Cockroach (band)
   HOME

TheInfoList



OR:

Cockroaches (or roaches) are a
paraphyletic In taxonomy (general), taxonomy, a group is paraphyletic if it consists of the group's most recent common ancestor, last common ancestor and most of its descendants, excluding a few Monophyly, monophyletic subgroups. The group is said to be pa ...
group of
insect Insects (from Latin ') are pancrustacean hexapod invertebrates of the class Insecta. They are the largest group within the arthropod phylum. Insects have a chitinous exoskeleton, a three-part body ( head, thorax and abdomen), three pairs ...
s belonging to
Blattodea Blattodea is an order of insects that contains cockroaches and termites. Formerly, termites were considered a separate order, Isoptera, but genetic and molecular evidence suggests they evolved from within the cockroach lineage, cladistically ...
, containing all members of the group except
termite Termites are small insects that live in colonies and have distinct castes (eusocial) and feed on wood or other dead plant matter. Termites comprise the infraorder Isoptera, or alternatively the epifamily Termitoidae, within the order Blattode ...
s. About 30 cockroach species out of 4,600 are associated with human habitats. Some species are well-known as
pest Pest or The Pest may refer to: Science and medicine * Pest (organism), an animal or plant deemed to be detrimental to humans or human concerns ** Weed, a plant considered undesirable * Infectious disease, an illness resulting from an infection ** ...
s. The cockroaches are an ancient group, with their ancestors, known as " roachoids", originating during the
Carboniferous The Carboniferous ( ) is a geologic period and system of the Paleozoic that spans 60 million years from the end of the Devonian Period million years ago ( Mya), to the beginning of the Permian Period, million years ago. The name ''Carbonifero ...
period, some 320 million years ago. Those early ancestors, however, lacked the internal
ovipositor The ovipositor is a tube-like organ used by some animals, especially insects, for the laying of eggs. In insects, an ovipositor consists of a maximum of three pairs of appendages. The details and morphology of the ovipositor vary, but typical ...
s of modern roaches. Cockroaches are somewhat generalized insects lacking special adaptations (such as the sucking mouthparts of
aphid Aphids are small sap-sucking insects and members of the superfamily Aphidoidea. Common names include greenfly and blackfly, although individuals within a species can vary widely in color. The group includes the fluffy white woolly aphids. A t ...
s and other
true bugs Hemiptera (; ) is an order of insects, commonly called true bugs, comprising over 80,000 species within groups such as the cicadas, aphids, planthoppers, leafhoppers, assassin bugs, bed bugs, and shield bugs. They range in size from to aroun ...
); they have chewing mouthparts and are probably among the most primitive of living
Neoptera Neoptera (Ancient Greek ''néos'' (“new”) + ''pterón'' (“wing”)) is a classification group that includes most orders of the winged insects, specifically those that can flex their wings over their abdomens. This is in contrast with the mo ...
n insects. They are common and hardy insects capable of tolerating a wide range of
climates Climate is the long-term weather pattern in an area, typically averaged over 30 years. More rigorously, it is the mean and variability of meteorological variables over a time spanning from months to millions of years. Some of the meteorologic ...
, from
Arctic The Arctic ( or ) is a polar regions of Earth, polar region located at the northernmost part of Earth. The Arctic consists of the Arctic Ocean, adjacent seas, and parts of Canada (Yukon, Northwest Territories, Nunavut), Danish Realm (Greenla ...
cold to
tropical The tropics are the regions of Earth surrounding the Equator. They are defined in latitude by the Tropic of Cancer in the Northern Hemisphere at N and the Tropic of Capricorn in the Southern Hemisphere at S. The tropics are also referred to ...
heat. Tropical cockroaches are often much larger than temperate species. Modern cockroaches are not considered to be a
monophyletic In cladistics for a group of organisms, monophyly is the condition of being a clade—that is, a group of taxa composed only of a common ancestor (or more precisely an ancestral population) and all of its lineal descendants. Monophyletic gro ...
group, as it has been found based on genetics that termites are deeply nested within the group, with some groups of cockroaches more closely related to termites than they are to other cockroaches. Some species, such as the gregarious
German cockroach The German cockroach (''Blattella germanica''), colloquially known as the croton bug, is a species of small cockroach, typically about long. In color it varies from tan to almost black, and it has two dark, roughly parallel, streaks on the prono ...
, have an elaborate social structure involving common shelter, social dependence, information transfer and kin recognition. Cockroaches have appeared in human culture since
classical antiquity Classical antiquity (also the classical era, classical period or classical age) is the period of cultural history between the 8th century BC and the 5th century AD centred on the Mediterranean Sea, comprising the interlocking civilizations of ...
. They are popularly depicted as dirty pests, although the majority of species are inoffensive and live in a wide range of habitats around the world.


