There is a group of generally dull-colored, dusky brown,
somber and drab little butterflies that appears to be quite
abundant now, the wood nymphs and satyrs. Five species are
considered to be either fairly common or common in Wisconsin.
They are the Appalachian brown, eyed brown, common wood-nymph,
little wood satyr and the northern pearly eye.
The eyed brown tends to favor open marshy meadows while the
other species like grassy meadows, the edges of woods and
especially woodland glades where sunlight penetrates to the
ground. The species that has been unusually abundant on our
property during the past few weeks has been the common
wood-nymph, the largest wood-nymph found in our state. It is
when we are walking along our driveway, bordered by woods, to the
mailbox on bright sunny days that one can expect to encounter
several dozen along the way.
Even though the name "common wood-nymph" is most
accepted today, some references use clouded wood-nymph, large
wood-nymph and the blue-eyed grayling to describe this relatively
large butterfly. The male, whose wingspan averages around one
and three-fourths inches, is a glossy shade of dark chocolate
brown. While he is distinctly darker than the female, the eye
spots, or ocelli (o-CELL-eye), on his forewings are smaller and
darker and, as seen from the top, are blue-pupiled.
A female’s wingspan averages about two inches. She is lighter
in color and her eye spots are larger, both as seen from above
and below. The two eye spots on each forewing are considerably
larger than the several eye spots on her hindwings.
One could appropriately call common wood-nymphs homebodies.
They tend to remain very close to their place of hatching for the
remainder of their short lives of five to ten days. The fact
that they occupy such small spaces, such as a few acres,
increases the likelihood that through the years each colony
develops minute differences from other colonies. There are bound
to be many blend zones in which intermediate forms exist. Viewed
on a country-wide basis, you can clearly imagine how difficult
this has made the study and identification of this challenging
group of butterflies.
A further problem surfaces, in light of the many individual
and slightly different colonies existing throughout, for example,
a county. Development can very easily and unknowingly wipe out
entire colonies of these butterflies. This is happening at a
frightening pace throughout the country today and sadly involves
butterflies of many species.
The larvae of all members of this genus, Cercyonis
(sir-see-O-nis), feed only on monocotyledons, plants having
parallel-veined leaves. Included in this large group of plants
are the wild grasses, the host food of the common wood-nymph.
Eggs of these butterflies were laid last summer from early July
into August on the thin stems of dried or living grasses. The
eggs hatched and the larvae immediately fell or crawled to the
ground where they worked their way into the grass clumps.
Strangely these tiny caterpillars would not eat until early
the following spring. In fact, by the time winter had arrived
their weight and size was roughly half that of when they were
hatched. It is upon the arrival of warming weather the following
April, along with the first growth of new wild grass plants, that
the larvae begin eating. Unlike a monarch butterfly caterpillar,
for example, that reaches the full extent of its growth in around
two weeks, the common wood-satyr caterpillar will take upwards
of two and one-half to three months to reach its full size before
forming into its chrysalis.
Male caterpillars will enter their chrysalis stage several
days before the females do. The male will not be ready to mate
until four or five days following its emergence as an adult
whereas the female will be ready to mate the first day of
emergence from her chrysalis. With their total life span as an
adult being so brief, as short as one week, timing for their
mating is extremely important. This species is single-brooded in
our region. Depending upon when eggs were laid last summer,
their flight sea son in Wisconsin can extend from late June into
mid-August.
Approach one of these nondescript butterflies slowly for a
close look. You will notice that only four of its six legs are
extended and used for perching. Its two front legs are very
small and usually are held tightly against the front of the body.
I pay close attention to the annuals planted along our front
sidewalk and to the small butterfly garden north of our house.
Some species of butterflies, such as the white admiral, black
swallowtail, monarch, Milbert’s tortoise-shell and the great
spangled fritillary spend countless hours sipping nectar from the
flowers including zinnias, purple coneflowers and Mexican
sunflowers (Tithonia).
Rarely, however, will you see a common wood-nymph feeding.
When they do feed it will be upon running tree sap, carrion, scat
(animal droppings), rotting fruit and alfalfa nectar.
It’s fun to make a sudden movement and then watch their antics
as they wing to safety. What erratic, bobbing flight they have,
and can they ever be difficult to net.
One technique they have for avoiding being caught by a
predator is to perch on the trunk of a tree trunk or branch, head
downward, and fold their wings in such a way that the
cryptically-colored undersides of their hind wings cover the more
noticeably spotted fore wings. In fact you have to be downright
lucky to find them in this position, so wonderfully do they blend
with their surroundings.
Get to know the wood-nymphs and satyrs. You’re in for
some fascinating observing and challenges.
Common wood nymph butterfly
More information on this topic is available at:
This column appeared in the Door County Advocate
on 08/04/2000.
© Copyright 2000 Roy Lukes. All rights reserved.
