Dragonflies are common insects found across nearly every continent, typically near freshwater habitats like ponds, rivers, and lakes. These creatures possess an ancient lineage, with ancestors dating back over 300 million years, predating dinosaurs. Characterized by large, multifaceted eyes, long bodies, and two pairs of transparent wings, dragonflies are prominent members of various ecosystems, known for their impressive flight and vibrant colors.
Reasons for Their Perching
Dragonflies often land on humans for practical reasons rooted in their biological needs and hunting strategies. As ectothermic creatures, their body temperature is regulated by external factors, making them highly dependent on environmental warmth. A human body can serve as a warm surface, allowing them to bask and warm up for efficient flight, particularly during cooler periods. Some species may adopt specific postures, like “obelisking” with their abdomen pointed skyward, to reduce sun exposure and avoid overheating.
Many dragonfly species are “perchers,” hunting from a stationary vantage point. An elevated human, such as a head, shoulder, or outstretched finger, provides an ideal, unobstructed platform. From here, they survey their territory for smaller flying insects like mosquitoes, gnats, or midges. They can swiftly launch to intercept prey, often returning to their temporary perch to consume their catch.
The moisture and salts in human sweat can also attract dragonflies, offering hydration, especially in dry conditions. Dragonflies do not perceive humans as threats, as humans are not their natural predators. They may simply interpret a stationary person as an available structure within their environment, much like a twig, tall grass, or a car antenna, making it a convenient spot for rest or observation.
Dragonflies’ Sensory World
Dragonflies perceive and interact with their environment through highly developed sensory systems, particularly their vision. Their two large compound eyes dominate much of their head, providing a nearly 360-degree field of view with only a small blind spot behind them. Each eye contains thousands of optical units called ommatidia, up to 30,000 in some species. This allows them to detect movement with extreme precision and speed, perceiving the world much faster than humans, akin to slow-motion video.
Beyond their compound eyes, dragonflies possess three simple eyes, or ocelli, on top of their head. These ocelli detect light intensity and changes, aiding flight stability and spatial orientation. Their visual spectrum extends beyond human perception, enabling them to see ultraviolet light. They also possess a greater diversity of light-sensitive proteins (opsins), allowing them to discern a broader range of colors. This advanced visual processing includes specialized neurons that track targets amidst distractions and predict their trajectory, making them highly effective predators.
Safety and Interaction
Dragonflies pose no threat to humans, despite their predatory nature towards other insects. They lack a stinger. While they possess mandibles for eating prey, their bite is too weak to break human skin unless handled roughly. These insects do not transmit diseases, making them safe.
Dragonflies are beneficial as natural pest control agents. Both as aquatic larvae (nymphs) and adults, they are efficient predators of mosquitoes, gnats, and other small flying insects, consuming hundreds daily. If a dragonfly lands on you, remain calm and avoid sudden movements; it will typically depart on its own.
Culturally, dragonflies are often seen as symbols of transformation, good luck, and wisdom in many parts of the world, including Asian and Native American traditions. While some historical European folklore attributed negative connotations, these are simply myths.