Taxonomy and evolution

Cockroaches are members of the superorder
Dictyoptera Dictyoptera (from Greek δίκτυον ''diktyon'' "net" and πτερόν ''pteron'' "wing") is an insect superorder that includes two extant orders of polyneopterous insects: the order Blattodea (termites and cockroaches together) and the ord ...
, which includes the
termite Termites are small insects that live in colonies and have distinct castes (eusocial) and feed on wood or other dead plant matter. Termites comprise the infraorder Isoptera, or alternatively the epifamily Termitoidae, within the order Blattode ...
s and
mantid Mantidae is one of the largest families in the order of praying mantises, based on the type species ''Mantis religiosa''; however, most genera are tropical or subtropical. Historically, this was the only family in the order, and many reference ...
s, a group of insects once thought to be separate from cockroaches. Currently, 4,600 species and over 460 genera are described worldwide. The name "
cockroach Cockroaches (or roaches) are a paraphyletic group of insects belonging to Blattodea, containing all members of the group except termites. About 30 cockroach species out of 4,600 are associated with human habitats. Some species are well-known as ...
" comes from the Spanish word for cockroach, ''cucaracha'', transformed by 1620s English
folk etymology Folk etymology (also known as popular etymology, analogical reformation, reanalysis, morphological reanalysis or etymological reinterpretation) is a change in a word or phrase resulting from the replacement of an unfamiliar form by a more famili ...
into "cock" and "roach". The scientific name derives from the Latin ''blatta'', "an insect that shuns the light", which in classical Latin was applied not only to cockroaches, but also to
mantids Mantidae is one of the largest families in the order of praying mantises, based on the type species '' Mantis religiosa''; however, most genera are tropical or subtropical. Historically, this was the only family in the order, and many referen ...
. Historically, the name Blattaria was used largely interchangeably with the name Blattodea, but whilst Blattaria was used to refer to 'true' cockroaches exclusively, the Blattodea also includes the termites. The current catalogue of world cockroach species uses the name Blattodea for the group. Another name,
Blattoptera "Roachoids", also known as "Roachids" or "Blattoids" are members of the stem group of Dictyoptera (the group containing modern cockroaches, termites and praying mantises). They generally resemble cockroaches, but most members, unlike modern dict ...
, is also sometimes used to refer to extinct cockroach relatives. The earliest cockroach-like fossils ("blattopterans" or "roachoids") are from the
Carboniferous The Carboniferous ( ) is a geologic period and system of the Paleozoic that spans 60 million years from the end of the Devonian Period million years ago ( Mya), to the beginning of the Permian Period, million years ago. The name ''Carbonifero ...
period 320 million years ago, as are fossil roachoid nymphs. According to one
hypothesis A hypothesis (plural hypotheses) is a proposed explanation for a phenomenon. For a hypothesis to be a scientific hypothesis, the scientific method requires that one can test it. Scientists generally base scientific hypotheses on previous obse ...
, cockroaches were an ancient group of insects that arose during the
Devonian The Devonian ( ) is a geologic period and system of the Paleozoic era, spanning 60.3 million years from the end of the Silurian, million years ago (Mya), to the beginning of the Carboniferous, Mya. It is named after Devon, England, whe ...
period. Fossil roachoids that lived during that time differ from modern cockroaches in that they had long external
ovipositor The ovipositor is a tube-like organ used by some animals, especially insects, for the laying of eggs. In insects, an ovipositor consists of a maximum of three pairs of appendages. The details and morphology of the ovipositor vary, but typical ...
s and are the ancestors of
mantis Mantises are an order (Mantodea) of insects that contains over 2,400 species in about 460 genera in 33 families. The largest family is the Mantidae ("mantids"). Mantises are distributed worldwide in temperate and tropical habitats. They ha ...
es, as well as modern cockroaches. As the body, hind wings and mouthparts are not preserved in fossils frequently, the relationship of these roachoids and modern cockroaches remains disputed. The first fossils of modern cockroaches with internal ovipositors appeared in the early
Cretaceous The Cretaceous ( ) is a geological period that lasted from about 145 to 66 million years ago (Mya). It is the third and final period of the Mesozoic Era, as well as the longest. At around 79 million years, it is the longest geological period of th ...
. A recent phylogenetic analysis suggests that cockroaches originated at least in the
Jurassic The Jurassic ( ) is a Geological period, geologic period and System (stratigraphy), stratigraphic system that spanned from the end of the Triassic Period million years ago (Mya) to the beginning of the Cretaceous Period, approximately Mya. The J ...
. The evolutionary relationships of the Blattodea (cockroaches and termites) shown in the
cladogram A cladogram (from Greek ''clados'' "branch" and ''gramma'' "character") is a diagram used in cladistics to show relations among organisms. A cladogram is not, however, an evolutionary tree because it does not show how ancestors are related to d ...
are based on Inward, Beccaloni and Eggleton (2007). The cockroach families
Anaplectidae Anaplectidae is a family of cockroaches in the order Blattodea. Previously placed as a subfamily of the Ectobiidae there are presently (2020) two genera and more than 90 described species in Anaplectidae. Genera These two genera belong to the ...
,
Lamproblattidae Lamproblattidae is a small family of South and Central American cockroaches in the order Blattodea Blattodea is an order of insects that contains cockroaches and termites. Formerly, termites were considered a separate order, Isoptera, but g ...
, and
Tryonicidae The Tryonicidae are a family of cockroaches. Biodiversity and distribution Two genera containing 17 species are currently confirmed as belonging to this family. Table 1: Number of species of Tryonicidae in each region in which it is present (A ...
are not shown but are placed within the superfamily Blattoidea. The cockroach families
Corydiidae Corydiidae, previously known as Polyphagidae, is a family of the order Blattodea (cockroaches). Many are known as sand cockroaches. The family is divided into five subfamilies, comprising some 40 genera. One prominent species is the desert cockroa ...
and
Ectobiidae Ectobiidae (formerly Blattellidae) is a family of the order Blattodea (cockroaches). This family contains many of the smaller common household pest cockroaches, among others. They are sometimes called wood cockroaches. A few notable species inclu ...
were previously known as the Polyphagidae and Blattellidae. Termites were previously regarded as a separate order
Isoptera Termites are small insects that live in colonies and have distinct castes (eusocial) and feed on wood or other dead plant matter. Termites comprise the infraorder Isoptera, or alternatively the epifamily Termitoidae, within the order Blattode ...
to cockroaches. However, recent genetic evidence strongly suggests that they evolved directly from 'true' cockroaches, and many authors now place them as an "
epifamily In biological classification, taxonomic rank is the relative level of a group of organisms (a taxon) in an ancestral or hereditary hierarchy. A common system consists of species, genus, family, order, class, phylum, kingdom, domain. While olde ...
" of Blattodea. This evidence supported a hypothesis suggested in 1934 that termites are closely related to the wood-eating cockroaches (genus ''
Cryptocercus ''Cryptocercus'' is a genus of Dictyoptera (cockroaches and allies) and the sole member of its own family Cryptocercidae. Species are known as wood roaches or brown-hooded cockroaches. These roaches are subsocial, their young requiring considera ...
''). This hypothesis was originally based on similarity of the symbiotic gut
flagellate A flagellate is a cell or organism with one or more whip-like appendages called flagella. The word ''flagellate'' also describes a particular construction (or level of organization) characteristic of many prokaryotes and eukaryotes and their ...
s in termites regarded as
living fossil A living fossil is an extant taxon that cosmetically resembles related species known only from the fossil record. To be considered a living fossil, the fossil species must be old relative to the time of origin of the extant clade. Living fossi ...
s and wood-eating cockroaches. Additional evidence emerged when F. A. McKittrick (1965) noted similar morphological characteristics between some termites and cockroach nymphs. The similarities among these cockroaches and termites have led some scientists to reclassify termites as a single family, the
Termitidae Termitidae is the largest family of termites whose members are commonly known as the higher termites. They are evolutionarily the most specialised termite group, with their highly compartmentalized hindgut lacking the flagellated protozoans comm ...
, within the order Blattodea. Other scientists have taken a more conservative approach, proposing to retain the termites as the
Termitoidae Termites are small insects that live in colonies and have distinct castes (eusocial) and feed on wood or other dead plant matter. Termites comprise the infraorder Isoptera, or alternatively the epifamily Termitoidae, within the order Blatto ...
, an
epifamily In biological classification, taxonomic rank is the relative level of a group of organisms (a taxon) in an ancestral or hereditary hierarchy. A common system consists of species, genus, family, order, class, phylum, kingdom, domain. While olde ...
within the order. Such a measure preserves the classification of termites at family level and below.


