View source for Cockroach

{{Short description|Insects of the order Blattodea}}
{{About|the insect}}
{{Good article}}
{{pp-semi-vandalism|small=yes}}
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{{Use dmy dates|date=June 2024}}
{{Automatic taxobox
|name=Cockroach
|fossil_range={{fossilrange|Late Jurassic|Present}}
|image=Snodgrass common household roaches.png
|image_upright=1.15
|image_caption ='''Common household cockroaches'''<br/>A) [[German cockroach]]<br/>B) [[American cockroach]]<br/>C) [[Australian cockroach]]<br />D&E) [[Oriental cockroach]] (♀ & ♂)
|taxon=Blattodea
|subdivision_ranks=Families
|subdivision =
[[Anaplectidae]]<br/>
[[Blaberidae]]<br/>
[[Blattidae]]<br/>
[[Corydiidae]]<br/>
[[Cryptocercidae]]<br/>
[[Ectobiidae]]<br/>
[[Lamproblattidae]]<br/>
[[Nocticolidae]]<br/>
[[Tryonicidae]]
}}

'''Cockroaches''' (or '''roaches'''<ref>[https://bugguide.net/node/view/342386 Order Blattodea - BugGuide.net]</ref><ref>[https://www.inaturalist.org/guides/10670 A guide to the Roaches & Termites (Order Blattodea), Grasshoppers, Crickets & Katydids (Order Orthoptera), Mantises (Order Mantodea), and Stick Insects (Order Phasmida) of Austin and Travis County, TX; USA] from [[iNaturalist]]</ref><ref>{{Cite web |url=https://insectcollection.umn.edu/blattodea |title=Blattodea: roaches - Univ. of Minnesota Insect Collection |access-date=2 July 2020 |archive-date=3 July 2020 |archive-url=https://web.archive.org/web/20200703055341/https://insectcollection.umn.edu/blattodea |url-status=dead }}</ref>) are insects belonging to the [[Order (biology)|order]] [[Blattodea]] (Blattaria). About 30 cockroach [[species]] out of 4,600 are associated with human [[habitats]]. Some species are well-known [[Pest (organism)|pest]]s.

Modern cockroaches are an ancient group that first appeared during the [[Late Jurassic]], with their ancestors, known as "[[Roachoid|roachoids]]", likely originating during the [[Carboniferous]] period around 320 million years ago. Those early ancestors, however, lacked the internal [[ovipositor]]s of modern roaches. Cockroaches are somewhat generalized insects lacking special adaptations (such as the sucking [[Insect mouthparts|mouthparts]] of [[aphid]]s and other [[Hemiptera|true bugs]]); they have chewing mouthparts and are probably among the most primitive of living [[Neoptera]]n insects. They are common and hardy insects capable of tolerating a wide range of [[Köppen climate classification|climates]], from [[Arctic]] cold to [[Tropics|tropical]] heat. Tropical cockroaches are often much larger than temperate species.

Modern cockroaches are not considered to be a [[monophyletic]] 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, thus rendering Blattaria [[paraphyletic]]. Both cockroaches and termites are included into Blattodea.

Some species, such as the gregarious [[German cockroach]], have an elaborate social structure involving common shelter, social dependence, information transfer and kin recognition. Cockroaches have appeared in [[human culture]] since [[classical antiquity]]. They are popularly depicted as large, dirty pests, although the majority of species are small and inoffensive and live in a wide range of habitats around the world.

==Taxonomy and evolution==
[[File:Cockroaches - then and now.jpg|left|thumb|A Turkestan cockroach (''[[Turkestan cockroach|Shelfordella lateralis]]'') next to an approximately 108-million-year-old fossil cockroach from the [[Cretaceous]] Period. |247x247px]]
[[File:Baltic amber inclusions - Cockroach (Pterygota, Neoptera, Dictyoptera, Blattodea).JPG|thumb|A 40- to 50-million-year-old cockroach in [[Baltic amber]] ([[Eocene]])|255x255px]]
Cockroaches are members of the superorder [[Dictyoptera]], which includes the [[termite]]s and [[mantid]]s,<ref>{{Cite web|url=https://www.britannica.com/animal/orthopteran|title=Orthopteran &#124; Description, Natural History, & Classification|date=<!--17 July 2024--> }}</ref> a group of insects once thought to be separate from cockroaches. Currently, 4,600 species and over 460 genera are described worldwide.<ref name="Cockroach.SpeciesFile.org">{{cite web |author=Beccaloni, G. W. |year=2014 |title=Cockroach Species File Online. Version 5.0 |url=http://Cockroach.SpeciesFile.org}}</ref><ref>{{cite web |title=Blattodea (Cockroaches & Termites) |url=http://anic.ento.csiro.au/INSECTFAMILIES/order_overview.aspx?OrderID=42509&PageID=overview |publisher=CSIRO Entomology |access-date=21 November 2015}}</ref> The name "[[wikt:cockroach|cockroach]]" comes from the Spanish word for cockroach, ''cucaracha'', transformed by 1620s English [[folk etymology]] into "cock" and "roach".<ref name=Cockroach_etymology>{{OEtymD|Cockroach}}</ref> 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 [[Mantidae|mantids]].<ref>{{cite book |last1=Gordh |first1=G. |last2=Headrick |first2=D. H. |title=A Dictionary of Entomology |date=2009 |publisher=CABI |location=Wallingford |isbn=978-1-84593-542-9 |page=200 |edition=2nd}}</ref><ref>{{cite web |last1=Lewis |first1=Charlton T. |last2=Short |first2=Charles |title=Blatta |url=https://www.perseus.tufts.edu/hopper/text?doc=Perseus%3Atext%3A1999.04.0059%3Aentry%3Dblatta1 |work=Perseus Digital Library |publisher=Tufts University |access-date=26 October 2015}}</ref>

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.<ref name="Cockroach.SpeciesFile.org"/> Another name, [[Blattoptera]], is also sometimes used to refer to extinct cockroach relatives.<ref>{{cite journal |last1=Grimaldi |first1=D. |title=A fossil mantis (Insecta, Mantodea) in Cretaceous amber of New Jersey: with comments on the early history of the Dictyoptera |journal=American Museum Novitates |date=1997 |issue=3204 |pages=1–11}}</ref> 

The earliest cockroach-like fossils ("blattopterans" or "[[roachoid]]s") are from the [[Carboniferous]] period 320 million years ago.<ref name="Archi">{{cite journal |last1=Garwood |first1=R. |last2=Sutton |first2=M. |title=X-ray micro-tomography of Carboniferous stem-Dictyoptera: new insights into early insects |journal=Biology Letters |date=2010 |volume=6 |issue=5 |pages=699–702 |doi=10.1098/rsbl.2010.0199 |pmid=20392720|pmc=2936155}}</ref><ref name="GrimaldiEngel2005">{{cite book |last1=Grimaldi |first1=David |last2=Engel |first2=Michael S. |title=Evolution of the Insects |date=2005 |publisher=Cambridge University Press |isbn=978-0-521-82149-0 |page=1}}</ref><ref>{{cite journal|last1=Garwood |first1=R. |last2=Ross |first2=A. |last3=Sotty |first3=D. |last4=Chabard|first4=D. |last5=Charbonnier |first5=S. |last6=Sutton |first6=M. |last7=Withers |first7=P.J. |author-link7=Philip J. Withers|last8=Butler |first8=R.J. |title=Tomographic Reconstruction of Neopterous Carboniferous Insect Nymphs |journal=PLOS ONE |date=2012 |volume=7 |issue=9 |pages=e45779 |doi=10.1371/journal.pone.0045779 |pmid=23049858 |pmc=3458060|bibcode=2012PLoSO...745779G|doi-access=free }}</ref> Fossil roachoids are considered the [[common ancestor]] of both [[mantis]]es and modern cockroaches, and are distinguished from the latter by the presence of a long external [[ovipositor]]. As the body, [[Hindwings|hind wings]] and mouthparts are not preserved in fossils frequently, the relationship of these roachoids and modern cockroaches remains disputed. The earliest definitive fossils of modern [[crown group]] cockroaches, specifically [[Corydiidae]], are known from the [[Late Jurassic]] strata of [[Russia]] and the [[Kimmeridgian]]-aged [[Karabastau Formation]] of [[Kazakhstan]].<ref>{{Cite journal|last1=Vršanský |first1=P. |last2=Palková |first2=H. |last3=Vršanská |first3=L. |last4=Koubová |first4=I. |last5=Hinkelman |first5=J. |year=2022 |title=Mesozoic origin-delayed explosive radiation of the cockroach family Corydiidae Saussure, 1864 |journal=Biologia |volume=78 |issue=6 |pages=1627–1658 |doi=10.1007/s11756-022-01279-1 |s2cid=254479766 }}</ref><ref>{{Cite journal|last=Vršanský |first=P. |title=Late Mesozoic cockroaches s.l. from the Karabastau Formation in Kazakhstan |year=2024 |journal=AMBA Projekty |volume=14 |issue=1 |pages=1–700 |url=https://geo.sav.sk/files/vrsansky/Vrsansky_2024.pdf }}</ref>

