Gomphus externus
(Plains Clubtail)


Order: Odonata
Suborder: Anisoptera
Order Description:
Dragonflies
Family: Gomphidae
Family Description: Clubtail

Description:
   Naiad- This is a large naiad with a maximum length of 1 5/16 inches (33 mm). The abdomen is thick for most of its length, then tapers to a rounded point at the end of segment ten. There is a single, rear-facing spine on each side of abdominal segments six through nine. There are no dorsal hooks.
   Adult- This is a medium to large dragonfly with a length of 2 1/16 to 2 3/8 inches (52 to 59 mm). The base color is brownish black. The face is marked with yellow. The top of the thorax behind the head is marked with a parallel pair of yellow stripes, and each side of the thorax is marked with several diagonal yellow stripes. The base of the wings may be clouded with yellow where they attach to the body. The abdomen is black and marked with a line of yellow dashes along the top. As with other Clubtails, the segments at the tip of the abdomen are wider than the rest.

Range:
This species is found from Manitoba south through Wisconsin and Minnesota to New Mexico and Texas, and in northeastern Utah and the southeast corner of Idaho. The population in Utah and Idaho is isolated from the main range of this species by several hundred miles.

Habitat:
This dragonfly can be found near large, slow, muddy streams and rivers.

Adult Flight Season:
Mid-July to mid-August

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 small fish and tadpoles.
   Adult- The dragonfly will eat almost any soft-bodied flying insect including mosquitoes, flies, butterflies, moths, mayflies, and flying ants or termites.

Ecology:
Clubtail naiads can be very selective in their habitat choice and will often occur only in certain stretches of a particular river or stream. They burrow into the sand or mud, leaving the upturned tip of their abdomen exposed. This allows them to breathe while buried by pumping water in and out of the tip of the abdomen. Unlike most species the Clubtail naiads emerge as adults during the day. Adults generally fly from mid-July to mid-August. They can not tolerate cooler temperatures and are rarely seen flying on cool or cloudy days. Hunting occurs from perches on rocks or bare sand. They perch with their abdomen elevated and their wings drooping so the tips just touch the ground.

Reproduction:
After males and females mate, the female flies singly, without the male attached, to lay her eggs by dipping the tip of her abdomen in rivers, lakes, or slow streams while hovering above it. Lab experiments have found that females are capable of laying over 5000 eggs.

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 , 2001
Design by Ean Harker, 2001.