Dragonfly Emergence

Dragonfly Emergence Sequence

The sequence shows the emergence of a Four-Spotted Libellula Dragonfly (Libellula quadrimaculata) from its larval case. They were taken in May 1999 on a reed stem at 'Round Pond' early morning to midday. This was one of the 'camera accessible' emergences of about 10 that took place over a few days on grass stems, daffodil tops and even a flowering bluebell. Notes are included below

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8

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15

16

The numbers of the images are not consecutive as we have removed parts of the sequence showing little change.
The temperature was about 16C in full shade (the images were taken with flash).

The whole sequence from the nymph exiting the water to flying off takes about 5 hours.

1 to 8: The Insect breaks through the case and works it's way out until it is just hanging on.
The white threads appear to be the inside-out lining of the spiracles (breathing tubes) that the nymph used underwater, now replaced by direct access to the air. This sequence lasted a bit over an hour.
9: Wow - how did this happen?
The process is gradual except for this sudden flip about. We kept missing it and finally left a video camera running to find out. This extract (from a different emergence, but same species) shows how it flips. This 14 second natural time MPEG movie is about 300Kb. Show Movie
10 to 15: The wings are pumped full of fluid to expand them, and the fluid is then taken back into the body and the wings allowed to harden
16: Two hours from picture 10 the wings are hardened, have become transparent.; The blob of green on the wing near the body (also visible in 15, and on 17 on the inside of the lower right wing) is atypical and was a drop of fluid.
17: This insect is partly on it's old case and partly on the stem, but most hang entirely on the old case until they fly off. The wings suddenly open and the insect is ready for lift-off. Often they don't fly for an hour or two, but any disturbance results in instant takeoff. They seem 'fully qualified pilots' from the first instant!

This is how you are more likely to see a Four-Spotted Libellula Dragonfly (Libellula quadrimaculata) at the pond side warming itself in the sun

Most dragonfly emergences take place in the comparative safety of night. We don't know whether morning emergence is typical for this species, or something about our site. On ponds where you find dragonflies have a good look at stems near the water's edge - they may reveal the empty larval cases as evidence of what took place one night. This is an old larval case, believed to be of an Emperor Dragonfly (Anax Imperator) that gives you an idea of what to look for.

At the other end of the size scale here is what we believe to be a Damselfly Laval case (species unknown). You can still see the threads of the spiracles. At first sight these look more like the splash of a bird dropping so look hard.