Description

Most species of cockroach are about the size of a thumbnail, but several species are larger. The world's heaviest cockroach is the Australian
giant burrowing cockroach The giant burrowing cockroach (''Macropanesthia rhinoceros'') is also known as the rhinoceros cockroach, and Queensland giant cockroach. These cockroaches are native to Australia and mostly found in tropical and subtropical parts of Queensland. ...
''Macropanesthia rhinoceros'', which can reach in length and weigh up to . Comparable in size is the Central American giant cockroach ''
Blaberus giganteus ''Blaberus giganteus'', the Central American giant cave cockroach or Brazilian cockroach, is a cockroach belonging to the family Blaberidae. Description ''Blaberus giganteus'' is considered one of the largest cockroaches in the world, with mal ...
''. The longest cockroach species is ''
Megaloblatta longipennis ''Megaloblatta longipennis'' is a species of cockroach in the family Ectobiidae Ectobiidae (formerly Blattellidae) is a family of the order Blattodea (cockroaches). This family contains many of the smaller common household pest cockroaches, amon ...
'', which can reach in length and across. A Central and South American species, ''
Megaloblatta blaberoides ''Megaloblatta'' is a genus of cockroaches in the family Ectobiidae. It includes the largest living species of cockroach, ''Megaloblatta longipennis'', which can grow to in length and have a wingspan of up to . ''Megaloblatta'', like many other ...
'', has the largest wingspan of up to . At the other end of the size scale, ''
Attaphila ''Attaphila'' is a genus of cockroaches that live as myrmecophiles in the nests of leaf-cutting ants. They have been suggested to feed on the fungus their host ants farm, or on the cuticular lipids of ant workers. ''Attaphila'' are not attacke ...
'' cockroaches that live with
leaf-cutter ants Leafcutter ants, a non-generic name, are any of 47 species of leaf-chewing ants belonging to the two genera '' Atta'' and ''Acromyrmex''. These species of tropical, fungus-growing ants are all endemic to South and Central America, Mexico, and p ...
include some of the world's smallest species, growing to about 3.5 mm in length. Cockroaches are generalized insects with few special adaptations, and may be among the most primitive living
Neoptera Neoptera (Ancient Greek ''néos'' (“new”) + ''pterón'' (“wing”)) is a classification group that includes most orders of the winged insects, specifically those that can flex their wings over their abdomens. This is in contrast with the mo ...
n insects. They have a relatively small head and a broad, flattened body, and most species are reddish-brown to dark brown. They have large
compound eye A compound eye is a visual organ found in arthropods such as insects and crustaceans. It may consist of thousands of ommatidia, which are tiny independent photoreception units that consist of a cornea, lens, and photoreceptor cells which disti ...
s, two
ocelli A simple eye (sometimes called a pigment pit) refers to a form of eye or an optical arrangement composed of a single lens and without an elaborate retina such as occurs in most vertebrates. In this sense "simple eye" is distinct from a multi-l ...
, and long, flexible antennae. The mouthparts are on the underside of the head and include generalized chewing
mandibles In anatomy, the mandible, lower jaw or jawbone is the largest, strongest and lowest bone in the human facial skeleton. It forms the lower jaw and holds the lower tooth, teeth in place. The mandible sits beneath the maxilla. It is the only movabl ...
,
salivary gland The salivary glands in mammals are exocrine glands that produce saliva through a system of ducts. Humans have three paired major salivary glands (parotid, submandibular, and sublingual), as well as hundreds of minor salivary glands. Salivary gla ...
s and various touch and taste receptors. The body is divided into a
thorax The thorax or chest is a part of the anatomy of humans, mammals, and other tetrapod animals located between the neck and the abdomen. In insects, crustaceans, and the extinct trilobites, the thorax is one of the three main divisions of the cre ...
of three segments and a ten-segmented abdomen. The external surface has a tough
exoskeleton An exoskeleton (from Greek ''éxō'' "outer" and ''skeletós'' "skeleton") is an external skeleton that supports and protects an animal's body, in contrast to an internal skeleton (endoskeleton) in for example, a human. In usage, some of the ...
which contains calcium carbonate; this protects the inner organs and provides attachment to muscles. This external exoskeleton is coated with wax to repel water. The wings are attached to the second and third thoracic segments. The
tegmina A tegmen (plural: ''tegmina'') designates the modified leathery front wing on an insect particularly in the orders Dermaptera (earwigs), Orthoptera (grasshoppers, crickets and similar families), Mantodea (praying mantis), Phasmatodea (stick an ...
, or first pair of wings, are tough and protective; these lay as a shield on top of the membranous hind wings, which are used in flight. All four wings have branching longitudinal veins, as well as multiple cross-veins. The three pairs of legs are sturdy, with large coxae and five claws each. They are attached to each of the three thoracic segments. Of these, the front legs are the shortest and the hind legs the longest, providing the main propulsive power when the insect runs. The spines on the legs were earlier considered to be sensory, but observations of the insect's gait on sand and wire meshes have demonstrated that they help in locomotion on difficult terrain. The structures have been used as inspiration for robotic legs. The abdomen has ten segments, each having a pair of
spiracle Spiracle or spiraculum may refer to: * Spiracle (arthropods), opening in the exoskeletons of some arthropods * Spiracle (vertebrates), openings on the surface of some vertebrates * Spiraculum, a genus of land snails in family Cyclophoridae Cycl ...
s for respiration. In addition to the spiracles, the final segment consists of a pair of cerci, a pair of anal styles, the anus and the external genitalia. Males have an
aedeagus An aedeagus (plural aedeagi) is a reproductive organ of male arthropods through which they secrete sperm from the testes during copulation with a female. It can be thought of as the insect equivalent of a mammal's penis, though the comparison ...
through which they secrete sperm during copulation, while females have
spermatheca The spermatheca (pronounced plural: spermathecae ), also called receptaculum seminis (plural: receptacula seminis), is an organ of the female reproductive tract in insects, e.g. ants, bees, some molluscs, oligochaeta worms and certain other ...
for storing sperm and an
ovipositor The ovipositor is a tube-like organ used by some animals, especially insects, for the laying of eggs. In insects, an ovipositor consists of a maximum of three pairs of appendages. The details and morphology of the ovipositor vary, but typical ...
through which the
oothecae An ootheca (pl. ''oothecae'' ) is a type of egg mass made by any member of a variety of species including mollusks (such as ''Turbinella laevigata''), mantises, and cockroaches. The word is a Latinized combination of ''oo-'', meaning "egg", fro ...
are laid.


Distribution and habitat

Cockroaches are abundant throughout the world and live in a wide range of environments, especially in the
tropics The tropics are the regions of Earth surrounding the Equator. They are defined in latitude by the Tropic of Cancer in the Northern Hemisphere at N and the Tropic of Capricorn in the Southern Hemisphere at S. The tropics are also referred to ...
and
subtropics The subtropical zones or subtropics are geographical and climate zones to the north and south of the tropics. Geographically part of the temperate zones of both hemispheres, they cover the middle latitudes from to approximately 35° north and ...
. Cockroaches can withstand extremely low temperatures, allowing them to live in the
Arctic The Arctic ( or ) is a polar regions of Earth, polar region located at the northernmost part of Earth. The Arctic consists of the Arctic Ocean, adjacent seas, and parts of Canada (Yukon, Northwest Territories, Nunavut), Danish Realm (Greenla ...
. Some species are capable of surviving temperatures of by manufacturing an antifreeze made out of
glycerol Glycerol (), also called glycerine in British English and glycerin in American English, is a simple triol compound. It is a colorless, odorless, viscous liquid that is sweet-tasting and non-toxic. The glycerol backbone is found in lipids known ...
. In
North America North America is a continent in the Northern Hemisphere and almost entirely within the Western Hemisphere. It is bordered to the north by the Arctic Ocean, to the east by the Atlantic Ocean, to the southeast by South America and the Car ...
, 50 species separated into five families are found throughout the continent. 450 species are found in
Australia Australia, officially the Commonwealth of Australia, is a Sovereign state, sovereign country comprising the mainland of the Australia (continent), Australian continent, the island of Tasmania, and numerous List of islands of Australia, sma ...
. Only about four widespread species are commonly regarded as pests. Cockroaches occupy a wide range of habitats. Many live in
leaf litter Plant litter (also leaf litter, tree litter, soil litter, litterfall or duff) is dead plant material (such as leaves, bark, needles, twigs, and cladodes) that have fallen to the ground. This detritus or dead organic material and its constituent ...
, among the stems of matted vegetation, in rotting wood, in holes in stumps, in cavities under bark, under log piles and among debris. Some live in arid regions and have developed mechanisms to survive without access to water sources. Others are aquatic, living near the surface of water bodies, including
bromeliad The Bromeliaceae (the bromeliads) are a family of monocot flowering plants of about 80 genera and 3700 known species, native mainly to the tropical Americas, with several species found in the American subtropics and one in tropical west Africa, ...
phytotelma Phytotelma (plural phytotelmata) is a small water-filled cavity in a terrestrial plant. The water accumulated within these plants may serve as the habitat for associated fauna and flora. A rich literature in German summarised by Thienemann (19 ...
ta, and diving to forage for food. Most of these respire by piercing the water surface with the tip of the abdomen which acts as a snorkel, but some carry a bubble of air under their thoracic shield when they submerge. Others live in the
forest canopy In biology, the canopy is the aboveground portion of a plant cropping or crop, formed by the collection of individual plant crowns. In forest ecology, canopy also refers to the upper layer or habitat zone, formed by mature tree crowns an ...
where they may be one of the main types of
invertebrate Invertebrates are a paraphyletic group of animals that neither possess nor develop a vertebral column (commonly known as a ''backbone'' or ''spine''), derived from the notochord. This is a grouping including all animals apart from the chordate ...
present. Here they may hide during the day in crevices, among dead leaves, in bird and insect nests or among
epiphyte An epiphyte is an organism that grows on the surface of a plant and derives its moisture and nutrients from the air, rain, water (in marine environments) or from debris accumulating around it. The plants on which epiphytes grow are called phoroph ...
s, emerging at night to feed.


