The success of cockroaches over millions of years can be attributed to their ability to adapt to environmental change; they are constantly evolving in order to survive in changing environments.American cockroaches are commonly referred to as Water bugs as they find their ways into man made structures through drains and pipes leading into homes or offices.
Cockroaches are among the most common households pests found in the
United States and almost always repulse their uninviting hosts. While
most species have wings, only some of them can actually fly.
There are around 4,000 different species of cockroaches but among
these approximately only 50 are common to the US. Those species that are
indigenous to the New York area are the German, Oriental, brown-banded
and American cockroaches.
Classifications, Types & Anatomy
Although there are over 4,000 species of cockroaches within the
insect order Blattodea, there are only approximately 70 species believed
to have human interaction.
Most cockroaches exhibit similar physical characteristics but each
species utilizes the different features of their anatomy in different
ways. Roaches -- one of the larger insects -- are usually dark in color,
either dark or light brown, black or even reddish-brown in some cases.
Although the male and female adults of most species have wings, not all
of them can fly. They all have 6 legs and a broadened flat back with a
relatively small head. The underside of their head is where the chewing
mandibulate mouthparts are located. On the top of their head are two
large eyes, a pair of ocelli or simple eyes, and long antennae.
Cockroaches generally have two pairs of wings. One pair, the tegmina,
are the outer wings and are the tough protective layer that cover the
hind wings. Their legs are sturdy and each have a combination of claws
and pads. Their legs also contain spines, which serve various functions
including sensory capacities. Recent studies suggest that these spines
actually seem to help with movement on tough surfaces and these spines
have actually been useful in helping to create better prosthetic and
robotic legs for humans.
The younger, immature cockroaches, also known as nymphs, look the
same as the adults but are smaller with incompletely developed wings. In
any case, their method of transportation helps them to scatter when
they are disturbed.
The species of cockroaches that are most common in the New York area
are the German, Oriental, Brownbanded and American cockroaches.
The German cockroach, Blattella germanica, varies in length from
about ½ to 5/8 inches and is most easily identified by their size as
they are among the smaller species of the cockroach family. Adults are
light-brown or tan in color with two black stripes extending from the
back of the head down the length of the pronotum, which is the shield
located directly behind the head. Both male and female adults have wings
that extend to the end of the abdomen but these insects do not fly.
Nymphs are similar to the adults, only smaller and don’t fully developed
wings until they mature. They appear dark-brown to black and also have
two stripes extending lengthwise down their back.
The American cockroach, Periplaneta americana, is the largest of the
peridomestic cockroaches, measuring approximately 1 ½- 2 inches. The
adults are reddish-brown with pale -yellow bands behind its head. Both
males and females are winged and are poor fliers, although they rarely
fly in the northeastern parts of the US. The wings of the male cover the
entire length of the abdomen, extending a little past the length of the
abdomen. The female wings do not extend past the length of their
abdomen. Aside from being smaller and having no wings, nymphs look
similar to the adults.
The Oriental cockroach, Blatta orientalis, measures approximately 1-
to 1¼- inches long and is dark-brown in the adult stage. Nicknamed the
“black beetle” because of their smooth, greasy, dark appearance, these
roaches are more sluggish than their relatives. While neither sex can
fly, they both have wings. The male’s wings cover the majority of the
abdomen but the female only has short wing pads. Nymphs are wingless but
otherwise have the same features as the adults but are a little darker
in color.
The Brown Banded cockroach, like the German cockroach is smaller in
size, approximately ½ inch long and light brown in color. Male and
female adults have wings: the male wings are fully developed; female’s
wings are underdeveloped and much shorter than the abdomen. This roach
gets its name from the two brown bands that appear across the base of
the wings on adults and across the bodies of nymphs.
Lifecycle, Breeding & Feeding Habits
Cockroaches have a three-stage life cycle: egg, nymph and adult. The
roaches develop in these stages over time. Typically a female will
produce 10 or more eggs that are sealed in an ootheca – a tan to dark
brown colored bean-shaped egg capsule. Depending on the particular
species, the ootheca may be deposited in a safe area or may be carried
around by the female until they are ready to hatch, a process that can
take weeks or months.
The eggs are forced open and the bright white nymphs then emerge.
