Among the most well-known species are the American cockroach, which
is about 3 cm long, and the German cockroach, about 1.5 cm long.
Tropical cockroaches are often much bigger. When infesting buildings,
cockroaches are considered pests.
Versatile eaters: Cockroaches are generally either scavengers or omnivores. The exception
to this is the wood eating Cryptocercus species found in China and
the United States. Although they are incapable of digesting plant
matter, they have a symbiotic relationship with a protozoan that
digests the cellulose in plants, allowing them to extract the nutrients.
In this, they are similar to termites and current research suggests
that the Cryptocercus is more closely related to termites than it
is to other cockroaches, making it an evolutionary link between
cockroaches and termites. Cockroaches are most common in tropical
and subtropical climates. Some species are in close association
with human dwellings and widely found around garbage or in the kitchen.
Night dwellers: Cockroaches are mainly nocturnal, and will run away when exposed
to light. A peculiar exception is the Oriental cockroach which is
attracted to light, thus making it a far more annoying pest. Roaches
are called the custodians of nature. They only live in houses where
there are crumbs to eat or the garbage can is uncovered. They lay
eggs inside the house's hollow walls.
Super-roach!: The roach is also one of the hardiest insects on the planet, capable
of living for a month without food and remaining alive headless
for up to a week. It can also hold its breath for 45 minutes and
has the ability to slow down its heart rate. Cockroaches also have
a very high resistance to radiation. A common urban legend that
cockroaches can survive a nuclear attack is in fact true.
Cockroaches have been shown to make group decisions.
Hansel and Roachel: New research being conducted at the University of Florida shows
that cockroaches leave chemical trails in their feces. Other cockroaches
will follow these trails to discover sources of food, water, and
where other cockroaches are hiding. One of the major implications
of this research is a new technique in cockroach pest control. Cockroaches
could be potentially removed from a home by leaving a chemical trail
that leads away from the home.
Female cockroaches are sometimes seen carrying egg cases on the
end of their abdomen; the egg case of the German cockroach holds
about 3040 long, thin eggs, packed like frankfurters in the
case called an ootheca. The eggs hatch from the combined pressure
of the hatchlings gulping air and are initially bright white nymphs
that continue inflating themselves with air and harden and darken
within about four hours. Their transient white stage while hatching
and later while molting has led to many individuals claiming to
have seen albino cockroaches.
A female German cockroach carries an egg capsule containing around
40 eggs. She drops the capsule prior to hatching. Development from
eggs to adults takes 34 months. Cockroaches live up to a year.
The female may produce up to eight egg cases in a lifetime. In other
words, in favorable conditions it can produce 300400 offspring.
A regular cockroach, however, can produce an extremely high number
of eggs in her lifetime. She lays up to 100 eggs in each egg sac.
She only needs to be impregnated once to be able to lay eggs for
the rest of her life, allowing one single cockroach to lay over
a million eggs in her lifetime.
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