Behavior

Cockroaches are social insects; a large number of species are either
gregarious Sociality is the degree to which individuals in an animal population tend to associate in social groups (gregariousness) and form cooperative societies. Sociality is a survival response to evolutionary pressures. For example, when a mother wasp ...
or inclined to aggregate, and a slightly smaller number exhibit parental care. It used to be thought that cockroaches aggregated because they were reacting to environmental cues, but it is now believed that
pheromone A pheromone () is a secreted or excreted chemical factor that triggers a social response in members of the same species. Pheromones are chemicals capable of acting like hormones outside the body of the secreting individual, to affect the behavio ...
s are involved in these behaviors. Some species secrete these in their feces with gut microbial
symbionts Symbiosis (from Greek , , "living together", from , , "together", and , bíōsis, "living") is any type of a close and long-term biological interaction between two different biological organisms, be it mutualistic, commensalistic, or parasit ...
being involved, while others use glands located on their
mandible In anatomy, the mandible, lower jaw or jawbone is the largest, strongest and lowest bone in the human facial skeleton. It forms the lower jaw and holds the lower tooth, teeth in place. The mandible sits beneath the maxilla. It is the only movabl ...
s. Pheromones produced by the
cuticle A cuticle (), or cuticula, is any of a variety of tough but flexible, non-mineral outer coverings of an organism, or parts of an organism, that provide protection. Various types of "cuticle" are non- homologous, differing in their origin, structu ...
may enable cockroaches to distinguish between different populations of cockroach by odor. The behaviors involved have been studied in only a few species, but German cockroaches leave fecal trails with an odor gradient. Other cockroaches follow such trails to discover sources of food and water, and where other cockroaches are hiding. Thus, cockroaches have
emergent behavior In philosophy, systems theory, science, and art, emergence occurs when an entity is observed to have properties its parts do not have on their own, properties or behaviors that emerge only when the parts interact in a wider whole. Emergence ...
, in which group or
swarm behavior Swarm behaviour, or swarming, is a collective behaviour exhibited by entities, particularly animals, of similar size which aggregate together, perhaps milling about the same spot or perhaps moving ''en masse'' or migrating in some direction. ...
emerges from a simple set of individual interactions. Daily rhythms may also be regulated by a complex set of hormonal controls of which only a small subset have been understood. In 2005, the role of one of these proteins,
pigment dispersing factor ''Pigment dispersing factor'' (''pdf'') is a gene that encodes the protein PDF, which is part of a large family of neuropeptides. Its hormonal product, pigment dispersing hormone (PDH), was named for the diurnal pigment movement effect it has i ...
(PDF), was isolated and found to be a key mediator in the
circadian rhythm A circadian rhythm (), or circadian cycle, is a natural, internal process that regulates the sleep–wake cycle and repeats roughly every 24 hours. It can refer to any process that originates within an organism (i.e., Endogeny (biology), endogeno ...
s of the cockroach. Pest species adapt readily to a variety of environments, but prefer warm conditions found within buildings. Many tropical species prefer even warmer environments. Cockroaches are mainly
nocturnal Nocturnality is an animal behavior characterized by being active during the night and sleeping during the day. The common adjective is "nocturnal", versus diurnal meaning the opposite. Nocturnal creatures generally have highly developed sens ...
and run away when exposed to light. An exception to this is the
Asian cockroach The Asian cockroach (''Blattella asahinai''), is a species of cockroach that was first described in 1981 from insects collected on Okinawa Island, Japan. It is a small species of cockroach, typically long and tan to dark brown in colour with ...
, which flies mostly at night but is attracted to brightly lit surfaces and pale colors.


Collective decision-making

Gregarious cockroaches display collective decision-making when choosing food sources. When a sufficient number of individuals (a "quorum") exploits a food source, this signals to newcomer cockroaches that they should stay there longer rather than leave for elsewhere. Other mathematical models have been developed to explain aggregation dynamics and conspecific recognition. Cooperation and competition are balanced in cockroach group decision-making behavior. Cockroaches appear to use just two pieces of information to decide where to go, namely how dark it is and how many other cockroaches there are. A study used specially scented roach-sized robots that seem real to the roaches to demonstrate that once there are enough insects in a place to form a
critical mass In nuclear engineering, a critical mass is the smallest amount of fissile material needed for a sustained nuclear chain reaction. The critical mass of a fissionable material depends upon its nuclear properties (specifically, its nuclear fissi ...
, the roaches accepted the collective decision on where to hide, even if this was an unusually lit place.


Social behavior

When reared in isolation, German cockroaches show behavior that is different from behavior when reared in a group. In one study, isolated cockroaches were less likely to leave their shelters and explore, spent less time eating, interacted less with conspecifics when exposed to them, and took longer to recognize receptive females. Because these changes occurred in many contexts, the authors suggested them as constituting a
behavioral syndrome In behavioral ecology, a behavioral syndrome is a correlated suite of behavioral traits, often (but not always) measured across multiple contexts. The suite of traits that are correlated at the population or species level is considered the behavi ...
. These effects might have been due either to reduced metabolic and developmental rates in isolated individuals or the fact that the isolated individuals had not had a training period to learn about what others were like via their antennae. Individual
American cockroach The american cockroach (''Periplaneta americana'') is the largest species of common cockroach, and often considered a pest. In certain regions of the U.S. it is colloquially known as the waterbug, though it is not a true waterbug since it is not ...
es appear to have consistently different "personalities" regarding how they seek shelter. In addition, group personality is not simply the sum of individual choices, but reflects conformity and collective decision-making. The gregarious German and American cockroaches have elaborate
social structure In the social sciences, social structure is the aggregate of patterned social arrangements in society that are both emergent from and determinant of the actions of individuals. Likewise, society is believed to be grouped into structurally rel ...
, chemical signaling, and "social herd" characteristics. Lihoreau and his fellow researchers stated: There is evidence that a few species of group-living roaches in the genera '' Melyroidea'' and '' Aclavoidea'' may exhibit a reproductive division of labor, which, if confirmed, would make these the only genuinely
eusocial Eusociality (from Greek εὖ ''eu'' "good" and social), the highest level of organization of sociality, is defined by the following characteristics: cooperative brood care (including care of offspring from other individuals), overlapping generat ...
lineage known among roaches, in contrast to the
subsocial Sociality is the degree to which individuals in an animal population tend to associate in social groups (gregariousness) and form cooperative societies. Sociality is a survival response to evolutionary pressures. For example, when a mother wasp ...
members of the genus ''
Cryptocercus ''Cryptocercus'' is a genus of Dictyoptera (cockroaches and allies) and the sole member of its own family Cryptocercidae. Species are known as wood roaches or brown-hooded cockroaches. These roaches are subsocial, their young requiring considera ...
''.