The evolutionary relationships of the Blattodea (cockroaches and termites) shown in the [[cladogram]] are based on Inward, Beccaloni and Eggleton (2007).<ref name="Eggleton, P. 2007">{{cite journal |last1=Inward |first1=D. |last2=Beccaloni|first2=G. |last3=Eggleton |first3=P. |title=Death of an order: a comprehensive molecular phylogenetic study confirms that termites are eusocial cockroaches |journal=Biology Letters |year=2007 |volume=3 |issue=3 |pages=331–335 |doi=10.1098/rsbl.2007.0102 |pmid=17412673 |pmc=2464702}}</ref> The cockroach families [[Anaplectidae]], [[Lamproblattidae]], and [[Tryonicidae]] are not shown but are placed within the superfamily Blattoidea. The cockroach families [[Corydiidae]] and [[Ectobiidae]] were previously known as the Polyphagidae and Blattellidae.<ref name="Beccaloni_Eggleton_2013">{{cite journal |last1=Beccaloni |first1=G.|last2=Eggleton|first2=P. |editor=Order Blattodea. In: Zhang |editor2=Z.-Q. |title=Animal Biodiversity: An Outline of Higher-level Classification |editor3=Survey of Taxonomic Richness |journal=Zootaxa |year=2013 |volume=3703 |issue=1 |pages=46–48 |url=http://www.mapress.com/zootaxa/2013/f/zt03703p048.pdf |doi=10.11646/zootaxa.3703.1.10}}</ref>

{{clade|style=font-size:85%;line-height:85%
|label1=[[Dictyoptera]]
|1={{clade
   |1={{clade
         |label1='''[[Blattodea]]'''
     	 |1={{clade
     		 |1={{clade
    			  |1={{clade
         			|1={{clade
                    |label1=[[Blattoidea]]
        			   	|1={{clade
           					 |1={{clade
              						 |label1=[[Termitoidae]] (termites) <!-- not "Termitoidea" -->
              						 |1={{clade
                 						 |1={{clade
                 						    |1={{clade
                  							     |1={{clade
                           						    		 |1=[[Termitidae]]
									  	         |2=[[Rhinotermitidae]]
                  							          }}
                  							     |2=[[Kalotermitidae]]
                       						          }}
                 						    |2={{clade
                  							     |1=[[Archotermopsidae]]
                  							     |2=[[Hodotermitidae]]
                  							  }}
                 						      }}
                 						 |2=[[Mastotermitidae]]
              						      }}
              						 |label2=[[Cryptocercoidae]]
              						 |2=[[Cryptocercidae]] (brown-hooded cockroaches)
           					     }}
                             |label2=[[Blattoidae]]
           					 |2=[[Blattidae]] (Oriental, American and other cockroaches)
        			   	     }}
        			   	|label2=[[Blaberoidea]]
        			   	|2={{clade
      			      			 |1={{clade
                 						 |1=[[Blaberidae]] (giant cockroaches)
                 						 |2=[[Ectobiidae]] (part)
      			      			      }}
      			      			 |2=Ectobiidae (part)
        			   	     }}
         			     }}
         			|label2=[[Corydioidea]]
         			|2={{clade
      			      			 |1=[[Corydiidae]] (sand cockroaches, etc)
      			      			 |2=[[Nocticolidae]] (cave cockroaches, etc)
         			     }}
    			       }}
     		       }}
     	     }}
     	 |2=[[Mantodea]] (mantises)
        }}
     }}
}}

Termites were previously regarded as a separate order [[Isoptera]] to cockroaches. However, recent genetic evidence strongly suggests that they evolved directly from 'true' cockroaches, and many authors now place them as an "[[epifamily]]" of Blattodea.<ref name="Eggleton, P. 2007"/> This evidence supported a hypothesis suggested in 1934 that termites are closely related to the wood-eating cockroaches (genus ''[[Cryptocercus]]''). This hypothesis was originally based on similarity of the symbiotic gut [[flagellate]]s in termites regarded as [[living fossil]]s and wood-eating cockroaches.<ref>{{cite journal |last1=Cleveland |first1=L. R. |last2=Hall |first2=S. K. |last3=Sanders |first3=E. P. |last4=Collier |first4=J. |title=The Wood-Feeding Roach ''Cryptocercus'', Its Protozoa, and the Symbiosis between Protozoa and Roach |journal=Memoirs of the American Academy of Arts and Sciences |date=1934 |volume=17 |issue=2 |pages=185–382 |doi=10.1093/aesa/28.2.216|doi-access=free }}</ref> Additional evidence emerged when F.&nbsp;A. McKittrick (1965) noted similar morphological characteristics between some termites and cockroach nymphs.<ref>{{cite journal|last1=McKittrick |first1=F.A. |title=A contribution to the understanding of cockroach-termite affinities |journal=Annals of the Entomological Society of America |year=1965 |volume=58 |issue=1 |pages=18–22 |doi=10.1093/aesa/58.1.18 |pmid=5834489|doi-access=free }}</ref> The similarities among these cockroaches and termites have led some scientists to reclassify termites as a single family, the [[Termitidae]], within the order Blattodea.<ref name="Eggleton, P. 2007"/><ref>{{cite journal |last1=Eggleton |first1=Paul |last2=Beccaloni |first2=George |last3=Inward |first3=Daegan |title=Response to Lo et al. |journal=Biology Letters |date=2007 |volume=3 |issue=5 |pages=564–565 |doi=10.1098/rsbl.2007.0367 |pmc=2391203}}</ref> Other scientists have taken a more conservative approach, proposing to retain the termites as the [[Termitoidae]], an [[epifamily]] within the order. Such a measure preserves the classification of termites at family level and below.<ref>{{cite journal |last1=Lo |first1=Nathan |last2=Engel |first2=Michael S. |last3=Cameron |first3=Stephen |last4=Nalepa |first4=Christine A. |last5=Tokuda |first5=Gaku |last6=Grimaldi |first6=David |last7=Kitade |first7=Osamu |last8=Krishna|first8=Kumar |last9=Klass |first9=Klaus-Dieter |last10=Maekawa |first10=Kiyoto |last11=Miura |first11=Toru |last12=Thompson |first12=Graham J. |title=Save Isoptera: A comment on Inward et al. |journal=Biology Letters |year=2007 |volume=3 |issue=5 |pages=562–563 |doi=10.1098/rsbl.2007.0264 |pmid=17698448 |pmc=2391185}}</ref>

==Description==
[[File:Domino cockroach Therea petiveriana.jpg|thumb|upright|left|Domino cockroach ''[[Therea petiveriana]]'', normally found in [[India]]]]
Most species of cockroach are about the size of a [[Nail (anatomy)|thumbnail]], but several species are notably larger. The world's heaviest cockroach is the Australian [[giant burrowing cockroach]] ''Macropanesthia rhinoceros'', which can reach {{convert|8|cm|in|frac=2}} in length and weigh up to {{convert|35|g|oz}}.<ref>{{cite web |title=Pet facts: giant burrowing cockroaches |url=http://www.abc.net.au/creaturefeatures/facts/cockroach.htm |publisher=[[Australian Broadcasting Corporation]] |access-date=3 December 2005 |archive-url=https://web.archive.org/web/20140218184323/http://www.abc.net.au/creaturefeatures/facts/cockroach.htm |archive-date=18 February 2014 |url-status=dead}}</ref> Comparable in size is the Central American giant cockroach ''[[Blaberus giganteus]]''.<ref name=Huang>{{cite journal |last1=Huang |first1=C. Y. |last2=Sabree |first2=Z. L. |last3=Moran |first3=N. A. |year=2012 |title=Genome Sequence of ''Blattabacterium'' sp. Strain BGIGA, Endosymbiont of the ''Blaberus giganteus'' Cockroach |journal=Journal of Bacteriology |volume=194 |issue=16 |pages=4450–4451 |doi=10.1128/jb.00789-12|pmid=22843586 |pmc=3416254}}</ref> The longest cockroach species is ''[[Megaloblatta longipennis]]'', which can reach {{convert|97|mm|in|abbr=on|frac=8}} in length and {{convert|45|mm|in|abbr=on|frac=8}} across.<ref>{{cite web |url=http://www.guinnessworldrecords.com/records-10000/largest-cockroach/ |title=Guinness World Records: World's Largest Cockroach |author=Guinness World Records }}</ref> A Central and South American species, ''[[Megaloblatta blaberoides]]'', has the largest wingspan of up to {{convert|185|mm|in|abbr=on|frac=8}}.<ref>{{cite web |url=http://www.nhm.ac.uk/about-us/news/2006/may/news_8129.html |title=Cockroaches hit the shelves |publisher=Natural History Museum |date=May 2006 |archive-url=https://web.archive.org/web/20060819141741/http://www.nhm.ac.uk/about-us/news/2006/may/news_8129.html |archive-date=19 August 2006 |access-date=23 November 2015}}</ref> At the other end of the size scale, ''[[Attaphila]]'' cockroaches that live with [[Leafcutter ant|leaf-cutter ants]] include some of the world's smallest species, growing to about 3.5 mm in length.<ref>{{cite journal |last=Wheeler |first=William Morton |date=November 1900 |title=A New Myrmecophile from the Mushroom Gardens of the Texan Leaf-Cutting Ant |journal=The American Naturalist |volume=34 |issue=407 |pages=851–862 |doi=10.1086/277806 |s2cid=85112362|doi-access=free |bibcode=1900ANat...34..851W }}</ref>

[[File:Cockroach head.jpg|thumb|upright|Head of ''[[Periplaneta americana]]'']]

Cockroaches are generalized insects with few special adaptations, and may be among the most [[Primitive (phylogenetics)|primitive]] living [[Neoptera]]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]]s, two [[ocelli]], and long, flexible [[antenna (biology)|antennae]]. The [[Insect mouthparts|mouthparts]] are on the underside of the head and include generalized chewing [[mandible (arthropod mouthpart)|mandibles]], [[salivary gland]]s and various touch and taste receptors.<ref name=ISC>{{cite web |url=http://biology4isc.weebly.com/7-morphology-and-anatomy-of-cockroach.html |title=Diversity of Life: Cockroach anatomy |work=Biology4ISC |access-date=8 November 2015 |archive-url=https://web.archive.org/web/20151208155941/http://biology4isc.weebly.com/7-morphology-and-anatomy-of-cockroach.html |archive-date=8 December 2015 |url-status=dead}}</ref>