They then become harder and darker over the following few hours as
proteins in their cuticles react to exposure to air. Nymphs live in the
same areas and feed off of the same substances as the adults.
Nymphs eventually molt to the adult stage and will survive anywhere
from 1-4 years. A single female can produce up to 400 offspring in her
lifetime and only needs to be inseminated once in order to produce
offspring for the rest of her life.
Mating for cockroaches, like many insects, occurs while the insects
face away from each other. Some species can even reproduce without the
need for males; this is known as parthenogenesis. Cockroaches are
attracted to their mates through pheromones, which may be either
airborne or left in trails. These trails can be found on surfaces and
are used by roaches to communicate suitable harborages or food sources.
Cockroaches must eat to survive, although they have been able to
survive several months without food or water. They are omnivores,
feeding on almost anything they come across including animal and human
food and waste, such as crumbs or spilled liquids. Cockroaches have a
preference for foods that are sugar and starch based, but will sip milk,
soda or beer that can be found on old bottles. They will also feed on
cheese, meats, pastry and grain products if left out. Aside from
conventional human foods, cockroaches are happy to feed on soles of
shoes, bookbindings or dead insects if they can’t find their preferred
foods.
The German cockroach is one of the fastest reproducing cockroaches.
The female will carry around the ootheca (egg case), which is tan and
about ¼ inch long, for 30-40 days while the nymphs develop inside. They
will release the egg case about day or two before the eggs actually
hatch, although some births do occur while they are still carrying the
ootheca. Each egg case contains 30-40 eggs and once hatched, it takes
about 3 months for the roach to reach the adult stage. The female is
able to produce a new egg case every few weeks and can therefore produce
3 to 4 generations per year.
The American cockroach deposits the dark reddish-brown 3/8-inch long
egg case anywhere from a few hours to a few days after mating. The egg
case is cemented – using secretions from the female’s mouth - to a
protected surface, typically near a suitable food source. Each egg case
contains about 16 offspring. The emerging nymphs are grayish brown and
eventually take on the reddish-brown adult color after several molts.
The length of the nymphal stage is highly dependent on temperature and
humidity but averages about 600 days. Female adults will live for up to
about 225 days and males about 200 days.
The Oriental cockroach develops in dark, red-brown egg cases. These
capsules, which are about 3/8 inches long and carry around 16 eggs, are
each deposited in safe, sheltered places near food sources. The female
deposits the egg case after carrying it for about 30 hours. The
developmental stages typically occur on a seasonal cycle for the
Oriental cockroach and are highly variable, taking at least one year to
reach the adult stage but sometime requiring up to 600 days. The life
span of an Oriental cockroach can be up to 18 months.
The Brown Banded cockroach egg capsules are approximately ¼ inch long
are light brown and carry about 13 eggs. The female will carry
approximately 14 capsules in her lifetime, fastening the egg case to
secure places such as closets, ceilings or other dark places after
approximately 30 hours. The nymphal stage lasts about 100 days,
depending on temperature, with the total developmental time highly
variable. . The adult life span averages about 160 days, with females
producing around 600 offspring in her lifetime.
Environments & Activities
Cockroaches are some of the most resilient and adaptive insects on
earth. They are able to survive the coldest of climates even though
their preference is for warm, moist habitats and to be near food. They
are also able to squeeze into very tight spaces.
While they frequently live outdoors, their most common hiding places
inside tend to be near sinks, dishwashers or stoves in kitchens,
bathrooms or restaurants and near refrigerators and cabinets that may be
contain sources of food. However, they can be found nearly anywhere in
any house or workplace. Roaches are typically introduced into houses
from food deliveries, shopping bags and laundry deliveries or in certain
cases, wander inside on their own. In multi-family buildings, they can
easily spread from an infested apartment to adjacent units.
Cockroaches are nocturnal creatures, hunting for food at night and
hiding when exposed to light. (In fact, if cockroaches are seen during
the day, it is likely the result of a high infestation.) Research shows
that the determinations on where to go are instinctually based on how
dark it is and how many other roaches there are.
The German cockroach is most commonly found indoors, most notably in
and around multi-family homes and apartment buildings. They are found
indoors as they prefer bathrooms, kitchens and other food preparation
areas because they are warm, moist areas near food and water sources.
