Winter doesn’t technically start for another week, but it certainly made an early arrival in our corner of the world. While I miss the noisy din of insects at the height of summer, winter has its own kind of quiet, sleepy magic. But the arrival of snow doesn’t mean every insect goes dormant; some not only survive in a snow-covered landscape, but thrive in it. I’m talking, of course, about the snow flea.
Snow fleas (Hypogastrura nivicola) are not actually fleas; they’re not even insects! They’re springtails, a group of arthropods that belong to the class Entognatha (meaning “internal mouthparts,” as opposed to insects, whose mouthparts are external and belong to the class Insecta). The common name “snow flea” comes from their jumping capabilities. Unlike fleas, however, springtails do not use their legs to catapult themselves; they use a specialized appendage known as a furcula. The furcula is folded under the body and held under tension. When it is released, the force of the furcula snapping against the ground propels the snow flea into the air.
The really remarkable trait of the snow flea is not its jumping ability, but its ability to thrive in such wintery conditions. Snow fleas produce antifreeze proteins (AFP’s – or, if you really want to impress your friends, thermal hysteresis factors (THFs)). Antifreeze proteins are produced by all freeze-avoidant insects, and they do exactly what you think they do. This family of proteins prevent freezing by binding to the surface of ice crystals forming in the animal’s body and preventing them from growing. The production of antifreeze proteins is triggered by day length; as daylight decreases and insects experience a shorter photoperiod, the production of antifreeze proteins ramps up, and reaches its peak during the darkest months of winter.
The snow flea’s antifreeze capabilities have sparked such a fascination that researchers at Queen’s University decided to sequence and synthesize the protein. Researchers hope to utilize the snow flea antifreeze protein in such freezer-related tasks as producing better ice cream and transplant organ storage and transport. I am all for medical breakthroughs but honestly, they had me at “better ice cream.”