Ixodida

Belongs within: Parasitiformes.
Contains: Haemaphysalis, Amblyomma, Hyalomma, Rhipicephalus, Dermacentor, Ixodes.

Fowl ticks Argas persicus, copyright Daktaridudu.

The Ixodida, ticks, are a group of large mites parasitic on vertebrates. The chelicerae are used to pierce the host’s skin after which the tick anchors itself in place using the toothed hypostome (Keirans 2009).

Ticks are divided between three families with most species belonging to the Argasidae and Ixodidae. The African Nuttalliella namaqua is assigned to its own family and possesses a leathery papillate podonotal pseudoscutum, apparently three-segmented palpi, and a short hypostome with few denticles. This species has been found in the nests of rock hyraxes and swallows but its feeding habits remain unknown (Keirans 2009).

The Ixodidae, hard ticks, are characterised by the presence of a hardened dorsal scutum. Members of this group include the most familiar disease-vectoring ticks. Males feed sparingly compared to females which require large blood meals.

Phylogenetically, the ixodids are divided between two lineages, Ixodes and the Metastriata. Representatives of the Metastriata usually possesses festoons (regular subdivisions of the posterior margin of the idiosoma) and the anal groove, if present, is restricted to the posterior of the anus. Genera of metastriate ticks include Bothriocroton, a group of ornate ticks found in Australasia on lizards, marsupials and echidnas. Bothriocroton is poorly defined morphologically and difficult to distinguish as adults from eyeless species of Amblyomma, but larvae bear three large wax glands laterally near setae s6 (anterior to the first festoon) whereas at most only one such gland is present in other metastriate ticks and none are found in Ixodes (Klompen et al. 2002).

The Argasidae, soft ticks, lack a well-developed scutum. Most feed on hosts returning to regular shelters such as nests, burrows or caves. Rather than permanently attaching to a single host like the hard ticks of the Ixodidae, females of Argasidae feed multiple times following maturity. Most argasids feed on their hosts for only short periods at a time, and may survive for extraordinarily long periods (up to several years) without feeding. However, the spinose ear tick Otobius megnini feeds deep within the ears of its mammalian host, causing damage that in extreme cases may even be fatal (Keirans 2009).

Species of Argas possess a distinct sutural line separating dorsal and ventral body surfaces that is absent in other genera. In Nothoaspis the anterior part of the dorsal integument is smooth and leathery (Keirans 2009).

The hard way to be a bloodsucker
Published 15 March 2010
A mature gorged female of Ixodes ricinus, the sheep tick or castor bean tick, ready to lay her eggs, photographed by Jarmo Holopainen.

Ticks are probably the most familiar of all mite groups. Not only do they include by far the largest mite species but they also feed on the blood of vertebrates, a habit guaranteed to bring them to our attention. The ticks themselves would usually be more irritating than dangerous, except on occasions when they attack in large numbers, but many ticks are vectors of some very unpleasant diseases. The largest of the families of ticks are the Ixodidae or hard ticks with a little under 700 species (Horak et al., 2002). Hard ticks are distinguished from members of the Argasidae or soft ticks by the presence of a hardened scutum at the front of the dorsum. In males, the scutum can cover almost the entire dorsal surface, whereas the female scutum is restricted to the front part of the body over the legs. Hard ticks also have the capitulum (the ‘head’) directed forward so that it is easily visible from above whereas soft ticks have the capitulum pointed downwards (Nicholson et al., 2009).

A female of the cattle tick Rhipicephalus microplus laying her not inconsiderable brood of eggs, from here.