The American cockroach is more common to outdoor environments in the
South but is also often found in homes and food establishments. They are
often found in dumpsters, trash facilities, sewers and basements. They
prefer extremely warm and humid environments and can be quite populous
in outdoor venues such as zoos if the weather permits.
The Oriental cockroach originally native to the Middle East, has
flourished in many parts of the U.S. Also common to warm and moist
environments, they frequently enter homes through sewers, where they
seek harborage near wet, decaying organic matter. In and around the
house they may prefer wood storage areas, basements, drains and trash.
They are also very common in vegetation and homes near plants and
fields. They do not fly and are unable to climb smooth vertical surfaces
and are therefore often found trapped in porcelain sinks or tubs.
The Brown Banded cockroach is an active species. Only the males can
fly. They also prefer dry, warm habitats and are often found away from
kitchens and bathrooms near warm equipment such as televisions and other
appliances.
Dangers & Effects On Humans
Most people think of cockroaches as nuisances because of offensive
odors and their unslightly presence. Odors are generally secreted by
German, American and Oriental roaches.
Cockroaches have also been directly linked to allergic reaction in
certain populations, especially in children. The allergies caused by
roaches are the second most common household allergy, next to dust.
Proteins from the cockroaches shed skin, such as BlaG1 are the causes
for allergic reaction, which can in turn trigger asthma attacks.
The primary threat cockroaches pose are the disease causing pathogens
they carry. Roaches are known to carry 33 kinds of bacteria and many
kinds of parasitic worms and other human pathogens. Roaches pick up
these pathogens while walking around trash and other unsanitary surfaces
and spread the diseases by walking on food or other items, which humans
come into contact with. They can cause food poisoning (eg. Salmonella
or Shigella) and have been linked to other disease-causing organisms
such as Staphylococcus, Streptococcus, hepatitis virus and typhoid.
Control & Treatment
Cockroach prevention is easier than cockroach treatment. There are
three primary tenets involved in proper cockroach prevention:
sanitation, monitoring and exclusion
Proper sanitation is the most important factor in cockroach
prevention. . Vacuum and clean your home on a constant basis. Keep all
food in tightly sealed containers. Fix leaking pipes or faucets.
Thoroughly clean the apartment and any spills that may have occurred.
Remove trash regularly and don’t let empty bottles, cans or leftovers
remain overnight. Use garbage cans with tight fitting lids Store dry pet
food in sealed containers.
It is also important to monitor and inspect cockroach activity in
your home or workplace to know the entry points and areas of focus for
treatment and prevention. Putting down monitors, such as glueboards
against the walls and in the corners can provide useful information on
roach activity. However, if they don’t turn up results in a day or so,
it would be best to move them to a more susceptible area.
Exclusion of cockroaches is certainly not an easy task, but there are
several options to help minimize vulnerable entry points. Seal any
cracks and crevices inside your home. Use caulk or expanding foam around
pipe entry points. Sealing windows, doors or baseboards with
weatherproofing strips, putty or silicone caulk, expanding foam or steel
wool and copper mesh will help to eliminate the problem. The
application of Diatomaceous earth – a talcum-like powder product, which
is harmless to humans, but fatal to cockroaches, bed bugs and other
insects – is a good treatment option for these pests.
References
http://www.entomology.cornell.edu/cals/entomology/extension/idl/upload/Cockroaches.pdfhttp://ento.psu.edu/extension/factsheets/brown-banded-cockroaches
http://insects.tamu.edu/extension/publications/epubs/e_359.cfm
http://www.ca.uky.edu/entomology/entfacts/ef614.asp
http://extension.entm.purdue.edu/eseries3/view.php?article=articles/cockroaches.txt&id=2§ion=Public Health
http://en.wikipedia.org/wiki/Cockroach
http://www.ipm.ucdavis.edu/PMG/PESTNOTES/pn7467.html
http://pestworld.org/identify-insect/Pest/american-cockroaches
http://ento.psu.edu/extension/factsheets/american-cockroaches
http://pestworld.org/identify-insect/Pest/oriental-cockroaches
http://ento.psu.edu/extension/factsheets/oriental-cockroaches
http://pestworld.org/identify-insect/Pest/brownbanded-cockroaches
http://ento.psu.edu/extension/factsheets/german-cockroaches
http://pestworld.org/cockroach
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