Blue-tailed Damselfly
Ischnura elegans
The Blue-tailed Damselfly is a small, widespread damselfly belonging to the family Coenagrionidae. It is characterized by its predominantly black abdomen with a bright blue eighth segment, often referred to as a 'tail light'. This species inhabits a wide range of aquatic environments and is known for its high tolerance to various environmental conditions. Females exhibit significant color polymorphism, appearing in several distinct color forms.
Details
Identification
Black thorax dorsum, bright blue 8th abdominal segment, bicolored (black-and-white) pterostigma in the forewings.
Social behavior
Solitary; males do not defend fixed territories but show aggressive behavior towards other males upon direct contact.
Diet
Predatory; larvae feed on small crustaceans, midge larvae, and other invertebrates. Adults hunt small flying insects such as mosquitoes, flies, and aphids.
Hunting strategy
Larvae are ambush predators using a prehensile labium; adults are visual hunters that catch prey in flight or glean it from vegetation.
Spawning substrate
Living tissue of aquatic plants into which the eggs are inserted (endophytic).
Overwintering
The species overwinters as a larva in the substrate of water bodies or on aquatic plants, usually in an advanced developmental stage.
Ecology
Ecological role
Important predator in both aquatic and terrestrial ecosystems; serves as a significant food source for birds, amphibians, and larger insects.
Natural predators
Birds (e.g., wagtails), frogs, larger dragonflies, spiders, and fish (for the larvae).
Competitor species
Other damselflies, particularly species of the genus Coenagrion (e.g., Azure Damselfly).
Ecosystem service
Biological pest control by consuming large quantities of mosquitoes and agricultural pests such as aphids.
Threats
Destruction of small water bodies, intensive use of pesticides in agriculture, and increasing desiccation of habitats due to climate change.
Scientific profile
Profile
Distinguishing features
Bicolored pterostigma on the forewings (black inner part, whitish outer part). The 8th abdominal segment is almost entirely blue, while adjacent segments are black. The posterior margin of the prothorax (pronotum) in females features a deep indentation and an erect process.
Role in food web
Important predator of aquatic invertebrates; serves as prey for fish, larger dragonfly larvae, birds, and spiders.
Protection & threats
Main threats
Currently not threatened. Potential threats include extreme desiccation of small water bodies due to climate change and massive pesticide input from agriculture.
Population trend
Stable to increasing; the species partially benefits from warming and the eutrophication of water bodies.
Conservation measures
No specific conservation measures required. Maintenance of diverse riparian structures and avoidance of total vegetation clearance in ditches.