As dragonfly and damselfly nymphs go through successive molts, small wing pads develop on the thorax. These become larger as the nymph matures, but give little indication of the size and beauty of the adult wings that will eventually break free. As adult emergence nears, the nymph stops feeding, shifts to aerial breathing, and crawls from the water to find a firm substrate on which to emerge. Some species climb up on aquatic vegetation to emerge, while others may crawl long distances from the water, even climbing onto tree trunks. The events that follow are spectacular. The new adult expands its thorax until the nymphal skin splits, allowing it to pull its head, legs, and thorax free. It then hangs backwards for a time to allow the body to harden and strengthen, at which point it reaches forward, holds on to the substrate, and pulls its abdomen free. The crumpled wings expand as body fluids are pumped through the network of veins; this fluid is then withdrawn and pumped into the body to lengthen the abdomen. Emerging adults are very vulnerable and subject to multiple threats such as being picked off by birds as tender morsels to feed nestlings.

Newly-emerged adults, called tenerals, have a distinctive shine on their recently unfurled wings, weak flight, and pale coloration, which can make them appear very different from mature adults. Tenerals seek refuge away from water, where they feed, develop their definitive color patterns, and become sexually mature. When a teneral makes its first flight it leaves behind it's the cast-off skin of the final-stage nymph, called an exuvia.

The presence of exuviae is evidence that a species is successfully breeding there. Reporting exuviae and first-of-the-year sightings of migratory species at your Pond Watch site helps us examine the timing of migration and differences in arrival of migrants vs. emergence of residents, and gives insights into the local life history of resident and migrant populations of the same species. The timing of your observations is key! Migratory and resident populations of Common Green Darner (Anax junius) can inhabit the same pond or wetland. Migratory adults emerge in the north in late summer and fly south; spring migrants return north to mate and lay eggs before overwintering resident nymphs have completed development to adults. Resident adults emerge in late spring and summer, laying eggs that hatch into nymphs that will spend the winter in diapause. This year, mature adult Common Green Darners were reported in February and March from California and southern Oregon and April saw a surge of migrant sightings in the southeast and northeast, while May 12 provided a surprisingly early report of a teneral Common Green Darner in southeast Massachusetts. Reports such as these give important clues about the phenology of migrants versus residents in different regions of North America.

So as the days grow longer and warmer and dragonfly development continues, explore the vegetation around your local pond for tenerals or the exuviae they left behind. If you're lucky, you might even get to witness an emergence!