View source for Adephaga

{{Short description|Suborder of beetles}}
{{more citations needed|date=March 2016}}
{{Automatic taxobox
| name = Adephaga
| image = Cybister limbatus (Fabricius, 1775) male (8160965402).png
| image_caption = ''[[Cybister]] limbatus'', a member of the family [[Dytiscidae]] (predaceous diving beetle)
| image2 = Catascopus facialis (Wiedemann, 1819).png
| image2_caption = ''[[Catascopus]] facialis'' a member of the family [[Carabidae]] (ground beetles)
| fossil_range = [[Changhsingian]]/[[Induan]]&ndash;[[Holocene]], {{Fossil range|251.2|0|earliest=254.14|ref=<ref name="Wang2016">{{cite journal | last1 = Wang | first1 = Yan-hui | last2 = Engel | first2 = Michael S. | last3 = Rafael | first3 = José A. | last4 = Wu | first4 = Hao-yang | last5 = Rédei | first5 = Dávid | last6 = Xie | first6 = Qiang | last7 = Wang | first7 = Gang | last8 = Liu | first8 = Xiao-guang | last9 = Bu | first9 = Wen-jun | date = 2016 | title = Fossil record of stem groups employed in evaluating the chronogram of insects (Arthropoda: Hexapoda) | journal = [[Scientific Reports]] | volume = 6 | page = 38939 | doi = 10.1038/srep38939 | pmid=27958352 | pmc=5154178| bibcode = 2016NatSR...638939W }}</ref>}}
| taxon = Adephaga
| authority = [[Johann Rudolph Schellenberg|Schellenberg]], 1806
| subdivision_ranks = Families
| subdivision = *[[Gyrinidae]] (whirligig beetles)
*Geadephaga
**[[Carabidae]] (ground beetles)
**[[Cicindelidae]] (tiger beetles)
**[[Trachypachidae]]
*†[[Triaplidae]]
*[[Haliplidae]]
*Dytiscoidea
**[[Amphizoidae]]
**[[Aspidytidae]]
**[[Dytiscidae]]  (diving beetles)
**[[Hygrobiidae]]
**[[Meruidae]]
**[[Noteridae]]
**†[[Coptoclavidae]]
**†[[Parahygrobiidae]]
**†[[Liadytidae]]
**†[[Colymbothetidae]]
}}
[[File:76-Indian-Insect-Life - Harold Maxwell-Lefroy - Adephaga.jpg|thumb|Image by [[Harold Maxwell-Lefroy]] - Adephaga]]
The '''Adephaga''' (from [[Greek language|Greek]] ἀδηφάγος, ''adephagos'', "gluttonous") are a suborder of [[beetles]], and with more than 40,000 recorded species in 10 families, the second-largest of the four beetle suborders. Members of this suborder are collectively known as '''adephagans'''. The largest family is [[Ground beetle|Carabidae]] (ground beetles) which comprises most of the suborder with over 40,000 species. Adephaga also includes a variety of aquatic beetles, such as [[predaceous diving beetle]]s and [[whirligig beetle]]s.
==Anatomy==
Adephagans have simple [[Antenna (biology)|antennae]] with no [[pectination]] or clubs. The [[wiktionary:galea|galeae]] of the [[Maxilla (arthropod mouthpart)|maxillae]] usually consist of two segments. Adult adephagans have visible [[notopleuron|notopleural]] [[Suture (anatomy)|sutures]]. The first visible [[abdomen|abdominal]] [[sternum (arthropod)|sternum]] is completely separated by the hind [[Arthropod leg|coxa]]e, which is one of the most easily recognizable traits of adephagans. Five segments are on each foot.
===Wings===
The [[transverse fold]] of the [[insect wing|hind wing]] is near the wing tip. The [[median nervure]] ends at this fold, where it is joined by a [[cross nervure]].
