Cockroaches are insects belonging to the order Blattodea. There are somCockroachese 3,490 species of cockroaches in six families and they exist worldwide, with the exception of the polar regions.

Among the most well-known species are the American cockroach, Periplaneta americana, which is about 3cm long, and the German cockroach, Blatotella germanica, about 1½ cm long.

Cockroaches1

Biology


Cockroaches are generally either scavengers or omnivores, with the exception of wood-eating Cryptocercus species found in China and the United States. Although they are incapable of digesting the cellulose themselves, they have a symbiotic relationship with a protozoan that digests the cellulose, allowing them to extract the nutrients.

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.

Female cockroaches carry egg cases on the end of their abdomens. A female German cockroach carries an egg capsule known as ootheca that contains around 40 eggs. A female cockroach may produce up to eight egg cases in a lifetime; in favorable conditions, it can produce 300 to 400 offspring.

A female cockroach drops the capsule prior to hatching. 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. Development from eggs to adults takes 3 to 4 months. Cockroaches can live up to a year.

Other species, however, can produce an extremely high number of eggs in a lifetime. They lay up to 100 eggs in each egg sac and they only need to be impregnated once to lay eggs for the rest of their lives. Thus, one female cockroach can lay over a million eggs during its lifespan.

The world’s largest cockroach is the Australian giant burrowing cockroach which can grow to 9 cm in length and weigh more than 30 grams.

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.

The cockroach is one of the hardiest insects around. It is capable of living for a month without food. It can hold its breath for 45 minutes and has the ability to slow down its heart rate.

Cockroaches have been shown to exhibit emergent behaviour. Cockroaches leave chemical trails in their faeces. Other cockroaches will follow these trails to discover sources of food and water, and also discover where other cockroaches are hiding.

Cockroaches live in a wide range of environments around the world. Pest species of cockroaches adapt readily to a variety of environments, but prefer warm conditions. Many tropical species prefer even warmer environments and do not fare well in the average household.

 

Cockroach Life Cycl

Comparison Between German And American Cockroaches
CharacteristicsGerman CockroachAmerican Cockroach
HabitatFound in restaurants, hotels and urban apartments. Usually found in dark, secluded harbourage areas such as under cupboards, behind refrigerators, etc.Prefer warm, moist environment, drain and sewers. Most predominant species in Malaysia.
Length10 – 15mm35 – 44mm
Adult lifespanMore than 100 days100 days – 3 years
Oothecae produced per female4 – 910 – 90
Eggs per oothecae37 – 4814 – 28
Incubation period14 – 28 days30 – 45 days
Nymphal development period30 – 60 days150 days

 

Problems Associated With Cockroaches


Cockroaches may become pests in homes, restaurants, hospitals, warehouses, offices, and virtually any structure that has food preparation or storage areas. They contaminate food and eating utensils, destroy fabric and paper products, and impart stains and unpleasant odours to surfaces they contact.

Cockroaches (especially the American cockroach, which comes into contact with human excrement in sewers or with pet droppings) may transmit bacteria that cause food poisoning (Salmonella spp. and Shigella spp.). German cockroaches are believed to be capable of transmitting disease-causing organisms such as Staphylococcus spp.,Streptococcus spp., hepatitis virus, and coliform bacteria. They also have been implicated in the spread of typhoid and dysentery. Some people, especially those with asthma, are sensitive to the allergens produced by these cockroaches. However, a major concern with cockroaches is that people are repulsed when they find cockroaches in their homes and kitchens.

Evidence of Cockroach Infestation

Live cockroach
Faecal pellets
Empty egg cases
Dead cockroaches
Cast skins
Cockroach smell


Tips on Managing Cockroaches

Cockroaches thrive where food and water are available to them. Even tiny amounts of crumbs or liquids caught between cracks provide a food source. Important sanitation measures include the following:

Store food in insect-proof containers such as glass jars or sealable plastic containers.
Keep garbage and trash in containers with tight-fitting lids. Remove trash, newspapers, magazines, boxes and other items that provide hiding places and harbourage.
Eliminate plumbing leaks and correct other sources of free moisture. Increase ventilation where condensation is a problem.
Vacuum cracks and crevices to remove food and debris. Be sure surfaces where food or beverages have been spilled are cleaned up immediately. Vacuuming also removes cockroaches, shed skins, and egg capsules. Removing cockroaches reduces their numbers and slows development. Vacuumed cockroaches and debris should be destroyed. Because bits of cuticle and droppings may be allergenic, it is recommended that the vacuum cleaner have HEPA (high efficiency particulate absorber) or triple filters.
Trim shrubbery around buildings to increase light and air circulation, especially near vents, and eliminate ivy or other dense ground covers near the house, as these may harbour cockroaches.
Remove trash and stored items such as stacks of lumber or firewood that provide hiding places for cockroaches from around the outside of buildings.

 

Tips on Managing Cockroaches

Cockroaches thrive where food and water are available to them. Even tiny amounts of crumbs or liquids caught between cracks provide a food source. Important sanitation measures include the following:

Store food in insect-proof containers such as glass jars or sealable plastic containers.
Keep garbage and trash in containers with tight-fitting lids. Remove trash, newspapers, magazines, boxes and other items that provide hiding places and harbourage.
Eliminate plumbing leaks and correct other sources of free moisture. Increase ventilation where condensation is a problem.
Vacuum cracks and crevices to remove food and debris. Be sure surfaces where food or beverages have been spilled are cleaned up immediately. Vacuuming also removes cockroaches, shed skins, and egg capsules. Removing cockroaches reduces their numbers and slows development. Vacuumed cockroaches and debris should be destroyed. Because bits of cuticle and droppings may be allergenic, it is recommended that the vacuum cleaner have HEPA (high efficiency particulate absorber) or triple filters.
Trim shrubbery around buildings to increase light and air circulation, especially near vents, and eliminate ivy or other dense ground covers near the house, as these may harbour cockroaches.
Remove trash and stored items such as stacks of lumber or firewood that provide hiding places for cockroaches from around the outside of buildings.

 

Exclude and Remove Hiding Places

During the day cockroaches hide around water heaters, in cupboard cracks, stoves, crawl spaces, outdoor vegetation, and many other locations. They invade kitchens and other areas at night. Limiting hiding areas or avenues of access to living areas is an essential part of an effective management strategy.
False-bottom cupboards, hollow walls, and similar areas are common cockroach refuges. Prevent access to the inside of buildings through cracks, conduits, under doors, or through other structural flaws. If it is not practical to remedy these problem areas, treat them with boric acid powder.

 

Cockroaches Migrating From Outdoors

Take the following measures if cockroaches are migrating into a building from outdoors or other areas of the building:

Seal cracks and other openings to the outside.
Look for other methods of entry, such as from items being brought into the building, especially appliances, furniture, and items that were recently in storage.
Look for oothecae glued to undersides of furniture, in refrigerator and other appliance motors, boxes, and other items. Remove and destroy any that are located.
Locate and seal cracks inside the treatment area where cockroaches can hide.