Cockroaches: A Brief Introduction
Cockroach Quick Facts
Common Name: Cockroach
Families: Blaberidae; Blattidae; Corydiidae; Cryptocercidae; Ectobiidae; Lamproblattidae; Nocticolidae; Tryonicidae
Common Household Cockroaches: German Cockroach; American Cockroach; Australian Cockroach; Oriental Cockroach
The cockroach is a species of insects belonging to the order Blattodea, which includes termites. There are approximately 4,600 types of cockroach known to currently exist in the world, with about thirty of these residing near (or in) human dwellings. Of these, four are considered pests. The word “cockroach” is derived from the Spanish word “cucaracha.” Its Latin (scientific) name, on the other hand, derives from the word “Blatta,” which refers to an insect that shuns the light.
Cockroaches are classified as “living fossils” by the scientific community, as they are believed to have been around since the Carboniferous period, approximately 320 million years ago. Early roaches differed in some ways from modern cockroaches, however, as the ancient species is believed to have lacked internal ovipositors. Fossilized remains of ancient roaches also indicates that the species may have lacked hind wings in its early years.
Cockroach Characteristics and Traits
Most species of cockroach are small (approximately the size of a thumbnail). However, some species, such as the Australian “Giant Burrowing Cockroach,” can reach lengths of 3.5 inches (nine centimeters). Largely considered to be one of the most “primitive” neopteran (winged) insects in the world, the cockroach possesses very few “special adaptations” to aid in its daily survival. Nevertheless, the cockroach is a highly resilient species.
Identification of cockroaches is relatively easy, as most possess a small head, a flattened body, as well as a reddish-brown or dark brown coloration. Cockroaches are also known for their large eyes, long antennas, and mouthparts along the underside of their head. The body of a cockroach is divided into three separate segments, with an external surface that contains a durable exoskeleton composed of calcium carbonate. This shell is crucial for the cockroach’s survival, as it helps to protect both its internal organs and muscular systems from harm. The shell is also capable of repelling water due to its waxy coating.
The cockroach also possesses a set of wings that allow the insect to fly. Combined with the three sets of legs (with five claws each), the cockroach is capable of travelling in nearly any terrain.
Distribution and Habitat of the Cockroach
Cockroaches are extremely abundant, and are found throughout the world in a variety of environments (due to their ability to withstand both hot and cold temperature extremes). Although mainly concentrated in the tropics, cockroaches are also capable of living in the Arctic. Some species have been observed surviving in temperatures of -188 Degrees Fahrenheit due to their ability to naturally produce a form of antifreeze (made from glycerol). In North America, alone, there are approximately fifty known species of cockroach found across the continent. Australia, in contrast, possesses an astounding 450 varieties of the cockroach.
Cockroaches can be found in a variety of habitats, including leaves, rotting wood and debris, or near bodies of water. Others can be found in forest canopies, crevices, or general areas that allow them to hide during the day (due to their nocturnal feeding habits).
Cockroach Behavioral Patterns
Nearly all cockroach species are known to be social insects; preferring to spend their time with other cockroaches, rather than being alone. Scientists believe that this natural tendency to aggregate may be caused by pheromones secreted in the fecal matter of the roach. Groups of cockroaches are known to emit particular scents that are unique to the group they belong; indicating the ability to engage in both social interaction as well as swarm behavior.
In more recent years, scientists have hypothesized that cockroaches may be capable of collective decision-making within their groups, particularly when it involves choosing various water and food sources for their survival. They are also known to communicate with one another using scent trails in order to alert others to food and water.
"Both the cockroach and the bird would get along very well without us, although the cockroach would miss us most."— Joseph Wood Krutch
Similar to many other animals on Earth, cockroaches are known to use pheromones to attract potential mates. Although a few species of the cockroach are parthenogenetic (asexual) and capable of reproducing alone, most roaches require both a male and female to reproduce.
After mating, the female develops egg cases known as “oothecae,” which she carries at the end of her abdomen. Just before hatching, the female lays her eggs in a process that takes approximately five hours to complete (usually positioning the egg casings in a crevice or hidden spot away from danger). The eggs, which are bright white in color, begin to hatch once the baby cockroaches begin to collectively gulp air; literally inflating themselves in a manner that causes the casing to break open. Once hatched, the baby cockroaches (called nymphs) are initially born bright white, but begin to darken after about four hours. Full maturity from baby to adult takes less than three months (with some species reaching full adulthood after only fifty days). Average lifespan of the cockroach is approximately one year for most species, with some living upwards of two years. During their lifetime, females have been known to produce upwards of eight egg casings (oothecae); the equivalent to nearly 300 to 400 baby cockroaches (although some species, such as the German Cockroach, can produce a lot more eggs).
