Stylurus
(Gomphus) olivaceous
(Olive Clubtail)
Description:
Naiad-
This is a large, slender naiad
with a maximum length of 1 ½ inches (36 mm). There is a short, rear-facing
spine on each side of abdominal segments eight and nine.
Adult-
This is a medium to large dragonfly
with a length of 2 � to 2 � inches (56 to 60 mm). The eyes
are a remarkable turquoise blue. The face and thorax are olive green, and there
may be some black markings on the top of the thorax behind the head. The abdomen
is brownish black and is marked along the top with yellowish, funnel-shaped
marks. The underside of the tip of the abdomen is also marked with yellow, and
the rearmost segments appear swollen as in other members of this family. The
female may be more yellowish green
than olive green, and may have more yellow on the sides
of the abdomen.
Range:
This species is found from
southern British Columbia south to central California and east to Nebraska.
In Idaho, it occurs along the Snake River from Massacre Rocks near American
Falls downstream, and along the Bear River.
Habitat:
This dragonfly can be
found at large, nutrient-rich rivers.
Adult Flight Season:
Early August
to mid-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:
Naiads can be very selective
in their habitat choices 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 other species, the Clubtail
naiads emerge as adults during the day. Adults generally fly from early August
to mid-October. They perch on trees and bushes, often far from the water.
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 it. This is
usually done in large rivers.
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.