Friday, July 16, 2004
Pond Skimmers — Painted, Slaty, Spangled and 12-Spotted
The family of skimmers, called Libellulidae, includes the most common and showy dragonflies. Many have conspicuous wing patterns and bright colors. There are over 1,000 species of skimmers worldwide, with 41 species occurring in Massachusetts. Skimmers range in size from less than an inch to two-and-a-half inches in length. They have large eyes that meet in a seam along the top of the head. The Meadowhawk and Blue Dasher that have been described in this column are members of this family. (See the Mosquito archives at www.carlislemosquito.org, July 19, 2002 and September 12, 2003.)
The dragonflies featured here are all members of the genus Libellula, known variously as King, Pond or Common Skimmers.
The Slaty Skimmer, Libellula incesta, is one of the most common dragonflies out now. It has a dark blue abdomen and thorax (the front part of the body between the head and abdomen) and has black eyes and face and clear wings. Several male Slaty Skimmers can be seen flying around the female, which has a brown abdomen with a black dorsal stripe.
The Spangled Skimmer, Libellula cyanea, is a beautiful dragonfly with spectacular white "spangles." Dragonfly wings have a small pigmented (usually black) area on the front edge of its wings known as stigmas and in this species the stigmas are white and black, the only North American species with white stigmas. Note the black stigma on the Slaty Skimmer. The male is blue while the female is easily spotted by her spangles and striking yellow and black abdomen. She can be seen laying her eggs while flying, dipping the tip of her abdomen into the water.
When and where seen: These dragonflies were observed at the Carlisle Cranberry Bog on June 30. The ponds at the State Park and our own Carlisle backyards are also good places for seeing these and other dragonflies.
Behavior: The Spangled Skimmer forages in fields and clearings close to water while the Painted Skimmer can be seen hunting in meadows far from water. There were several Painted Skimmers flying around the fields at Malcolm Meadows in June and early July.
Observation: The best tool for watching dragonflies is to have binoculars that focus within a range of four to eight feet. But a walk around the Bog on a sunny day provides plenty of chances for observation with the naked eye. Dragonflies seem to be "solar-powered" and tend to hide on cloudy days.
Some other dragonflies: One of the most abundant pond skimmers in our area is the Common Whitetail (Libellula lydia), which as its name implies has a showy white abdomen and also a broad black band on each of its wings. The Whitetail often lands on the ground and is easy to observe. Another very noticeable dragonfly is the Twelve-spotted Skimmer (Libellula pulchella), which has three black patches on all four wings. The older males have white patches between the black, making a spectacular pattern in flight. This skimmer tends to land on stalks, often flying up and returning to the same spot.
Field Guides and Video: Recently published field guides have made dragonfly watching a popular activity for naturalists. One of the newest and best is A Field Guide to the Dragonflies and Damselflies of Massachusetts by Blair Nikula, Jennifer Loose and Matthew Burne. I got hooked on dragonflies from watching the video tape guide, Common Dragonflies of the Northeast by Richard Walton and Richard Foster, 1997. I also use the pocket guide Beginner's Guide to Dragonflies by Blair Nikula, Jackie Sones and Donald and Lillian Stokes.
© 2004 The Carlisle Mosquito