I was staking out the kitchen garden pond whenever I could. By my reckoning about 60 Emperor dragonflies emerged over a 10 day period, either side of a peak on June 1st. The process from leaving the water to flying off takes around two to three hours, but varies greatly between individuals. My own observation leads me to believe that the the bigger the nymph, the quicker the process. Also the failure rate (individuals that failed to break free of their larval cases) seemed to increase towards the end of the period of emergence.
After a few years watching, I have failed to detect an obvious correlation with either weather conditions or time of day providing triggers for the process. It does though seem that they are encouraged by my failure to get out of bed of a morning, or by my needing to be elsewhere at any given time of day. Thanks to the Tyntesfield gardeners for tolerating my pond loitering.
The first picture below is a female Broad-bodied Chaser, taken by Tyntesfield gardener Joel Bunting. Then my own Emperor shots from the pond, a late emerging damselfly and a random green bug to finish.
|Broad-bodied Chaser (Libellula depressa) female (photo by Joel Bunting)|
|Newly emerged Emperor dragonfly (on its own larval case)|
|Emperor dragonfly (Anax imperator)|
|Common Blue Damselfly female|
|Green Nettle Weevil (Phyllobius pomaceus)|