The large, often blue spotted, and indefatigable fliers found around the ponds, streams and lakes of the United States, go by the common name darners.
While the family breaks down into approximately forty different species, divided into thirteen genera, almost forty per cent of the species belong to the genus Aeshna, or Mosaic Darners.
While species within specific genera often display slightly different physical characteristics, many darner species also share some common physical characteristics.
For convenience sake, think of darner identification in terms of two general rules of thumb.
First, body color serves as the distinguishing gender detail. Most males show blue patterns on otherwise darker colored thorax and abdomen. Females often, but not always, produce similar patterns in shades of yellow and green.
The absence or presence of thoracic stripes (top and side), along with their shape when present, serve as the second leading mosaic darner identification clue.
Tricanthagyna darners, a sutropical genera, make their presence known in North America with the Phantom Darner (Tricanthagyna trifida), top picture.
Also called Three-spined Darners because of the three spines that protrude from the lower abdomen of females, Phantom Darners inhabit the forest areas of southern Georgia and Florida.
Adults emerge during the late summer and fall, and can be found flying through most of the warm spells of early Florida winter.
Typically adults hang out on trees and shrubs during the day, preferring to hunt for food as dusk approaches.
Male eye color changes over time from green to blue. Female eye color changes from green to brown over time.
Another primarily tropical darner genus, Gynacantha, also go by the name Two-spined Darners.
The Twilight Darner (Gynacantha nervosa), second picture, one of two native species, inhabits temporary waterways and wooded areas of Florida and South Georgia.
The name Twilight refers to the fact they they are often seen flying at dusk and dawn. However, they are also known to fly and perch in wooded areas during daylight hours.
The picture highlights its minimally marked abdomen. As Twilight darners age, their wings turn dark, again an uncommon darner trait.
Brief presentations of Mosaic Darners and those in the Anax and Rhionaeschna genera can be views by clicking on a link in the box.
© 2007-2011. Patricia A. Michaels