The Orchid Mantis That Glides with Its Legs

In forest canopies, many animals have evolved specialized structures that allow them to glide from branch to branch. Flying squirrels possess skin membranes, and flying lizards deploy rib-supported wing-like membranes. These aerodynamic surfaces typically originate from extensions of body skin, and for a long time such gliding organs were thought to be a feature limited to vertebrates.

Among wingless arthropods, no comparable structures had previously been documented. This assumption began to change in 2020, when researchers observed that juvenile orchid mantises (Hymenopus coronatus) could actively leap into the air and glide. Building on this observation, a study published in 2023 proposed that the mantis might use the petal-shaped structures on its legs—known as femoral lobes—to assist in gliding.

An orchid mantis camouflaged as an orchid on a moth orchid（圖片來源：Philipp Psurek，採用 CC BY-SA 3.0 DE 授權。）

The orchid mantis has been famous for more than two centuries because of its remarkable resemblance to flowers. Its body coloration and shape mimic petals, leading scientists to long believe that the insect disguises itself as a flower to lure pollinating insects before capturing them as prey. This interpretation received experimental support in 2013. The conspicuous petal-like lobes on its legs were therefore assumed to function primarily as visual mimicry. However, later experiments showed that removing these lobes did not significantly reduce hunting success. This result suggested that the structures were not essential for flower mimicry and might instead serve another purpose. Such findings motivated the hypothesis that the lobes could play a role in aerial gliding.

To test whether orchid mantises truly glide using their femoral lobes, researchers conducted experiments with three groups of juvenile mantises. The first group consisted of intact individuals, the second group included mantises that had been anesthetized, and the third group consisted of individuals whose femoral lobes had been surgically removed.

An orchid mantis showing the conspicuous petal-shaped structures on its legs（圖片來源：solarflare233 ，採用 CC BY-NC 4.0 授權。）

At the beginning of the experiment, mantises were released one by one from a platform ten meters above the ground. When the intact mantises were released, they did not tumble or fall uncontrollably. Instead, they rapidly stabilized their bodies, oriented themselves upright, and glided forward through the air. On average, these juvenile mantises traveled more than six meters horizontally, with some individuals approaching ten meters. Their flights lasted roughly three seconds. Such performance clearly indicates controlled gliding rather than simple falling.

The anesthetized mantises, by contrast, were unable to perform any gliding maneuver and dropped straight downward. This result showed that gliding requires active control of body posture and leg position.

Mantises whose femoral lobes had been removed could still glide to some extent, but their performance was noticeably reduced. Their average glide distance was about 4.08 meters—approximately 33% shorter than that of intact mantises. These results demonstrate that the petal-shaped lobes contribute significantly to lift generation and are important components of the mantis gliding system.

Researchers also observed that as orchid mantises grow, the femoral lobes enlarge disproportionately relative to body size and gradually become more rounded in shape. This enlargement continues throughout the juvenile stages and only stops when the mantis reaches adulthood. Consequently, the research team released mantises of different developmental stages from the same ten-meter height to examine how gliding ability changes during growth.

The results revealed that although female mantises increased dramatically in body mass during development, their glide distances remained relatively stable, typically between four and six meters. Their glide speed increased with body size—from roughly 2 meters per second in early stages to about 4 meters per second in later stages—but overall gliding performance remained consistent. In males, however, gliding ability declined more noticeably as they matured.

Based on these observations, researchers suggested that maintaining gliding ability during growth may be particularly important for female mantises. Female orchid mantises grow larger, which increases both the energetic cost of movement and their visibility to predators. Gliding therefore provides an efficient strategy for escaping danger and moving between locations within the canopy. When the mantises reach adulthood, their wings are fully developed, allowing them to fly. At this stage the relative size of the femoral lobes decreases because gliding is no longer their primary aerial strategy.

This study provides the first evidence that arthropod legs can evolve wing-like aerodynamic structures used for gliding. For more than two centuries, the orchid mantis' petal-shaped lobes were interpreted primarily as decorative elements involved in flower mimicry. Experimental evidence now shows that their functional significance lies in enhancing aerial locomotion rather than attracting prey.

The discovery also suggests that many flattened or ornamental structures found on insects may serve aerodynamic roles that have not yet been recognized. Insects such as leaf insects, stick insects, and mantises often spend their lives in forest canopies and undergo multiple growth stages while exposed to intense predation pressure. Under such conditions, gliding may evolve as an advantageous means of escape or movement.

Unlike the flexible membranes seen in vertebrate gliders, arthropod exoskeletons are rigid and cannot change shape during flight. Consequently, these leg-based aerodynamic structures cannot expand or retract. Although larger lobes may improve gliding performance, they may also create disadvantages, such as increased difficulty during molting, interference with movement, or greater visibility to predators. The final shape of these structures therefore likely reflects a balance between aerodynamic efficiency and survival costs.

Future research tracking the full three-dimensional trajectories of orchid mantises in flight, as well as examining gliding in other large wingless insects, may provide new insights into how diverse gliding adaptations evolved across different evolutionary lineages.

Author: Bai Leng

Reference:

Zhao, X., Liu, J.-X., Charles-Dominique, T., Campos-Arceiz, A., Dong, B., Yan, L., O’Hanlon, J. C., Zeng, Y., Chen, Z. (2023). Petal-shaped femoral lobes facilitate gliding in orchid mantises. Current Biology.