Editing Parrotfish (section)

==Feeding==
[[File:Scaridae - Bolbometopon muricatum.jpg|thumb|The strong beak of ''[[Bolbometopon muricatum]]'' is suited to 'excavating', grinding the sturdiest corals.]]
[[File:BuDIha.jpg|thumb|The beak of ''[[Calotomus japonicus]]'' is suited to 'browsing' on seagrass, macroalgae, and epilithic algae without touching the rocky substrate.]]
Most parrotfish species are [[herbivore]]s, feeding mainly on [[epilithic]] algae.<ref name=":2">{{Cite journal|last=Bellwood|first=David R.|date=1994-07-14|title=A phylogenetic study of the parrotfish family Scaridae (Pisces: Labroidea), with a revision of genera|journal=Records of the Australian Museum, Supplement|language=en|volume=20|pages=1–86|doi=10.3853/j.0812-7387.20.1994.51|issn=0812-7387|doi-access=free}}</ref><ref name=Bellwood>{{cite journal | last1 = Bellwood | first1 = D.R. | last2 = Choat | first2 = J.H. | year = 1990 | title = A functional analysis of grazing in parrotfishes (family Scaridae): the ecological implications | journal = Environ Biol Fish | volume = 28 | issue = 1–4| pages = 189–214 | doi = 10.1007/BF00751035 | s2cid = 11262999 }}</ref><ref name=Bonaldo2018>Bonaldo, R.M. & R.D. Rotjan (2018). The Good, the Bad, and the Ugly: Parrotfishes as Coral Predators. ''in'' Hoey, A.S. & R.M. Bonaldo, eds. Biology of Parrotfishes. CRC Press. {{isbn|978-1482224016}}</ref> A wide range of other small organisms are sometimes eaten, including invertebrates ([[Sessility (motility)|sessile]] and [[benthic]] species, as well as [[zooplankton]]), bacteria and [[detritus]].<ref>{{cite journal | last1 = Comeros-Raynal | first1 = Choat | last2 = Polidoro | first2 = Clements | last3 = Abesamis | first3 = Craig | last4 = Lazuardi | first4 = McIlwain | last5 = Muljadi | first5 = Myers | last6 = Nañola Jr | first6 = Pardede | last7 = Rocha | first7 = Russell | last8 = Sanciangco | first8 = Stockwell | last9 = Harwell | last10 = Carpenter | year = 2012 | title = The Likelihood of Extinction of Iconic and Dominant Herbivores and Detritivores of Coral Reefs: The Parrotfishes and Surgeonfishes | journal = PLOS ONE | volume = 7 | issue = 7| page = e39825 | doi = 10.1371/journal.pone.0039825 | pmid = 22808066 | pmc = 3394754 | bibcode = 2012PLoSO...739825C | doi-access = free }}</ref> A few mostly larger species such as the green humphead parrotfish (''Bolbometopon muricatum'') feed extensively on living [[Corallivore|coral]] ([[polyp (zoology)|polyp]]s).<ref name=EoF/><ref name=Bellwood/><ref name=Bonaldo2018/> None of these are exclusive [[corallivore]]s, but polyps can make up as much as half their diet<ref name=Bonaldo2018/> or even more in the green humphead parrotfish.<ref name=":2"/> Overall it has been estimated that fewer than one percent of parrotfish bites involve live corals and all except the green humphead parrotfish prefer algae-covered surfaces over live corals.<ref name=Bonaldo2018/> Nevertheless, when they do eat coral polyps, localized coral death can occur.<ref name=Bonaldo2018/> Their feeding activity is important for the production and distribution of coral sands in the reef [[biome]], and can prevent algal overgrowth of the reef structure. The teeth grow continuously, replacing material worn away by feeding.<ref name=Lieske/> Whether they feed on coral, rock or seagrasses, the substrate is ground up between the [[pharyngeal teeth]].<ref name=Bonaldo2018/><ref>{{cite book |title=Coral Reefs: Cities Under The Seas |last=Murphy |first=Richard C. |year=2002 |isbn=978-0-87850-138-0 |publisher=The Darwin Press, Inc.}}</ref> After they digest the edible portions from the rock, they excrete it as sand, helping create small islands and the sandy beaches. The humphead parrotfish can produce {{convert|90|kg|abbr=on}} of sand each year.<ref name=Thurman/> Or, on average (as there are so many variables i.e. size/species/location/depth etc.), almost {{convert|250|g|abbr=on|0}} per parrotfish per day.
While feeding, parrotfish must be cognizant of predation by one of their main predators, the [[lemon shark]].<ref>{{cite book|last=Bright|first=Michael|title=The private life of sharks : the truth behind the myth|year=2000|publisher=Stackpole Books|location=Mechanicsburg, PA|isbn=978-0-8117-2875-1}}</ref> On Caribbean coral reefs, parrotfish are important consumers of [[sponge]]s.<ref>{{Cite journal|title = Video-monitored predation by Caribbean reef fishes on an array of mangrove and reef sponges|journal = Marine Biology|date = 1996|pages = 117–123|volume = 126|doi = 10.1007/BF00571383|first1 = M|last1 = Dunlap|first2 = JR|last2 = Pawlik|s2cid = 84799900}}</ref> An indirect effect of parrotfish grazing on sponges is the protection of reef-building corals that would otherwise be overgrown by fast-growing sponge species.<ref name=":0">{{Cite journal|title = Chemical defenses and resource trade-offs structure sponge communities on Caribbean coral reefs|journal = Proceedings of the National Academy of Sciences|date = 2014|pmid = 24567392|pages = 4151–4156|volume = 111|issue = 11|doi = 10.1073/pnas.1321626111|first1 = T-L|last1 = Loh|first2 = JR|last2 = Pawlik |pmc=3964098|bibcode = 2014PNAS..111.4151L|doi-access = free}}</ref><ref name=":1">{{Cite journal|title = Indirect effects of overfishing on Caribbean reefs: sponges overgrow reef-building corals|last = Loh|first = TL|date = 2015|journal = PeerJ|doi = 10.7717/peerj.901|display-authors=etal|volume=3|pages=e901|pmid=25945305|pmc=4419544 | doi-access=free }}</ref>