===Internal organs===
Adephagans have four [[Malpighian tubule]]s. Unlike the [[Insect reproductive system|genetical structures]] of other beetles, yolk chambers alternate with egg chambers in the ovarian tubes of adephagans. The coiled, tubular [[testes]] consist of a single follicle, and the [[ovary|ovaries]] are [[polytrophic]].
==Chemical glands==
All families of adephagan have paired [[pygidium|pygidial]] [[gland]]s located posterodorsally in the [[abdomen]], which are used for secreting chemicals. The glands consist of complex [[invagination]]s of the [[cuticle]] lined with [[Squamous epithelium|epidermal]] cells contiguous with the [[integument]]. The glands have no connection with the [[rectum]] and open on the eighth abdominal [[tergum]].
Secretions pass from the [[secretory lobe]]s, which are aggregations of secretory cells, through a tube to a reservoir lined with muscles. This reservoir then narrows to a tube leading to an opening valve.  The secretory lobes differ structurally from one taxon to another; it may be elongated or oval, branched [[Anatomical terms of location#Elongated organisms|basally or apically]], or unbranched.
==Delivery of glandular compounds==
Secretion can occur in multiple manners:
*Oozing: if the gland is not muscle-lined, the discharge is limited in amount.
*Spraying: if the gland is muscle-lined, which is typically the case of carabids, the substances are ejected more or less forcefully.
*Crepitation: boiling noxious chemical spray ejected with a popping sound. Crepitation is only associated with the [[Brachininae]] carabids and several related species. See [[bombardier beetle]] for a detailed description.
The secretions differ in the chemical constituents, according to the taxa. [[Gyrinidae|Gyrinids]], for instance, secrete [[Sesquiterpene|norsesquiterpenes]] such as gyrinidal, gyrinidione, or gyrinidone. [[Dytiscidae|Dytiscids]] discharge aromatic [[aldehyde]]s, [[ester]]s, and [[acid]]s, especially [[benzoic acid]]. [[Carabidae|Carabids]] typically produce [[carboxylic acid]]s, particularly [[formic acid]], [[methacrylic acid]], and [[tiglic acid]], but also [[aliphatic ketone]]s, [[saturated ester]]s, [[phenol]]s, aromatic aldehydes, and [[quinone]]s.
[[Glossary of entomology terms|Accessory glands]] or modified structures are present in some taxa: the [[Dytiscidae]] and [[Hygrobiidae]] also possess paired [[prothorax|prothoracic]] glands secreting [[steroid]]s; and the Gyrinidae are unique in the extended shape of the external opening of the pygidial gland.
The function of many compounds remain unknown, yet several hypotheses have been advanced:
*As [[toxin]]s or deterrent against [[predator]]s; some compounds indirectly play this role by easing the penetration of the deterrent into the predator's [[integument]].
*[[Antimicrobial]] and [[Fungicide|antifungal]] agents (especially in Hydradephaga)
*A means to increase [[Wetting|wettability]] of the integument (especially in Hydradephaga)
*Alarm [[pheromone]]s (especially in Gyrinidae)
*Propellant on water surfaces (especially in Gyrinidae)
*Conditioning plant tissues associated with [[oviposition]]
==Distribution and habitat==
[[Habitat (ecology)|Habitat]]s range from [[cave]]s to [[rainforest]] [[Canopy (forest)|canopy]] and [[alpine climate|alpine]] habitats. The body forms of some are structurally modified for adaptation to habitats: members of the family Gyrinidae live at the [[Neuston|air-water interface]], [[Rhysodinae]] live in [[heartwood]], and [[Paussinae]] carabids inhabit [[ant nest]]s.
==Feeding==
Most species are [[predator]]s. Other less-typical forms of feeding include: [[algophagy|eating algae]] (family [[Haliplidae]]), seed-feeding ([[Harpalinae|harpaline]] carabids), [[mycophagy|fungus-feeding]] (rhysodine carabids), and [[snail|snail-feeding]] ([[Licininae|licinine]] and [[Cychrini|cychrine]] carabids). Some species are [[ectoparasitoid]]s of insects ([[Brachininae|brachinine]] and [[Lebiinae|lebiine]] carabids) or of [[millipede]]s ([[Peleciinae|peleciine]] carabids).
