Pachydiplax
longipennis
(Blue Dasher)
Description:
Naiad-
This is a relatively small naiad with a length of 3/4 to 7/8 inch (18 to 21
mm). It is brownish above and bright green underneath. There is a single, rear-facing
spine on each side of abdominal segments eight and nine, with those on segment
nine being noticeably longer. There are no hooks on the back, as some naiads
have.
Adult- This
dragonfly is small to medium in size, with a length
of 1 3/8 to 1 13/16 inches (35 to 45 mm), and has a fairly broad abdomen.
Females and immature males are greenish on the face and thorax, with a brownish
black abdomen marked along the top with two parallel lines of pale yellow to
yellowish green dashes. Mature males are greenish on the face and thorax but
the abdomen is pruinose blue. The wings are mostly clear but may be clouded
with brownish yellow at the bases, especially on the hindwings.
Range:
This species is found from
southern British Columbia east to Ontario, extending south through the U.S.
from southern California east to Florida. It also occurs in the Bahamas. In
Idaho, it can be found throughout the state at lower elevations, usually below
3000 feet (914 meters).
Habitat:
This dragonfly can be
found near lakes, ponds and slow streams at low elevations.
Adult Flight Season:
Late June to
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
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 in submerged
vegetation. They do not actively pursue prey but wait for it to pass by, a strategy
which affords them protection from other predators. The naiads of this species
can tolerate water with low oxygen content. This is used by biologists in Florida
who interpret their presence as a possible indicator of low water quality. Naiads
emerge as adults at night. Adults generally fly from late June to October. Hunting
occurs from perches on twigs and rocks. This is the only member of this genus.
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 the water while hovering 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.