The body is divided into a [[thorax]] of three segments and a ten-segmented abdomen. The external surface has a tough [[exoskeleton]] 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 [[Tegmen|tegmina]], or first pair of wings, are tough and protective; these lay as a shield on top of the membranous [[Hindwings|hind wings]], which are used in flight. All four wings have branching longitudinal veins, as well as multiple [[Cross vein|cross-veins]].<ref name=IIBD>{{cite book |last1=Hoell |first1=H. V. |author2=Doyen, J. T. |author3=Purcell, A. H. |year=1998 |title=Introduction to Insect Biology and Diversity |edition=2nd |publisher=Oxford University Press |pages=362–364 |isbn=978-0-19-510033-4}}</ref>

The three pairs of legs are sturdy, with large [[Arthropod leg|coxae]] and five claws each.<ref name=IIBD/> 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.<ref name=ISC/> 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.<ref>{{cite journal |last1=Ritzmann |first1=Roy E. |last2=Quinn |first2=Roger D. |last3=Fischer |first3=Martin S. |year=2004 |title=Convergent evolution and locomotion through complex terrain by insects, vertebrates and robots |url=http://www.case.edu/artsci/biol/ritzmann/Ritzmann%204.pdf |journal=Arthropod Structure & Development |volume=33 |issue=3 |pages=361–379 |doi=10.1016/j.asd.2004.05.001 |pmid=18089044|bibcode=2004ArtSD..33..361R }}</ref><ref>{{cite journal |last1=Spagna |first1=J. C. |last2=Goldman |first2=D.I. |last3=Lin |first3=P-C. |last4=Koditschek |first4=D. E. |last5=Full |first5=Robert J. |year=2007 |title=Distributed mechanical feedback control of rapid running on challenging terrain |journal=Bioinspiration & Biomimetics |volume=2 |issue=1 |pages=9–18 |doi=10.1088/1748-3182/2/1/002 |pmid=17671322 |bibcode=2007BiBi....2....9S |s2cid=21564918 }}</ref>

The abdomen has ten segments, each having a pair of [[Spiracle (arthropods)|spiracle]]s for respiration. In addition to the spiracles, the final segment consists of a pair of [[Cercus|cerci]], a pair of anal styles, the anus and the external genitalia. Males have an [[aedeagus]] through which they secrete sperm during copulation, while females have [[spermatheca]] for storing sperm and an [[ovipositor]] through which the [[ootheca|oothecae]] are laid.<ref name=ISC/>

==Distribution and habitat==
Cockroaches are abundant throughout the world and live in a wide range of environments, especially in the [[tropics]] and [[subtropics]].<ref name="Meyer">{{cite web |last1=Meyer |first1=J. |title=Blattodea |url=https://www.cals.ncsu.edu/course/ent425/library/compendium/blattodea.html |work=General Entomology |publisher=University of North Carolina |access-date=9 November 2015}}</ref> In [[North America]], 50 species separated into five families are found throughout the continent.<ref name="Meyer"/> 450 species are found in [[Australia]].<ref name=assu>{{cite web |title=Cockroaches: Order Blattodea |url=https://australian.museum/learn/animals/insects/cockroaches-order-blattodea/|publisher=Australian Museum |access-date=10 November 2015|date=13 January 2012}}</ref> Only about four widespread species are commonly regarded as pests.<ref>{{Cite journal |last1=Valles |first1=S. M. |last2=Koehler |first2=P. G. |last3=Brenner |first3=R. J. |year=1999 |title=Comparative insecticide susceptibility and detoxification enzyme activities among pestiferous blattodea |journal=Comp Infibous Biochem Physiol C Pharmacol Toxicol Endocrinol |volume=124 |issue=3 |pages=227–232 |doi=10.1016/S0742-8413(99)00076-6 |pmid=10661713}}</ref><ref name="are">{{Cite journal |last1=Schal |first1=C. |last2=Hamilton |first2=R. L. |year=1990 |title=Integrated suppression of synanthropic cockroaches |url=http://www4.ncsu.edu/~coby/schal/1990SchalAREreview.pdf |journal=Annu. Rev. Entomol. |volume=35 |pages=521–551 |doi=10.1146/annurev.en.35.010190.002513 |pmid=2405773 |archive-url=https://web.archive.org/web/20060526114717/http://www4.ncsu.edu/~coby/schal/1990SchalAREreview.pdf|archive-date=2006-05-26 }}</ref>

Cockroaches occupy a wide range of habitats. Many live in [[leaf litter]], 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 [[Bromeliaceae|bromeliad]] [[phytotelma]]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 [[snorkeling|snorkel]], but some carry a bubble of air under their thoracic shield when they submerge. By doing this, cockroaches can remain submerged for up to 40 minutes.<ref>{{Cite web |url=https://www.pestworld.org/news-hub/pest-articles/fascinating-cockroach-facts/ |title="10 Fascinating Cockroach Facts" |author=<!--Not stated--> |date= |website=Pestworld.org |publisher=National Pest Management Association |access-date=2024-12-30|quote=}}</ref> Others live in the [[Canopy (biology)|forest canopy]] where they may be one of the main types of [[invertebrate]] present. Here they may hide during the day in crevices, among dead leaves, in bird and insect nests or among [[epiphyte]]s, emerging at night to feed.<ref name=Bell>{{cite book |last1=Bell |first1=William J. |last2=Roth |first2=Louis M. |author3=Nalepa, Christine A. |title=Cockroaches: Ecology, Behavior, and Natural History |url=https://books.google.com/books?id=R7eVRP08kasC&pg=PA55 |year=2007 |publisher=JHU Press |isbn=978-0-8018-8616-4 |pages=55–58}}</ref>

==Behavior==
[[File:Cockroach, post-ecdysis.jpg|thumb|upright|A cockroach soon after [[ecdysis]]]]
<!--[[File:Bush Cockroach.jpg|thumb|right|A bush cockroach (''Ellipsidion australe'')]] Purpose of this image? -->
Cockroaches are social insects; a large number of species are either [[gregarious]] or inclined to aggregate, and a slightly smaller number exhibit parental care.<ref name=Costa2006>{{cite book |last=Costa |first=James T. |title=The Other Insect Societies |url=https://books.google.com/books?id=PYRFDrZs9QAC&pg=PA148 |year=2006 |publisher=Harvard University Press |isbn=978-0-674-02163-1 |page=148}}</ref> It used to be thought that cockroaches aggregated because they were reacting to environmental cues, but it is now believed that [[pheromone]]s are involved in these behaviors. Some species secrete these in their feces with gut microbial [[Symbiosis|symbionts]] being involved, while others use glands located on their [[mandible]]s. Pheromones produced by the [[cuticle]] 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.<ref name=Costa2006/> Other cockroaches follow such trails to discover sources of food and water, and where other cockroaches are hiding. Thus, cockroaches have [[Emergent properties|emergent behavior]], in which group or [[swarm behavior]] emerges from a simple set of individual interactions.<ref name=LihoreauEtAl2012/>

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]] (PDF), was isolated and found to be a key mediator in the [[circadian rhythm]]s of the cockroach.<ref>{{cite journal |last1=Hamasaka |first1=Yasutaka |title=Chronobiological analysis and mass spectrometric characterization of pigment-dispersing factor in the cockroach Leucophaea maderae |journal=The Journal of Insect Science |date=22 December 2005|volume=5 |issue=43 |pmc=1615250 |pmid=17119625 |last2=Mohrherr |first2=C. J. |last3=Predel |first3=R. |last4=Wegener |first4=C. |page=43 |doi=10.1093/jis/5.1.43}}</ref>

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 [[Nocturnality|nocturnal]]<ref name="ucipm">{{cite web |url=http://www.ipm.ucdavis.edu/PMG/PESTNOTES/pn7467.html |title=Cockroaches |author=Rust, M. K. |date=2007 |work=University of California Integrated Pest Management Program |publisher=University of California |access-date=24 November 2015}}</ref> and run away when exposed to light. An exception to this is the [[Asian cockroach]], which flies mostly at night but is attracted to brightly lit surfaces and pale colors.<ref name=Richman>{{cite web |url=http://entomology.ifas.ufl.edu/creatures/urban/roaches/asian_cockroach.htm |title=Asian cockroach |author=Richman, Dina L. |date=1 June 2014 |work=featured Creatures |publisher=University of Florida |access-date=4 November 2015}}</ref>

