Cockroaches are one of the oldest and most primitive of insects. They
flourished during the Carboniferous period of the earth's history, 350
to 320 million years ago, which has been nicknamed "The Age of
Cockroaches" by paleontologists. The fossil evidence uncovered indicates
that during this time, cockroaches made up about 40 percent of the
world's insect population. Cockroaches from 340 million years ago looked
much like roaches living today. Cockroaches have a flattened, oval
body, long, slender antennae, and a shiny black or brown exoskeleton.
Most species also have wings that are held flat over the back. The
exoskeleton, or shell, is made of chitin, which is about as thick as a
human hair. The chitin covers the roach's entire body, even its eyes.
Cockroaches range fromabout 0.5 to 2 inches in length, with the largest
being found in the tropics. They have grasshopper-like mouth parts for
chewing and feed on plants or animal matter, including dead insects and
bedbugs or even cardboard, paper, books, glue, and other manufactured
products. They are nocturnal insects and are rarely active or visible
during the day. They live and hide in warm, damp, dark places, coming
out at night to hunt for food. The cockroach has three life stages: egg,
nymph, and adult. Cockroach eggs are deposited in groups in a leathery
case or capsule, the ootheca. There may be from thirty to forty-eight
eggs in the capsules of some species, while others have only ten to
twenty-eight. The newly hatched nymphs have no wings and shed their
skins (molt) several times before becoming winged adults. Indoor roaches
generally have several generations of young per year, but outdoor
species may require a full year to develop from egg to adult.
Cockroach Classification
The German cockroach, Blatella germanica, also called the "water bug"
in some places, is found throughout the world. It is commonly carried
home in paper grocery bags and boxes (where it hides because it loves
the taste of glue) and also likes to live around water pipes. Though it
has only a 150-day life span, one adult female can produce as many as
eight egg capsules, each filled with up to forty eggs. Thus, a female
can produce more than 3,200 young in its lifetime. According to a
bulletin from the U.S. Food and Drug Administration, one female could be
the source of over ten million females in a single year, and over ten
billion females in 1.5 years, assuming that all the babies survived and
reproduced and food supplies were adequate. The German roach is
relatively small in size, about one-half inch long, compared to some of
its Asian relatives. The Asiatic (or oriental) cockroach, Blatta
orientalis, can be up to two inches in length and is considered one of
the dirtiest household pests. It is oval in shape, with a shiny black
exoskeleton. Males have short wings and can fly, unlike females, who
have only vestigial wings. This species is found throughout the world,
having been carried almost everywhere by ships, trucks, railroad cars,
and airplanes. The American cockroach, Periplaneta americana, is found
in most warm climates throughout the world. It prefers to live indoors
and is found in basements and furnace rooms. It has a life span of about
1.5 years and lays about sixteen eggs every forty-five days. It
originally came from Central and South American rain forests. The
American roach has a set of wings that enable it to fly long distances.
The American and German species are cannibals. Young nymphs eat their
own kind if there is not enough food available. Mothers frequently eat
their own egg capsules if food shortages develop. However, roaches can
survive for more than a month without water or food. This feature has
consequences for the food industry-for instance, roaches accidentally
sealed in shipping crates can survive fairly comfortably even if shipped
long distances with extremely limited resources. Cockroaches are found
in the desert as well as the forest. Desert roaches, Arenivaga
investigata, burrow under the sand during the hottest part of the day,
coming out to feed only at night. They can absorb water merely by
sticking out their tongues. The brown-hooded wood cockroach,
Cryptocercus punctulatus, lives in decaying logs in the forest along the
Atlantic coast. Only three other species of this genus survive, one in
China, one in Russia, and one in the western United States, because the
forest habitat in which it thrives is disappearing. The common wood
cockroach, Parcolblatta pennsylvanica, on the other hand, is found in
abundance under logs and stones in northern forests. This species eats
wood, which it digests with the help of bacteria living in its stomach,
and is not considered a household pest.
Cockroach Control
Closing spaces and cracks around pipes, doorframes, and baseboards can
prevent cockroach infestations. Paper bags and cardboard boxes should be
inspected for roaches when they are brought into the home. Store food
in containers with tight fitting lids. Pet food should be served by
placing the bowl in a second, shallow bowl filled with soapy water.
Roaches cannot swim across this barrier. Leaking water attracts roaches,
so plumbing leaks should be fixed quickly. Sink and bathtub drains
without stoppers are also inviting homes for roaches. Garbage cans
should have lids and be emptied frequently. Cool temperatures can also
kill roaches; few survive temperatures below freezing.
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