Some cockroach species are capable of flight due to the presence of wings along their backside. Asian, Smoky brown, Wood, and Brown Roaches are all known for their remarkable flight abilities. Others, such as the Cuban and Austrlian Cockroaches are capable of flying for short distances as well, while the American Cockroach primarily uses its wings to glide through the air. More common roaches, such as the German and Oriental Cockroaches, however, possess wings but are incapable of flight due to their awkward body design and weight.
Flying cockroaches are a common concern for homeowners, as the ability to fly often aids the roach in infiltrating homes and various dwellings. Flying species are especially drawn to interior lights, prompting many of the bugs to venture indoors during evening hours. The ability to fly also allows the bug to reach most places with ease, including countertops, appliances, and hiding spots away from human reach.
Although most cockroaches don’t produce milk, the Diploptera punctate species of roaches is the only known cockroach to have live births and to produce milk that contains protein crystals. This incredibly rare trait (particularly for an insect) is currently under investigation by researchers and nutritionists around the world. Of particular interest to scientists is the nutritional aspects of the cockroach milk, which is believed to be nearly four times healthier than regular cow’s milk. It is also estimated that cockroach milk contains more than three times the amount of energy found in buffalo milk (which contains more calories than regular cow’s milk).
Although milking cockroaches is not a feasible option for researchers, replication of the proteins contained in cockroach milk are a very real possibility, and may help to alleviate food shortages worldwide in the near future.
In addition to being able to engage in social interactions with other roaches, some species of cockroach are able to make either hissing or chirping noises. In species that exhibit this odd trait, different hisses are believed to correspond to various emotions, including aggression, anger, fear, and courtship. The roach accomplishes this by forcing air through modified spiracles along its abdominal region. In times of mating, a number of Australian species have even been known to make rhythmic sounds that follow repetitive patterns in order to attract potential females.
The cockroach is one of the hardiest species known to exist in the world, and is capable of not only living in extreme environments, but also with little food or water sources (for extended periods of time). Some cockroach species have been known to live over a month without food or water. Others have been observed surviving on very limited resources, such as glue from postage stamps.
Besides the ability to live extended periods without sustenance, the cockroach also possesses a strong resistance to radiation. Cockroaches can withstand fifteen times the level of radiation (in regard to lethal doses) than humans. For this reason, it has often been suggested that cockroaches will inherit the Earth if the world is destroyed in a nuclear war. It remains unclear why radiation has less of an effect on the cockroach than humans. However, the insect’s cell cycle may offer the best explanation for this profound trait, as the cockroach’s cells divide only when it molts (weekly). As a result, sudden bursts of radiation are relatively harmless to the creature, since cells are most vulnerable to radiation when they are in the process of dividing.
Of the numerous species of cockroach in the world, approximately thirty are known to actively seek shelter alongside humans. Of these thirty, four species of cockroach have been designated as pests in more recent years. These include the American Cockroach, German Cockroach, Oriental Cockroach, and the Australian Cockroach. Cockroach infestations are a common concern for homeowners. Because cockroaches transport pathogenic microbes (passively), the insect is capable of spreading harmful bacteria and germs throughout homes such as salmonella, staphylococcus, and streptococcus. Cockroaches are also known to cause allergic reactions in humans due to the protein tropomyosin that is prevalent in the species. Eliminating cockroaches is crucial, therefore, as they pose a significant health risk to humans, particularly the elderly, youth, and individuals with allergies and compromised immune systems.
Even in homes that have no visible signs of cockroach infestation, recent surveys have indicated that approximately sixty-three percent of all homes contain roaches, roach droppings, or their decomposing parts (including particles and saliva).
Common Name: American Cockroach
Binomial Name: Periplaneta Americana
Species: P. Americana
The American Cockroach (also erroneously known as the “waterbug”) is one of the largest species of roaches. Despite their name, the American Cockroach is native to Africa and the Middle East, but is believed to have been brought to the United States (unintentionally) during the Seventeenth Century aboard commercial ships to the New World. They are now extremely common in the United States, as well as parts of Europe, including Spain, Portugal, and the Canary Islands where temperatures range from warm to hot. The roach is nearly 1.6 inches long and possesses a reddish-brown coloration. The bug is incredibly fast, and is capable of moving at nearly 3.4 mph. For its body size and weight, this is comparable to a human being running at a speed of 210 mph. The American Cockroach is both omnivorous and opportunistic in its feeding habits, and is known to eat cheese, tea, beer, dried skin, dead animals, as well as various plants, and glossy paper. In times of hunger, the roach has also been observed eating both dead and wounded cockroaches of their own species.
