How dragonfly nymphs hunt

Wait, orient, and judge range

Many nymphs are ambush predators among sediment or vegetation, though some stalk more actively. Compound eyes detect moving prey, and mechanoreceptors can register currents made by nearby animals even when vision is reduced. The hunter rotates or advances until its head and folded labium face the target. A failed judgment wastes energy and may alert prey, so approach and strike distance change with prey behavior and habitat. [1][2]

Unfold a prehensile lower lip

The so-called mask is not a projectile jaw. It is the labium, greatly enlarged into two main hinged segments called postmentum and prementum. At the tip, paired palps open before extension. During a successful strike, both joints unfold in sequence, carrying the palps forward; their edges and movable hooks close around the target while shapes ranging from flat to scoop-like suit different ecological types. [1][2][3]

Release two loaded springs

Older explanations treated hydraulic pressure as the primary motor of labial projection. Manipulation experiments and detailed anatomy instead support two independently loaded elastic catapults that release together across the linked joints. Muscle contraction stores energy in resilin-rich and other cuticular structures before the strike, allowing the apparatus to exceed the power available from direct muscle shortening alone. Internal pressure may still assist other movements. [3][4]

Grip, retract, and chew

The closing palps hold rather than chew. Retraction muscles fold the captured animal toward the mouth, where mandibles and other compact mouthparts process it. High-speed recordings show palps slicing through water in a way that can reduce drag, and robust cutting surfaces withstand repeated feeding. Nymphs take insects and other small aquatic prey, but capture success and the exact sequence depend on body form, target, temperature, and experience. [1][2][3]

Related guides

• Watching dragonflies and damselflies
• Watching pond life
• Reading a wetland