Several years ago, Clemson University’s Konstantin Kornev accompanied his young daughters as they chased butterflies around a sunny South Carolinian field. The girls found the insects’ ebullient colors and fitful flight behavior irresistibly alluring.
Soon Kornev too fell under the insects’ spell. Flitting from rock to mud to flower, the butterflies repeatedly uncurled and re-curled a long, thin tube-like appendage that protruded from the mouth area. Often they laid these unfurled instruments atop various surfaces and left them there for several seconds at a time.
He assumed they were acquiring food. But how? Received wisdom purported that butterflies use these tools to sip, much the way we use drinking straws.
However, what he saw did not make sense. Sometimes a butterfly seemed to insert its appendage—called a proboscis—into a flower, apparently “sipping” nectar. At other times these proboscices were laid out along hardened soil or even rock surfaces. “Sipping” from a rock seemed unlikely.
The bio-genius of these gaudy, glittering creatures struck him full force. Something far more interesting than mere sipping was going on. But what?
His curiosity was not idle. Kornev is a materials engineer. Materials engineers—make new materials. But Kornev does not create from scratch. Like evolution itself, he builds on what already exists.
He suspected that butterflies might provide important clues as to a question he and other researchers were facing: how to transport infinitesimally tiny fluid droplets, measuring no more than a few microns in diameter, along lengthy, narrow tubes.
Solving this problem would have important implications for fields as diverse as brain surgery, heart surgery, pure physics, applied electronics … Could the butterfly proboscis, which after all has been working on the same problem for more than 130 million years of evolution, have any clever solutions to offer?
To find out, Kornev put droplets of water containing sugar on a countertop and filmed the butterflies as they fed. By slowing down the film, he could watch the insects in slow motion.
Just as expected, the butterflies were not simply sipping. But they were clearly ingesting. He searched the scientific literature and found out that, remarkably, no published papers addressed this question. For hundreds of years, virtually everyone had taken for granted that the butterfly proboscis was a drinking straw.
Availing themselves of modern high-tech microscopes that allow for viewing on the multi-micron level, Kornev and Clemson butterfly biologist Peter Adler, along with graduate student Matthew Lehnert, began examining the proboscis, both inside and out.
They found that butterflies have devised various highly efficient transport systems that move droplets, only a few microns in diameter, through their proboscices by taking advantage of basic physical forces like capillary action.
Each species does this in it own unique way. Some species can alter the diameter of the interior tube, either widening or thinning it, to accommodate fluids of different viscosities. Honey or tree sap, for example, would require a wider diameter than would water.
Some proboscises are highly perforated, allowing the insects to “blot” up films on rock surfaces, like paper towels blot up kitchen spills. Another species has sharp saw-like “teeth” on the tips of their proboscises that can cut through the flesh of fruits—or in some cases, animals (including humans)—to get at the nutrients inside.
These discoveries have important applications for human technologies. For example, butterfly-inspired probes may soon deliver toxic anti-cancer agents to the interior of cancerous cells—a revolutionary breakthrough that would allow doctors to destroy wildly replicating cancerous cells but minimize risks to healthy tissues.
Or, the evolutionary strategies worked out by butterflies may help surgeons deliver nano-liter quantities of blood to the tiniest of human blood vessels, thus preventing them from becoming oxygen-deprived. Other butterfly-inspired tools may help medical professionals deliver vaccines without risking infections associated with needle injections.
Other research teams are excited by other butterfly accoutrements. Biologist Adrianna Briscoe and engineer Jahoe Lee, both of the University of California have teamed up to study the micro-structures on butterfly wings that allow the insects to heat up and cool down in extreme environments. Aided by graduate student Anirudh Krishna, their discovery may help develop new and more energy-efficient building materials.
Nipam Patel, director of Massachusetts’ Marine Biological Laboratory and lifelong collector of butterflies, has studied the microscopic structure of the scales that cover butterfly wings. His research has shown that the stunning blue morpho butterfly gets its glittering blue color not from pigment, but from the Christmas-tree like shapes of the scale’s microstructures that scatter all frequencies of light but blue.
This discovery also has a variety of practical applications. GE Global’s Radislav Potyrailo, for example, expects the blue morpho’s scale structure to help him solve the practical problem of how to develop small, inexpensive sensors that can detect poisonous gases in the atmosphere, or that can alert asthma sufferers to the presence of airborne irritants that trigger breathing emergencies.
Butterflies are awe-inspiring in their own right, as engineer Kornev’s two young daughters knew. But the genius of butterflies is also helping us save human lives.