Emergence
Unlike other winged insects, such as butterflies, dragonflies do not have a pupal stage, but progress to adults through a final larval moult that takes place out of water. Triggered by day length and temperature, emergence is synchronised in some species, such as Emperor Dragonfly, which emerge in spring, but is more extended in the later-emerging species.
Final-stage larvae sit in shallow water near the margins for several days, getting ready for their final moult and starting to breathe air. Most species leave the water during the morning, but hawkers do so under cover of darkness. Larvae climb up robust emergent vegetation, although some may walk several metres over dry land before finding somewhere suitable. After finding a secure support, they redistribute their body fluids – first to push the thorax, head, legs and wings out of the larval skin. There is then a pause of about 30 minutes to allow their legs to harden enough for the next stage, when the abdomen is withdrawn. The wings and then the abdomen are expanded and start to harden. This process leaves behind a cast skin, called an exuvia, and lasts for between one hour (in the case of damselflies) and three hours (in the case of dragonflies).
Maiden flights are weak and typically cover only a few metres. However, in very warm conditions some species, such as Scarce Blue-tailed Damselfly, may rise into the air and drift for long distances at high altitude. At such times, dragonflies are especially vulnerable to predation by birds such as the Hobby. Smaller predators, such as Blackbirds, spiders and ants, also take a heavy toll during emergence. Other hazards include physical obstructions or rainfall, which can result in many individuals suffering from imperfectly expanded wings or damage to the soft tissues.