Like most roaches, the American Cockroach lives primarily in moist areas, with a base temperature preference of eighty-four degrees Fahrenheit. They are common in basements, cracks, foundations, sewers, walkways, and various crawl spaces. Because of its preference for warm climates, the American Cockroach often enters houses (particularly during the winter months) via sewer connections, plumbing, air ducts, or openings around doors, windows, and cracks.
Common Name: German Cockroach
Binomial Name: Blattella germanica
Species: B. germanica
The German Cockroach is another species of roach with similarities to the American Cockroach in both behavior and preferences. At approximately half an inch in length, however, the German Cockroach is much smaller and maintains a tan (almost black) coloration that differentiates it from the American roach. Of all the cockroach species, the German Cockroach is perhaps one of the most troublesome pests due to its ability to rapidly reproduce.
German Cockroaches are found in a variety of habitats including homes. However, they are mostly found in restaurants, hotels, and food-processing facilities. Although it is unknown where the bug originated, scientists believe that the roach likely came from Southeast Asia (despite its name), and spread via commercial shipping throughout the last few centuries to all the continents of the world (except Antarctica).
Like their American cousins, the German Cockroach is nocturnal, omnivorous, and opportunistic in its feeding habits. They are particularly drawn to meat, sugars, fatty foods, as well as starches. However, when items such as these are not available, the roach is known to also consume toothpaste, soap, glue, and other roaches (in times of starvation). One particular trait of the German Cockroach is its natural ability to emit foul odors when frightened or scared. The species also reproduces faster than any other roach species, with the ability to reach full maturity at only fifty days old.
Common Name: Oriental Cockroach
Binomial Name: Blatta orientalis
Species: B. orientalis
The Oriental Cockroach, also known as the waterbug or black beetle, is a species of cockroach that reaches approximately 1.14 inches in length. Maintaining a dark brown or black coloration, along with a pair of long wings (also brown in color), the bug is very similar in appearance to the German Cockroach. Although researchers remain uncertain as to the origins of the Oriental Cockroach, it is believed that the roach originated from the Crimean Peninsula region (including the surrounding areas of the Black Sea and Caspian Sea). As with most roach species, commercial shipping and trading, however, has made this cockroach common on each of the continents (except for Antarctica).
Known for their relatively slow speed, and preference for dark, moist areas, the Oriental Cockroach can often be found near sewers, plumbing fixtures, basements, porches, and areas that contain leaf cover, mulch, or bushes. Due to their preference for warm areas (Sixty-Eight to Eighty-Four Degrees Fahrenheit), the Oriental Cockroach has became a major pest for much of the Southern, Midwestern, and Northwestern regions of the United States in recent decades due to the naturally warm conditions in these areas.
Common Name: Australian Cockroach
Binomial Name: Periplaneta australasiae
Species: P. australasiae
Synonyms: Periplaneta repanda (Walker, 1868); Blatta australasiea (Fabricus, 1775); Blatta aurantiaca (Stoll, 1813); Blatta domingensis (Palisot de Beauvois, 1805); Periplaneta zonata (Haan, 1842); Periplaneta subcincta (Walker, 1868); Polyzosteria subornata (Walker, 1871); Periplaneta inclusa (Walker, 1868); Periplaneta emittens (Walker, 1871)
The Australian Cockroach is a common species of roaches known to reach nearly 1.38 inches in length (maximum). Possessing a goldish brown body, along with a pale stripe, and yellow pronotum, the Australian Cockroach is easily identifiable due to its distinguishing marks and coloration. Similar to the American Cockroach, the Australian species is extremely common throughout the United States, but can be found throughout most of the world (with a preference for warm, tropical climates).
The Australian Cockroach is unable to tolerate cold temperatures, and prefers indoor environments that are both warm and damp. Unlike other species of cockroach, however, the Australian Cockroach prefers plants over most foods. Nevertheless, the roach is still omnivorous and opportunistic (due to its scavenger qualities), and will consume most organic materials, including other cockroaches when hungry.
Comparison of Most Common Cockroach Species
29-53 mm (1.1 - 2.1 inches)
13-16 mm (0.51 - 0.63 inches)
18-29 mm (0.71 - 1.14 inches)
68 - 84 Degrees F.
