Editing Tick (section)

===Diet and feeding===
[[File:20140704-TickWaitingOnGrassBlade-CentralMA-USA.JPG|left|thumb|A questing tick, fingers for scale]]

Ticks are [[Parasitism#Types|ectoparasites]] and consume [[blood]] to satisfy all of their nutritional requirements. They are obligate [[hematophagy|hematophages]], and require blood to survive and move from one stage of life to another. Ticks can fast for long periods of time, but eventually die if unable to find a host.<ref name=cdcticklife >{{cite web |url=https://www.cdc.gov/ticks/life_cycle_and_hosts.html |title=Life cycle of Hard Ticks that Spread Disease |website=Centers for Disease Control and Prevention |access-date=22 June 2013}}</ref> Hematophagy evolved independently at least six times in arthropods living during the late [[Cretaceous]]; in ticks it is thought to have evolved 120 million years ago through adaptation to blood-feeding.<ref name="KlompenGrimaldi">{{cite journal |title=First Mesozoic Record of a Parasitiform Mite: a Larval Argasid Tick in Cretaceous Amber (Acari: Ixodida: Argasidae) |vauthors = Klompen H, Grimaldi D |journal=Annals of the Entomological Society of America |volume=94 |issue=1 |pages=10–15 |year=2001 |doi=10.1603/0013-8746(2001)094[0010:FMROAP]2.0.CO;2 |url=http://www.nhm.ac.uk/hosted_sites/acarology/saas/e-library/pdf000200/a000130.pdf?origin=publication_detail|doi-access=free }}</ref><ref name="Mans_2002">{{cite journal|vauthors=Mans BJ, Louw AI, Neitz AW|date=October 2002|title=Evolution of hematophagy in ticks: common origins for blood coagulation and platelet aggregation inhibitors from soft ticks of the genus Ornithodoros|journal=Molecular Biology and Evolution|volume=19|issue=10|pages=1695–705|doi=10.1093/oxfordjournals.molbev.a003992|issn=1537-1719|pmid=12270896|doi-access=free}}</ref> This behavior evolved independently within the separate tick families as well, with differing host-tick interactions driving the evolutionary change.<ref name="KlompenGrimaldi" />
 	
Some ticks attach to their host rapidly, while others wander around searching for thinner skin, such as that in the ears of mammals. Depending on the species and life stage, preparing to feed can take from ten minutes to two hours. On locating a suitable feeding spot, the tick grasps the host's skin and cuts into the surface.<ref name=cdcticklife /> It extracts blood by cutting a hole in the host's [[Epidermis (zoology)|epidermis]], into which it inserts its [[hypostome (tick)|hypostome]] and prevents the blood from clotting by excreting an [[anticoagulant]] or [[Platelet#Aggregation|platelet aggregation]] inhibitor.<ref>[[#Goddard|Goddard (2008)]]: [https://books.google.com/books?id=f-huycwyEvwC&pg=PA82 p. 82]</ref><ref name = "Mans_2002" />

Ticks find their hosts by detecting an animals' breath and body odors, sensing body heat, moisture, or vibrations.<ref name=CVBDhost/> A common misconception about ticks is they jump onto their host; however, they are incapable of jumping, although [[static electricity]] from their hosts has been shown to be capable of pulling the tick over distances several times their own body length.<ref>[https://www.cell.com/current-biology/fulltext/S0960-9822(23)00772-8 Static electricity passively attracts ticks onto hosts]</ref> Many tick species, particularly Ixodidae, lie in wait in a position known as "questing". While questing, ticks cling to leaves and grasses by their third and fourth pairs of legs. They hold the first pair of legs outstretched, waiting to grasp and climb on to any passing host. Tick questing heights tend to be correlated with the size of the desired host; nymphs and small species tend to quest close to the ground, where they may encounter small mammalian or bird hosts; adults climb higher into the vegetation, where larger hosts may be encountered. Some species are hunters and lurk near places where hosts may rest. Upon receiving an [[olfactory]] stimulus or other environmental indication, they crawl or run across the intervening surface.<ref name=CVBDhost>{{cite web |url=http://www.cvbd.org/en/tick-borne-diseases/about-ticks/tick-feeding/host-seeking/ |title=Host seeking |work=CVBD: Companion Vector-Borne Diseases |access-date=8 December 2016}}</ref>

