An Aquatic Alien
by Chris Grondahl
North Dakota Outdoors
I'm sure you have heard the phrases "you should have been there,"
or "guess you had to be there."
A lot can be said about those statements, which often refer to unique phenomena
occurring in nature.
I was lucky enough to "be there" for one such event last summer.
It occurred during a weekend camping and fishing trip to Lake Oahe. We launched
the boat at Langeliers Bay and proceeded to a favorite camping spot. We
set up camp and put out some fishing rods. As I walked along the shoreline,
a peculiar object rolling in the water along the small rocks and sand caught
my attention. I had seen these objects before in other wetlands, but only
the light tan, paperthin shells. This one was not empty.
Fortunately, I had my camera. After taking some photographs of this small
brown object atop a driftwood piece, I went back to fishing.
Some time later, it must have been my conscience that made me look to the
end of my cottonwood sofa to see if I had released the alienlooking creature
back to the water. What I found was that not only had I not released it,
but now there were two. I had to get up to inspect this situation, believing
that possibly I had absorbed too much sun and was seeing double.
What I witnessed upon close inspection revealed a mystery that is recreated
every summer season. A dragonfly had emerged from the brown alien lifeform.
This lifeform was actually the aquatic nymph stage of a dragonfly, or naiad.
Naiads are commonly found on submerged vegetation and in shallow water of
various wetlands. These naiads have overwintered and grown through at least
one previous season. They originated from eggs laid in the water by the
adult during the summer. Some actually live two or three years before metamorphosis.
Just before the naiad is ready to transform into a dragonfly, it will naturally
crawl out of the water onto a piece of vegetation or other solid object.
Whether this naiad had needed help or not, I had placed it in a position
to transform into a dragonfly at the exact time it was ready.
The transformation took place quickly. In minutes the adult grew before
my eyes from a mass barely able to fit within its case to a dragonfly three
to four times as large.
Dragonflies belong to the order Odonata, which is probably the most wellknown
insect having an aquatic stage as part of its life cycle. Damselflies also
belong to the order Odonata but are generally smaller and hold their wings
against their body to rest; dragonflies keep their wings extended.
Often, adult dragonflies and damselflies can be seen mating and later depositing
eggs on the surface of the water with the tip of their abdomen. There are
several types of dragonflies and damselflies displaying many brilliant colors,
including blue, green, red, yellow and brown.
Odonata in the United States vary in length from a little under an inch
to about 3.5 inches. The largest known dragonfly, a prehistoric insect that lived
about 250 million years ago, had a wingspread of more than two feet.
The average damselfly adult lives approximately three or four weeks and
some dragonflies live six or eight weeks. Odonata are beneficial to man
because they prey on a variety of small insects including midges and mosquitoes.
They do not bite or sting.
The aquatic nymph stage of a dragonfly is pictured minutes before it began
a metamorphosis into an adult. A close look at shorelines of wetlands may
reveal many light tan exoskeletons after the metamorphosis season in midsummer.
The adult dragonfly dried off minutes after emerging from the case that
had held it over the previous fall and winter. After a few hours, the dragonfly
will fly away and begin its six to eight week life eating small insects
and laying eggs.
An adult dragonfly dries its wings after existing from the shell of
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Chris Grondahl is a biologist with the Department's natural resources division
Last modified Feb. 24, 1996