Sounds

Some species make a buzzing noise while other cockroaches make a chirping noise. ''
Gromphadorhina ''Gromphadorhina'' is one of several roach genera in the tribe Gromphadorhini, all from the island of Madagascar. It is one of several genera known collectively known as hissing cockroaches, and common in the pet trade. In the older literature, t ...
'' species and '' Archiblatta hoeveni'' produce sound through the modified
spiracle Spiracle or spiraculum may refer to: * Spiracle (arthropods), opening in the exoskeletons of some arthropods * Spiracle (vertebrates), openings on the surface of some vertebrates * Spiraculum, a genus of land snails in family Cyclophoridae Cycl ...
s on the fourth abdominal segment. In the former species, several different hisses are produced, including disturbance sounds, produced by adults and larger nymphs; and aggressive, courtship and copulatory sounds produced by adult males. '' Henschoutedenia epilamproides'' has a
stridulatory organ Stridulation is the act of producing sound by rubbing together certain body parts. This behavior is mostly associated with insects, but other animals are known to do this as well, such as a number of species of fish, snakes and spiders. The mech ...
between its thorax and abdomen, but the purpose of the sound produced is unclear. Several Australian species practice acoustic and vibration behaviour as an aspect of courtship. They have been observed producing hisses and whistles from air forced through the spiracles. Furthermore, in the presence of a potential mate, some cockroaches tap the substrate in a rhythmic, repetitive manner. Acoustic signals may be of greater prevalence amongst perching species, particularly those that live on low vegetation in Australia's tropics.


Biology


Digestive tract

Cockroaches are generally
omnivorous An omnivore () is an animal that has the ability to eat and survive on both plant and animal matter. Obtaining energy and nutrients from plant and animal matter, omnivores digest carbohydrates, protein, fat, and fiber, and metabolize the nutri ...
; the American cockroach (''Periplaneta americana''), for example, feeds on a great variety of foodstuffs including bread, fruit, leather, starch in book bindings, paper, glue, skin flakes, hair, dead insects and soiled clothing. Many species of cockroach harbor in their gut
symbiotic Symbiosis (from Greek , , "living together", from , , "together", and , bíōsis, "living") is any type of a close and long-term biological interaction between two different biological organisms, be it mutualistic, commensalistic, or parasit ...
protozoa Protozoa (singular: protozoan or protozoon; alternative plural: protozoans) are a group of single-celled eukaryotes, either free-living or parasitic, that feed on organic matter such as other microorganisms or organic tissues and debris. Histo ...
ns and
bacteria Bacteria (; singular: bacterium) are ubiquitous, mostly free-living organisms often consisting of one biological cell. They constitute a large domain of prokaryotic microorganisms. Typically a few micrometres in length, bacteria were among ...
which are able to digest
cellulose Cellulose is an organic compound with the formula , a polysaccharide consisting of a linear chain of several hundred to many thousands of β(1→4) linked D-glucose units. Cellulose is an important structural component of the primary cell wall ...
. In many species, these symbionts may be essential if the insect is to utilize cellulose; however, some species secrete
cellulase Cellulase (EC 3.2.1.4; systematic name 4-β-D-glucan 4-glucanohydrolase) is any of several enzymes produced chiefly by fungi, bacteria, and protozoans that catalyze cellulolysis, the decomposition of cellulose and of some related polysaccharide ...
in their
saliva Saliva (commonly referred to as spit) is an extracellular fluid produced and secreted by salivary glands in the mouth. In humans, saliva is around 99% water, plus electrolytes, mucus, white blood cells, epithelial cells (from which DNA can be ...
, and the wood-eating cockroach, ''
Panesthia cribrata ''Panesthia cribrata'', commonly called the Australian wood cockroach, is a wood-eating species found in rotten logs. It is found from south east Queensland south to the east coast to Tasmania, also seen at Norfolk Island. It depends on wood fo ...
'', is able to survive indefinitely on a diet of crystallized cellulose while being free of microorganisms. The similarity of these symbionts in the genus ''
Cryptocercus ''Cryptocercus'' is a genus of Dictyoptera (cockroaches and allies) and the sole member of its own family Cryptocercidae. Species are known as wood roaches or brown-hooded cockroaches. These roaches are subsocial, their young requiring considera ...
'' to those in termites are such that these cockroaches have been suggested to be more closely related to termites than to other cockroaches, and current research strongly supports this hypothesis about their relationships. All species studied so far carry the obligate mutualistic
endosymbiont An ''endosymbiont'' or ''endobiont'' is any organism that lives within the body or cells of another organism most often, though not always, in a mutualistic relationship. (The term endosymbiosis is from the Greek: ἔνδον ''endon'' "within" ...
bacterium ''
Blattabacterium ''Blattabacterium'' is a genus of obligate mutualistic endosymbiont bacteria that are believed to inhabit all species of cockroach studied to date, with the exception of the genus ''Nocticola''. The genus' presence in the termite ''Mastotermes ...
'', with the exception of ''
Nocticola ''Nocticola'' is a genus of cockroaches in the family Nocticolidae distributed in Africa, south-east Asia and Australia. Nocticola are different from every other cockroach in that they are not infected with '' Blattabacterium cuenoti''. This make ...
'', an Australian cave-dwelling genus without eyes, pigment or wings, which recent genetic studies indicate is a very primitive cockroach. It had previously been thought that all five families of cockroach were descended from a common ancestor that was infected with '' B. cuenoti''. It may be that ''N. australiensis'' subsequently lost its symbionts, or alternatively this hypothesis will need to be re-examined.


Tracheae and breathing

Like other insects, cockroaches breathe through a system of tubes called
tracheae The trachea, also known as the windpipe, is a cartilaginous tube that connects the larynx to the bronchi of the lungs, allowing the passage of air, and so is present in almost all air- breathing animals with lungs. The trachea extends from the ...
which are attached to openings called spiracles on all body segments. When the
carbon dioxide Carbon dioxide (chemical formula ) is a chemical compound made up of molecules that each have one carbon atom covalently double bonded to two oxygen atoms. It is found in the gas state at room temperature. In the air, carbon dioxide is transpar ...
level in the insect rises high enough, valves on the spiracles open and carbon dioxide diffuses out and
oxygen Oxygen is the chemical element with the symbol O and atomic number 8. It is a member of the chalcogen group in the periodic table, a highly reactive nonmetal, and an oxidizing agent that readily forms oxides with most elements as wel ...
diffuses in. The tracheal system branches repeatedly, the finest
tracheole Tracheole (trā'kē-ōl') is a fine respiratory tube of the trachea of an insect or a spider, part of the respiratory system. Tracheoles are about 1 µm in diameter, and they convey oxygen to cells while providing a means for carbon dioxide ...
s bringing air directly to each
cell Cell most often refers to: * Cell (biology), the functional basic unit of life Cell may also refer to: Locations * Monastic cell, a small room, hut, or cave in which a religious recluse lives, alternatively the small precursor of a monastery w ...
, allowing gaseous exchange to take place. While cockroaches do not have
lung The lungs are the primary organs of the respiratory system in humans and most other animals, including some snails and a small number of fish. In mammals and most other vertebrates, two lungs are located near the backbone on either side of t ...
s as do
vertebrate Vertebrates () comprise all animal taxa within the subphylum Vertebrata () ( chordates with backbones), including all mammals, birds, reptiles, amphibians, and fish. Vertebrates represent the overwhelming majority of the phylum Chordata, ...
s, and can continue to respire if their heads are removed, in some very large species, the body musculature may contract rhythmically to forcibly move air in and out of the spiracles; this may be considered a form of breathing.