Other ticks, mainly the Argasidae, are [[nidicolous]], finding hosts in their nests, burrows, or caves. They use the same stimuli as non-nidicolous species to identify hosts, with body heat and odors often being the main factors.<ref name=CVBDhost/> Many of them feed primarily on [[bird]]s, though some ''Ornithodoros'' species, for example, feed on small [[mammal]]s. Both groups of soft tick feed rapidly, typically biting painfully and drinking their fill within minutes. Unlike the Ixodidae that have no fixed dwelling place except on the host, they live in sand, in crevices near animal dens or nests, or in human dwellings, where they come out nightly to attack roosting birds or emerge when they detect [[carbon dioxide]] in the breath of their hosts.<ref name="SamuelPybus2001">[[#Allan|Allan (2001)]]</ref>

Ixodidae remain in place until they are completely engorged. Their weight may increase by 200 to 600 times compared to their prefeeding weight. To accommodate this expansion, cell division takes place to facilitate enlargement of the cuticle.<ref name=CVBDhard>{{cite web |url=http://www.cvbd.org/en/tick-borne-diseases/about-ticks/general-morphology/hard-ticks/ |title=Hard ticks |work=CVBD: Companion Vector-Borne Diseases |access-date=6 December 2016}}</ref> In the Argasidae, the tick's cuticle stretches to accommodate the fluid ingested, but does not grow new cells, with the weight of the tick increasing five- to tenfold over the unfed state. The tick then drops off the host and typically remains in the nest or burrow until its host returns to provide its next meal.<ref name=CVBDsoft />

Tick saliva contains about 1,500 to 3,000 proteins, depending on the tick species. The proteins with anti-inflammatory properties, called [[evasin]]s, allow ticks to feed for eight to ten days without being perceived by the host animal. Researchers are studying these evasins with the goal of developing drugs to neutralise the chemokines that cause [[myocarditis]], heart attack, and stroke.<ref>{{cite web|url=https://phys.org/news/2017-06-bug-drugtick-saliva-key-heart.html|title=From bug to drug—tick saliva could be key to treating heart disease|date=27 June 2017|publisher=Phys.org|author=University of Oxford}}</ref>
The saliva of ticks also contains [[anticoagulant]] and [[antiplatelet|aniplatelet]] proteins (integrin inhibitors), to stop the blood from coagulating while they suck.<ref>{{Cite journal |last1=van den Kerkhof |first1=Danique L. |last2=van der Meijden |first2=Paola E. J. |last3=Hackeng |first3=Tilman M. |last4=Dijkgraaf |first4=Ingrid |date=2021-03-25 |title=Exogenous Integrin αIIbβ3 Inhibitors Revisited: Past, Present and Future Applications |journal=International Journal of Molecular Sciences |volume=22 |issue=7 |pages=3366 |doi=10.3390/ijms22073366 |doi-access=free |issn=1422-0067 |pmc=8036306 |pmid=33806083}}</ref>

