Springtails—Worldwide Jumpers

Springtails are tiny, six-legged animals that you meet every day, but hardly notice. They can survive in big cities, on ice in Antarctica, in the deepest caves, and in rainforest canopies. Some scientists call them the earliest known and the most numerous insects on Earth. Springtails are famous jumpers—if they were as large as humans, they would easily be jumping over 10-story buildings. This ability allows them to escape from danger. Every day, springtails are very busy, improving soil health and supporting numerous species of spiders, beetles, ants, and other small predators on our planet. They are a key part of soil biodiversity, but we still need to learn a lot about them and many of these beautiful animals are yet to be discovered.

place for a springtail to live is the forest floor, where you can find thousands of them in a handful of fallen leaves. But they can also live in other environments, often in moist places where fungi are growing ( Figure ). In fact, springtails live almost everywhere: they are numerous in Antarctica on snow and rocks, they are diverse in tree canopies of tropical forests, they are found on the highest mountains and down in the deepest caves. Several years ago, scientists found the springtail Plutomurus, which lives two kilometers below the land surface in a cave in the Caucasus mountains [ ]. They lured it out with the help of a smelly cheese. In winter, some springtails jump and wander on the snow surface, which earned them the name "snow fleas." Snow fleas like Hypogastrura ( Figure F) can exist in herds of millions, making the snow gray with their bodies! As masters of survival, springtails also live with us-in gardens, backyards, parks, and sometimes flowerpots.
Springtails were surviving and thriving on the planet long before dinosaurs, and they are among the first animals that walked on land. We know this because scientists found a fossil springtail in prehistoric rocks dated about million years old. This springtail was named Rhyniella praecursor, "the earliest known insect." Interestingly, some

WHAT DOES A SPRINGTAIL LOOK LIKE?
The name "springtail" comes from the organism's furca, which looks FURCA A forked tail-like appendage attached to the abdomen of many springtail species. like a forked tail and allows many springtails to spring away from danger, just like tiny grasshoppers ( Figure ). The furca can be found under the body, on the abdomen, but not all springtails have one. If a springtail is walking or eating, the furca is attached to the body under high tension, like a compressed spring. As soon as springtail wants to jump, the furca is released and the animal catapults itself at jumping-if they were the size of humans, they could jump over -story buildings! As you can imagine, after such a jump it is not easy to land without a parachute. Instead, springtails use a special tube called collaphore, which allows them to stick to the surface (for COLLAPHORE A tube-like structure that is used by springtails to attach to surfaces. example to a leaf or a stone) when landing.
Like insects, springtails are hexapods, meaning that they have six walking legs. Unlike insects, they never have wings. Springtails can have from two to sixteen eyes ( Figure D), but species living in soil are often blind. To orient themselves in the environment and communicate with others, many springtails use antennae, which are long organs on their heads. They move the antennae to touch and check the surfaces in front of them. If they find some food, they grasp it and chew it with their mandibles.

MANDIBLES
Lower jaws, used to bite and chew the food. Unlike humans, arthropods chew horizontally, not vertically.

HOW DO YOU CATCH A SPRINGTAIL?
If you are interested enough to look for a real springtail, you need to know where to look and how to do it. Springtails like wet places, like moist fallen leaves or mosses. Some large species can be found hiding under the bark of decaying fallen trees. Others are found on stream banks, rocks, mosses, or flowers. If you are lucky, you can also find springtails in flowerpots-if so, chances are it will be the white Folsomia candida-one of the most commonly used soil animals in laboratory experiments. While searching for a springtail, be very patient-they are everywhere, but they are masters of hiding and often are colored like things in the environment around them ( Figure E) which can be built with relatively little e ort at home. Springtails can be closely inspected under a microscope. Scientists also keep springtails as laboratory pets-they need a permanently moist surface (for example, a jar with fallen leaves, soil, or clay), some food (baker's yeast would be a good choice), and air (make holes in the lid). Unfortunately, only a few dozen species like to live at home or in the laboratory-and we do really not know why.

BUSY SPRINGTAILS RUN THE WORLD
What are all these springtails doing in nature and why should we care about them? Springtails have an important role in ecosystems: as ecosystem "cleaners" they recycle dead material called detritus, DETRITUS Dead organic material, for example dead leaves or wood, bodies of dead animals, and excrements. Detritus is inseparable from the microorganisms that decompose it, such as bacteria and fungi. and they feed on microbes, such as bacteria and fungi [ ]. By doing this, they improve soil structure and make nutrients available to plants. Springtails can also pollinate mosses, just like bees pollinate flowers [ ].
Being delicious food for many predators is also important-numerous species of spiders, beetles, ants, and other invertebrates survive by hunting springtails. Sometimes springtails are also directly useful to humans. In agricultural fields, they may help plants by feeding on the microbes that cause plant diseases, or they may support other predators that can kill plant pests. However, scientists have only recently started to explore these functions of springtails, and there is a lot to learn yet.
In the modern world many ecosystems are changing. Cities are growing, tropical forests are being cut down to grow food, and increasing temperatures are making frozen places like Antarctica and the northern tundra melt. These changes a ect springtails as well as other soil organisms. The most remarkable species are often also the most vulnerable and can become extinct if their natural environments are destroyed. The number of springtails on our planet is likely to decline in the future, since they are numerous in the cold, Polar regions that will be strongly a ected by climate change. One hectare of tundra can be inhabited by as many springtails as there are humans on the entire planet. As masters of survival, springtails will adapt to the changing world and live in the new ecosystems. However, many species are likely to become extinct even before being discovered. Studying springtails and sharing the knowledge about them as a hidden but very important part of biodiversity can help us to understand how the nature is organized and how we change it with our actions. Sharing your new knowledge with your friends and family can help with this-the more people who will know about the importance of hidden biodiversity, the better we will be able to understand and protect the nature and our future as a part of it.

AUTHOR CONTRIBUTIONS
AP developed the idea and wrote this manuscript. . doi: . /frym. .

CONFLICT OF INTEREST:
The author declares that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.
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