Reproduction

Cockroaches use
pheromone A pheromone () is a secreted or excreted chemical factor that triggers a social response in members of the same species. Pheromones are chemicals capable of acting like hormones outside the body of the secreting individual, to affect the behavio ...
s to attract mates, and the males practice courtship rituals, such as posturing and
stridulation Stridulation is the act of producing sound by rubbing together certain body parts. This behavior is mostly associated with insects, but other animals are known to do this as well, such as a number of species of fish, snakes and spiders. The mech ...
. Like many insects, cockroaches mate facing away from each other with their genitalia in contact, and copulation can be prolonged. A few species are known to be
parthenogenetic Parthenogenesis (; from the Greek grc, παρθένος, translit=parthénos, lit=virgin, label=none + grc, γένεσις, translit=génesis, lit=creation, label=none) is a natural form of asexual reproduction in which growth and development ...
, reproducing without the need for males. Female cockroaches are sometimes seen carrying egg cases on the end of their abdomens; the German cockroach holds about 30 to 40 long, thin eggs in a case called an
ootheca An ootheca (pl. ''oothecae'' ) is a type of egg mass made by any member of a variety of species including mollusks (such as ''Turbinella laevigata''), mantises, and cockroaches. The word is a Latinized combination of ''oo-'', meaning "egg", f ...
. She drops the capsule prior to hatching, though live births do occur in rare instances. The egg capsule may take more than five hours to lay and is initially bright white in color. The eggs are hatched from the combined pressure of the hatchlings gulping air. The hatchlings are initially bright white
nymphs A nymph ( grc, νύμφη, nýmphē, el, script=Latn, nímfi, label=Modern Greek; , ) in ancient Greek folklore is a minor female nature deity. Different from Greek goddesses, nymphs are generally regarded as personifications of nature, are typ ...
and continue inflating themselves with air, becoming harder and darker within about four hours. Their transient white stage while hatching and later while
molting In biology, moulting (British English), or molting (American English), also known as sloughing, shedding, or in many invertebrates, ecdysis, is the manner in which an animal routinely casts off a part of its body (often, but not always, an outer ...
has led to claims of
albino Albinism is the congenital absence of melanin in an animal or plant resulting in white hair, feathers, scales and skin and pink or blue eyes. Individuals with the condition are referred to as albino. Varied use and interpretation of the term ...
cockroaches. Development from eggs to adults takes three to four months. Cockroaches live up to a year, and the female may produce up to eight egg cases in a lifetime; in favorable conditions, she can produce 300 to 400 offspring. Other species of cockroaches, however, can produce far more eggs; in some cases a female needs to be impregnated only once to be able to lay eggs for the rest of her life. The female usually attaches the egg case to a substrate, inserts it into a suitably protective crevice, or carries it about until just before the eggs hatch. Some species, however, are
ovoviviparous Ovoviviparity, ovovivipary, ovivipary, or aplacental viviparity is a term used as a "bridging" form of reproduction between egg-laying oviparous and live-bearing viviparous reproduction. Ovoviviparous animals possess embryos that develop insi ...
, keeping the eggs inside their body, with or without an egg case, until they hatch. At least one genus, ''
Diploptera ''Diploptera'', also known as the beetle cockroach, is a genus of blaberid cockroaches. Cockroaches of this genus resemble beetles, with hardened tegmina and cross-folded hindwings. They live in tropical forests in South China and Southeast A ...
'', is fully
viviparous Among animals, viviparity is development of the embryo inside the body of the parent. This is opposed to oviparity which is a reproductive mode in which females lay developing eggs that complete their development and hatch externally from the m ...
. Cockroaches have
incomplete metamorphosis Hemimetabolism or hemimetaboly, also called incomplete metamorphosis and paurometabolism,McGavin, George C. ''Essential Entomology: An Order-by-Order Introduction''. Oxford: Oxford University Press, 2001. pp. 20. is the mode of development of certa ...
, meaning that the
nymphs A nymph ( grc, νύμφη, nýmphē, el, script=Latn, nímfi, label=Modern Greek; , ) in ancient Greek folklore is a minor female nature deity. Different from Greek goddesses, nymphs are generally regarded as personifications of nature, are typ ...
are generally similar to the adults, except for undeveloped wings and genitalia. Development is generally slow, and may take a few months to over a year. The adults are also long-lived; some have survived for as many as four years in the laboratory. File:Cockroach nymph australia.jpg, 3 millimeter cockroach nymph File:Cockroach egglaying 1.jpg, Female ''
Periplaneta fuliginosa The smokybrown cockroach (''Periplaneta fuliginosa'') is a large species of cockroach, winged, and growing to a length of .Appel, A. G., & Smith II, L. M. (2002). Biology and management of the smokybrown cockroach. ''Annual Review of Entomology' ...
'' with
ootheca An ootheca (pl. ''oothecae'' ) is a type of egg mass made by any member of a variety of species including mollusks (such as ''Turbinella laevigata''), mantises, and cockroaches. The word is a Latinized combination of ''oo-'', meaning "egg", f ...
File:Old Ootheca.jpg, Empty
ootheca An ootheca (pl. ''oothecae'' ) is a type of egg mass made by any member of a variety of species including mollusks (such as ''Turbinella laevigata''), mantises, and cockroaches. The word is a Latinized combination of ''oo-'', meaning "egg", f ...
File:Periplaneta-americana-Eier.jpg, American cockroach oothecae


Parthenogenesis

When female
American cockroach The american cockroach (''Periplaneta americana'') is the largest species of common cockroach, and often considered a pest. In certain regions of the U.S. it is colloquially known as the waterbug, though it is not a true waterbug since it is not ...
es (''Periplaneta americana'') are housed in groups, this close association promotes
parthenogenic reproduction Parthenogenesis (; from the Greek grc, παρθένος, translit=parthénos, lit=virgin, label=none + grc, γένεσις, translit=génesis, lit=creation, label=none) is a natural form of asexual reproduction in which growth and development ...
.Katoh K, Iwasaki M, Hosono S, Yoritsune A, Ochiai M, Mizunami M, Nishino H. Group-housed females promote production of asexual ootheca in American cockroaches. Zoological Lett. 2017 Mar 13;3:3. doi: 10.1186/s40851-017-0063-x. PMID: 28331632; PMCID: PMC5348754
Oothecae An ootheca (pl. ''oothecae'' ) is a type of egg mass made by any member of a variety of species including mollusks (such as ''Turbinella laevigata''), mantises, and cockroaches. The word is a Latinized combination of ''oo-'', meaning "egg", fro ...
, a type of egg mass, are produced asexually. The parthenogenetic process by which eggs are produced in ''P. americana'' is automixis. During
automixis ''Automixis'' is the fusion of (typically haploid) nuclei or gametes derived from the same individual. The term covers several reproductive mechanisms, some of which are parthenogenetic. Diploidy might be restored by the doubling of the chromoso ...
, meiosis occurs, but instead of giving rise to haploid gametes as ordinarily occurs, diploid gametes are produced (probably by terminal fusion) that can then develop into female cockroaches.


