Ancient hunters, forever on the wing

Dragonflies and damselflies are predatory flying insects that have remained largely unchanged since the Carboniferous period—315 years ago. Specialized hunters, their legs are so adapted to snatching prey from midair that it is impossible for them to walk.

Vivid Dancer - Argia vivida

The state insect of Nevada, the Vivid Dancer is one of the most widespread damselfly species because of its ability to regulate its own body temperature, a rare trait among invertebrates. The vividness of their colors is known to increase as the temperature rises during the day, falling with night. They prefer denser forests in the night, as such an environment helps slow the radiant loss of their body heat, migrating to sunnier positions in the morning. They require cool water for their eggs to mature. In these ways, San Francisco provides an ideal habitat for these agile gliders, as our urban parks contain dense wooded tickets, creeks, and clearings.

Vivid Dancer - female

Pictured below is the female of the species.

Variegated Meadowhawk-Sympetrum Corruptum

The Variegated Meadowhawk gets its name for its preference for hunting in grassy, open spaces and for the highly diverse coloration the species presents in different biomes and throughout its life cycle. Pictured here is in immature male Meadowhawk. Prevalent across North America, these grand and powerful fliers can camouflage themselves cleverly clinging to grasses, before they soar above, ready to swoop down on the flying insects that they consume. Though they hunt away from freshwater, they return to ponds and streams to find mates and to lay eggs. These dragonflies, like many species, migrate thousands of miles south in the fall.

San Francisco Forktail - Ischnura gemina

The San Francisco Forktail, the rarest odonate in North America, can be found only in cool, wet woods of the coastal Bay Area. Threatened by habitat loss, the US National Park Service and San Francisco State University are coordinating the restoration of the species to their historic range, including in Mountain Lake in the Presidio. As nymphs, these beauties hunt mosquito larvae and are food for fish and amphibians; as adults, they love to target slow-moving flying insects like mosquitoes and dance flies. Their dark colors help them maintain body temperature in the foggy and cool habitats where they take up residence. The insect is listed as Endangered by the International Union for Conservation of Nature and its populations have been in steady decline for decades. However, it was delisted from the U.S. Endangered Species list in the 1990s so that conservation efforts would not hinder the development of natural areas in the Bay. 

Sooty Dancer - argia lugens

Sooty Dancers, like this one, prefer to hunt along moving water. This beautiful female was discovered near the gentle creek deep inside Glen Canyon Park. Like other members of the “Dancer Group” of damselflies, Sooty Dancers have long spines son their legs. These spines help their legs create a basket-like trap for the insects they hunt—often snatching them directly out of midair. Spines also act as rudimentary sensory organs, helping damselflies, and other invertebrates, detect wind and vibrations. They may hold prey towards their mouths while on the wing, to incapacitate it—and begin the meal.

Pacific Forktail - Ischnura cervula

These beautiful predators prefer salty or basic ponds or marshes and love to rest on emergent vegetation like cattails, rushes, and reeds.  These plants provide them excellent vantage points from which they use their near-360 degree vision to scope out potential prey. Quietly floating off these perches, these hunters can easily snatch mosquitos from midair—and eat them while still on the wing. Forktails, of the genus Ischurna, are the smallest of North American odonates (the order that includes dragonflies and damselflies. These hunters are weak fliers, and prefer to hunt in secluded wet dells, where the winds are gentle.