===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.<ref name=LihoreauEtAl2010>{{cite journal |author1=Lihoreau, Mathieu |author2= Deneubourg, Jean-Louis |author3= Rivault, Colette |title=Collective foraging decision in a gregarious insect|journal=Behavioral Ecology and Sociobiology |year=2010 |volume=64 |issue=10 |pages=1577–1587 |doi=10.1007/s00265-010-0971-7|bibcode= 2010BEcoS..64.1577L |s2cid= 35375594 }}</ref> Other mathematical models have been developed to explain aggregation dynamics and conspecific recognition.<ref name=AmeEtAl2004>{{cite journal |last1=Ame |first1=Jean-Marc |author2=Rivault, Colette |author3=Deneubourg, Jean-Louis |title=Cockroach aggregation based on strain odour recognition|journal=Animal Behaviour |date=Oct 2004 |volume=68 |issue=4 |pages=793–801 |doi=10.1016/j.anbehav.2004.01.009|s2cid=7295380 }}</ref><ref name=JeansonEtAl2005>{{cite journal |last1=Jeanson |first1=Raphael |author2=Rivault, Colette |author3=Deneubourg, Jean-Louis |author4=Blanco, Stephane |author5=Fournier, Richard |author6=Jost, Christian |author7=Theraulaz, Guy |title=Self-organized aggregation in cockroaches |journal=Animal Behaviour |date=Jan 2005 |volume=69 |issue=1 |pages=169–180 |doi=10.1016/j.anbehav.2004.02.009|s2cid=16747884 }}</ref><ref name="Havens Spain Salmon Keller 2008 p. ">{{cite conference | last1=Havens | first1=Timothy C. | last2=Spain | first2=Christopher J. | last3=Salmon | first3=Nathan G. | last4=Keller | first4=James M. | title=2008 IEEE Swarm Intelligence Symposium | chapter=Roach Infestation Optimization | publisher=IEEE | year=2008 | pages=1–7 | doi=10.1109/sis.2008.4668317 | isbn=978-1-4244-2704-8 | quote=There are many function optimization algorithms based on the collective behavior of natural systems - Particle Swarm Optimization (PSO) and Ant Colony Optimization (ACO) are two of the most popular. This paper presents a new adaptation of the PSO algorithm, entitled Roach Infestation Optimization (RIO), that is inspired by recent discoveries in the social behavior of cockroaches.| hdl=10355/2092 | hdl-access=free }}</ref>

<!--http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0019748 "In group-living organisms, consensual decision of site selection results from the interplay between individual responses to site characteristics and to group-members." Paper byStéphane Canonge, Jean-Louis Deneubourg, Grégory Sempo, June 20, 2011 https://doi.org/10.1371/journal.pone.0019748-->
Cooperation and competition are balanced in cockroach group decision-making behavior.<ref name=LihoreauEtAl2012/>

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 (sociodynamics)|critical mass]], the roaches accepted the collective decision on where to hide, even if this was an unusually lit place.<ref>{{cite magazine |last=Lemonick |first=Michael D. |title=Robotic Roaches Do the Trick |magazine=[[Time (magazine)|Time]] |date=15 November 2007 |access-date=24 November 2015|url=http://www.time.com/time/health/article/0,8599,1684427,00.html?imw=Y |archive-url=https://web.archive.org/web/20071116222235/http://www.time.com/time/health/article/0,8599,1684427,00.html?imw=Y |url-status=dead |archive-date=16 November 2007}}</ref>

===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, among males, took longer to recognize receptive females. Because these changes occurred in many contexts, the authors suggested them as constituting a [[behavioral syndrome]]. 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.<ref name=LihoreauEtAl2009>{{cite journal |author1= Lihoreau, Mathieu |author2= Brepson, Loïc|author3= Rivault, Colette |title=The weight of the clan: Even in insects, social isolation can induce a behavioural syndrome |journal=Behavioural Processes |year=2009 |volume=82 |issue= 1|pages=81–84 |doi=10.1016/j.beproc.2009.03.008 |pmid=19615616|s2cid= 20809920}}</ref>

Individual [[American cockroach]]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.<ref name="Planas-SitjàEtAl">{{cite journal |last1=Planas-Sitjà |first1=Isaac |author2=Deneubourg, Jean-Louis |author3= Gibon, Céline |author4= Sempo, Grégory |title=Group personality during collective decision-making: a multi-level approach |journal=Proc. R. Soc. B |date=2015 |doi=10.1098/rspb.2014.2515 |pmid= 25652834 |pmc= 4344149 |url=https://dipot.ulb.ac.be/dspace/bitstream/2013/190793/1/Planasetal.pdf |volume=282 |issue= 1802 |pages=20142515}}</ref><ref name=Morell2015>{{cite news |last1=Morell |first1=Virginia |title=Even cockroaches have personalities |journal=Science |url=https://www.science.org/content/article/even-cockroaches-have-personalities|access-date=19 February 2015 |agency=Science |date=3 February 2015 |doi=10.1126/science.aaa7797}}</ref>

The gregarious German and American cockroaches have elaborate [[social structure]], chemical signaling, and "social herd" characteristics. Lihoreau and his fellow researchers stated:<ref name=LihoreauEtAl2012>{{cite journal |last1=Lihoreau |first1=M. |author2=Costa, J.T. |author3=Rivault, C. |title=The social biology of domiciliary cockroaches: colony structure, kin recognition and collective decisions |journal=Insectes Sociaux |date=November 2012 |volume=59 |issue=4 |pages=445–452 |doi=10.1007/s00040-012-0234-x|s2cid=10205316 }}</ref>

{{pull quote|1=The social biology of domiciliary cockroaches&nbsp;... can be characterized by a common shelter, overlapping generations, non-closure of groups, equal reproductive potential of group members, an absence of task specialization, high levels of social dependence, central place foraging, social information transfer, [[kin recognition]], and a meta-population structure.<ref name=LihoreauEtAl2012/>}}

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 [[eusociality|eusocial]] lineage known among roaches, in contrast to the [[Sociality#Subsociality|subsocial]] members of the genus ''[[Cryptocercus]]''.<ref>{{Cite journal |last1=Hinkelman |first1=Jan |last2=Vršanský |first2=Peter |last3=Garcia |first3=Thierry |last4=Tejedor |first4=Adrian |last5=Bertner |first5=Paul |last6=Sorokin |first6=Anton |last7=Gallice |first7=Geoffrey R. |last8=Koubová |first8=Ivana |last9=Nagy |first9=Štefan |last10=Vidlička |first10=Ľubomír |date=2020 |title=Neotropical Melyroidea group cockroaches reveal various degrees of (eu)sociality |url=https://link.springer.com/10.1007/s00114-020-01694-x |journal=The Science of Nature |language=en |volume=107 |issue=5 |page=39 |doi=10.1007/s00114-020-01694-x|pmid=32870399 |bibcode=2020SciNa.107...39H |url-access=subscription }}</ref>

===Sounds===
Some species make a buzzing noise while other cockroaches make a chirping noise. ''[[Gromphadorhina]]'' species and ''[[Archiblatta hoeveni]]'' produce sound through the modified [[Spiracle (arthropods)|spiracle]]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.<ref>{{cite journal |author=Nelson, Margaret C. |year=1979 |title=Sound production in the cockroach, ''Gromphadorhina portentosa'': The sound-producing apparatus |journal=[[Journal of Comparative Physiology]]|volume=132 |issue=1 |pages=27–38 |doi=10.1007/BF00617729|s2cid=45902616 }}</ref> ''[[Henschoutedenia epilamproides]]'' has a [[Stridulation|stridulatory organ]] between its thorax and abdomen, but the purpose of the sound produced is unclear.<ref>{{cite journal |author=Guthrie, D.M. |year=1966 |title=Sound production and reception in a cockroach |journal=Journal of Experimental Biology |volume=45 |issue=2 |pages=321–328 |doi=10.1242/jeb.45.2.321 |bibcode=1966JExpB..45..321G |url=http://jeb.biologists.org/content/45/2/321.short|url-access=subscription }}</ref>

Several Australian species practice [[Acoustics|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.<ref>{{cite book|url=http://www.publish.csiro.au/pid/6710.htm |title=A Guide to the Cockroaches of Australia |last=Rentz |first=David |publisher=CSIRO Publishing |year=2014 |isbn=978-0-643-10320-7}}</ref>

==Biology==
===Digestive tract===
Cockroaches are generally [[Omnivore|omnivorous]]; 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.<ref name=bell>{{cite book |last1=Bell |first1=William J. |last2=Adiyodi |first2=K. G. |title=American Cockroach |url=https://books.google.com/books?id=7JCsYtH-VcYC&pg=PA4 |year=1981 |publisher=Springer |isbn=978-0-412-16140-7 |page=4}}</ref> Many species of cockroach harbor in their gut [[Symbiosis|symbiotic]] [[protozoa]]ns and [[bacteria]] which are able to digest [[cellulose]]. In many species, these symbionts may be essential if the insect is to utilize cellulose; however, some species secrete [[cellulase]] in their [[saliva]], and the wood-eating cockroach, ''[[Panesthia cribrata]]'', is able to survive indefinitely on a diet of crystallized cellulose while being free of microorganisms.<ref>{{cite journal |last=Slaytor |first=Michael |year=1992 |title=Cellulose digestion in termites and cockroaches: What role do symbionts play? |journal=Comparative Biochemistry and Physiology B |volume=103 |issue=4 |pages=775–784 |doi=10.1016/0305-0491(92)90194-V}}</ref>