Analysis of parrotfish feeding biology describes three functional groups: excavators, scrapers and browsers.<ref name=":2"/> Excavators have larger, stronger jaws that can gouge the substrate,<ref name=":3">{{Cite journal|last1=Price|first1=Samantha A.|last2=Wainwright|first2=Peter C.|last3=Bellwood|first3=David R.|last4=Kazancioglu|first4=Erem|last5=Collar|first5=David C.|last6=Near|first6=Thomas J.|date=2010-10-01|title=Functional Innovations and Morphological Diversification in Parrotfish|journal=Evolution|volume=64|issue=10|pages=3057–3068|doi=10.1111/j.1558-5646.2010.01036.x|pmid=20497217|s2cid=19070148|issn=1558-5646}}</ref> leaving visible scars on the surface.<ref name=":2" /> Scrapers have less powerful jaws that can but infrequently do leave visible scraping scars on the substrate.<ref name=":2" /><ref name=":3" /> Some of these may also feed on sand instead of hard surfaces.<ref name=":2" /> Browsers mainly feed on seagrasses and their [[epiphyte]]s.<ref name=":2" /> Mature excavating species include ''[[Bolbometopon muricatum]]'', ''[[Cetoscarus]]'', ''[[Chlorurus]]'' and ''[[Sparisoma viride]]''.<ref name=":2" /> These excavating species all feed as scrapers in early juvenile stages, but ''[[Hipposcarus]]'' and ''[[Scarus]]'', which also feed as scrapers in early juvenile stages, retain the scraping feeding mode as adults.<ref name=":2" /><ref name=":3" /> Browsing species are found in the genera ''[[Calotomus]]'', ''[[Cryptotomus]]'', ''[[Leptoscarus]]'', ''[[Nicholsina]]'' and ''Sparisoma''.<ref name=":2" /> Feeding modes reflect habitat preferences, with browsers chiefly living in the grassy seabed, and excavators and scrapers on coral reefs.<ref>Environmental Biology of Fishes 28: 189–214, 1990</ref><ref name=":2" />

Recently, the microphage feeding hypothesis challenged the prevailing paradigm of parrotfish as algal consumers by proposing that:

{{Blockquote|text=Most parrotfishes are microphages that target cyanobacteria and other protein-rich autotrophic microorganisms that live on (epilithic) or within (endolithic) calcareous substrata, are epiphytic on algae or seagrasses, or endosymbiotic within sessile invertebrates.<ref>{{Cite journal|last1=Clements|first1=Kendall D.|last2=German|first2=Donovan P.|last3=Piché|first3=Jacinthe|last4=Tribollet|first4=Aline|last5=Choat|first5=John Howard|date=November 2016|title=Integrating ecological roles and trophic diversification on coral reefs: multiple lines of evidence identify parrotfishes as microphages|journal=Biological Journal of the Linnean Society|doi=10.1111/bij.12914}}</ref>}}

Microscopy and molecular barcoding of coral reef substrate bitten by scraping and excavating parrotfish suggest that coral reef cyanobacteria from the order Nostocales are important in the feeding of these parrotfish.<ref>Georgina M Nicholson, Kendall D Clements, Micro-photoautotroph predation as a driver for trophic niche specialization in 12 syntopic Indo-Pacific parrotfish species, Biological Journal of the Linnean Society, Volume 139, Issue 2, June 2023, Pages 91–114, https://doi.org/10.1093/biolinnean/blad005</ref> Additional microscopy and molecular barcoding research indicates that some parrotfish may ingest microscopic biota associated with endolithic sponges.<ref>Nicholson, G.M., Clements, K.D. A role for encrusting, endolithic sponges in the feeding of the parrotfish Scarus rubroviolaceus? Evidence of further trophic diversification in Indo-Pacific Scarini. Coral Reefs (2024). https://doi.org/10.1007/s00338-024-02482-z</ref>