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 Tarantulas
(Aphonopelma)
Over 800 species of tarantulas live
throughout the world. Those found in
North America thrive in the southern and
southwestern states, including the dry and
warmer parts of southern California.
These are smaller than other varieties, and
generally have a body length of less than
2", with a leg span of 3 - 4". Many
tarantulas can live between 24 and 40 years.
The majority of tarantulas are black or
brown, but some species exhibit striking
colors. The Mexican Red-legged Tarantula (Brachypelma
smithi) has bright-red leg markings,
while the Cobalt Blue Tarantula (Haplopelma lividum)
has legs that are deep blue. The
Rose-Haired Tarantula (Grammostola
rosea)
and Chilean Copper Tarantula (Paraphysa
scrofa) are also beautiful,
mild-tempered arachnids.
The tarantula family includes the largest
spiders known. The Goliath Tarantula (Theraposa
leblondi) which inhabits South America,
reaches a body length of 5", with a leg
span of up to 12". Even the small
tarantulas reach a relatively large body
length of 1½". Certain South American tarantulas,
which have a body length of up to almost 3", build large webs and eat small birds.
The Desert Tarantula (Aphonopelma chalcodes)
grows 2 - 3" long, and is colored gray to
dark brown. It is common to the
Sonoran, Chihuahuan, and Mohave deserts of
Arizona, New Mexico, and southern
California. The most common North American tarantula is
Eurypelma californicum, found in California,
Texas, and Arizona.
A conspicuous bald spot seen on the abdomen
of many tarantulas results from the spider's
defensive behavior against its vertebrate
enemies. When confronted, the spider will
rub its hind legs over its body, brushing
off annoying "urticating" hairs into an enemy's eyes.
These hairs are replaced during each
successive molt.
The tarantula's cephalothorax and abdomen,
the front and rear parts of the body, are
round. Its eight eyes are closely grouped,
with a pair in the middle and three on each side
of the face. it has large fangs, and two pairs
of slits on the underside of the abdomen
that lead to the respiratory organs, called
"book lungs." Book lungs have many folds lying
close together, like the pages of a book,
through which blood passes to acquire oxygen
from the outside air.
Most tarantulas pursue and catch their prey
(crickets, moths, and other insects) rather
than building webs.
Many also produce a hissing sound by rubbing
their jaws, front legs, or palps (arm-like appendages between the
mouth and legs) against
each other.
Despite all the B-rated horror flicks you
may have seen, tarantulas are completely
harmless to humans, and can easily be
trained as pets. They will only bite
if provoked, and their bite is not
considered poisonous. The venom
injected into a human causes only slight
swelling, with some possible numbness and
itching which disappears in a short time. Skin exposure to the urticating hairs will cause itching and a
rash.
First Aid: Clean the bite site with soap and
water, and protect against infection. Skin
exposures to the urticating hairs are
managed by removing the hairs with tape.
Habitat
The tarantula prefers to live in dry,
well-drained soil. If the soil is suitable,
the female digs a deep burrow which she
lines with silk webbing. This helps prevent
sand and dirt from trickling in. Otherwise,
she hides inside cracked logs, and under any
loose-lying debris.
Tarantulas are sluggish during the day, and spend most of their
time hidden in burrows or other retreats.
In the spring through fall, they
become active in the late afternoon. Some dig their own
burrows, while others use ready-made crevices or
abandoned rodent holes. Others make their
homes under rocks or logs, or under the bark
of trees. They are not gregarious, meaning
there is only one spider per burrow.
While North American tarantulas are
exclusively ground-dwellers, living in
burrows, others build silken retreats on
trees, cliff faces, the walls of buildings,
or in crop plants such as bananas and
pineapples.
Food &
Hunting
The tarantula is a nocturnal hunter. With
very few exceptions (noted above), it does
not spin a web to capture its prey, but
catches its food by speed. It will take
virtually anything of the right size that
moves within its range, but feeds primarily on
small insects like crickets, grasshoppers, beetles,
sow bugs, other small spiders, and sometimes
small lizards.
The tarantula strikes with its fangs,
injecting a tiny amount of venom and grasping the prey with
its palps. Then the tarantula grinds
its victim into a ball, secretes digestive
juices onto it, and sucks up the liquefied
prey. It may also wrap the ball in silk for
a later meal.
Breeding
Tarantulas do not reach sexual maturity for
several years. During this time, they undergo
a series of molts, and until they reach
maturity it's impossible to tell a male from
a female. The mature male is quite dark,
nearly black, while the mature female is
brown. The degree of coloring varies with
the species and geographical location. Upon
maturity, the males abandon their burrows and
go forth to seek a mate.
In the
fall, males locate a receptive female by
the scent she leaves on the silk of her
burrow. After performing a courtship
dance, the two spiders mate. Males usually die a few months
after mating, but females may live and
produce eggs for 25 years or more. Males may
die a natural death or be eaten by the
female, sometimes even before mating can
occur.
Once mated, female tarantulas store sperm in
special organs known as seminal receptacles.
Immediately before fertilization and egg
laying begins, she partially constructs a
cocoon within her burrow.
With the silken foundation laid, the female
then releases a mixture of eggs and sperm
through her genital opening into the cocoon. Once the eggs are deposited, she finishes
sealing up the cocoon with silk, then stands
guard until the 500 to 1,000 young hatch.
Young tarantulas emerge from their cocoon 6
to 9 weeks after fertilization, then venture
off on their own in another 2 to 3 weeks.
Conservation
Tarantulas have many natural enemies,
including lizards, snakes, spider-eating
birds, and the Tarantula Hawk. The large
metallic blue, green, and red wasp is the
Tarantula’s fiercest and most dreaded enemy.
Once it has found and paralyzed the spider
with its poisonous sting, the wasp drags its
victim to a prepared burrow, deposits its
eggs in the spider's abdomen, and seals its
victim in. Upon hatching, the wasp larvae
feed on the tarantula's body.
Although the tarantula is frightening in
appearance, the chances of being bitten by
it are rare and, because it has a rightful
place in the outdoors, it should not be
wantonly killed or persecuted. If its
presence is not desired, it can be easily
placed in a container and transported to
another area where it can continue, unmolested,
to live its useful life. |
