Libellula (Ladona) julia
(Chalk-Fronted Corporal)


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

Description:
   Naiad- This is a medium-sized naiad with a length of 15/16 to 1 inch (24 to 25 mm). It is dark brown in color. The abdomen is rounded, giving it a short, stocky appearance known as the sprawler form. There are hooks on the tops of abdominal segments four through eight (the hook on segment six is noticeably longer), and a single, slender, rear-facing spine on each side of abdominal segments eight and nine.
   Adult- This is a medium-sized dragonfly with a length of 1 5/8 to 1 13/16 inches (41 to 45 mm). The wings are clear except for a patch of brown at their bases (where they attach to the body). Immature males and females are uniformly dark brown on the thorax and abdomen. Both mature males and females have a powdery-appearing coating (a condition called pruinosity) on the thorax and the first part of the abdomen; in males it is bluish white while in females it is grayish. The rest of the abdomen is blackish brown, possibly fading to orangish brown along each side.

Range:
This dragonfly has a fairly narrow but lengthy range centered on the U.S.-Canadian border, extending from British Columbia and Washington east to Nova Scotia and Maine. It occurs in the northern half of Idaho at low elevations.

Habitat:
This dragonfly can be found near nutrient-poor lakes, ponds, and marshes. Unlike most Libellula, this species seems to prefer acidic waters like peat bogs.

Adult Flight Season:
Mid-June to September

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:
The naiads live on the bottom in decaying vegetation. They do not actively pursue prey but wait for it to pass by, a strategy which affords them protection from other predators. Naiads emerge as adults at night. Although records are sparse, the adults are believed to fly from mid-June to September. Hunting occurs from perches on vegetation.

Reproduction:
After males and females mate, the female flies singly, without the male attached, to lay her eggs. She does this by dipping the tip of her abdomen in the shallows of lakes, bogs, and ponds while hovering just above its surface.

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.