The similarity of these symbionts in the genus ''[[Cryptocercus]]'' to those in termites are such that these cockroaches have been suggested to be more closely related to termites than to other cockroaches,<ref>{{cite journal |last=Eggleton |first=P. |year=2001 |title=Termites and trees: a review of recent advances in termite phylogenetics |journal=Insectes Sociaux |volume=48 |pages=187–193 |doi=10.1007/PL00001766 |issue=3 |s2cid=20011989 }}</ref> and current research strongly supports this hypothesis about their relationships.<ref>{{cite journal |title=Evidence for Cocladogenesis Between Diverse Dictyopteran Lineages and Their Intracellular Endosymbionts |doi=10.1093/molbev/msg097 |year=2003 |last1=Lo |first1=N. |journal=Molecular Biology and Evolution |volume=20 |issue=6 |pages=907–13 |pmid=12716997 |last2=Bandi |first2=C. |last3=Watanabe |first3=H. |last4=Nalepa |first4=C. |last5=Beninati |first5=T. |doi-access=free}}</ref> All species studied so far carry the obligate [[Mutualism (biology)|mutualistic]] [[endosymbiont]] bacterium ''[[Blattabacterium]]'', with the exception of ''[[Nocticola]]'', an Australian cave-dwelling genus without eyes, pigment or wings, which recent genetic studies indicate is a very primitive cockroach.<ref>{{cite news |title=Cave may hold missing link |author=Leung, Chee Chee |url=http://www.theage.com.au/news/national/cave-may-hold-missing-link/2007/03/21/1174153159560.html |newspaper=The Age |date=22 March 2007 |access-date=24 November 2015}}</ref><ref name=Beninati>{{cite journal |pmid=17376757 |year=2007 |last1=Lo |first1=N. |last2=Beninati|first2=T. |last3=Stone |first3=F. |last4=Walker |first4=J. |last5=Sacchi |first5=L. |title=Cockroaches that lack ''Blattabacterium'' endosymbionts: The phylogenetically divergent genus ''Nocticola'' |volume=3 |issue=3 |pages=327–30 |doi=10.1098/rsbl.2006.0614 |pmc=2464682 |journal=Biology Letters}}</ref> It had previously been thought that all five families of cockroach were descended from a common ancestor that was infected with ''[[Blattabacterium cuenoti|B. cuenoti]]''. It may be that ''N.&nbsp;australiensis'' subsequently lost its symbionts, or alternatively this hypothesis will need to be re-examined.<ref name=Beninati/>

===Tracheae and breathing===
Like other insects, cockroaches breathe through a system of tubes called [[Invertebrate trachea|tracheae]] which are attached to openings called spiracles on all body segments. When the [[carbon dioxide]] level in the insect rises high enough, valves on the spiracles open and carbon dioxide [[Diffusion|diffuses]] out and [[oxygen]] diffuses in. The tracheal system branches repeatedly, the finest [[tracheole]]s bringing air directly to each [[cell (biology)|cell]], allowing gaseous exchange to take place.<ref name=Umass>{{cite web |url=http://www.bio.umass.edu/biology/kunkel/cockroach_faq.html#Q21 |title=The Cockroach FAQ |publisher=University of Massachusetts |access-date=24 November 2015}}</ref>

While cockroaches do not have [[lung]]s as do [[vertebrate]]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.<ref name=Umass/>

===Reproduction===
Cockroaches use [[pheromone]]s to attract mates, and the males practice courtship rituals, such as posturing and [[stridulation]]. 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 [[parthenogenesis|parthenogenetic]], reproducing without the need for males.<ref name=IIBD/>

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]]. 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 [[nymph (biology)|nymphs]] and continue inflating themselves with air, becoming harder and darker within about four hours. Their transient white stage while hatching and later while [[ecdysis|molting]] has led to claims of [[albino]] cockroaches.<ref name=IIBD/> 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.<ref name=IIBD/>

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]], keeping the eggs inside their body, with or without an egg case, until they hatch. At least one genus, ''[[Diploptera]]'', is fully [[viviparous]].<ref name=IIBD/>

Cockroaches have [[incomplete metamorphosis]], meaning that the [[nymph (biology)|nymphs]] 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.<ref name=IIBD/>

<gallery mode="nolines">
File:Cockroach nymph australia.jpg|3&nbsp;millimeter cockroach nymph
File:Cockroach egglaying 1.jpg|Female ''[[Periplaneta fuliginosa]]'' with [[ootheca]]
File:Captured roach with babies.jpg|Captured adult and baby roaches around [[ootheca]]
File:Old Ootheca.jpg|Empty [[ootheca]]
File:Periplaneta-americana-Eier.jpg|American cockroach oothecae
</gallery>

===Parthenogenesis===

When female [[American cockroach]]es (''Periplaneta americana'') are housed in groups, this close association promotes [[parthenogenesis|parthenogenic reproduction]].<ref name = Katoh2017>{{cite journal|pmid=28331632 |date=2017 |last1=Katoh |first1=K. |last2=Iwasaki |first2=M. |last3=Hosono |first3=S. |last4=Yoritsune |first4=A. |last5=Ochiai |first5=M. |last6=Mizunami |first6=M. |last7=Nishino |first7=H. |title=Group-housed females promote production of asexual ootheca in American cockroaches |journal=Zoological Letters |volume=3 |page=3 |doi=10.1186/s40851-017-0063-x |pmc=5348754 |doi-access=free }}</ref> [[Ootheca|Oothecae]], a type of egg mass, are produced asexually.<ref name = Katoh2017/> The parthenogenetic process by which eggs are produced in ''P.&nbsp;americana'' is automixis.<ref>{{cite journal|pmid=29389065 |date=2019 |last1=Tanaka |first1=M. |last2=Daimon |first2=T. |title=First molecular genetic evidence for automictic parthenogenesis in cockroaches |journal=Insect Science |volume=26 |issue=4 |pages=649–655 |doi=10.1111/1744-7917.12572 |bibcode=2019InsSc..26..649T |s2cid=3879178 }}</ref> During [[automixis]], 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.<ref name='M & V E'>{{cite book |editor1-last=Mullen |editor1-first=Gary |editor2-last=Durden |editor2-first=Lance |title=Medical and Veterinary Entomology |year= 2002 |publisher=Academic Press |location=Amsterdam |isbn=978-0-12-510451-7 |page=32}}</ref> Some can go without air for 45 minutes. [[Japanese cockroach]] (''Periplaneta japonica'') [[nymph (biology)|nymphs]], which [[hibernate]] in cold winters, have survived twelve hours at {{convert|-5|to|-8|C}} in laboratory experiments.<ref name=Tanaka1997>{{cite journal |last1=Tanaka |first1=K. |last2=Tanaka |first2=S. |title=Winter Survival and Freeze Tolerance in a Northern Cockroach, ''Periplaneta japonica'' (Blattidae: Dictyoptera)|journal=Zoological Science |date=1997 |volume=14 |issue=5 |pages=849–853 |doi=10.2108/zsj.14.849 |s2cid=86223379 |url=http://ci.nii.ac.jp/naid/110003323491|doi-access=free }}</ref>

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.<ref name=berenbaum2009>{{cite book|last=Berenbaum|first=May|title=The Earwig's Tail: A Modern Bestiary of Multi-legged Legends|url=https://books.google.com/books?id=FOlpPl_15csC&pg=PA53|date=30 September 2009|publisher=Harvard University Press|isbn=978-0-674-03540-9|pages=53–54}}</ref><ref name=choi2007/> The severed head is able to survive and wave its antennae for several hours, or longer when refrigerated and given nutrients.<ref name=choi2007>{{cite news |title=Fact or fiction?: a cockroach can live without its head |first=Charles |last=Choi |work=Scientific American |date=15 March 2007 |url=http://www.scientificamerican.com/article.cfm?id=fact-or-fiction-cockroach-can-live-without-head |access-date=27 December 2013}}</ref>

It is [[urban legend|popularly suggested]] that cockroaches will "inherit the Earth" if humanity destroys itself in a [[nuclear warfare|nuclear war]]. While cockroaches do, indeed, have a much higher radiation resistance than [[vertebrate]]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 [[Drosophila melanogaster|fruit fly]].<ref>{{cite web |url=http://www.abc.net.au/science/k2/moments/s1567313.htm |author=Kruszelnicki, Karl S. |date=23 February 2006 |title=Cockroaches and Radiation |publisher=ABC Science |access-date=24 November 2015}}</ref>

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<ref name=JGKunk/>). 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{{clarification needed|reason="More" as in increased radiation or as in repeated bursts?|date=March 2024}} acute radiation would still be harmful.<ref name=Umass/>

==Relationship with humans==

[[File:"Periplaneta americana" connected to the electrophysiology equipment.JPG|thumb|Cockroaches in research: ''Periplaneta americana'' in an [[electrophysiology]] experiment]]
[[File:Cockroach - Tokyo Japan - 2018 9 19.webm|thumb|Cockroach climbing on a wall in [[Japan]], 2018]]

===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]], [[reproductive physiology]] and [[social behavior]].<ref name=Costa2006/> 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]]s, spatial orientation, [[aggression]], activity rhythms and the [[Circadian clock|biological clock]], and [[behavioral ecology]].<ref name="Bell2012">{{cite book |last=Bell |first=W. J. |title=The Laboratory Cockroach: Experiments in cockroach anatomy, physiology and behavior |url=https://books.google.com/books?id=2gkjBQAAQBAJ&pg=PA92 |date=2012 |orig-year=1981 |publisher=Springer |isbn=978-94-011-9726-7}}</ref> Research conducted in 2014 suggests that humans fear cockroaches the most, even more than [[mosquito]]es, due to an evolutionary aversion.<ref>{{cite web|url=https://www.bbc.com/future/article/20140918-the-reality-about-roaches|title=Cockroaches: The insect we're programmed to fear|date=18 September 2014|work=BBC}}</ref>

===As pests===
[[File:Blatta orientalis - Wilhelma 01.jpg|thumb|[[Oriental cockroach]] feeding on human food]]