75 - 95 Degrees F.
68 - 86 Degrees F.
DEVELOPMENT (TIME TO REACH FULL MATURITY)
90 - 706 Days
35 - 190 Days
ABILITY TO FLY?
Signs of Cockroach Infestation
- Fecal Droppings: One of the most common signs of cockroach infestation is signs of fecal matter. Cockroach droppings are very similar to coffee grounds or black pepper in both their size and appearance. Large numbers of fecal matter are an indicator of extreme infestation and should be dealt with immediately by a pest control service, or local exterminator. Concentrations of fecal droppings are also indicative of a high-traffic area for roaches; likely a source area of food and water. If a local exterminator isn’t an option, these are critical areas that should be targeted by you when placing traps and poison.
- Cockroach Odor: Another trait of cockroach infestations is foul odors that are not easily explained. What does a cockroach smell like? Most describe roaches as having both a musky and oily smell. Although a single cockroach can give off unpleasant odors, ever-present smells are indicative of a large-scale infestation, requiring immediate attention.
- Cockroach Egg Casings: When reproducing, the cockroach is known to produce egg casings that hold multiple eggs inside (called oothecae). Finding casings or unhatched eggs is a serious problem, and often means that other roaches are present within your home. A single egg is ootheca contains, on average, ten to twenty eggs, with German Cockroach oothecae holding as many as fifty eggs. One complete hatching, therefore, is a major issue for homeowners, and requires immediate follow up.
- Dead Roaches: While dead roaches are far better than live cockroaches, finding dead insects (with no apparent cause) is a sure sign that additional roaches are inside your home. Finding dead ones on a regular basis is even more alarming, as it indicates a significant infestation occurring.
- Spotting Roaches During the Day: As nocturnal creatures, it is often difficult to spot cockroaches since they try to avoid daylight and come out when most of us are already asleep and in bed. When cockroaches are spotted during the day, however, it is usually indicative of a very serious infestation. Cockroaches only venture out during the day when competition for food and water is particularly hard with other roaches, or when nest sizes have become so large that the cockroach is literally forced from its daytime hiding spots.
Common Diseases Associated With Cockroaches
Although the cockroach, itself, isn’t responsible for any known diseases, their feeding and nesting practices often result in the insect coming into contact with a large array of bacteria, viruses, fungi, diseases, and microorganisms. The roach, in turn, often becomes a carrier of these organisms (indirectly), contaminating food and surfaces that they touch within human dwellings. Common diseases and infections associated with the organisms carried by roaches include:
- Typhoid Fever
- E. Coli
- Staphylococcus aureus
Natural Remedies for Cockroach Control
- Baking Soda and Sugar: One effective home remedy for cockroaches is to mix baking soda and sugar; placing the concoction in heavy traffic areas, as well as suspected hiding spots of the roaches. Mix the ingredients in a small cup or bowl using equal parts baking soda with equal parts sugar (1/4 cup of each works fine). Use the cup to sprinkle the mixture in the desired location and wait approximately a week before cleaning it up. Repeat if necessary. The mixture is highly effective as the roach is incapable of digesting the baking soda and sugar, causing it to die over time.
- Bay Leaves: Bay leaves are an incredibly effective remedy for roaches, as the insect hates their smell and avoids them at all costs. Simply grind the leaves into a powder, and sprinkle in areas that you’ve spotted roaches (or suspect they may be nesting in).
- Lemon Peels and Lemon Juice: Similar to bay leaves, both lemon peel and juice are effective for keeping cockroaches away from your home due to their strong scent. Simply combine lemon juice with water (ensuring that the lemon juice isn’t too diluted by the water), and use as a cleaning agent along your cabinets, countertops and high-traffic areas for suspected roaches. The natural scent will keep the roaches away, while simultaneously making your house smell exceptionally clean in the process.
- Garden Herbs: Another natural remedy for Cockroaches is using garden herbs, such as catnip, peppermint, and garlic to ward off roach populations. Planting these herbs around the perimeter of your home, or sprinkling their leaves alongside potential openings to your house are effective due to their strong smell. The odor acts, in turn, as an invisible barrier to cockroaches.