[[File:Oocysts of ticks and their endosymbionts.jpg|thumb|Mature oocysts of the seabird soft tick ''Ornithodoros maritimus'' and their ''Coxiella'' endosymbionts (labelled in yellow).]]
Ticks do not use any other food source than vertebrate blood and therefore  ingest high levels of protein, iron and salt, but few carbohydrates, lipids or vitamins.<ref name="tickconv">{{cite journal | vauthors = Duron O, Gottlieb Y | title = Convergence of Nutritional Symbioses in Obligate Blood Feeders | journal = Trends in Parasitology | volume = 36 | issue = 10 | pages = 816–825 | date = October 2020 | pmid = 32811753 | doi = 10.1016/j.pt.2020.07.007 | s2cid = 221181791 | url = https://hal.archives-ouvertes.fr/hal-03000781/file/Duron%20%26%20Gottlieb%20TIP%20May11_edited_revised.pdf }}</ref> Ticks’ genomes have evolved large repertoires of genes related to this nutritional challenge, but they themselves cannot synthesize the essential vitamins that are lacking in blood meal. To overcome these nutritional deficiencies, ticks have evolved obligate interactions with nutritional [[endosymbionts]].<ref name="tickconv" /> The first appearance of ticks and their later diversification were largely conditioned by this nutritional endosymbiosis lasting for millions of years. The most common of these nutritional endosymbionts belong to the ''Coxiella'' and ''Francisella'' bacterial genera.<ref>{{cite journal | vauthors = Binetruy F, Buysse M, Lejarre Q, Barosi R, Villa M, Rahola N, Paupy C, Ayala D, Duron O | title = Microbial community structure reveals instability of nutritional symbiosis during the evolutionary radiation of Amblyomma ticks | journal = Molecular Ecology | volume = 29 | issue = 5 | pages = 1016–1029 | date = March 2020 | pmid = 32034827 | doi = 10.1111/mec.15373 | bibcode = 2020MolEc..29.1016B | s2cid = 211065648 | url = https://hal.archives-ouvertes.fr/hal-03001756/file/MS-Binetruy_15-01-Revised%20version.pdf }}</ref><ref name="Duron_2017">{{cite journal | vauthors = Duron O, Binetruy F, Noël V, Cremaschi J, McCoy KD, Arnathau C, Plantard O, Goolsby J, Pérez de León AA, Heylen DJ, Van Oosten AR, Gottlieb Y, Baneth G, Guglielmone AA, Estrada-Peña A, Opara MN, Zenner L, Vavre F, Chevillon C | title = Evolutionary changes in symbiont community structure in ticks | journal = Molecular Ecology | volume = 26 | issue = 11 | pages = 2905–2921 | date = June 2017 | pmid = 28281305 | doi = 10.1111/mec.14094 | bibcode = 2017MolEc..26.2905D | hdl = 10067/1422810151162165141 | s2cid = 40962020 | url = https://hal.inria.fr/hal-01523998/file/Duron_et_al-2017-Molecular_Ecology.pdf | hdl-access = free }}</ref> These intracellular symbiotic microorganisms are specifically associated with ticks and use [[transovarial transmission]] to ensure their persistence.<ref>{{cite journal | vauthors = Buysse M, Plantard O, McCoy KD, Duron O, Menard C | title = Tissue localization of Coxiella-like endosymbionts in three European tick species through fluorescence in situ hybridization | journal = Ticks and Tick-Borne Diseases | volume = 10 | issue = 4 | pages = 798–804 | date = June 2019 | pmid = 30922601 | doi = 10.1016/j.ttbdis.2019.03.014 | url = https://hal.archives-ouvertes.fr/hal-03012100/file/Buysse.pdf | doi-access = free }}</ref><ref name="Duron_2018">{{cite journal | vauthors = Duron O, Morel O, Noël V, Buysse M, Binetruy F, Lancelot R, Loire E, Ménard C, Bouchez O, Vavre F, Vial L | title = Tick-Bacteria Mutualism Depends on B Vitamin Synthesis Pathways | journal = Current Biology | volume = 28 | issue = 12 | pages = 1896–1902.e5 | date = June 2018 | pmid = 29861133 | doi = 10.1016/j.cub.2018.04.038 | s2cid = 44095809 | doi-access = free | bibcode = 2018CBio...28E1896D }}</ref><ref name="Lalzar_2014">{{cite journal | vauthors = Lalzar I, Friedmann Y, Gottlieb Y | title = Tissue tropism and vertical transmission of Coxiella in Rhipicephalus sanguineus and Rhipicephalus turanicus ticks | journal = Environmental Microbiology | volume = 16 | issue = 12 | pages = 3657–68 | date = December 2014 | pmid = 24650112 | doi = 10.1111/1462-2920.12455 | bibcode = 2014EnvMi..16.3657L | issn = 1462-2920 }}</ref> Although ''Coxiella'' and ''Francisella'' endosymbionts are distantly related bacteria, they have converged towards an analogous B vitamin-based nutritional mutualism with ticks.