Cockroaches
Overview
Cockroaches (or simply "roaches") are insects of the order Blattaria. This name derives from the Latin word for "cockroach",
blatta.
There are about 4,000 species of cockroach of which 30 species are associated with human habitations and about four species
are well known as pests.
Among the most well-known pest species are the American cockroach, Periplaneta americana, which is about 30 millimetres
(1.2 in) long, the German cockroach, Blattella germanica, about 15 millimetres (½ in) long, the Asian cockroach, Blattella
asahinai, also about 15 millimetres (½ in) in length, and the Oriental cockroach, Blatta orientalis, about 25 millimetres (1 in).
Tropical cockroaches are often much bigger, and extinct cockroach relatives such as the Carboniferous Archimylacris and the
Permian Apthoroblattina were several times as large as these.
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 found within buildings. Many tropical species prefer even warmer environments and do
not fare well in the average household.
The spines on the legs were earlier considered to be sensory, but observations of their locomotion on sand and wire meshes has
demonstrated that they help in locomotion on difficult terrain. The structures have been used as inspiration for robotic legs.
Cockroaches leave chemical trails in their feces as well as emitting airborne pheromones for swarming and mating. Other
cockroaches will follow these trails to discover sources of food and water, and also discover where other cockroaches are hiding.
Thus, cockroaches can exhibit emergent behavior, in which group or swarm behavior emerges from a simple set of individual
interactions.
Research has shown that group-based decision-making is responsible for complex behavior such as resource allocation. In a
study where 50 cockroaches were placed in a dish with three shelters with a capacity for 40 insects in each, the insects arranged
themselves in two shelters with 25 insects in each, leaving the third shelter empty. When the capacity of the shelters was
increased to more than 50 insects per shelter, all of the cockroaches arranged themselves in one shelter. Researchers found a
balance between cooperation and competition exists in group decision-making behavior found in cockroaches. The models used
in this research can also explain the group dynamics of other insects and animals.
Cockroaches are mainly nocturnal and will run away when exposed to light. A peculiar exception is the Asian cockroach, which is
attracted to light. Another study tested the hypothesis that cockroaches use just two pieces of information to decide where to go
under those conditions: how dark it is and how many of their friends are there.
Click on the links to the left to find out more on individual UK species.
</i> is the largest cockroach found in the UK. Reddish-brown in colour, this beast is nearly two inches long when fully grown.<p>At warm temperatures, American cockroaches fly quite readily.<p>Like most cockroaches, they eat practically anything. American cockroaches prefer to live in warm damp areas such as risers, pipe ducts, drains and basements.<p>They lay egg cases - "parcels" of eggs, containing up to 28 eggs each, so populations can grow very quickly.<p><h3>Biology</h3><p>Nymphs hatch from eggs laid in oothecae (egg cases) with between 14 & 28 eggs per ootheca. The eggs take between 29 & 58 days to develop. The newly hatched nymphal (developmental) stage takes between 130 - 150 days, before the nymphs attain maturity. Females lay eggs in oothecae, which may be cemented in place in groups. The average life span of an adult American cockroach is approx. one year.<p><h3>Distribution</h3><p>Found around the world in tropical areas, but can live quite comfortably in less temperate zones, inside buildings - tending to favour large, centrally heated buildings such as hotels, apartment blocks, hospitals etc.<p><h3>Significance</h3><p>Cockroach infestations present a serious threat of disease, and cockroaches act as vectors of such diseases as E. Coli, Salmonellosis, and others. The presence of cockroaches in Food Preparation Areas is a serious threat to the safety of food.<p><h3>Control</h3><p>A thorough inspection is necessary to determine the source and extent of any cockroach infestation. Once the source of the infestation and any harbourages are located, they should be treated using an integrated approach, using insect monitors, night inspections, baits, and perhaps residual insecticides which incorporate an insect growth regulator.','success')){kind=link}
</i> are seldom found in Britain. They prefer a far warmer climate, of between 32 and 36 degrees centigrade. Where they do occur in the UK, they have been invariably imported into the country, most likely in foodstuffs. They are very occasionally found in greenhouses, inbound ships and containers. They are quite large cockroaches (30 - 35mm) and have characteristic markings on the thoracic carapace. <p><h3>Biology</h3><p>The young cockroaches (nymphs) hatch from egg cases (oothecae). Each female can lay up to 30 oothecae, and each ootheca can contain up to 24 eggs. The eggs take approximately 40 days to incubate.<p>The nymphs are like smaller versions of the adults, but have NO wings. Each nymph takes between 120 and 180 days to mature into adulthood.<p><h3>Distribution</h3><p>Contrary to their name, Australian cockroaches do not originate from Australia, but from Asia. They are extremely well established in the Southern states of the USA, extending from Florida to California.<p><h3>Significance</h3><p>Cockroach infestations present a serious threat of disease, and cockroaches act as vectors of such diseases as E. Coli, Salmonellosis, and others. The presence of cockroaches in Food Preparation Areas is a serious threat to the safety of food.<p><h3>Control</h3><p>A thorough inspection is necessary to determine the source and extent of any cockroach infestation. Once the source of the infestation and any harbourages are located, they should be treated using an integrated approach, using insect monitors, night inspections, baits, and perhaps residual insecticides which incorporate an insect growth regulator.','success')){kind=link}
