endangered species 111The Karner Blue—
New York’s Endangered Butterfly
by Robert Dirig
The Karner blue (Lycaeides melissa samuelis) is a small,
beautifully colored blue butterfly that died out in southern
Canada in the early 1990s and was listed as an endangered
species by the U.S. government in 1992.
The wings of male Karner blues are deep purplish-blue
with a narrow black rim above, but females have wider dark
gray borders around blue central areas on all four wings,
and a row of bright orange spots on the upper hindwing
edges. In both sexes, the wings have elegant white fringes,
and are pale gray beneath with arcs of black, white-rimmed
dots and orange and satiny blue spots along the hindwing
margin. The wings expand about an inch, so the butterfly is
quite small.
The Karner blue was first discovered in Canada near
London, Ontario, by lepidopterist William Saunders in 1861,
and in the United States at Center (now Karner), New York,
by Joseph Albert Lintner in 1869. It was originally con-
fused with Scudder’s blue (Lycaeides idas scudderi), a
very similar and closely related but more northern butter-
fly. Vladimir Nabokov, the world-famous author best
known for his controversial novel Lolita,also studied but-
terflies and described the Karner blue as new to science
in 1943.
The Karner blue is restricted to a special kind of dry,
sandy habitat where wild blue lupine (Lupinus perennis), its
one caterpillar food plant, grows. Such areas of extensive
sand, commonly called “sand plains,” are of postglacial ori-
gin and occur along major rivers or around large lakes in
northeastern and north-central North America.
The type locality, or the place from which the Karner
blue was first scientifically described, is the Karner Pine
Bush, a large inland pine barrens between Albany and Sch-
enectady, New York. This habitat is unusual in being formed
on undulating sand dunes that are stabilized by a low plant
cover and widely scattered pitch pines (Pinus rigida).
Resplendent clumps of wild blue lupine bloom in open areas
between shrubby oaks (Quercus ilicifoliaand Q. prinoides),
blueberries (Vaccinium angustifolium and V. pallidum),
prairie grasses (Schizachyrium scoparium), and other low
herbaceous plants that carpet the dunes. Such landscapes
are a type of savannah, maintained by a natural fire cycle
that keeps them open. Their parklike vegetation is often
very beautiful and quite different from the dense forests that
surround the sand plains.
The Karner blue occurs very locally throughout its
range, with small clusters of populations living many miles
apart. The butterfly was historically known from sites in
Maine, New Hampshire, Massachusetts, New York, New
Jersey, Pennsylvania, Ohio, Indiana, Illinois, Wisconsin,
Iowa, Minnesota, Michigan, and Ontario. Many locality
records are very old, and the butterfly has since been extir-
pated in areas such as Brooklyn, in New York City, and the
suburbs of Chicago. More recently, Karner blues have died
out in New England and from New York City to Illinois along
the southern edge of their range, except for northern Indi-
ana. The butterfly is presently known to persist naturally
only in Indiana, Michigan, Minnesota, Wisconsin, and the
upper Hudson River Valley in New York, with reintroductions
attempted in Ohio and planned for several other areas
where it formerly lived.
The Karner blue’s annual life cycle proceeds like
clockwork: the first hatch of Karner blue adults flies in late
May and early June, when the lupines bloom. After mating,
females lay tiny greenish-white, turban-shaped eggs on
lupine plants at the same season. Within a week, minuscule
caterpillars hatch from the eggs and begin to feed on lupine
leaflets, leaving translucent holes as their unique feeding
sign. They are often attended by ants, which feed on a
sweet fluid the caterpillars produce in glands on their
abdomens, incidentally reducing predation and parasitism.
When fully grown three weeks later, the caterpillars are half
an inch long, with black heads, velvety green bodies, a dark
stripe along their backs, and light stripes along their sides.
They crawl off the plant to find a sheltered place in the litter
for their chrysalis, which is smooth, bright green, and held
to the substrate by a white silken thread around the middle
and by microscopic hooks embedded in a silk pad at the tail
end. Over the next week the developing butterfly’s wings
slowly change from green to white to orange and finally to
purplish-blue inside the transparent chrysalis skin. The sec-
ond brood of adults hatches from mid-July to early August,
and after mating, females again lay eggs on or near the
lupine plants, which by now have largely withered. These
summer eggs do not hatch until the following April, when
new lupine leaves are pushing through the sand. The tiny
spring caterpillars grow, pupate, and produce a new brood
of butterflies in late May, finishing the cycle of two full
broods per year. These dates are for New York State. The
timing of this annual calendar may shift a week or two later
at the northern and western edges of the butterfly’s range,
but the sequence remains the same.
Because this butterfly naturally occurred along or near
waterways where major human settlements have grown,
the Karner blue has been frequently subjected to urbaniza-(continues)