<ref name="tickconv" /> Their experimental elimination typically results in decreased tick survival, molting, fecundity and egg viability, as well as in physical abnormalities, which all are fully restored with an oral supplement of B vitamins.<ref name="Duron_2018" /><ref name="Guizzo_2017">{{cite journal | vauthors = Guizzo MG, Parizi LF, Nunes RD, Schama R, Albano RM, Tirloni L, Oldiges DP, Vieira RP, Oliveira WH, Leite MS, Gonzales SA, Farber M, Martins O, Vaz ID, Oliveira PL | title = A Coxiella mutualist symbiont is essential to the development of Rhipicephalus microplus | journal = Scientific Reports | volume = 7 | issue = 1 | pages = 17554 | date = December 2017 | pmid = 29242567 | pmc = 5730597 | doi = 10.1038/s41598-017-17309-x | bibcode = 2017NatSR...717554G | issn = 2045-2322 }}</ref><ref>{{cite journal | vauthors = Ben-Yosef M, Rot A, Mahagna M, Kapri E, Behar A, Gottlieb Y | title = Rhipicephalus sanguineus Is Required for Physiological Processes During Ontogeny | journal = Frontiers in Microbiology | volume = 11 | pages = 493 | date = 2020-04-22 | pmid = 32390951 | pmc = 7188774 | doi = 10.3389/fmicb.2020.00493 | issn = 1664-302X | doi-access = free }}</ref> The genome sequencing of ''Coxiella'' and ''Francisella'' endosymbionts confirmed that they consistently produce three B vitamin types, biotin (vitamin B<sub>7</sub>), riboflavin (B<sub>2</sub>) and folate (B<sub>9</sub>).<ref name="Duron_2018" /><ref name="Guizzo_2017" /><ref>{{cite journal | vauthors = Smith TA, Driscoll T, Gillespie JJ, Raghavan R | title = A Coxiella-like endosymbiont is a potential vitamin source for the Lone Star tick | journal = Genome Biology and Evolution | volume = 7 | issue = 3 | pages = 831–8 | date = January 2015 | pmid = 25618142 | pmc = 4994718 | doi = 10.1093/gbe/evv016 }}</ref> As they are required for tick life cycle, these obligate endosymbionts are present in all individuals of the tick species they infect, at least at early stages of development since they may be secondarily lost in males during nymphal development.<ref name="Duron_2017" /><ref name="Duron_2018" /><ref name="Lalzar_2014" /> Since ''Coxiella'' and ''Francisella'' endosymbionts are closely related to pathogens, there is a substantial risk of misidentification between endosymbionts and pathogens, leading to an overestimation of infection risks associated with ticks.<ref>{{cite journal | vauthors = Duron O, Sidi-Boumedine K, Rousset E, Moutailler S, Jourdain E | title = The Importance of Ticks in Q Fever Transmission: What Has (and Has Not) Been Demonstrated? | journal = Trends in Parasitology | volume = 31 | issue = 11 | pages = 536–552 | date = November 2015 | pmid = 26458781 | doi = 10.1016/j.pt.2015.06.014 | s2cid = 25636125 | issn = 1471-4922| url = https://hal.inrae.fr/hal-02637724/file/1-s2.0-S1471492215001518-main.pdf }}</ref><ref>{{cite journal | vauthors = Duron O | title = The IS1111 insertion sequence used for detection of Coxiella burnetii is widespread in Coxiella-like endosymbionts of ticks | journal = FEMS Microbiology Letters | volume = 362 | issue = 17 | pages = fnv132 | date = September 2015 | pmid = 26269380 | doi = 10.1093/femsle/fnv132 | issn = 0378-1097 | doi-access = free }}</ref>