Hardiness

Cockroaches are among the hardiest insects. Some species are capable of remaining active for a month without food and are able to survive on limited resources, such as the glue from the back of postage stamps. Some can go without air for 45 minutes.
Japanese cockroach The Japanese cockroach (''Periplaneta japonica''), also known as the Yamato cockroach, is a cockroach native to Japan, adapted to cooler northern climates. It has a flexible univoltine or semivoltine (one- or two-year) lifecycle, depending on th ...
(''Periplaneta japonica'')
nymphs A nymph ( grc, νύμφη, nýmphē, el, script=Latn, nímfi, label=Modern Greek; , ) in ancient Greek folklore is a minor female nature deity. Different from Greek goddesses, nymphs are generally regarded as personifications of nature, are typ ...
, which
hibernate Hibernation is a state of minimal activity and metabolic depression undergone by some animal species. Hibernation is a seasonal heterothermy characterized by low body-temperature, slow breathing and heart-rate, and low metabolic rate. It most ...
in cold winters, have survived twelve hours at in laboratory experiments. Experiments on decapitated specimens of several species of cockroach found a variety of behavioral functionality remained, including shock avoidance and escape behavior, although many insects other than cockroaches are also able to survive decapitation, and popular claims of the longevity of headless cockroaches do not appear to be based on published research. The severed head is able to survive and wave its antennae for several hours, or longer when refrigerated and given nutrients. It is popularly suggested that cockroaches will "inherit the earth" if humanity destroys itself in a
nuclear war Nuclear warfare, also known as atomic warfare, is a theoretical military conflict or prepared political strategy that deploys nuclear weaponry. Nuclear weapons are weapons of mass destruction; in contrast to conventional warfare, nuclear w ...
. While cockroaches do, indeed, have a much higher radiation resistance than
vertebrate Vertebrates () comprise all animal taxa within the subphylum Vertebrata () ( chordates with backbones), including all mammals, birds, reptiles, amphibians, and fish. Vertebrates represent the overwhelming majority of the phylum Chordata, ...
s, with a lethal dose perhaps six to 15 times that for humans, they are not exceptionally radiation-resistant compared to other insects, such as the fruit fly. The cockroach's ability to withstand radiation has been explained through the cell cycle. Cells are most vulnerable to the effects of radiation while they are dividing. A cockroach's cells divide only once each molting cycle (which is weekly, for the juvenile German cockroach). Since not all cockroaches would be molting at the same time, many would be unaffected by an acute burst of radiation, although lingering and more acute radiation would still be harmful.


Relationship with humans


In research and education

Because of their ease of rearing and resilience, cockroaches have been used as insect models in the laboratory, particularly in the fields of
neurobiology Neuroscience is the scientific study of the nervous system (the brain, spinal cord, and peripheral nervous system), its functions and disorders. It is a multidisciplinary science that combines physiology, anatomy, molecular biology, development ...
,
reproductive physiology Reproductive endocrinology and infertility (REI) is a surgical subspecialty of obstetrics and gynecology that trains physicians in reproductive medicine addressing hormonal functioning as it pertains to reproduction as well as the issue of in ...
and
social behavior Social behavior is behavior among two or more organisms within the same species, and encompasses any behavior in which one member affects the other. This is due to an interaction among those members. Social behavior can be seen as similar to an ...
. The cockroach is a convenient insect to study as it is large and simple to raise in a laboratory environment. This makes it suitable both for research and for school and undergraduate biology studies. It can be used in experiments on topics such as learning, sexual
pheromone A pheromone () is a secreted or excreted chemical factor that triggers a social response in members of the same species. Pheromones are chemicals capable of acting like hormones outside the body of the secreting individual, to affect the behavio ...
s, spatial orientation,
aggression Aggression is overt or covert, often harmful, social interaction with the intention of inflicting damage or other harm upon another individual; although it can be channeled into creative and practical outlets for some. It may occur either reacti ...
, activity rhythms and the biological clock, and
behavioral ecology Behavioral ecology, also spelled behavioural ecology, is the study of the evolutionary basis for animal behavior due to ecological pressures. Behavioral ecology emerged from ethology after Niko Tinbergen outlined four questions to address when ...
. Research conducted in 2014 suggests that humans fear cockroaches the most, even more than
mosquito Mosquitoes (or mosquitos) are members of a group of almost 3,600 species of small flies within the family Culicidae (from the Latin ''culex'' meaning " gnat"). The word "mosquito" (formed by ''mosca'' and diminutive ''-ito'') is Spanish for "li ...
es, due to an evolutionary aversion.


As pests

The Blattodea include some thirty species of cockroaches associated with humans; these species are atypical of the thousands of species in the order. They feed on human and pet food and can leave an offensive odor. They can passively transport
pathogen In biology, a pathogen ( el, πάθος, "suffering", "passion" and , "producer of") in the oldest and broadest sense, is any organism or agent that can produce disease. A pathogen may also be referred to as an infectious agent, or simply a germ ...
ic microbes on their body surfaces, particularly in environments such as hospitals. Cockroaches are linked with
allergic reaction Allergies, also known as allergic diseases, refer a number of conditions caused by the hypersensitivity of the immune system to typically harmless substances in the environment. These diseases include hay fever, food allergies, atopic derma ...
s in humans. One of the proteins that trigger allergic reactions is
tropomyosin Tropomyosin is a two-stranded alpha-helical, coiled coil protein found in actin-based cytoskeletons. Tropomyosin and the actin skeleton All organisms contain organelles that provide physical integrity to their cells. These type of organelles ar ...
, which can cause cross-reactive allergy to house dust mites, dust mites and shrimp. These allergens are also linked with asthma. Some species of cockroach can live for up to a month without food, so just because no cockroaches are visible in a home does not mean that they are not there. Approximately 20–48% of homes with no visible sign of cockroaches have detectable cockroach allergens in dust.


