Tramea lacerata
(Black Saddlebags)


Order: Odonata
Suborder: Anisoptera
Order Description:
Dragonflies
Family: Libellulidae
Family Description: Saddlebags

Description:
   Naiad- This is a medium to large naiad, with a length of 15/16 to 1 inch (24 to 25 mm). It is pale green and marked with light brown. The head is large and the eyes are big. The last abdominal segments each have a single, large, flattened and slightly curved spine on either side.
   Adult- This is a large dragonfly with a length of 2 to 2 3/8 inches (50 to 55 mm). It is largely black with hints of metallic royal blue. It has a distinctive wavy black band of black spanning the width of each hindwing near where it attaches to the body, which gives it a humpbacked appearance in flight. The hindwings are triangular and noticeably broad.

Range:
This species is found from southern Washington east across the U.S. to Massachusetts, extending south to California, Texas, and Florida. It also occurs in Mexico and the Hawaiian Islands. In Idaho, it occurs throughout the Snake River Plain from Twin Falls west to the Oregon border, and north along the Snake River to Lewiston.

Habitat:
This dragonfly can be found near ponds and lakes with abundant aquatic vegetation.

Adult Flight Season:
Early July to early October

Diet:
   Naiad- Naiads feed on a wide variety of aquatic insects, such as mosquito larvae, other aquatic fly larvae, mayfly larvae, and freshwater shrimp. They will also eat very small fish and tadpoles.
   Adult- The dragonfly will eat almost any soft-bodied flying insect including mosquitoes, flies, small moths, mayflies, and flying ants or termites.

Ecology:
The naiads live in debris and submerged vegetation on the bottom of ponds and lakes and actively pursue prey. Adults generally fly from early July to early October. This species can be observed migrating south in August and September, often with the Common Green Darner (Anax junius) and the Variegated Meadowhawk (Sympetrum corruptum). The adults that appear in Idaho in the early part of the flight season generally emerged in the southern portion of their range and have migrated north. In Idaho they produce a successive generation that emerges later in the summer to early fall and migrates south, where it again reproduces.. The adults hunt throughout the day primarily while flying. When they do perch, they generally hang vertically on the underside of branches or twigs, rather than sitting on top like most members of this family. This dragonfly appears to be deeply suspicious of humans with nets and so is often underrepresented in collections from areas where it is quite common.

Reproduction:
The female flies with the male still attached after mating (a position called "in tandem") and lays her eggs in lakes and ponds by dipping the tip her abdomen on the surface of the water. However, the male releases the female just before her abdomen touches the water, and then grabs her again with his abdominal appendages as she rises. In this way, he avoids being eaten by fish while still preventing other males from mating with his chosen female.

Conservation:
Populations are widespread, abundant, and secure.
Status: Unprotected nongame species
Global Rank: G5
State Rank: S?

References:
Corbet, P. S. 1999. Dragonflies: Behavior and Ecology of Odonata. Cornell University Press, Ithaca, New York, USA, 829pp.

Logan, E. R. 1967. The Odonata of Idaho. Unpublished M. S. thesis. University of Idaho, Moscow, Idaho, USA, 105 pp.

Needham, J. G. and M. J. Westfall. 1955. Dragonflies of North America. University of California Press, Berkely, California, USA, 615 pp.

Paulson, D. R. 1999. Dragonflies of Washington. Seattle Audubon Society, Seattle, Washington, USA, 32 pp.

Walker, E. M. and P. S. Corbet. 1975. The Odonata of Canada and Alaska, Vol. III. University of Toronto Press, Toronto, Ontario, Canada, 307 pp.


Written by Mark Lung and Stefan Sommer, 2001
Photos by Dennis Paulson, 2001
Design by Ean Harker, 2001.