Needless to say insects and arachnids are everywhere
in the rainforest. Most are harmless to humans, and only pose a possible
threat in some cases when disturbed. The insects are among the most
diverse and abundant groups in the rainforest. One particularly notable
species that many who may have visited the tropics are aware of, are chiggers.
Chiggers are mites. It is in the larval stage that the chiggers use
humans as a host, burrowing into the skin at "pressure points"
i.e. elastic waistbands. The best way to deal with chiggers is to avoid
sitting in grass or on logs, and use insect repellent where clothing
meets skin. If one has become a host to some chiggers, do not worry.
There may be some discomfort from itching, but other than that the
chiggers are relatively harmless.
Mosquitoes, while present in the rainforest, are
not much of a concern. True, some of them do carry serious diseases such
as yellow fever, malaria and other tropical diseases; and it is wise for
the expectant traveler to inquire about inoculations or other
preventative measures before embarking on a trip to the Amazon. Seasonal
mosquito swarms are not common in tropical rainforests as they are in
temperate areas. Immediately following sudden heavy down pours there may
be increased mosquito activity, and these insects do tend to be more
abundant in the rainy season than in the dry season. In temperate or
artic zones where the mosquitoes life cycle is compressed into a few
short weeks or months, the presence of mosquito swarms can be
undeniable. In the tropics, some insect repellent, long sleeves and
pants, and mosquito netting for sleeping are usually adequate.
Botflies are quite common in the Peruvian
Amazon. Botfly eggs are transported to a host by a bloodsucking fly. The
maggots hatch on the skin of the host and burrow inside; the host then
acts as shelter and a food source as the larval botfly (Dermatobia
hominis) matures. As the botfly grows, it turns under the skin of
the host causing a tingling sensation from the tiny spines that cover
the body of the larva. As the botfly grows so does the lesion on the
host; this condition is called "specific myiasis". After an
incubation period of 40-50 days the botfly emerges. If one wishes to
eliminate this parasite before it emerges itself, one might try putting
petroleum jelly on the lesion. The jelly obstructs the larvaís tiny
breathing tube that remains outside of the skin. The larva will
suffocate and then can be extracted from the host. Another suggestion is
to tape a piece of meat over the lesion, the larvae will leave the host
for the meat.
There are many different species of ants in
the rainforest. Two species that most people have heard of are the Leaf
Cutter Ants (Atta spp.) and the Army Ants (Eciton spp.).
The Leaf Cutter ants are frequently seen carrying leaves across the
forest floor, a more than significant feat considering it is comparable
to a six-foot man carrying a 750 pound (338 kg) load at a remarkable speed over
at least a few miles! The leaves are dropped into an underground nest
where more ants chew the leaves and form them into pellets that are then
inserted into a mass of leaf paste. A fungus grows on this mat; the
fungus and leaf sap make up the antsí diet.
Although the movies may portray army ants as mass
swarms devouring everything in site with no escape for anything in their
path, this is hardly a reality. Typically army ants move at night. They
are group predators and their prey consists of baby birds, small
lizards, caterpillars and spiders. If you encounter a group of army ants
during the day, simply step over them.
The lesser known but impressive bullet ant (Paraponera
clavata) is a large tropical ant that delivers a particularly nasty
sting and bite. These insects are one inch or more in length, tend to be
solitary, and can be found anywhere from the forest floor to the trees.
If a nest is disturbed it is believed they give off a chemical alarm; in
addition the worker ants may emit a loud squeaking noise.
Spiders of course are not insects, but
arachnids. For many people, spiders, like snakes, induce feelings of
both fear and intrigue. There are a number of different species of
spiders all generally referred to as tarantulas, and they are all
non-aggressive towards humans. If one should accidentally get bitten,
their bite is harmless to humans (unless you have an allergic reaction
to the venom). The enemy of the tarantula is the hunting wasp, whose
sting will paralyze the spider that is then used as food for the wasp
larvae. If you would like to see a Tarantula while visiting the
rainforest, take a flashlight out at night; these nighttime predators
can usually be found not to far from their burrows in the ground.
Termites are an essential part of the
rainforest. One can find their nests either attached to tree trunks or
underground. The nests are composed of digested wood and termite fecal
matter. Interestingly it is a protozoan that lives in the termitesí
intestines that actually digests the cellulose from the wood. Without
these intestinal fauna, the termites could not digest the wood. Although
these protozoa enable the termites to digest wood, many topical trees
are hard wood trees, possibly an evolutionary response to termite
herbivory; some of the woods are actually poisonous to termites. The
termites themselves have developed some interesting defenses against
predators. The soldier termites emit a sticky substance that smells
similar to turpentine which can be irritating to predators including the
anteater. Termites are an essential part of the rainforest for
decomposing wood; but they are also valuable because of their nests. As
they abandon their nests, which they do regularly, the mounds are full
of nutrients. As the mounds decompose they leave patches of high
nutrient concentration in the soil. These areas are then prime spots for
new tree growth. What a beautiful example of the circle of life!
The Lantern Fly (Fulgora laternaria) is
one of the more unique looking insects. This creature has a long head
that resembles a cross between an alligator and a lizard. Its wingspan
is about five inches and when perched on a tree, it resembles a lizard.
The Lantern Fly gets its name from folklore that speaks of an insect
with a bioluminescent head, however its head does not glow in the dark!
Butterflies and moths are common in the
rainforest; one of the most spectacular is the Menelausí Blue Morpho (Morpho
menelaus). This butterfly displays a deep blue color on its upper
wings; they are cryptic when their wings are closed on the ground or on
a tree. This beautiful butterfly can usually be seen around streams and
in sunlit areas. Its diet consists of a variety of plant species.
The Owl butterfly (Caligo memnon) is
distinguishable by a prominent eye-spot on the base of each wing. This
otherwise cryptic species flashes the underside when disturbed.
Researchers frequently find specimens with injuries (probably from bird
beaks) in the area of the eye-spots; they hypothesize that these
markings draw the predatorís attention, and thus the attack, to that
area, allowing the butterfly to at least survive the encounter.
There is a group of butterfly species, commonly
called antbutterflies, which follow army ants. These butterflies are
members of the Nymphalidae family and subfamily Ithomiinae. It is only
the females that follow the ants, to feed on the droppings of the
antbirds, which provide the butterflies with a nitrogen source essential
to make eggs.