The Blattodea include some thirty species of cockroaches associated with humans; these species are atypical of the thousands of species in the order.<ref name=GullanCranston>{{cite book|last1=Gullan |first1=P. J. |last2=Cranston |first2=P. S. |title=The Insects: An Outline of Entomology |date=2014 |publisher=Wiley |isbn=978-1-118-84615-5 |page=508}}</ref> Of those thirty species, four are most commonly encountered as pests: the [[German cockroach]] (''Blattella germanica''), [[American cockroach]] (''Periplaneta americana''), [[oriental cockroach]] (''Blatta orientalis''), and [[brown-banded cockroach]] (''Supella longipalpa'').<ref>{{cite web |url=https://www.forbes.com/home-improvement/pest-control/types-of-cockroaches/ |title=5 Common Types Of Cockroaches |last=Glover |first=Emily |date=30 July 2024 |website=[[Forbes]] |access-date=19 Aug 2024}}</ref><ref>{{cite web |url=https://www.ecolab.com/articles/2024/03/common-pest-cockroaches |title=Common Pest Cockroaches |date=20 Mar 2024 |website=[[Ecolab]] |access-date=19 Aug 2024}}</ref>

Pest cockroaches feed on human and pet food and can leave an offensive odor.<ref>{{Cite journal |last1=Brenner |first1=R.J. |last2=Koehler |first2=P. |last3=Patterson |first3=R.S. |year=1987 |title=Health Implications of Cockroach Infestations |journal=Infestations in Med |volume=4 |issue=8|pages=349–355}}</ref> They can passively transport [[pathogen]]ic microbes on their body surfaces, particularly in environments such as hospitals.<ref>{{Cite journal |doi=10.1017/S0950268800068254 |last1=Rivault |first1=C. |last2=Cloarec |first2=A. |last3=Guyader |first3=A. Le |year=1993 |title=Bacterial load of cockroaches in relation to urban environment|journal=Epidemiology and Infection |volume=110 |issue=2|pages=317–325 |pmid=8472775 |pmc=2272268}}</ref><ref>{{Cite journal |doi=10.1179/136485906X78463 |last1=Elgderi |first1=R.M. |last2=Ghenghesh |first2=K.S. |last3=Berbash |first3=N. |year=2006 |title=Carriage by the German cockroach (''Blattella germanica'') of multiple-antibiotic-resistant bacteria that are potentially pathogenic to humans, in hospitals and households in Tripoli, Libya |journal=Ann Trop Med Parasitol |volume=100 |issue=1|pages=55–62 |pmid=16417714|s2cid=29755450 }}</ref> Cockroaches are linked with [[allergic reaction]]s in humans.<ref>{{Cite journal |last1=Bernton |first1=H.S. |last2=Brown |first2=H. |year=1964 |title=Insect Allergy Preliminary Studies of the Cockroach |journal=J. Allergy |volume=35 |issue=506–513 |pmid=14226309 |pages=506–13 |doi=10.1016/0021-8707(64)90082-6}}</ref><ref>{{Cite journal |last1=Kutrup |first1=B |year=2003 |title=Cockroach Infestation in Some Hospitals in Trabzon, Turkey |url=http://journals.tubitak.gov.tr/zoology/issues/zoo-03-27-1/zoo-27-1-12-0005-1.pdf |journal=Turk. J. Zool. |volume=27 |pages=73–77 |access-date=2 August 2008 |archive-url=https://web.archive.org/web/20060204194754/http://journals.tubitak.gov.tr/zoology/issues/zoo-03-27-1/zoo-27-1-12-0005-1.pdf |archive-date=4 February 2006 |url-status=dead}}</ref> One of the proteins that trigger allergic reactions is [[tropomyosin]], which can cause cross-reactive allergy to [[house dust mites|dust mites]] and [[shrimp]].<ref>{{Cite journal |doi=10.1016/S0091-6749(99)70375-1 |vauthors=Santos AB, Chapman MD, Aalberse RC, Vailes LD, Ferriani VP, et al |year=1999 |title=Cockroach allergens and asthma in Brazil: identification of tropomyosin as a major allergen with potential cross-reactivity with mite and shrimp allergens |journal=The Journal of Allergy and Clinical Immunology |volume=104 |issue=2|pages=329–37 |pmid=10452753}}</ref> These allergens are also linked with [[asthma]].<ref>{{Cite journal |doi=10.1016/0091-6749(79)90196-9 |last1=Kang |first1=B. |last2=Vellody |first2=D. |last3=Homburger |first3=H. |last4=Yunginger |first4=J. W. |year=1979 |title=Cockroach cause of allergic asthma. Its specificity and immunologic profile |journal=The Journal of Allergy and Clinical Immunology |volume=63 |issue=2|pages=80–86 |pmid=83332|doi-access=free }}</ref> 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.<ref>{{Cite journal |last1=Eggleston|first1=P.A. |last2=Arruda|first2=L.K.|date=2001 |title=Ecology and elimination of cockroaches and allergens in the home.|doi=10.1067/mai.2001.113671|pmid=11242603 |journal=Journal of Allergy and Clinical Immunology |volume=107 |issue=3 |pages=S422–S429|s2cid=28424188 |doi-access=free }}</ref>

====Control====
{{See also|Pest control#In homes and cities}}
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.<ref>{{cite web |url=http://homeremediesandtips.whw1.com/home/pests/6-top-home-remedies-to-kill-and-control-cockroaches#BakingSoda |title=Best Home Remedies To Kill And Control Cockroaches – Baking Soda |website=HRT.whw1.com |access-date=20 June 2015 |archive-date=20 June 2015 |archive-url=https://web.archive.org/web/20150620181510/http://homeremediesandtips.whw1.com/home/pests/6-top-home-remedies-to-kill-and-control-cockroaches#BakingSoda |url-status=dead }}</ref> Garden herbs including [[bay leaves|bay]], [[catnip]], [[Mentha|mint]], [[cucumber]], and [[garlic]] have been proposed as repellents.<ref>{{cite web |url=http://homeremediesandtips.whw1.com/home/pests/6-top-home-remedies-to-kill-and-control-cockroaches#Catnip |title=Best Home Remedies To Kill And Control Cockroaches – Catnip |website=HRT.whw1.com |access-date=20 June 2015 |archive-date=20 June 2015 |archive-url=https://web.archive.org/web/20150620181510/http://homeremediesandtips.whw1.com/home/pests/6-top-home-remedies-to-kill-and-control-cockroaches#Catnip |url-status=dead }}</ref> Poisoned bait containing [[hydramethylnon]] or [[fipronil]], and [[boric acid]] powder is effective on adults.<ref name="alamance">{{cite web |url=http://www.alamance-nc.com/Alamance-NC/Departments/Environmental+Health/Environmental+Hazards/Cockroaches.htm |title=Cockroaches |publisher=[[Alamance County]] Department of Environmental Health |access-date=11 May 2008 |url-status=dead |archive-url=https://web.archive.org/web/20090312045904/http://www.alamance-nc.com/Alamance-NC/Departments/Environmental%2BHealth/Environmental%2BHazards/Cockroaches.htm |archive-date=12 March 2009}}</ref> Baits with egg killers are also quite effective at reducing the cockroach population. Alternatively, [[insecticide]]s containing [[deltamethrin]] or [[pyrethrin]] are very effective.<ref name="alamance" /> In Singapore and Malaysia, taxi drivers use [[Pandanus amaryllifolius|pandan]] leaves to repel cockroaches in their vehicles.<ref>Li J. and Ho S.H. [http://www.ntu.edu.sg/eee/urop/congress2003/Proceedings/abstract/NUS_FoS/TDP%20USP/Li%20Jingmei.pdf Pandan leaves (''Pandanus amaryllifolius'' Roxb.) As A Natural Cockroach Repellent] {{Webarchive|url=https://web.archive.org/web/20170110161259/http://www3.ntu.edu.sg/eee/urop/congress2003/proceedings/abstract/nus_fos/tdp%20usp/li%20jingmei.pdf |date=10 January 2017 }}. ''Proceedings of the 9th National Undergraduate Research Opportunities Programme'' (13 September 2003).</ref> Natural methods of cockroach control have been advanced by several published studies<ref name="NYTroach" /> especially by ''[[Metarhizium robertsii]]'' (syn. ''M.&nbsp;anisopliae'').<ref name="Zimmermann-2007">{{cite journal | last=Zimmermann | first=Gisbert | title=Review on safety of the entomopathogenic fungus ''Metarhizium anisopliae'' | journal=[[Biocontrol Science and Technology]] | publisher=[[Taylor & Francis]] | volume=17 | issue=9 | year=2007 | issn=0958-3157 | doi=10.1080/09583150701593963 | pages=879–920| bibcode=2007BioST..17..879Z | s2cid=84614415 }}</ref>

