If Hollywood directors and screenwriters are
looking for a creature to base a future horror
movie on they need look no further than the
dragonfly. Fearsome predators, dragonflies date
back to prehistoric times. Archeologists have
found fossilized remains dating back over 300
million years. During this time dragonflies have
changed little except for their size. Thankfully
they have shrunk since their early beginnings.
All species of dragonflies have an incomplete life
cycle or metamorphosis. Upon hatching, the nymphs
grow and feed at a feverish pace. No creature is
safe. Using their keen eyesight, dragons hunt mayflies,
damsels, Chironomid larvae, tadpoles, even small fish.
I can remember a two-inch dragon nymph attacking an
equally sized leech. The dragon latched onto one end
of the leech chomping away the whole time. The leech
wriggled and writhed in an attempt to flee its attacker.
After a furious struggle the leech finally broke free,
its back end tattered and chewed. The dragon nymph dusted
itself off, regained its composure and then carried on
its merciless trek.
Depending upon the species and location, dragonfly
nymphs can take up to 4 years to mature. Owing to
their year-round availability, dragon nymphs are
a stillwater staple. Growing through a series of
instars, dragon nymphs reach large sizes. A typical
dragonfly nymph will molt some 10 to 15 times and
with each molt the nymph increases in size and overall
development. For instance, wing pads only become a
prominent feature in the later instars. Some species
attain lengths of close to 3 inches at maturity. Many
fly-fishers confidently tie dragon patterns onto their
leaders owing to the availability and overall size of
the nymphs. All dragonfly nymphs are capable of
absorbing water into their internal gill chamber
and expelling it out of their rectal orifice. This
natural jet-propulsion system enables the nymph to
scoot along in 3- to 5-inch bursts.
Mature nymphs lumber along the bottom in preparation
for emergence. Depending upon temperature and elevation,
dragonflies emerge from June through August. Crawling
out of the water, the nymph clambers up weeds, fallen
debris and rocks. It is not uncommon to see nymphs crawl
10 to 20 feet from shore and emerge 6 feet up the
backside of a tree. Tough customers, wet or dry.
Warmed by the sun, a split forms along the back
of the nymph and the adult dragonfly crawls out.
This is a long and tedious process often taking
an hour or more. Sensing their vulnerability, most
dragonfly species prefer to hatch under low light
conditions or darkness. Of course there are
exceptions. The newly transformed adult is at
the mercy of birds, frogs, mice, and even other
dragonflies. I stumbled upon a hatch one day after
noticing unusually large concentrations of robins
hopping about the shoreline. Closer examination of
the shoreline and tulles revealed numerous nymphs
crawling from the water struggling to emerge.
With the emergence process complete the adult flies
off to continue the ravenous feeding habits it
developed as a nymph. Adults are strong fliers
and often travel miles from any known bodies of
water. Clipping along at speeds in excess of 30
miles an hour these aerial hunters easily chase
down any meal. The adult seizes its prey in its
basket-like legs and devours its prey on the fly.
Favorite foods include mosquitoes and Chironomids.
Gaggles of adults patrol the shoreline margins
like helicopter gunships, diving and darting in
their relentless hunt for food. It is easy to
distinguish dragonflies from their damselfly
cousins by their large size and the
outstretched manner in which they hold their wings
when at rest. After feeding for a couple of weeks,
the adults pair up and mate. The fertilized females
dip and skim the water's surface depositing their
eggs, unleashing new generations to terrorize the
underwater jungle. Some species even crawl beneath
the surface, depositing their eggs directly onto
the submerged vegetation and debris. From time to
time adult dragonflies end up on the water's surface.
One would think a food source of this magnitude would
draw trout for miles. Instead, if unable to regain
their freedom, the adults struggle until they drown.
I have talked to many experienced anglers and none
recall ever seeing an adult dragonfly taken or found
in any stomach sample. Other species such as bass don't
share the trout's prejudice towards the adults.
For the stillwater fly-fisher there are two families
of dragon flies we need to be aware of, the climbing
nymphs from the family Aeshnidae and the sprawling
nymphs from the family Libellulidae. As adults these
families resemble each other somewhat. But as nymphs
they differ markedly both body structure and habits.
It is important to be aware these differences both
at the vise and in the boat. ~ PR
More on dragonflies for lakes from Phil Rowley's excellent book,
Fly Patterns for Stillwaters next time.
Credits: Excerpt from Fly Patterns
for Stillwaters By Philip Rowley, published
by Frank Amato Publications. We appreciate use