- Boric Acid: A highly effective (but potentially dangerous) remedy for cockroaches is boric acid. Due to its natural poison and high acidity, boric acid kills cockroaches quickly when applied correctly. Simply sprinkle a light coating of the boric acid in areas that are believed to be high-traffic areas for roaches. They key is have roaches walk directly through the powder, causing their legs, antennas, and body to be lightly covered. While grooming, the roach will ingest the acid causing rapid death for both it and nearby roaches that feed on its body. It is important to note, however, that while this natural treatment is highly effective, boric acid should always be kept out of reach of both children and pets as the powder is highly toxic and poisonous; causing severe skin irritation in the event of prolonged contact.
"Long after the bomb falls and you and your good deeds are gone, cockroaches will still be here, prowling the streets like armored cars."— Tama Janaowitz
Sometimes cockroach infestations are so severe that natural remedies are ineffective. Even more troublesome is the fact that many store-bought pesticides are ineffective options as well, due to the fact that cockroaches develop cross resistance to a variety of common insecticides. For this reason, professional-grade traps are often the best option for homeowners. Employing a professional roach exterminator, particularly during the early signs of infestation, is often the best option for individuals as early treatment can help save a lot of time and money (Average cost for a single extermination job ranges between $100 to $400).
In addition to laying traps, roach exterminators often work alongside the homeowner to discover the root cause of your infestation, as well as potential entry points for the cockroach. Eliminating potential food sources and entryways can go a long way in preventing further damage and infestation.
Common Traps and Poisons
Because there are so many different species of cockroach in the world, every infestation is different and requires specialized tools and equipment to effectively manage your issue. Common poisons and traps used by professional exterminators include:
- Glue Traps
- Gel Bait
- Roach Hotels (Bait Stations)
- Boric Acid
- Foggers (Mist-based Tool)
- Ultrasonic Pest Repellent (Employs High-Frequency Sound to Repel Roaches)
Disgusting Facts About Cockroaches
Disgusting Fact #1: Cockroaches will actively feed on human eyebrows, eyelashes, toenails (and fingernails), dead skin, as well as hair during the night hours. They are also drawn to dog and cat fur as well.
Disgusting Fact #2: In China (and Southeast Asia in general) roaches are considered a delicacy, and are often used for various snacks, protein powders, medicines, and cosmetics.
Disgusting Fact #3: Cockroaches are able to survive a week without their heads due to the fact that their vital organs are found near the thorax.
Disgusting Fact #4: Despite having extremely tiny brains, the cockroach possesses nearly a million brain cells. As a result, they are capable of memorizing both complicated routes, and can even be trained.
Disgusting Fact #5: The cockroach is capable of holding its breath for nearly forty minutes, and can be fully submerged underwater for over half an hour before dying.
In closing, the cockroach is a fascinating (yet disgusting) insect. Despite being a pest and nuisance to many homeowners, the seemingly primitive roach is actually quite complex and intelligent when compared to most insect species. Its hardiness and ability to adapt to a variety of weather patterns and climates is also quite remarkable; a fact substantiated by the bug’s presence on all of the world’s continents (with the exception of Antarctica). While much is known about the Cockroach, there is still much to be learned about this extraordinary creature. Only time will tell what new and exciting information can be learned about these exceptional bugs and their behavioral patterns.
Before reading this article, how familiar were you with cockroaches?
Articles / Books:
Culver, Jordan. "Researchers Tried (and Failed) to Kill Cockroaches for Six Months: 'We Thought Something Was Going to Work'." USA Today. July 03, 2019. Accessed August 07, 2019. https://www.usatoday.com/story/news/nation/2019/07/02/cockroaches-rapidly-evolving-resist-insecticides-study-finds/1624129001/.
"How to Manage Pests." UC IPM Online. Accessed August 07, 2019. http://ipm.ucanr.edu/PMG/PESTNOTES/pn7467.html.
Images / Photographs:
Wikipedia contributors, "American cockroach," Wikipedia, The Free Encyclopedia, https://en.wikipedia.org/w/index.php?title=American_cockroach&oldid=902501421 (accessed July 26, 2019).
Wikipedia contributors, "Australian cockroach," Wikipedia, The Free Encyclopedia, https://en.wikipedia.org/w/index.php?title=Australian_cockroach&oldid=831890843 (accessed July 26, 2019).
Wikipedia contributors, "Cockroach," Wikipedia, The Free Encyclopedia, https://en.wikipedia.org/w/index.php?title=Cockroach&oldid=907405093 (accessed July 26, 2019).
Wikipedia contributors, "Madagascar hissing cockroach," Wikipedia, The Free Encyclopedia, https://en.wikipedia.org/w/index.php?title=Madagascar_hissing_cockroach&oldid=892817231(accessed July 26, 2019).
Questions & Answers
© 2019 Larry Slawson