Photograph © W. Davies
When the final instar larva is ready to emerge it sits near the waters edge where it stops feeding and starts to breathe air. The larva then climbs up emergent vegetation or indeed any object that will take it out of the water, sometimes walking many metres from the water before finding a suitable emergence support. Here whilst clinging to the support with the claws, the body fluids are redistributed forcing the upper adult body to burst out of the larval skin or exuvia.
Photograph © W. Davies
A subsequent resting phase then allows the adult legs to harden. This will then enable the dragonfly to reach forward, grip the exuvia and pull the abdomen free.
Photograph © W. Davies
Again the body fluids are redistributed to inflate the wings and extend the abdomen, the latter being assisted also by the gulping of air.
Photograph © W. Davies
And finally…
The expanded wings now harden and the insect dries out losing considerable body weight before the first flight. The whole process takes between 1-3 hours depending upon the species.
But sometimes things go wrong….
During emergence the dragonfly is very vulnerable to predation so emergence usually happens under the cover of night or early in the morning. Despite such precautions mortality rates are high and in addition insects are often damaged by rainfall, wind or obstacles preventing successful expansion of the wings or body. Some species that emerge early in the year such as Broad-bodied Chaser do so on mass within a short time period whereas others emerge over a far broader time period throughout the summer.