The hard tick life cycle contains four stages of a single instar each—egg, larva, nymph and mature adult (soft ticks have multiple nymphal instars). Eggs are laid in large clusters of hundreds or thousands—the record number of eggs laid by a single female is 34,000 for a specimen of Amblyomma variegatum (Nicholson et al., 2009). Like other mites, larval ticks have only six legs when they first hatch out; the fourth pair doesn’t appear until the nymphal stage. In both the larval and nymphal stages the young ticks will find a suitable host and feed then usually drop off and moult away from the host* (a small number of species don’t leave the host before moulting and remain on a single host for their entire life). Some tick species are very choosy about their hosts (the best-known of which being the cattle tick, Rhipicephalus microplus [aka Boophilus microplus]) while others such as the sheep tick Ixodes ricinus are far more catholic. Some species feed on different hosts at different life stages. Even if suitable hosts are few and far between, some ticks can survive for over a year without feeding while they wait for one to turn up (some soft ticks can survive for several years without food).

*I have to admit to being surprised when I learnt that ticks didn’t just latch onto their final host right away, even though in retrospect it should have been bloody obvious. After all, they would hardly be as much concern as disease vectors if they only ever attacked a single individual.

Cattle ticks removed from a single calf, from here.

Males of Ixodes do not feed after reaching maturity and usually mate with females before they attach themselves to the final host (though some may mate on the host) while mature males of other ixodid genera do feed and copulation between the sexes takes place on the host (all together now—ewww). After copulation, the attached female gorges herself on her host’s blood, swelling up to many times her original size. Once her eggs are mature, she drops off the host, lays her eggs in a suitable sheltered site, and dies (in contrast, female soft ticks can find another host and mate with another male, eventually surviving for several years).

Back when she was skinny—a female lone star tick Amblyomma americanum sitting on vegetation waiting for a host, photographed by James Gathany.

Phylogenetic analysis supports a basal division in Ixodidae between Ixodes and other genera which is consistent with the differences in life cycles between the two groups (Murrell et al., 2003).

Systematics of Ixodida

Characters (from Keirans 2009): Hypostome typically produced as anteriorly projecting holdfast organ bearing a series of retrorse teeth. Chelicerae with two segments, with an inner (paraxial) digit on which a dorsal uncate appendage is articulated and a dentate outer (antiaxial) digit attached near the base of inner element; membranous mantle surrounding inner digit, leaving only cutting teeth of digits exposed. Palpi usually with four segments (rarely three). Epistome, corniculi and tritosternum absent. One or two pairs of simple eyes may be present on lateral margins of scutum or in pleural integument above coxae. Haller’s organ (a complex sensory field consisting of an anterior pit and a posterior capsule) located dorsally on tarsi I.