Control

Many remedies have been tried in the search for control of the major pest species of cockroaches, which are resilient and fast-breeding. Household chemicals like sodium bicarbonate (baking soda) have been suggested, without evidence for their effectiveness. Garden herbs including bay leaves, bay, catnip, Mentha, mint, cucumber, and garlic have been proposed as repellents. Poisoned bait containing hydramethylnon or fipronil, and boric acid powder is effective on adults. Baits with egg killers are also quite effective at reducing the cockroach population. Alternatively, insecticides containing deltamethrin or pyrethrin are very effective. In Singapore and Malaysia, taxi drivers use Pandanus amaryllifolius, pandan leaves to repel cockroaches in their vehicles. Natural methods of cockroach control have been advanced by several published studies especially by ''Metarhizium robertsii'' (syn. ''M. anisopliae''). Some parasites and predators are effective for biological control of cockroaches. Parasitoidal wasps such as ''Ampulex'' wasps sting nerve Ganglion, ganglia in the cockroach's
thorax The thorax or chest is a part of the anatomy of humans, mammals, and other tetrapod animals located between the neck and the abdomen. In insects, crustaceans, and the extinct trilobites, the thorax is one of the three main divisions of the cre ...
, causing temporary paralysis and allowing the wasp to deliver an incapacitating sting into the cockroach's brain. The wasp clips the antennae with its mandibles and drinks some hemolymph before dragging the prey to a burrow, where an egg (rarely two) is laid on it. The wasp larva feeds on the subdued living cockroach. Another wasp considered to be a promising candidate for biological control is the ensign wasp ''Evania appendigaster'', which attacks cockroach oothecae to lay a single egg inside. Ongoing research is still developing technologies allowing for mass-rearing these wasps for application releases. Latrodectus, Widow spiders commonly prey on cockroaches. Cockroaches can be trapped in a deep, smooth-walled jar baited with food inside, placed so that cockroaches can reach the opening, for example with a ramp of card or twigs on the outside. An inch or so of water or stale beer (by itself a cockroach attractant) in the jar can be used to drown any insects thus captured. The method works well with the American cockroach, but less so with the German cockroach. A study conducted by scientists at Purdue University concluded that the most common cockroaches in the United States, US,
Australia Australia, officially the Commonwealth of Australia, is a Sovereign state, sovereign country comprising the mainland of the Australia (continent), Australian continent, the island of Tasmania, and numerous List of islands of Australia, sma ...
and Europe were able to develop a “cross resistance” to multiple types of pesticide. This contradicted previous understanding that the animals can develop resistance against one pesticide at a time. The scientists suggested that cockroaches will no longer be easily controlled using a diverse spectrum of chemical pesticides and that a mix of other means, such as traps and better sanitation, will need to be employed. Researchers from Heriot-Watt University demonstrated that a power laser can, with high effectiveness, neutralise cockroaches in a home, and suggest it might be an alternative to pesticides.


As food

Although considered disgusting in Western culture, cockroaches are eaten in many places around the world.Marion Copeland [2004]
Cockroach
(Pages 86 to 88). Published by Reaktion Books
Whereas household pest cockroaches may carry
bacteria Bacteria (; singular: bacterium) are ubiquitous, mostly free-living organisms often consisting of one biological cell. They constitute a large domain of prokaryotic microorganisms. Typically a few micrometres in length, bacteria were among ...
and viruses, cockroaches bred under laboratory conditions can be used to prepare nutritious food. In Thailand and Mexico, the heads and legs are removed, and the remainder may be boiled, sautéed, grilled, dried or diced. In China, cockroaches have become popular as medicine and cockroach farming is rising with over 100 farms. The cockroaches are fried twice in a wok of hot oil, which makes them crispy with soft innards that are like cottage cheese. Fried cockroaches are ground and sold as pills for stomach, heart and liver diseases. A cockroach recipe from Taiwan, Formosa (Taiwan) specifies salting and frying cockroaches after removing the head and entrails.Richard Schweid [2015]
The Cockroach Papers: A Compendium of History and Lore
(Page 69). Published by University of Chicago Press.


In traditional medicine

In China, cockroaches are raised in large quantities for medicinal purposes.


Conservation

While a small minority of cockroaches are associated with human habitats and viewed as repugnant by many people, a few species are of conservation concern. The Lord Howe Island wood-feeding cockroach (''Panesthia lata'') is listed as endangered by the New South Wales Scientific Committee, but the cockroach may be extinct on Lord Howe Island itself. The introduction of rats, the spread of Rhodes grass (''Chloris gayana'') and fires are possible reasons for their scarcity. Two species are currently listed as Endangered species, endangered and critically endangered by the IUCN Red List, ''Delosia ornata'' and ''Nocticola gerlachi''. Both cockroaches have a restricted distribution and are threatened by habitat loss and sea level rise, rising sea levels. Only 600 ''Delosia ornata'' adults and 300 nymphs are known to exist, and these are threatened by a hotel development. No action has been taken to save the two cockroach species, but protecting their natural habitats may prevent their extinction. In the former Soviet Union, cockroach populations have been declining at an alarming rate; this may be exaggerated, or the phenomenon may be temporary or cyclic. One species of roach, ''Simandoa conserfariam'', is considered extinct in the wild.Roth, L. M. & Naskrecki (2004) A new genus and species of cave cockroach (Blaberidae: Oxyhaloinae) from Guinea, West Africa., Journal of Orthoptera Research 13(1):57-61


Cultural depictions

Cockroaches were known and considered repellent but medicinally useful in Classical times. An insect named in Greek "σίλφη" (''silphe'') has been identified with the cockroach, though the scientific name ''Silpha'' refers to a genus of carrion beetles. It is mentioned by Aristotle, saying that it sheds its skin; it is described as foul-smelling in Aristophanes' play ''Peace (play), Peace''; Euenus called it a pest of book collections, being "page-eating, destructive, black-bodied" in his ''Analect''. Virgil named the cockroach "Lucifuga" ("one that avoids light"). Pliny the Elder recorded the use of "Blatta" in various medicines; he describes the insect as disgusting, and as seeking out dark corners to avoid the light. Pedanius Dioscorides, Dioscorides recorded the use of the "Silphe", ground up with oil, as a remedy for earache. Lafcadio Hearn (1850–1904) asserted that "For tetanus cockroach tea is given. I do not know how many cockroaches go to make up the cup; but I find that faith in this remedy is strong among many of the American population of New Orleans. A poultice of boiled cockroaches is placed over the wound." He adds that cockroaches are eaten, fried with garlic, for indigestion. Several cockroach species, such as ''Blaptica dubia'', are raised as food for insectivorous pets. A few cockroach species are raised as pets, most commonly the giant Madagascar hissing cockroach, ''Gromphadorhina portentosa''. Whilst the hissing cockroaches may be the most commonly kept species, there are many species that are kept by cockroach enthusiasts; there is even a specialist society: the Blattodea Culture Group (BCG), which was a thriving organisation for about 15 years although now appears to be dormant. The BCG provided a source of literature for people interested in rearing cockroaches, which was otherwise limited to either scientific papers, general insect books, or books covering a variety of exotic pets; in the absence of an inclusive book, one member published ''Introduction to Rearing Cockroaches'', which still appears to be the only book dedicated to rearing cockroaches. Cockroaches have been used for space tests. A cockroach given the name Nadezhda (cockroach), Nadezhda was sent into space by Russian scientists as part of a Foton (satellite)#Foton-M, Foton-M mission, during which she mated, and later became the first terrestrial animal to produce offspring that had been conceived in space. Because of their long association with humans, cockroaches are frequently referred to in popular culture. In Western culture, cockroaches are often depicted as dirty pests. In a 1750–1752 journal, Pehr Osbeck noted that cockroaches were frequently seen and found their way to the bakeries, after the sailing ship ''Gothenburg'' ran aground and was destroyed by rocks. Donald Harington (writer), Donald Harington's satirical novel ''The Cockroaches of Stay More'' (Harcourt, 1989) imagines a community of "roosterroaches" in a mythical Ozark town where the insects are named after their human counterparts. Madonna (entertainer), Madonna has famously quoted, "I am a survivor. I am like a cockroach, you just can't get rid of me." An urban legend maintains that cockroaches are radiation-resistant, and thus would survive a nuclear war.


References


External links


Cockroach Species File
Online world catalogue of cockroaches.

chapter in United States Environmental Protection Agency and UF/IFAS National Public Health Pesticide Applicator Training Manual
''Cockroach Studies'' journal
(ISSN 1862-6491) {{DEFAULTSORT:Cockroach Cockroaches, Cockroaches Household pest insects Insect common names Insects in culture