8 / OutdoorIllinois August 2006
The Pennsylvania leatherwing is a
soldier beetle (similar in shape to a
“lightning bug”) that is abundant on gold-enrod.
Gold and brown markings allow it
to blend into the flower, providing pro-tection
from birds. The carnivorous
leatherwing larvae eat grasshopper
eggs and soft-bodied insects such as
small caterpillars. Adults are omnivo-rous,
depending on pollen and nectar as
well as small insects.
Known as a crab spider for its habit
of holding its legs outstretched to the
sides like a crab, the goldenrod spider
scuttles sideways through flower tufts.
Goldenrod spiders do not spin webs or
snares; they wander from flower to
flower in search of prey they capture by
ambush, relying on yellow coloring for
camouflage. Venom injected through the
fangs immobilizes prey that venture too
close. A butterfly hanging motionless
from a flower often has fallen prey to a
crab spider.
Some insects provoke goldenrod
plants into building them a safe, well-stocked
pantry. Living inside the plant,
they stimulate it to create unusual
growths, called galls. These may be
shaped like a round ball or elliptical
mass in the stem, a rosette of leaves at
the top of the plant, or a raised black dot
on a leaf.
The ball gall is a globular stem
swelling about an inch in diameter made
by a fly with brown-marked wings. This
gall fly deposits an egg in the stem tis-
It has been said that no other flower
attracts as many kinds of insects as
goldenrod. Hover flies and bees are
among goldenrod’s principal pollinators.
Hover flies resemble bees, but can
neither sting nor bite and possess only
one pair of wings while bees have two
pair. Often seen hovering stationary
over flowers, hover flies eat nectar,
inadvertently getting pollen on their legs
and bodies, carrying it from flower to
flower.
For bumblebees, pollen is an excel-lent
source of protein. Using brushes on
their feet to gather it and combs on their
legs to collect it, bumblebees can often
be observed carrying bright orange balls
of goldenrod pollen in pollen baskets on
the backs of their hind legs.
Just as goldenrod flowers are adapt-ed
in shape and color to attract insects,
some insect species are specially adapt-ed
in shape and color to live in golden-rod
flowers.
The jagged ambush bug is cryptically
camouflaged on goldenrod flowers. Hid-den
by its mottled gold, green and
brown coloring, the ambush bug lies in
wait for a careless insect to wander
within reach of its powerful forelegs—
adapted for seizing and holding prey.
Immobilizing bumblebees, wasps and
honeybees by injecting them with saliva
through a piercing and sucking beak,
the ambush bug is able to capture
insects much larger than itself.
August 2006 OutdoorIllinois / 9
appear as a rosette at the tip instead of
growing evenly along the normal length
of the stem.
Although it welcomes insects, the
goldenrod plant produces chemicals that
repress the growth of competing plants.
Each goldenrod plant sends out rhi-zomes
in a spoke-like pattern, forming a
circular cluster of genetically identical
goldenrod.
A field of goldenrod is a fascinating
place to take a late summer walk. Take
along a hand lens to see how many dif-ferent
members of the goldenrod com-munity
you can find—and enjoy some
autumn gold.
sue below the growing tip of the plant.
Glandular secretions produced by the
adult insect stimulate abnormal plant
growth and the formation of the gall. The
developing insect secretes additional
fluids while it feeds, so the gall contin-ues
to grow until the larva stops feeding.
The larva chews an exit tunnel to the
surface, without breaking through,
pupates just below the surface and
emerges as an adult in the spring.
Downy woodpeckers often feed on
these galls during the winter months.
The elliptical gall is spindle-shaped
rather than globular and is stimulated by
a gall moth. The interior of the gall is kept
smooth and hollow as the larva devours
the plant tissue. It has been suggested
that the exit hole for this gall often faces
north, lack of intense sunlight keeping it
soft and moist to facilitate escape.
The goldenrod bunch gall is pro-duced
when a gall midge deposits an
egg at the growing tip of a
main shoot. The cell of this
midge larva is in the center
of a cluster of shortened,
deformed leaves that
Carol McFeeters Thompson is the site
interpreter at Weldon Springs State
Recreation Area.
Boldly colored monarchs are easily
seen fluttering between goldenrod
plants, but finding the cryptic crab
spider takes patience and closer
examination.
Yellow and brown markings camou-flage
the Pennsylvania leatherwing
from predatory birds while it feeds on
goldenrod pollen and nectar.
The shape and location of
goldenrod galls helps
identify the insect that created it. Ball
and elliptical galls are located on the
stem while the bunch gall creates a
rosette on the tip of the main shoot.
Sitting head-down at the hub of its
goldenrod-based web, the common,
and distinctive, black-and-yellow
garden spider waits for its next meal.
(Photo by Bev Wigney)
(Photo by Carol Thompson McFeeters.)
(Photo by Carol Thompson McFeeters.)
(Photo by Carol Thompson McFeeters.)
Gall
Fly
Black Monarrch Butttterrfflly Black-and-Yellllow Arrgiiope
Crrab Spiiderr
Pennsyllvaniia Leattherrwiing
Bunch Gallll
Elllliipttiicall Gallll
Ballll Gallll
(Photo courtesy Patrick Coin, nature@cotinis.com.)