<==Ixodida [Ixodoidea, Metastigmata]
    |  i. s.: Alveonasus lahorensis (Neumann 1908)K91
    |--Argasidae [Argasini]Ke09
    |    |--AntricolaKe09
    |    |--Parantricola marginatusDC91
    |    |--Nothoaspis reddelliKe09
    |    |--Otobius Banks 1912H98
    |    |    |--O. lagophilusKe09
    |    |    `--O. megnini (Dugès 1884) [=Argas megnini]H98
    |    |--Ornithodoros Koch 1844H98
    |    |    |--O. amblusKe09
    |    |    |--O. coriaceus Koch 1844H07
    |    |    |--O. dugesi Mazzotti 1943M-PV-G01
    |    |    |--O. gurneyi Warburton 1926 [=Ornithodorus (l. c.) gurneyi]H98
    |    |    |--O. hermsi Wheeler et al. 1935M-PV-G01
    |    |    |--O. kelleyiKr09
    |    |    |--O. macmillani Hoogstraal & Kohls 1966H98
    |    |    |--O. maritimusNJ91
    |    |    |--O. (Ornithodoros) moubata (Murray 1877)DJS91, P91
    |    |    |--O. muesebeckiKe09
    |    |    |--O. nicollei Mooser 1932H07
    |    |    |--O. papillipes (Birula 1895)P91 [incl. O. tholozani (Laboulbène & Mégnin 1882)A56]
    |    |    |--O. parkeri Cooley 1936M-PV-G01
    |    |    |--O. porcinusLL07
    |    |    |--O. savignyiF-M91
    |    |    |--O. talajeH07
    |    |    |--O. (Pavlovskyella) tartakovskyiDJS91
    |    |    |--O. tholozaniF-M91
    |    |    |--O. transversusWP99
    |    |    |--O. turicata (Dugès 1876) [=Argas turicata]H07
    |    |    `--O. verrucosusB96a
    |    `--Argas Latreille 1795H98
    |         |  i. s.: A. erraticus Lucas 1847E12
    |         |         A. hermanniJO99
    |         |         A. lahorensisOW01
    |         |--A. (Argas)KH75
    |         |    |--A. (A.) cooleyiKH75
    |         |    |--A. (A.) falco Kaiser & Hoogstraal 1974KH75
    |         |    |--A. (A.) japonicusKH75
    |         |    |--A. (A.) lagenoplastis Froggatt 1906KH75, H98
    |         |    |--A. (A.) latusLD91
    |         |    |--A. (A.) lowryae Kaiser & Hoogstraal 1975KH75
    |         |    |--A. (A.) marginatus [=Ixodes (A.) marginatus]G20
    |         |    |--A. (A.) polonicusDJS91
    |         |    |--A. (A.) reflexusDJS91 [=Acarus reflexusCF77; incl. Rhynchoprion columbaeCF77]
    |         |    |--A. (A.) tridentatusLD91
    |         |    |--A. (A.) radiatusB96b
    |         |    `--A. (A.) vulgarisLD91
    |         |--A. (Carios Latreille 1796)E-PAG91, H98
    |         |    |--A. (C.) australiensis Kohls & Hoogstraal 1962H98
    |         |    |--‘Carios’ capensis (Neumann 1901) [=Ornithodoros talaje var. capensis]H98
    |         |    |--A. (C.) daviesi Kaiser & Hoogstraal 1973H98
    |         |    |--A. (C.) dewae Kais & Hoogstraal 1974H98
    |         |    |--‘Carios’ jerseyiGE05
    |         |    |--A. (C.) macrodermae Hoogstraal et al. 1977H98
    |         |    `--A. (C.) vespertilionis Latreille 1802E-PAG91
    |         `--A. (Persicargas)KH75
    |              |--A. (P.) arboreusDJS91
    |              |--A. (P.) nullaborensis Hoogstraal & Kaiser 1973KH75
    |              |--A. (P.) persicus (Oken 1818)KH75, H98 (see below for synonymy)
    |              |--A. (P.) robertsi Hoogstraal et al. 1968KH75
    |              `--A. (P.) walkeraeDJS91
    |--Ixodidae [Ixodini]Ke09
    |    |  i. s.: Dermacentonomma Dias 1978KDB02
    |    |         Palpoboophilus minningi Kishida 1936TYM08
    |    |--MetastriataKe09
    |    |    |--HaemaphysalisKe09
    |    |    |--AmblyomminaeKDB02
    |    |    |    |--AmblyommaKe09
    |    |    |    `--HyalommaLD91
    |    |    |--Bothriocroton Keirans, King & Sharrad 1994Ke09, KDB02 [Bothriocrotoninae]
    |    |    |    |--*B. glebopalma (Keirans, King & Sharrad 1994) [=Aponomma (*Bothriocroton) glebopalma]KDB02
    |    |    |    |--B. auruginans (Schulze 1936) [=Aponomma auruginans]KDB02
    |    |    |    |--B. concolor (Neumann 1899)KDB02 (see below for synonymy)
    |    |    |    |--B. hydrosauri (Denny 1843)KDB02 (see below for synonymy)
    |    |    |    `--B. undatum (Fabricius 1775)KDB02 (see below for synonymy)
    |    |    `--RhipicephalinaeWN01
    |    |         |--RhipicephalusKe09
    |    |         |--DermacentorJR91
    |    |         |--Anomalohimalaya Hoogstraal, Kaiser & Mitchell 1970K99, KDB02
    |    |         |--Cosmiomma hippopotamensisK99, Ke09
    |    |         |--Margaropus winthemiK99, B91
    |    |         |--NosommaK99
    |    |         `--RhipicentorK99
    |    `--IxodesKe09
    `--Nuttalliella Bedford 1931AL37 [NuttalliellidaeKe09]
         `--*N. namaqua Bedford 1931AL37

