Snow Flea (springtails)
| Scientific Name | Hypogastrura sp. |
| Survival Strategy | Freeze-avoidance |
| Conservation status | Least Concern |
Spring
Mating takes place in the spring, after the snow melts. The female snow flea lays eggs in the soil. The eggs hatch into nymphs in about three weeks.
Summer
Snow fleas spend the summer in the soil and leaf litter, feeding on fungi and decaying plant matter. The nymphs continue to grow and go through several molts.
Fall
The nymphs mature into adults after their final molt in the fall.
Winter
Snow fleas remain inactive in the soil and leaf litter for most of the winter. Adults become active on the snow surface on warm, late winter days.
Behavior
Why gather on the snow?
Often on sunny days in late winter, snow fleas work their way to the snow surface in numbers that amaze even the experienced outdoor adventurer. Why snow fleas gather on the surface of the snow is still being debated by biologists. One theory is that overcrowding and lack of food trigger them to migrate. Another theory suggests that the melting snow concentrates food at the surface.
It’s worth noting that these springtails are year-round residents, and although they are challenging to see, their numbers are about the same in summer. Their role in recycling organic matter and improving the soil is similar to that of earthworms, and unlike earthworms, springtails are native species. There are no native earthworms in the upper Midwest.
Why Are Snow Fleas Called Springtails?
Snow fleas, like all springtails, don’t jump using their legs; they catapult using their furcula (Latin for “little fork”). The furcula is a fork-shaped, spring-loaded lever folded up against the abdomen and held by two hooks. When these hooks are released, the furcula pushes against the ground and launches the Springtail somersaulting into the air (imagine tripping an upside-down mousetrap). The uncontrolled flight is often 100 times the length of the springtails body, which is often enough to escape from a hungry predator.
Springtails and the Smell of Soil
The “earthy” smell of soil comes from a chemical called geosmin, made by bacteria in the genus Streptomyces. These bacteria produce geosmin at the same time they release spores for reproduction. Springtails are attracted to geosmin and eat the bacteria that make it. After feeding, the springtails become covered with bacterial spores and carry spores in their digestive tract, which they disperse to new locations.
Physiology
Antifreeze
Snow fleas produce an antifreeze that protects their cells from damage caused by freezing and allows these cold-blooded animals (ectotherms) to remain active in the snow. The antifreeze is a glycine-rich protein that binds to ice crystals as soon as they start to form, preventing them from growing larger.
A popular child’s toy can model how glycine works. The LEGO® company makes a brick they call a “tile” that doesn’t have studs on the upper surface. Once this smooth-topped tile is attached to a project, no additional bricks can be added at that spot. In the same way, once the glycine binds to an ice crystal, there is nowhere for more water molecules to connect, and the ice crystal stops growing and cannot damage a cell.
Researchers are exploring the possibility of using glycine-rich protein to improve the longevity of organs donated for human organ transplants.
Diet
The omnivorous diet of the snow flea includes decaying leaves, fungi, bacteria, pollen, algae, lichens, and insect feces.
Lifespan and Mortality
Snow fleas live for about two years.
Predators
Snow fleas have few predators in the winter, but as the weather warms, they are eaten by beetles, ants, centipedes, mites, and pseudoscorpions.
Killer Fungus
Mycorrhizal fungi have a mutualist relationship with the roots of specific plants, and most could not survive without their host. Plants absorb nitrogen, a nutrient vital to all life, through its roots. These fungi can detect when the nitrogen level in the soil is insufficient for both them and their plant hosts.
The fungi remedy any shortage of nitrogen by releasing pheromones to attract fungi-eating springtails. After using toxins to paralyze the springtails, the fungi penetrate the still-alive body with their hyphae which decomposes the carcass and releases the precious nitrogen. In one study of eastern white pines, researchers found that 25% of the trees’ nitrogen came from springtails.
Climate Vulnerability
The impact of a warmer climate on springtails is currently the subject of several research projects. In one study of arctic springtails, the number of individuals declined significantly in artificially warmed plots compared to control plots. The decline was most significant at sites with drier, well-drained soil.
Never stop learning
Confusing Names
“Springtail” is the common name for members of the suborder Collembola. “Snow flea” is a common name for several species of springtails that are often found in the snow. Curious learners will likely find the terms “Springtail,” “Snow flea,” and Collembola used interchangeably in online references (such as this one).
References
| Species Hypogastrura harveyi – BugGuide.Net https://bugguide.net/node/view/96858 |
| Graham, Laurie & Davies, Peter. (2005). Glycine-Rich Antifreeze Proteins from Snow Fleas. Science (New York, N.Y.). 310. 461. 10.1126/science.1115145. https://www.researchgate.net/publication/7527974_Glycine-Rich_Antifreeze_Proteins_from_Snow_Fleas |
| Super Springtails, March 22, 2016 – UWM Field Station https://uwm.edu/field-station/super-springtails/ |
| Snow Fleas: When a “Flea” isn’t a Flea https://insectlab.russell.wisc.edu/2020/02/27/snow-fleas-when-a-flea-isnt-a-flea/ |
| Snow Fleas: The Unsung Heroes of the Natural World https://youtu.be/8BOIpiua_z4 |
| Snow Fleas | WIRED https://www.wired.com/2014/01/snow-fleas/ |
| Collembola planet https://youtu.be/B9z7E4hIihU |
| All About Springtails – Care, Culturing, Seeding & More https://youtu.be/c7UgKFtSjD0 |
| The Springtail https://youtu.be/OwOL-MHcQ1w |
| The Springtail – part two https://youtu.be/0Sq2gjsysG0 |
| Springtail Jumps Off Water and in Super Slow Motion! https://youtu.be/MXeSnWY6DNc |
| Root Fungi Can Turn Pine Trees into Carnivores https://blogs.scientificamerican.com/artful-amoeba/root-fungi-can-turn-pine-trees-into-carnivores-8212-or-at-least-accomplices/ |
| The furca – Jumping organ of springtails https://collemboles.fr/en/morphology-and-physiology/63-the-furca-jumping-organ-of-springtails.html |
| Springtails – Encyclopedia of Life https://eol.org/pages/336 |
| Springtails Smell, Spread Streptomyces | ASM.org https://asm.org/Podcasts/BacterioFiles/Episodes/Springtails-Smell,-Spread-Streptomyces-BacterioFil |
| Research Council of Norway. “Pole-to-pole climate research: Adaptation lessons from tiny springtails.” ScienceDaily. ScienceDaily, 13 September 2010. www.sciencedaily.com/releases/2010/06/100607065900.htm |
| Effects of experimental temperature elevation on high-arctic soil microarthropod populations Coulson, S.J.; Hodkinson, I.D.; Webb, N.R.; Block, W.; Bale, J.S.; Strathdee, A.T.; Worland, M.R.; Wooley, C. Polar Biology 16(2): 147-153. 1996 https://eurekamag.com/research/008/566/008566942.php |