Blue Emperor

Adventure step • Meet the species

Overview

The Blue Emperor is one of Europe's largest and most impressive dragonflies, with a body length of up to 8.4 centimeters and a wingspan that can reach 11 centimeters. Males are particularly striking with their brilliant sky-blue abdominal segments and green eyes that gleam like jewels in sunlight. Females have more subdued coloring with greenish and tawny-brown tones, which helps them blend into vegetation when laying eggs. Both sexes have powerful, transparent wings with prominent veins and a characteristic black line along the wing edge. This magnificent insect is a master of the air and can reach speeds of up to 30 kilometers per hour. The Blue Emperor can fly in all directions – forward, backward, sideways, and even hover in mid-air like a helicopter. Its enormous compound eyes consist of up to 30,000 individual lenses and provide nearly 360-degree vision, making it a consummate hunter. It feeds on other flying insects such as mosquitoes, flies, butterflies, and even other dragonflies, which it catches with its spiny legs while in flight. The Blue Emperor undergoes a fascinating transformation during its life. It spends the majority of its existence – up to two years – as a larva (nymph) underwater. The larva is a feared predator in the pond, eating everything from aquatic insects to tadpoles and small fish. When ready to become an adult, the larva climbs up a plant stem above water, and the adult dragonfly emerges from the larval skin in a dramatic process that can take several hours. Newly emerged individuals are soft and pale but soon acquire their brilliant colors. During the summer months, males are highly territorial and aggressively patrol their areas around ponds and lakes, driving away rivals and pursuing females. A male may have a territory of up to 300 meters of shoreline. After mating, the female lays her eggs alone, either directly into the water or into aquatic plants, and can produce hundreds of eggs during the season. The Blue Emperor is an important indicator of healthy aquatic environments, and its presence suggests good water quality.