Moving on snowflakes and melting ice: Jumping, glandular-landing and meniscus-climbing abilities of snow springtails

Snow springtails are enigmatic because during winter they have to endure sub-zero temperatures and move effectively on frozen soils covered with snow in order to survive. In contrast, during springtime the melting ice creates a real challenge to these animals because their tiny jumping organ (furcula) could impose limits for self-catapulting on the surface of water. However, it is uncertain how these millimeter-sized animals actually move on frozen or melting ice surfaces. We found that snow springtails are extraordinarily fast when jumping on snow. These arthropods have a rose-shaped sticky gland located at the tip of their abdomen which is inflated before launching and subsequently used to anchor itself to the snow. On water, individuals were unable to take off and they fought to climb on each other’s back to jump and escape this way the watery trap that represents the air-water interface for them. Remarkably, we discovered that these colemboleans deform the body and use their mouth and tiny furcula to exert lateral capillary forces and climb the water meniscus. Our results highlight the tradeoffs imposed by phase changes of water on the locomotion performance of millimetric arthropods living in extreme weather. This study can help design jumping robots with the capacity to move effectively on both solid and melting ice surfaces.