Hairy dragonfly

The Hairy dragonfly (Latin: Brachytron pratense) is a species of dragonfly belonging to the family Aeshnidae, order Odonata. While adult dragonflies are beneficial predators of mosquitoes and other flying insects, their larval stage, known as a naiad, plays a complex role in aquatic ecosystems, particularly within managed fish ponds.

This species is widely distributed across Europe and parts of Asia. It favors stagnant waters, including marshy areas and densely vegetated ponds. Unlike agricultural pests that target crops like wheat or maize, Brachytron pratense is not considered a threat to standard field agriculture, as it is strictly aquatic during its juvenile stage.

The biology of the species involves a long larval development phase, which typically lasts for two to three years. These larvae are voracious predators equipped with a specialized labium for capturing prey. They hunt aquatic invertebrates, tadpoles, and small fish, which may cause concern in highly specialized hatcheries or fingerling production ponds.

The damage caused is primarily economic, occurring in the aquaculture sector. High concentrations of larvae can lead to decreased survival rates of young fish populations. However, there is no damage to terrestrial crops, and any attempt to eliminate these insects in natural or agricultural environments would cause unnecessary ecological disruption.

Management strategies in aquaculture focus on habitat manipulation to reduce larval populations:

• Draining and drying of ponds during the winter season to disrupt the life cycle.
• Mechanical removal of aquatic vegetation, which serves as a site for egg-laying and larval shelter.
• Use of biological control agents and sustainable management of water quality to limit larval success.