Red-eyed damselfly

The red-eyed damselfly (Erythromma najas) belongs to the order Odonata and the family Coenagrionidae. This species is commonly found in still or slow-flowing waters, where it relies on diverse aquatic vegetation for its survival and reproductive cycle.

The biology of this insect involves a transformation from aquatic larvae to winged adults. Females utilize their ovipositor to insert eggs into the tissues of aquatic macrophytes. The nymphs are predatory, living underwater and feeding on a variety of small aquatic organisms.

While typically considered a beneficial part of natural ecosystems, Erythromma najas can become a nuisance in managed aquatic environments. In nurseries for water plants or ornamental ponds, their oviposition behavior can compromise the structural integrity of plant stems.

The damage caused is primarily mechanical. By piercing plant tissues to lay eggs, the damselfly creates lesions that are susceptible to secondary infections by pathogens. This can lead to localized necrosis, particularly in young or sensitive aquatic plant species.

Control measures are strictly non-chemical to preserve water quality. Management strategies include manual removal of infested plant debris, physical barriers to prevent oviposition, and maintaining healthy fish populations that naturally prey on damselfly larvae to keep their numbers in check.