Libellula
quadrimaculata
(Four-Spotted Skimmer)
Description:
Naiad-
This is a medium to large naiad, with
a length of 7/8 to 1 1/16 inches (22 to 26 mm). It is orange-brown in color,
and the abdomen is rounded, giving it a short, stocky appearance known as the
sprawler form. There is a small hook on the top of abdominal segments three
through eight, while the hooks on segments five through seven are noticeably
larger. There is a small, rear-facing spine on each side of abdominal segment
eight and nine.
Adult- This
is a medium-sized dragonfly with a length of 1 5/8 to 1 13/16 inches (40 to
45 mm). Each wing is clear except
for along the leading edge, which is clouded with a transparent yellowish brown.
The center of each wing is marked with a small dark spot, also on the leading
edge. Additionally, each hindwing is marked with a dark patch near the base.
Males and females
look alike, generally dark brown. The face and each side of the thorax are marked
with patches of greenish yellow, and the sides of the abdomen lined with yellowish
orange dashes.
Range:
This species is found around
the world from Alaska east to Labrador and south to northern California and
Texas, and from northern Europe east to Siberia. In Idaho, it is found near
lakes, ponds, and marshes throughout the state.
Habitat:
This dragonfly can be
found near lakes, ponds, bogs, and marshes.
Adult Flight Season:
Early April to
mid-August
Diet:
Naiad-
Naiads feed on a variety of aquatic insects as well as on small fish and tadpoles.
Adult-
The dragonfly feeds on small flying insects.
Ecology:
The naiad does particularly
well in acidic bogs, and lives in the debris on the bottom of lakes, ponds,
bogs, and marshes. 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. Adults generally fly from early April to mid-August. Hunting
occurs from perches on twigs or rocks. This is the only Libellula species in
our area in which the males do not become pruinose. Although it does not regularly
migrate in North America, this species has been known to migrate in Europe,
generally in 10 to 15-year cycles. The direction of the migration varies, and
the migrations are thought to be triggered by a trematode parasite (it is known
that several types of parasites can cause unusual behaviors in their hosts that
promote the dispersal of the parasite). This species has also been known to
form large swarms in Europe, often covering 100 square miles (roughly 300 square
km).
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 water 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.