{{Short description|Family of true bug}} {{Automatic taxobox | fossil_range = {{fossilrange|Aptian|Present}}<ref>{{cite journal |author1=Jerzy A. Lis |author2=Barbara Lis |author3=Ernst Heiss |year=2018 |title=''Chilamnestocoris mixtus'' gen. et spec. nov., the first burrower bug (Hemiptera: Pentatomoidea: Cydnidae) in Upper Cretaceous Burmese amber |journal=Cretaceous Research |volume=91 |pages=257–262 |doi=10.1016/j.cretres.2018.06.017 |url=http://osf.io/e5qsu/ }}</ref> | image = Cydnus aterrimus MHNT.jpg | image_caption = ''Cydnus aterrimus''<br /> Type genus for the family | taxon = Cydnidae | authority = Billberg, 1820 | subdivision_ranks = Subfamilies }}

'''Cydnidae''' are a family of pentatomoid bugs, known by common names including '''burrowing bugs''' or '''burrower bugs'''.<ref>{{cite web |url=http://stri.discoverlife.org/mp/20q?search=Cydnidae&guide=Groups_Insecta |title=Cydnidae |publisher=Discover Life |access-date=2007-03-09}}</ref> As the common name would suggest, many members of the group live a subterranean lifestyle, burrowing into soil using their head and forelegs, only emerging to mate and then laying their eggs in soil. Other members of the group are not burrowers, and live above the soil layer, often in close association with plants. Several species are known as agricultural pests.<ref name="Acanthamnestus" />

== Description == Burrowing bugs range from 2 to 20&nbsp;mm in length.<ref name=":0">{{Cite web |title=Family Cydnidae - Burrowing Bugs |url=https://bugguide.net/node/view/6980 |access-date=2023-01-05 |website=bugguide.net}}</ref> They are dark, ovoid in shape and highly sclerotised. The head is generally subquadrate to semicircular in shape, and has a pair of 5-segmented antennae. The coxae of the legs have setal combs, while the apices of the mid and hind coxae are fringed with rigid setae. The tibiae of the legs (also often the head and pronotum) have spines. The tarsi of the legs are 3-segmented and often reduced.<ref name=":1">{{Cite web |title=Australian Faunal Directory |url=https://biodiversity.org.au/afd/taxa/CYDNIDAE |access-date=2023-01-05 |website=biodiversity.org.au |language=en}}</ref>

Similar to other pentatomoids, Cydnidae have glands in the thorax (adults) or the lateral part of the abdomen (nymphs) that secrete a foul-smelling mix of chemicals for defense against predators.<ref name=":2">{{Cite journal |last1=Malhotra |first1=Amit K. |last2=Lis |first2=Jerzy A. |last3=Ramam |first3=M. |date=2015-02-01 |title=Cydnidae (Burrowing Bug) Pigmentation: A Novel Arthropod Dermatosis |url=http://archderm.jamanetwork.com/article.aspx?doi=10.1001/jamadermatol.2014.2715 |journal=JAMA Dermatology |language=en |volume=151 |issue=2 |page=232 |doi=10.1001/jamadermatol.2014.2715 |issn=2168-6068|url-access=subscription }}</ref>

== Ecology == Cydnidae in subfamilies Cydninae and Cephalocteinae live mostly in soil and feed on roots of plants. Those in subfamilies Parastrachinae, Sehirinae and Thyreocorinae instead live on aboveground parts of plants. Adults are attracted to light and sometimes in large numbers.<ref name=":1" />

Cydnidae feed on sap from phloem, unlike other heteropterans.<ref name=":0" />

== Importance == As of 2003, there were 27 cydnid species reported as crop pests and six that feed on peanut. Of the peanut-feeding species, ''Pangaeus bilineatus'' is the most abundant and the only one associated with feeding injury to peanut kernels.<ref>{{Cite journal |last1=Chapin |first1=Jay W. |last2=Thomas |first2=James S. |date=2003-08-01 |title=Burrower Bugs (Heteroptera: Cydnidae) in Peanut: Seasonal Species Abundance, Tillage Effects, Grade Reduction Effects, Insecticide Efficacy, and Management |journal=Journal of Economic Entomology |volume=96 |issue=4 |pages=1142–1152 |doi=10.1093/jee/96.4.1142 |issn=1938-291X}}</ref>

Another pest is ''Fromundus pygmaeus'', which attacks rice seedlings, sugarcane, fallen seeds of grasses and roots of soybean and clover.<ref name=":3">{{Cite journal |last1=Shehta, Manar |last2=Sawaby, Rabab F. |last3=Gad-Allah, Sohair |last4=Okely, Mohammed |date=2022-09-15 |title=Fromundus pygmaeus (Dallas, 1851), the first species of the genus Fromundus Distant, 1901 (Hemiptera: Heteroptera: Cydnidae) recorded in Egypt |url=https://zenodo.org/record/7058518 |language=en |doi=10.5281/ZENODO.7058518}}</ref>

