A few weekends ago, I was leading a ladybug hunt at work and took everyone into the garden to see if we could find anything different. The kids eventually wandered over to the garden pond, pulled in by whatever irresistible lure that pond holds for people under the age of 12, and peered in. The boy quickly called me over to look at something and pointed to the leaf. This is what he saw:
Dragonfly emergence! As much time as I spend around water and as much time as I spend watching dragonflies, I’ve never had a camera with me when I’ve seen dragonflies emerging. I was thrilled! I snapped a few shots before we looked at other plants in the pond. There were a half-dozen dragonflies dragging their soft, squishy bodies out of their last exoskeletons as nymphs and preparing to join the world above the water. I finished the program, but as soon as the ladybug hunters left, I went right back to the pond to look for more dragonflies. Over the course of the day, I spent about 2 hours watching the dragonflies emerging and snapping photos of a dozen dragonflies that transformed from nymph to adult. It was magical! I naturally couldn’t wait to share some photos with you all.
Transforming from a nymph to an adult as a dragonfly is not as complex as it the more familiar transformation from a larva to a butterfly. Dragonflies undergo what is called incomplete, or hemimetabolous, metamorphosis, so they move from egg to nymph to adult with no pupal stage. Even though most of the kids I work with will never see it, dragonfly nymphs actually look quite a bit like the adults. Butterflies have to rearrange all their caterpillar tissues into butterfly tissues while dragonflies simply lose a mouthpart, gain a pair of wings, and fly away. Still, there are all sorts of horrible things that can go wrong. I saw one dragonfly get blown off its perch as it was pulling the last of its abdomen free from the exoskeleton, only to be blown into the water. I tried to rescue her, but she eventually died. Another dragonfly couldn’t free itself from its exoskeleton at all and remained stuck inside until it died. But, 10 of the 12 dragonflies I observed emerged with no problems. Here’s how it works.
First, the dragonfly nymph must crawl out of the water. This appears to be a rather laborious process as the adult dragonfly is just about to burst out of an exoskeleton that is much too small and the nymph practically drags its body up and out of the water:
That particular dragonfly took a good 20 minutes to get 10 inches up the stem before wrapping her legs around it and starting to puff herself up. Eventually, the dragonfly breaks the exoskeleton open along the thorax and begins to spill out of the hole. The head is extracted first:
You know how I mentioned that dragonfly that got stuck in its exoskeleton? This is as far as that one got. It still looked like this when I left work 6 hours later. Assuming all goes well, however, the dragonfly begins to pull its body out of the nymphal exoskeleton. I saw two different methods of this. This blue dasher female freed her legs, then used them to grasp the stem and pull the rest of her body out:
The female eastern pondhawk, however, started bending her body over backwards, using gravity to help pull her head and thorax down to extract her abdomen:
Both dragonflies eventually rested on the plant for a while, pumping hemolymph into their wings to extend them fully. The blue dasher sat above her exoskeleton:
…while the eastern pondhawk rested below hers:
The pondhawk was too close to the water to extend her wings fully, however, so she eventually moved up the stem so that she could finish her wing development and stretch them all the way out:
I know I’ve mentioned it several times in the past, but insects shed all of their exoskeleton when they molt, which includes the exoskeleton-lined respiratory system. Those little white strings hanging out of that shed exoskeleton is the shed respiratory system. I never get tired of marveling at just how amazing it is that insects replace whole systems when they molt, both internally and externally!
eventually, both the blue dasher and the eastern pondhawk had dried their wings sufficiently to move them out to their sides, holding them in the manner characteristic of dragonflies:
At this point, the dragonflies began to harden, their bodies darkening in color until they approached their final color. The blue dasher female was a dusky black:
The eastern pondhawk became an even more vivid green and her black markings became dark and vibrant:
The whole process took about three hours for each species. Eventually, the 10 successfully molted new adults all flew off, ready to spend their short lives on land and leaving their old lives behind:
What an amazing process! If I had to spend a Saturday at work (and a very long Saturday at work at that), these sorts of things make it completely worth it. I was thrilled I got to see all these dragonflies emerging. Every time I go into the garden now, I am drawn immediately to the pond. Will there be more dragonflies emerging? So far I haven’t seen another, but it’s only a matter of time.