The Seaside Dragonlet (Erythrodiplax berenice) spends most of its time perched atop salt marsh plants; here, one rests on a stem of marsh bristlegrass (Setaria parviflora).
Perhaps ‘saltmarsh dragonlet’ would be a better name, since they’re often the only dragonfly in the marshes. Other dragonflies appear in coastal habitats, hunting insects over dunes and wetlands, but no other species is as tied to the coast as the dragonlet; they rarely appear inland, and are considered to be our only marine dragonfly.
The primary reason is their adaptation to salt. Like all dragonfly larvae, seaside dragonlet nymphs are aquatic, but their ability to regulate the concentration of salt within their bodies allows them to thrive in saltwater; researchers have found them tolerating water as much as three times the salinity of the ocean. In salt marshes, the seaside dragonlet often is the only medium-sized dragonfly — about an inch and a half long — that’s encountered.
Salt marshes are insect-rich, so dragonlets can afford to be a little lazy. They do less flying and more waiting than many species: launching themselves out to capture passing prey before returning to their perch.
Adult males are deep blue or black, with clear or nearly-clear wings; females show varying amounts of yellow atop the abdomen, and elaborate patterns of black-and-yellow striping on the sides of the thorax. As accomodating as they are attractive, they make fine subjects for a photographer.