</i> are a fairly rare visitor to our shores. Like American cockroaches, they may fly at high temperatures, but they are much smaller than their American cousins, being between 11 & 14mm in length.<p>Where they do infest buildings, they tend to disperse widely through the building, making control more difficult in multi-occupancy buildings.<p>Brown banded cockroaches are nocturnal and can eat practically anything.<p><h3>Biology</h3><p>Juvenile cockroackroaches (nymphs) hatch from egg cases (oothecae) which contain 16 eggs. Each female produces 5 - 18 oothecae in her life, each of which she carefully cements into a safe hiding place. The incubation period per egg case is approx. 40 days.<p>The nymphs take between 5- & 60 days to mature into the adult phase, so mature faster than most cockroaches.<p><h3>Distribution</h3><p>Brown Banded cockroaches originate in the African sub-continent, but are becoming more common in Europe. They tend to prefer starchy foods, often feeding on wall paper pastes, and similar substrates.<p>They seem to occur more frequently in domestic premises than in Commercial environments.<p><h3>Significance</h3><p>Cockroach infestations present a serious threat of disease, and cockroaches act as vectors of such diseases as E. Coli, Salmonellosis, and others. The presence of cockroaches in Food Preparation Areas is a serious threat to the safety of food.<p><h3>Control</h3><p>A thorough inspection is necessary to determine the source and extent of any cockroach infestation. Once the source of the infestation and any harbourages are located, they should be treated using an integrated approach, using insect monitors, night inspections, baits, and perhaps residual insecticides which incorporate an insect growth regulator.','success')){kind=link}
</i> are small, straw coloured cockroaches, between 12 & 15mm in length. Sometimes called the "steam fly" german cockroaches prefer a hot and humid atmosphere and so are commonly found in kitchens and bathrooms, in commercial laundries, and boiler-rooms. They are also a common pest in ships.They tend to aggregate together in their hiding places, and are always nocturnal in habit. German cockroaches can easily climb walls using the special sticky pads on their feet.<p><h3>Biology</h3><p>Females carry their egg cases (oothecae) with them until they are ready to hatch, releasing 35 - 40 young cockroaches at a time. The nymphs grow rapidly, sometimes attaining adulthood within six weeks, and will live for approximately six months.<p><h3>Distribution</h3><p>German Cockroaches are found all over the world, but most commonly in multi-occupancy buildings with a rapid resident turnover, in restaurants with poor hygiene, and in peoples homes.<p><h3>Significance</h3><p>Cockroach infestations present a serious threat of disease, and cockroaches act as vectors of such diseases as E. Coli, Salmonellosis, and others. The presence of cockroaches in Food Preparation Areas is a serious threat to the safety of food.<p><h3>Control</h3><p>A thorough inspection is necessary to determine the source and extent of any cockroach infestation. Once the source of the infestation and any harbourages are located, they should be treated using an integrated approach, using insect monitors, night inspections, baits, and perhaps residual insecticides which incorporate an insect growth regulator.','success')){kind=link}
</i> is usually dark brown in colour, between 25 & 30mm in length. They are always nocturnal.<p>Oriental cockroaches eat practically anything, and can tolerate lower ambient temperatures than other cockroach species. They can exist outside in Britain, but tend to infest cooler duct works, cellars and similar damp areas inside buildings.<p>Oriental cockroaches produce characteristic droppings which are "ridged", but which are sometimes confused with the droppings of young mice.<p>Oriental cockroaches also produce a characteristic unpleasant smell, when present in numbers.<p><h3>Biology</h3><p>Oriental cockroach nymphs hatch from eggs held in egg cases (oothecae) with a characteristic "purse shape". Each egg case carries up to 18 eggs, which take between 37 & 81 days to develop. The female drops the ootheca at birth. The nymphs develop more slowly than those of the german cockroach, taking some 24 - 130 weeks to develop fully.<p>Live for between 60 - 250 days dependent upon temperature.<p><h3>Distribution</h3><p>Oriental cockroaches are found all over the world, particularly in large buildings with central heating systems, such as tenement blocks, hotels and hospitals.<p><h3>Significance</h3><p>Cockroach infestations present a serious threat of disease, and cockroaches act as vectors of such diseases as E. Coli, Salmonellosis, and others. The presence of cockroaches in Food Preparation Areas is a serious threat to the safety of food.<p><h3>Control</h3><p>A thorough inspection is necessary to determine the source and extent of any cockroach infestation. Once the source of the infestation and any harbourages are located, they should be treated using an integrated approach, using insect monitors, night inspections, baits, and perhaps residual insecticides which incorporate an insect growth regulator.','success')){kind=link}