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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