Some cydnids are medically important. The aforementioned ''F.'' ''pygmaeus'' facultatively sucks blood from humans,<ref name=":3" /> while ''Chilocoris assmuthi'' can cause brown lesions on skin (usually on the feet) with its defensive secretions.<ref name=":2" />

==Subfamilies and taxonomy== ''BioLib'' includes the following subfamilies: *Amnestinae {{small|Hart, 1919}} ** †''Acanthamnestus'' {{small|Du, Yao & Engel, 2022}} Burmese Amber, Myanmar, mid Cretaceous (latest Albian-earliest Cenomanian)<ref name=Acanthamnestus>{{cite journal |last1=Du |first1=S. |last2=Gu |first2=L. |last3=Engel |first3=M. S. |last4=Ren |first4=D. |last5=Yao |first5=Y. |year=2022 |title=Morphological Phylogeny of New Cretaceous Fossils Elucidates the Early History of Soil Dwelling Among Bugs |journal=Frontiers in Ecology and Evolution |volume=10 |article-number=908044 |doi=10.3389/fevo.2022.908044 |doi-access=free }}</ref> ** ''Amnestus'' {{small|Dallas, 1851}} ** †''Chilamnestocoris'' {{small|Lis ''et al.'', 2018}} Burmese Amber, Myanmar ** †''Cilicydnus'' {{small|Yao ''et al.'', 2007}} Yixian Formation, China, Early Cretaceous (Aptian) ** ''Lattinestus'' {{small|Eger, 2008}} ** †''Latiscutella'' {{small|Pinto & de Ornellas, 1974}} Crato Formation, Codo Formation, Brazil, Aptian ** †''Orienicydnus'' {{small|Yao ''et al.'', 2007}} Yixian Formation, China ** †''Pricecoris'' {{small|Pinto & de Ornellas, 1974}} Codo Formation, Brazil ** †''Punctacorona'' {{small|Wang ''et al.'', 2019}} Burmese Amber, Myanmar * Cephalocteninae {{small|Mulsant & Rey, 1866}} ** Cephaloctenini {{small|Mulsant & Rey, 1866}} *** ''Cephalocteus'' {{small|Dufour, 1834}} *** ''Heissocteus'' {{small|Lis, 2006}} ** Scaptocorini {{small|Froeschner, 1960}} *** ''Afroropus'' {{small|Lis, 1999}} *** ''Atarsocoris'' {{small|Becker, 1967}} *** ''Pseudostibaropus'' {{small|Lis, 1991}} *** ''Scaptocoris'' {{small|Perty, 1833}} *** ''Schiodtella'' {{small|Signoret, 1882}} *** ''Stibaropus'' {{small|Dallas, 1851}} * †Clavicorinae {{small|Popov, 1986}} ** †''Clavicoris'' {{small|Popov, 1986}} Gurvan-Eren Formation, Mongolia, Aptian ** †''Cretacoris'' {{small|Popov, 1986}} Daya Formation, Russia, Early Cretaceous, Gurvan-Eren Formation, Mongolia * Cydninae {{small|Billberg, 1820}} * Garsauriinae {{small|Froeschner, 1960}} ** ''Garsauria'' {{small|Walker, 1868}} ** ''Garsauriella'' {{small|Linnavuori, 1993}} * Sehirinae {{small|Amyot & Audinet-Serville, 1843}} ** †''Eocenocydnus'' {{small|Popov, 2019}} Bembridge Marls, United Kingdom, Eocene (Priabonian)

In some older classifications, Cydnidae ''sensu lato'' includes the subfamily Thyreocorinae (now a separate family, Thyreocoridae), which are known commonly as "negro bugs" or "ebony bugs", and/or the families Thaumastellidae and Parastrachiidae.<ref>{{Cite journal|author=Dolling, W. R.|year=1981|title=A rationalized classification of the burrower bugs (Cydnidae)|journal=Systematic Entomology |volume=6 |issue=1 |pages=61&ndash;76 |doi=10.1111/j.1365-3113.1981.tb00016.x |s2cid=84097067}}</ref><ref>{{Cite journal|author1=Yao, Yunzhi |author2=Ren, Dong |author3=Rider, David A. |author4=Cai, Wanzhi |year=2012|title=Phylogeny of the Infraorder Pentatomomorpha Based on Fossil and Extant Morphology, with Description of a New Fossil Family from China|journal=PLOS ONE|volume=7|issue=5|article-number=e37289|doi=10.1371/journal.pone.0037289 |pmid=22655038 |pmc=3360028|doi-access=free }}</ref>

==References== {{Wikispecies|Cydnidae}} {{Reflist}}

{{Hemiptera|3}} {{Taxonbar|from=Q616135}}

Category:Cydnidae Category:Heteroptera families