Some parasites and predators are effective for [[biological control]] of cockroaches. [[Parasitoid]]al [[wasp]]s such as ''[[Ampulex]]'' wasps sting nerve [[Ganglion|ganglia]] in the cockroach's [[thorax]], 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.<ref>{{cite journal |last1=Paterson Fox |first1=Eduardo Gonçalves |last2=Bressan-Nascimento |first2=Suzete |last3=Eizemberg |first3=Roberto |title=Notes on the Biology and Behaviour of the Jewel Wasp, Ampulex compressa (Fabricius, 1781) (Hymenoptera; Ampulicidae), in the Laboratory, Including First Record of Gregarious Reproduction |journal=Entomological News |date=September 2009 |volume=120 |issue=4 |pages=430–437 |doi=10.3157/021.120.0412|s2cid=83564852 }}</ref> The wasp larva feeds on the subdued living cockroach.<ref>{{cite journal |last1=Fox |first1=Eduardo G P |last2=Buys |first2=Sandor Cristiano |last3=Mallet |first3=Jace-Nir Reis Dos Santos |last4=Bressan-Nacimento |first4=Suzete |title=On the morphology of the juvenile stages of Ampulex compressa (Fabricius 1781) (Hymenoptera, Ampulicidae) |journal=Zootaxa |date=3 August 2006 |volume=1279 |issue=1 |pages=43 |doi=10.11646/zootaxa.1279.1.2|url=http://www.mapress.com/zootaxa/2006f/z01279p051f.pdf |hdl=11449/69026|hdl-access=free }}</ref><ref>{{cite book |author-link=Ross Piper |author=Piper, Ross |year=2007 |title=Extraordinary Animals: An Encyclopedia of Curious and Unusual Animals |url=https://archive.org/details/extraordinaryani0000pipe |url-access=registration |publisher=[[Greenwood Press (publisher)|Greenwood Press]] |isbn=9780313339226 }}</ref> 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.<ref>{{cite web |last1=Fox |first1=Eduardo G P |title=''Evania appendigaster'' Development |url=https://www.youtube.com/watch?v=0iGF5P3td9k | archive-url=https://ghostarchive.org/varchive/youtube/20211030/0iGF5P3td9k| archive-date=30 October 2021|website=YouTube |date=10 May 2011}}{{cbignore}}</ref><ref>{{cite journal |last1=Fox |first1=Eduardo Gonçalves Paterson |last2=Solis |first2=Daniel Russ |last3=Rossi |first3=Mônica Lanzoni |last4=Eizemberg |first4=Roberto |last5=Taveira |first5=Luiz Pilize |last6=Bressan-Nascimento |first6=Suzete |title=The preimaginal stages of the ensign wasp ''Evania appendigaster'' (Hymenoptera, Evaniidae), a cockroach egg predator |journal=Invertebrate Biology |date=June 2012 |volume=131 |issue=2 |pages=133–143 |doi=10.1111/j.1744-7410.2012.00261.x |url=https://www.researchgate.net/publication/260099527 |language=en|doi-access=free |bibcode=2012InvBi.131..133F }}</ref> Ongoing research is still developing technologies allowing for mass-rearing these wasps for application releases.<ref>{{cite journal |last1=Bressan-Nascimento |first1=S. |last2=Oliveira |first2=D.M.P. |last3=Fox |first3=E.G.P. |title=Thermal requirements for the embryonic development of Periplaneta americana (L.) (Dictyoptera: Blattidae) with potential application in mass-rearing of egg parasitoids |journal=Biological Control |date=December 2008 |volume=47 |issue=3 |pages=268–272 |doi=10.1016/j.biocontrol.2008.09.001|bibcode=2008BiolC..47..268B }}</ref><ref>{{cite journal |last1=Bressan-Nascimento |first1=S. |last2=Fox |first2=E.G.P. |last3=Pilizi |first3=L.G.T. |title=Effects of different temperatures on the life history of ''Evania appendigaster'' L. (Hymenoptera: Evaniidae), a solitary oothecal parasitoid of ''Periplaneta americana'' L. (Dictyoptera: Blattidae) |journal=Biological Control |date=February 2010 |volume=52 |issue=2 |pages=104–109 |doi=10.1016/j.biocontrol.2009.10.005|bibcode=2010BiolC..52..104B }}</ref> [[Latrodectus|Widow spiders]] commonly prey on cockroaches.<ref>{{cite web |url=https://www.orkin.com/other/spiders/black-widows/eat |title=What Do Black Widows Eat? |website=Orkin.com |date=11 April 2018 |access-date=30 July 2021 |url-status=live|archive-url=https://web.archive.org/web/20200720081904/https://www.orkin.com/other/spiders/black-widows/eat |archive-date=20 July 2020 }}</ref><ref>[https://www.desertusa.com/insects/black-widow-spider.html Black widow spider]</ref> 

{{Anchor|Vegas roach trap}}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.<ref>{{cite book |author=Herms, William Brodbeck |title=Medical and Veterinary Entomology |publisher=MacMillan |year=1915 |url=https://archive.org/details/bub_gb_SWsoAAAAYAAJ |page=[https://archive.org/details/bub_gb_SWsoAAAAYAAJ/page/n58 44]}}</ref>

A study conducted by scientists at [[Purdue University]] concluded that the most common cockroaches in the [[United States|US]], [[Australia]] 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.<ref name="the guardian 2019-07-03">{{Cite news|url=https://www.theguardian.com/environment/2019/jul/03/cockroaches-could-soon-be-almost-impossible-to-kill-with-pesticides|title=Cockroaches could soon be almost impossible to kill with pesticides|last=Wahlquist|first=Calla|date=3 July 2019|work=The Guardian|access-date=4 July 2019|language=en-GB|issn=0261-3077}}</ref> 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.<ref name="the guardian 2019-07-03" />

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.<ref>{{cite journal |author=Rakhmatulin, I. |author2=Lihoreau, M. |author3=Pueyo, J. |title=Selective neutralisation and deterring of cockroaches with laser automated by machine vision |journal=Oriental Insects |publisher=tandfonline|year=2022 |volume=57 |issue=2 |pages=728–745|doi=10.1080/00305316.2022.2121777 |s2cid=252457820 |doi-access=free }}</ref>

=== As food ===
{{See also|Entomophagy|}}

Although considered disgusting in [[Western culture]], cockroaches are eaten in many places around the world.<ref name="Copeland">Marion Copeland [2004]. [https://books.google.com/books?id=MNQSAgAAQBAJ&pg=PA86 Cockroach] (Pages 86 to 88). Published by Reaktion Books</ref><ref>Ronald L. Taylor, Barbara J. Carter [1976]. [https://books.google.com/books?id=OgJ8PQAACAAJ&q=the+original+guide+to+insect+cookery Entertaining with Insects: Or, The Original Guide to Insect Cookery]. Published by Woodbridge Press Publishing Company.</ref> Whereas household pest cockroaches may carry [[bacteria]] and [[virus]]es, cockroaches bred under laboratory conditions can be used to prepare nutritious food.<ref>David George Gordon [1998]. [https://books.google.com/books?id=i0Mcxow-66QC&q=Cockroach+Á+La+King The Eat-a-bug Cookbook] (Page 78). Published by Ten Speed Press.</ref> In [[Thailand]] and [[Mexico]], the heads and legs are removed, and the remainder may be boiled, sautéed, grilled, dried, or diced.<ref name="Copeland" /> Frying makes the insect crispy with soft innards that taste like [[cottage cheese]].<ref>Malcolm Moore [2013]. [https://web.archive.org/web/20131027111927/http://www.telegraph.co.uk/news/worldnews/asia/china/10399940/How-to-eat-a-cockroach-a-Telegraph-guide.html How to eat a cockroach: a Telegraph guide]. Published by Washington Post.</ref><ref>[2015]. [https://www.bbc.com/news/magazine-34517443 How cockroaches could save lives]. Published by BBC News.</ref> Recipes from [[Taiwan]] also call for its use in omelets.<ref name="papers">Richard Schweid [2015]. [https://books.google.com/books?id=K4ZoCQAAQBAJ&dq=cockroach+recipe&pg=PT69 The Cockroach Papers: A Compendium of History and Lore] (Page 69). Published by University of Chicago Press.</ref><ref name=":0">{{Cite web |last=Charlier |first=Phillip |date=23 June 2023 |title=Taiwanese man creates culinary masterpiece: cockroach omelet |url=https://taiwanenglishnews.com/taiwanese-man-creates-culinary-masterpiece-cockroach-omelet/ |website=Taiwan English News}}</ref> It can be a [[Live food|feeder insect]] for pet reptiles.<ref name=":0" />

===Medicinal use===
{{See also|Cockroach farming|}}

Cockroaches are raised in large quantities in China for the production of traditional medicine and cosmetics.<ref>David McKenzie [2014]. [http://www.cnn.com/2014/08/31/travel/china-cockroach-farming-food/ Eating cockroaches in China: Healing and delicious?]. Published by CNN.</ref> There are about 100 cockroach farms in the country. Running a farm involves relatively low starting and operating costs due to how hardy and easy to process the insects are. Chinese and South Korean researchers are investigating cockroaches for treating baldness, AIDS, cancer, and as a dietary supplement.<ref>{{cite news |last=Chen |first=Stephen |url=http://www.scmp.com/news/china/society/article/2142316/giant-indoor-farm-china-breeding-six-billion-cockroaches-year |title=A giant indoor farm in China is breeding 6 billion cockroaches a year. Here's why |work=[[South China Morning Post]] |date=19 April 2018 |access-date=20 April 2018}}</ref><ref>{{cite news|last1=Demick|first1=Barbara|title=Cockroach farms multiplying in China|url=http://www.latimes.com/world/la-fg-c1-china-cockroach-20131015-dto-htmlstory.html|access-date=20 April 2018|work=[[Los Angeles Times]]|date=15 October 2013}}</ref>

===Other uses===
Recent experiments have shown that some species of cockroaches may be used as a plastic scavenger.<ref name= Li_2024>{{cite journal | vauthors = Li MX, Yang SS, Ding J, Ding MQ, He L, Xing DF, Criddle CS, Benbow ME, Ren NQ, Wu WM |title= Cockroach Blaptica dubia biodegrades polystyrene plastics: Insights for superior ability, microbiome and host genes |journal= J Hazard Mater |date=November 5, 2024 | volume = 479| issue = |pages=135756|doi=10.1016/j.jhazmat.2024.135756
|pmid=39255668|bibcode= 2024JHzM..47935756L | url=https://www.sciencedirect.com/science/article/pii/S0304389424023355|url-access=subscription}}</ref>

