Praying mantises are recognized as ambush predators, known for their distinct, elongated bodies and triangular heads that can swivel nearly 180 degrees. These insects possess raptorial forelegs, held in a folded, “praying” posture, ready to strike prey with lightning speed. Their terrestrial nature leads to questions about their capabilities in water, an environment they seem ill-suited for. While not aquatic insects, mantises are sometimes observed interacting with water, revealing an unexpected survival mechanism.
The Ability to Traverse Water
Praying mantises can move through water, a capability that often surprises observers and contradicts the older belief that they would simply drown. This movement is not true, efficient swimming, but a frantic, temporary traversal driven by survival. Entering water is an emergency measure, used as a last-resort effort to reach safety or escape immediate danger.
The ability to move effectively in water is considered an unusual behavior for these terrestrial insects. When forced into water, they are not naturally streamlined or adapted for aquatic life. They possess enough physical attributes to keep from sinking immediately, providing a brief window of survival in a hostile environment.
The Unique Mechanics of Mantis Movement in Water
The mechanics of a mantis moving in water rely on physical attributes and an instinctive paddling motion. Their lightweight bodies and waxy, water-repellent exoskeleton contribute to buoyancy, often trapping small air bubbles that aid in flotation. This low body density prevents rapid sinking, allowing them to remain on the surface or suspended just beneath it.
When propelling itself, the mantis uses its four walking legs (the mid and hind pairs) in a coordinated, strained paddling effort. These legs are adapted for climbing, not aquatic propulsion, making the movement appear awkward. The mantis holds its large raptorial forelegs up and out of the water to prevent drag and keep its head above the surface. The entire effort is aimed at reaching the nearest solid object, such as debris or the bank. The movement is directional but often appears frantic, reflecting the insect’s desperation to exit the aquatic environment.
Why Mantises Use Water as an Escape Route
Water entry by a praying mantis is almost exclusively a defensive or forced response. One scientifically documented reason for water-seeking behavior is manipulation by a parasitic hairworm (Chordodes species). This parasite matures inside the mantis and must return to water to reproduce, chemically compelling its host to jump into a body of water. The parasite manipulates the mantis’s perception of horizontally polarized light, which is strongly reflected by water surfaces, leading the host to its demise.
Mantises may also enter water as a genuine escape from terrestrial predators. When pursued by non-aquatic threats like birds, lizards, or small mammals, a sudden dive into a pond or stream creates a temporary barrier. Water instantly removes the threat of aerial or ground-based pursuit. The mantis’s ability to paddle allows it to escape a predator that cannot follow, turning an unfavorable situation into a short-term survival opportunity.