==Reproduction and larval stage==
Some species are [[ovoviviparous]], such as [[Pseudomorphinae|pseudomorphine]] carabids.
The [[larva]]e are active, with well-[[chitin]]ized cuticle, often with elongated [[cercus|cerci]] and five-segmented legs, the foot-segment carrying two claws.  Larvae have a fused [[Insect mouthparts|labrum]] and no [[mandibular mola]]e.
==Phylogeny==
Adephagans diverged from their sister group in the [[Lopingian|Late Permian]], the most recent common ancestor of living adephagans probably existing in the early [[Triassic]], around 240 million years ago. Both aquatic and terrestrial representatives of the suborder appear in fossil records of the late Triassic. The Jurassic fauna consisted of [[trachypachid]]s, carabids, gyrinids, and [[haliplid]]-like forms. The familial and tribal diversification of the group spans the [[Mesozoic]], with a few tribes radiating explosively during the [[Tertiary]].
The adephagans were formerly grouped into the Geadephaga with the two terrestrial families Carabidae and Trachypachidae  and the Hydradephaga, for the aquatic families. However this is no longer used as the Hydradephaga are not a monophyletic group. Modern analysis has supported the clade Dytiscoidea instead, which includes many aquatic adephagans, notably excluding Gyrinidae.<ref>{{Cite journal |last1=Cai |first1=Chenyang |last2=Tihelka |first2=Erik |last3=Pisani |first3=Davide |last4=Donoghue |first4=Philip C.J. |date=2020 |title=Data curation and modeling of compositional heterogeneity in insect phylogenomics: A case study of the phylogeny of Dytiscoidea (Coleoptera: Adephaga) |url=https://linkinghub.elsevier.com/retrieve/pii/S1055790320300543 |journal=Molecular Phylogenetics and Evolution |language=en |volume=147 |pages=106782 |doi=10.1016/j.ympev.2020.106782|pmid=32147574 |bibcode=2020MolPE.14706782C |hdl=1983/76336e99-05af-4ea3-b684-fb2c7e00bc21 |s2cid=212640135 |hdl-access=free }}</ref><ref>{{Cite journal |last1=Beutel |first1=Rolf G. |last2=Wang |first2=Bo |last3=Tan |first3=Jing-Jing |last4=Ge |first4=Si-Qin |last5=Ren |first5=Dong |last6=Yang |first6=Xing-Ke |date=April 2013 |title=On the phylogeny and evolution of Mesozoic and extant lineages of Adephaga (Coleoptera, Insecta) |url=https://onlinelibrary.wiley.com/doi/10.1111/j.1096-0031.2012.00420.x |journal=Cladistics |language=en |volume=29 |issue=2 |pages=147–165 |doi=10.1111/j.1096-0031.2012.00420.x|pmid=34814378 |s2cid=85234655 }}</ref> [[Rhysodinae|Rhysodidae]] is suggested to represent a subgroup of Carabidae rather than a distinct family, with [[Cicindelidae]] often being treated as a distinct family from Carabidae.<ref>{{Cite journal |last1=Gustafson |first1=Grey T. |last2=Baca |first2=Stephen M. |last3=Alexander |first3=Alana M. |last4=Short |first4=Andrew E. Z. |date=July 2020 |title=Phylogenomic analysis of the beetle suborder Adephaga with comparison of tailored and generalized ultraconserved element probe performance |journal=Systematic Entomology |language=en |volume=45 |issue=3 |pages=552–570 |doi=10.1111/syen.12413 |s2cid=214439873 |issn=0307-6970|doi-access=free |bibcode=2020SysEn..45..552G }}</ref><ref name=":0">{{Cite journal |last1=Vasilikopoulos |first1=Alexandros |last2=Balke |first2=Michael |last3=Kukowka |first3=Sandra |last4=Pflug |first4=James M. |last5=Martin |first5=Sebastian |last6=Meusemann |first6=Karen |last7=Hendrich |first7=Lars |last8=Mayer |first8=Christoph |last9=Maddison |first9=David R. |last10=Niehuis |first10=Oliver |last11=Beutel |first11=Rolf G. |last12=Misof |first12=Bernhard |date=October 2021 |title=Phylogenomic analyses clarify the pattern of evolution of Adephaga (Coleoptera) and highlight phylogenetic artefacts due to model misspecification and excessive data trimming |journal=Systematic Entomology |language=en |volume=46 |issue=4 |pages=991–1018 |doi=10.1111/syen.12508 |s2cid=237486696 |issn=0307-6970|doi-access=free |bibcode=2021SysEn..46..991V }}</ref><ref>{{Cite journal |last1=Baca |first1=Stephen M. |last2=Gustafson |first2=Grey T. |last3=Alexander |first3=Alana M. |last4=Gough |first4=Harlan M. |last5=Toussaint |first5=Emmanuel F. A. |date=October 2021 |title=Integrative phylogenomics reveals a Permian origin of Adephaga beetles |url=https://onlinelibrary.wiley.com/doi/10.1111/syen.12506 |journal=Systematic Entomology |language=en |volume=46 |issue=4 |pages=968–990 |doi=10.1111/syen.12506 |bibcode=2021SysEn..46..968B |s2cid=237486703 |issn=0307-6970}}</ref>
[[Cladogram]] of the relationships of living adephagan families after Vasilikopoulos et al. 2021<ref name=":0" /> and Baca et al. 2021:<ref>{{Cite journal |last1=Baca |first1=Stephen M. |last2=Gustafson |first2=Grey T. |last3=Alexander |first3=Alana M. |last4=Gough |first4=Harlan M. |last5=Toussaint |first5=Emmanuel F. A. |date=2021-07-26 |title=Integrative phylogenomics reveals a Permian origin of Adephaga beetles |url=http://dx.doi.org/10.1111/syen.12506 |journal=Systematic Entomology |volume=46 |issue=4 |pages=968–990 |doi=10.1111/syen.12506 |bibcode=2021SysEn..46..968B |s2cid=237486703 |issn=0307-6970}}</ref>
{{Clade|label1=Adephaga|{{Clade
|label1=Gyrinoidea
|1=[[Gyrinidae]]
|2={{Clade
|label1=Caraboidea
|sublabel1=(Geadephaga)
|1={{Clade
|1=[[Trachypachidae]]
|2={{Clade
|1=[[Cicindelidae]]
|2=[[Carabidae]]}} }}
|2={{Clade
|label2=Dytiscoidea
|1=[[Haliplidae]]
|label1=Haliploidea
|2={{Clade
|1=[[Noteridae]]
|2={{Clade
|1={{Clade
|1=[[Hygrobiidae]]
|2={{Clade
|1=[[Aspidytidae]]
|2=[[Amphizoidae]] }} }}
|2=[[Dytiscidae]] }} }} }} }} }}}}
== See also ==
* [[List of subgroups of the order Coleoptera]]
== References ==
*{{cite journal|last1=Balke|first1=M.|last2=Ribera|first2=I.|last3=Beutel|first3=R.|last4=Viloria|first4=A.|last5=Garcia|first5=M.|last6=Vogler|first6=A.P.|year=2008|title=Systematic placement of the recently discovered beetle family Meruidae (Coleoptera: Dytiscoidea) based on molecular data|journal=[[Zoologica Scripta]]|volume=37|issue=6|pages=647–650|doi=10.1111/j.1463-6409.2008.00345.x|s2cid=86012007 }}
*{{ITIS|id=109226|taxon=Adephaga}}
*[http://tolweb.org/Adephaga Adephaga] Tree of Life
{{Reflist}}
{{Coleoptera|2}}
{{Taxonbar|from=Q131060}}
{{Authority control}}
{{DEFAULTSORT:Adephaga}}
[[Category:Adephaga| ]]
[[Category:Insect suborders]]