Phil Peters
Adam's County Master Gardener Program
They’re out
there! And as fall comes on we are going
to see more of them right in our own
back yards. All summer they have been
quietly going about their business
policing our gardens, Occasionally,
their paths have crossed ours, sometimes
with disastrous results for them.
Spiders! Despite
their size and proximity to man these
little creatures that do so much good at
keeping our insect pest population down
are among the most universally feared
inhabitants of the garden. The fact that
they often drop out of nowhere and run
with astonishing speed startles us. Even
though most of them have jaws so small
that they can not pierce human skin, the
fear of their bite makes them seem more
of a threat than the honeybee. Indeed,
bee sting reactions cause many more
deaths per year than spider bites.
The 37,000
species known worldwide are perhaps one
fourth of all species out there. They
are native to every continent but
Antarctica, and from desert valleys to
mountain peaks. Scientific counts show
over 11,000 spiders per acre in the U.S.
Imagine how many insects they take out
of a field each day!
Spiders are not
insects. Whereas insects are
distinguished by six legs and two
antennae, spiders are arachnids who have
no antennae, nor wings, and have four
pairs (8) legs on two body segments.
Most spiders have eight eyes that are
arranged differently on the head
depending on the species. Their bodies
are covered with fine hairs and often
have beautiful geometric patterns,
sometimes with iridescent markings. With
autumn coming on some of the most
interesting species will be very evident
in our gardens.
The most
spectacular is the large, black &
yellow argiope (Argiope aurantea) whose
conspicuously colored body hangs
head-downward in the center of a huge
orb web. She’s the spider we refer to
when we think of garden spider. A
slightly smaller cousin, the banded
argiope (A. trifasciata), has an abdomen
covered by silvery bands. You might
notice the heavy zigzag pattern in the
center of the web before you see the
spider. The spider you see is the
female. In late summer look near the
margins of the web. You may be fortunate
enough to see the male, or even several.
Only a fraction of the size of the
female, they will try to get her
attention by twanging on the support
thread of the web. It pays to knock in
this world!
Other orb webs
may reveal the large barn spider,
Araneus cavaticus. This spider with its
mottled brown abdomen likes to build its
web near buildings. Look around your
porch or deck railings.
Maybe the web is
an orb with a line of debris down the
center. Look closely and you will see a
small dark brown spider with a
cone-shaped abdomen in the midst of the
debris. Cyclosa conica likes to
camouflage herself and her egg sac in
this way.
Walking beneath
trees in our garden or on woodland paths
we may have met another small orb-weaver
when we ran face first into an unseen
web. The spider who built it has a
unique abdomen covered with small
spines. You can pick her up easily; she
won’t bite. The whit and black ones
are Micrathena mitrata. You may be luck
to find a black and yellow one,
Micrathena sagittata. Both are common in
the fall.
Some spiders
build their orbs horizontally and hang
under it. Leucage spp. is one such,
often called an orchard spider. She
prefers trees and low bushes and shrubs.
A small spider (.3") she can be
recognized by her colorful oblong
abdomen marked with white & yellow
stripes on a black background. At the
tip of the abdomen are some
pinkish-orange spots.
Looking closely
at your flowers or the garden fence you
may see one of the many species of
jumping spider (Salticidae). As the name
says they run along the fence and pounce
on their prey. They attach a drag line
as they move about so that if they fall
they can pull themselves back up. Able
to see a distance of 8" or more,
they have the best vision of all
spiders. Many have very colorful
iridescent coats.
Lurking inside
the petals of your roses or zinnias may
be a small crab-shaped spider lying in
wait for a victim to land. These spiders
are distinguished by their very long
forelegs that they use to grab their
prey. Thy look like small crabs which
are close relatives of the spiders. The
crab spider can change color to blend in
with its background flower. But, unable
to distinguish friend from foe, the
spider will eat a bee if it buzzes too
close.
In the grass or
along the garden wall you will see many
funnel webs made by a common grass
spider, Agelenopsis sp. Vibrations on
the web will bring her out. Despite her
fast movements and hairy appearance she
won’t bite you. Look around the edge
of the web and try to find her
prospective mate. He’s a very small
version of the female.
The wolf spider
is the one you have seen racing along
the ground in your garden. Often she may
be carrying an egg sac on her back,
sometimes even young spiders. There are
two large varieties In Pennsylvania.
Lycosa carolinensis is one of the
largest spiders in the state at an inch
to an inch & a half long. She and
her cousin, Lycosa aspera, who has a
yellow line of hairs on her head and
light-brown bands on her legs, may be
trying to com in the house this fall.
If you would
like to know more about spiders, the
best and most affordable is Spiders
& Their Kin by Herbert W. and Lorna
R. Levi in the Golden Guide series.
Read other articles on birds, wildlife & beneficial insects
Read other articles by Phillip Peters