Dragonflies and mosquitoes often share habitats, prompting questions about their interaction and impact on mosquito populations. Understanding this relationship reveals how dragonflies fit into the broader ecological landscape.
Dragonflies as Mosquito Predators
Dragonflies are effective predators of mosquitoes throughout their life cycle. In their aquatic larval stage, known as nymphs, they inhabit freshwater environments such as ponds and wetlands. These nymphs are voracious hunters, using an extendable jaw to capture and consume mosquito larvae and pupae within the water. A single dragonfly nymph can consume an average of 40 mosquito larvae daily, significantly reducing mosquito populations in their developmental stages.
As dragonflies mature into winged adults, they become aerial hunters. Adult dragonflies are known for their exceptional eyesight and acrobatic flight, allowing them to catch mosquitoes and other small flying insects mid-air. They can fly at speeds up to 30 mph, hovering and even flying backward to snatch prey with their legs. One adult dragonfly can consume hundreds of mosquitoes daily, making them efficient pest controllers.
Do Dragonflies Deter Mosquitoes?
While dragonflies are highly effective at consuming mosquitoes, little scientific evidence suggests their mere presence actively “scares away” or deters mosquitoes. The reduction in local mosquito populations is primarily due to direct predation, where dragonflies physically hunt and eat mosquitoes, rather than mosquitoes avoiding an area out of fear. Mosquitoes do not possess the cognitive ability to perceive dragonflies as a threat and actively flee from their presence.
Dragonflies are generalist predators, meaning their diet includes a variety of small flying insects, not exclusively mosquitoes. They eat midges, gnats, and other small insects. A high density of dragonflies correlates with fewer mosquitoes due to consumption, not deterrence.
Encouraging Dragonflies for Mosquito Management
Supporting dragonfly populations can be a component of managing mosquitoes in a local environment. Dragonflies require suitable habitats for both their aquatic nymph stage and their aerial adult stage. Creating or maintaining clean, still water sources like ponds or water gardens with varied depths and native aquatic plants provides breeding grounds and shelter for nymphs. These plants offer places for egg-laying and for nymphs to climb out when they emerge as adults.
For adult dragonflies, providing native plants around water features offers perching spots, shelter, and attracts their prey. It is important to avoid using chemical pesticides, as these can harm dragonflies directly or indirectly by reducing their food sources, disrupting the ecosystem. While dragonflies contribute to natural pest control, they are generally not a standalone solution for widespread mosquito issues and are most effective as part of an integrated approach to mosquito management.