===Conservation===
{{See also|Depopulation of cockroaches in post-Soviet states}}
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 [[rat]]s, the spread of Rhodes grass (''[[Chloris gayana]]'') and fires are possible reasons for their scarcity.<ref>{{cite web |title=Lord Howe Island wood-feeding cockroach – endangered species listing |url=http://www.environment.nsw.gov.au/determinations/PanesthiaLataEndangeredDeclaration.htm |work=Office of Environment and Heritage |publisher=Government of New South Wales |access-date=10 November 2015 |date=2011}}</ref> Two species are currently listed as [[Endangered species|endangered]] and [[critically endangered]] by the [[IUCN]] Red List, ''[[Delosia ornata]]'' and ''[[Nocticola gerlachi]]''.<ref name=IUCN2012>{{Cite iucn |last1=Gerlach |first1=J. |title=''Delosia ornata'' |volume=2012 |page=e.T199490A2593559 |date=2012 |doi=10.2305/IUCN.UK.2012.RLTS.T199490A2593559.en}}</ref><ref name=IUCN20122>{{Cite iucn |last1=Gerlach |first1=J. |title=''Nocticola gerlachi'' |volume=2012 |page=e.T199508A2595807 |date=2012 |doi=10.2305/IUCN.UK.2012.RLTS.T199508A2595807.en}}</ref> 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.<ref>{{cite news |title=Исчезновение тараканов на Белгородчине не связано с радиацией |url=http://www.bel.ru/news/2006/12/04/21613.html |access-date=24 November 2015 |work=Bel.ru |date=4 December 2006 |language=ru |archive-url=https://web.archive.org/web/20131016063634/http://www.bel.ru/news/2006/12/04/21613.html |archive-date=16 October 2013 |url-status=dead}}</ref> One species of roach, ''[[Simandoa conserfariam]]'', is considered [[extinct in the wild]].<ref name = "roth">{{cite journal |last1=Roth |first1=Louis M. |last2=Naskrecki |first2=Piotr |title=A new genus and species of cave cockroach (Blaberidae: Oxyhaloinae) from Guinea, West Africa |journal=[[Journal of Orthoptera Research]] |volume=13 |issue=1 |pages=57–61 |date=2004 |issn=1082-6467 |doi=10.1665/1082-6467(2004)013[0057:ANGASO]2.0.CO;2}}</ref>

==Cultural depictions==
{{see also|Cockroaches in popular culture}}
[[File:Roachies.JPG|thumb|[[Madagascar hissing cockroach]]es kept as pets]]
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.<ref name=Smith>{{cite book |last=Anthon |first=Charles |editor=Smith, William |title=A Dictionary of Greek and Roman Antiquities |url=https://books.google.com/books?id=30LCBp71dBsC&pg=PA161 |edition=3rd American |year=1843 |publisher=American Book Company |location=New York – Cincinnati – Chicago |page=161}}</ref><ref name="Lockyer1871">{{cite book |last=Lockyer |first= Norman |title=Nature |url=https://books.google.com/books?id=vrdCAQAAMAAJ&pg=PA27 |year=1871 |publisher=Macmillan Journals |page=27}}</ref> [[Pedanius Dioscorides|Dioscorides]] recorded the use of the "Silphe", ground up with oil, as a remedy for [[earache]].<ref name="Lockyer1871"/>

[[Lafcadio Hearn]] (1850–1904) asserted that "For [[tetanus]]<!--sic, no comma--> 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]].<ref name="HearnStarr2001">{{cite book |last1=Hearn |first1=Lafcadio |last2=Starr |first2=S. Frederick |title=Inventing New Orleans: Writings of Lafcadio Hearn |url=https://books.google.com/books?id=H8Y6GZW483cC&pg=PA68 |year=2001 |publisher=University Press of Mississippi |isbn=978-1-57806-353-6 |pages=68–69}}</ref>

Several cockroach species, such as ''[[Blaptica dubia]]'', are raised as food for insectivorous pets.<ref>{{cite journal |last1=Wu |first1=Hao|last2=Appel |first2=Arthur G. |last3=Hu |first3=Xing Ping |title=Instar Determination of ''Blaptica dubia'' (Blattodea: Blaberidae) Using Gaussian Mixture Models |journal=Annals of the Entomological Society of America |volume=106 |issue=3 |year=2013|pages=323–328 |issn=0013-8746|doi=10.1603/AN12131|doi-access=free}}</ref> A few cockroach species are raised as pets, most commonly the giant [[Madagascar hissing cockroach]], ''Gromphadorhina portentosa''.<ref>{{cite web |author=Mulder, Phil |title=Madagascar Hissing Cockroaches: Information and Care |publisher=Oklahoma 4-H Youth Development. Oklahoma State University |access-date=31 October 2013 |url=http://agweb.okstate.edu/fourh/aitc/lessons/extras/cockroach.pdf |archive-url=https://web.archive.org/web/20131102194649/http://agweb.okstate.edu/fourh/aitc/lessons/extras/cockroach.pdf |archive-date=2 November 2013 |url-status=dead}}</ref> 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&nbsp;years although now appears to be dormant.<ref>{{cite web|url=http://blattodea-culture-group.org/|title=Blattodea Culture Group|website=Blattodea-culture-group.org|access-date=10 November 2017|archive-date=20 August 2021|archive-url=https://web.archive.org/web/20210820161646/http://www.blattodea-culture-group.org/|url-status=dead}}</ref> 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.<ref>Bragg, P.E. (1997) ''An Introduction to Rearing Cockroaches.'' P.E. Bragg, Ilkeston.</ref>

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 produced 33 offspring after returning to Earth.<ref>{{Cite news|url=https://ria.ru/science/20071023/85189078.html|title=Первые "космические" тараканы родились в Воронеже|work=РИА Новости|access-date=2017-05-17|language=ru}}</ref>

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.<ref>{{cite journal |doi=10.1177/1534650106288965 |title=Graded Exposure Therapy for Long-Standing Disgust-Related Cockroach Avoidance in an Older Male |year=2007 |last1=Berle |first1=D. |journal=Clinical Case Studies |volume=6 |issue=4 |pages=339–347|s2cid=145501916 |hdl=1959.4/unsworks_42620 |hdl-access=free }}</ref><ref>{{cite journal |doi=10.1089/cpb.2005.8.162 |pmid=15938656 |title=Mixing Realities? An Application of Augmented Reality for the Treatment of Cockroach Phobia |year=2005 |last1=Botella |first1=C.M. |last2=Juan |first2=M. C. |last3=Baños |first3=R. M. |last4=Alcañiz |first4=M. |last5=Guillén |first5=V. |last6=Rey |first6=B. |journal=CyberPsychology & Behavior |volume=8 |issue=2 |pages=162–171|hdl=10550/97251 |hdl-access=free }}</ref> 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.<ref>{{cite book |last1=Klausnitzer |first1=B. |title=Insects: their biology and cultural history |date=1987 |publisher=Universe Books |location=New York |isbn=978-0-87663-666-4 |page=[https://archive.org/details/insectstheirbiol00klau/page/42 42] |url-access=registration |url=https://archive.org/details/insectstheirbiol00klau/page/42}}</ref>

[[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".<ref>{{cite web |url=http://thinkexist.com/quotation/i_am_a_survivor-i_am_like_a_cockroach-you_just/333818.html |title=Madonna |quote=I am a survivor. I am like a cockroach, you just can't get rid of me |author=Madonna |website=Thinkexist.com |access-date=29 April 2012}}</ref> An [[urban legend]] maintains that cockroaches are radiation-resistant, and thus would survive a nuclear war.<ref>{{cite news |title=Cockroaches are not radiation-proof and most are not pests |url=http://www.bbc.com/earth/story/20160926-cockroaches-are-not-radiation-proof-and-most-are-not-pests |access-date=1 June 2018 |publisher=BBC Earth}}</ref><ref>{{cite news |title=Cockroaches are not radiation-proof and most are not pests |url=https://m.theindependentbd.com/arcprint/details/62541/2016-10-04 |access-date=29 August 2022 |publisher=Third party appears to have reposted the original, for which the original URL doesn't seem to work. |date=4 October 2016}}</ref>

==References==
{{reflist|refs=
<ref name=JGKunk>Kunkel JG. (1966). [http://www.bio.umass.edu/biology/kunkel/ms/k1966/ Development and the availability of food in the German cockroach, ''Blattella germanica'' (L.). J. Insect Physiol. 12, 227-235.]</ref>
<ref name=NYTroach>Ashley Dunn (NYT 24 April 1994) Wary of the Dangers of Insecticides, Scientists Have Developed Techniques For Killing the Ultimate Urban Pest In Safer, Ecologically Sensitive Ways </ref>
}}

==External links==
{{wikt|cockroach}}
{{Wikispecies|Blattodea}}
{{Commons|Blattodea}}
* [https://cockroach.speciesfile.org Cockroach Species File]—Online world catalogue of cockroaches.
* [https://entnemdept.ufl.edu/fasulo/vector/chapter_04.htm "Cockroaches"] chapter in [[United States Environmental Protection Agency]] and UF/IFAS ''Public-Health Pesticide Applicator Training Manual''
* [https://gutenberg.org/ebooks/46802 The Biotic Associations of Cockroaches by Louis M. Roth and Edwin R. Willis]

{{Cockroach}}
{{Orders of Insects}}
{{Blattodea}}
{{Authority control}}

{{DEFAULTSORT:Cockroach}}
[[Category:Cockroaches| ]]
[[Category:Household pest insects]]
[[Category:Insect common names]]
[[Category:Insects in culture]]
[[Category:Extant Late Jurassic first appearances]]