Argas (Persicargas) persicus (Oken 1818)KH75, H98 [=Rhynchoprion persicumH98; incl. A. americana Packard 1873H98, A. americanusH98, A. victoriensis Sweet 1910H98]

Bothriocroton concolor (Neumann 1899)KDB02 [=Aponomma concolorKDB02; incl. A. galactites Schulze 1941H98, A. oudemansi Neumann 1910H98, A. tropicum Roberts 1953H98]

Bothriocroton hydrosauri (Denny 1843)KDB02 [=Aponomma hydrosauriKDB02; incl. A. tachyglossi Roberts 1953H98, Ixodes trachysauri Lucas 1861H98, A. trachysauriKDB02]

Bothriocroton undatum (Fabricius 1775)KDB02 [=Acarus undatusKDB02, Aponomma undatumKDB02; incl. Ixodes decorosus Koch 1867H98, Ap. decorosumKDB02, I. varani Koch 1867H98]

*Type species of generic name indicated

References

[A56] Anastos, G. 1956. The ticks (Acarina: Ixodoidea) of the J. Klapperich Afghanistan Expedition, 1952 and 1953. Journal of the Washington Academy of Sciences 46 (1): 18–19.

[AL37] André, M., & É. Lamy. 1937. Les Idées actuelles sur la Phylogénie des Acariens. Published by the author: Paris.

[B91] Belozerov, V. N. 1991. Evolution of life cycles in ticks (Ixodidae) due to climate seasonality. In: Dusbábek, F., & V. Bukva (eds) Modern Acarology: Proceedings of the VIII International Congress of Acarology, held in České Budĕjovice, Czechoslovakia, 6–11 August 1990 vol. 2 pp. 135–139. SPB Academic Publishing: The Hague.

[B96a] Buczek, A. 1996a. Anomalies in Argas reflexus (Fabr.) (Argasidae) collected from nature. In: Mitchell, R., D. J. Horn, G. R. Needham & W. C. Welbourn (eds) Acarology IX vol. 1. Proceedings pp. 319–324. Ohio Biological Survey: Columbus (Ohio).

[B96b] Buczek, A. 1996b. Regeneration of legs in Argas (Argas) reflexus (Fabricius) (Argasidae). In: Mitchell, R., D. J. Horn, G. R. Needham & W. C. Welbourn (eds) Acarology IX vol. 1. Proceedings pp. 709–711. Ohio Biological Survey: Columbus (Ohio).

[CF77] Canestrini, G., & F. Fanzago. 1877. Intorno agli Acari Italiani. Atti del Reale Istituto Veneto di Scienze, Lettere ed Arti, Serie 5, 4: 69–208, pls 2–7.

[DC91] Daniel, M., V. Černý, J. Štěrba & J. de la Cruz. 1991. Morphological study of adults of trombiculid mites from Cuban hot caves. In: Dusbábek, F., & V. Bukva (eds) Modern Acarology: Proceedings of the VIII International Congress of Acarology, held in České Budĕjovice, Czechoslovakia, 6–11 August 1990 vol. 2 pp. 261–263. SPB Academic Publishing: The Hague.

[DJS91] Dusbábek, F., A. Jegorov & P. Šimek. 1991. Artificial assembly pheromone of argasid ticks (Ixodoidea: Argasidae). In: Dusbábek, F., & V. Bukva (eds) Modern Acarology: Proceedings of the VIII International Congress of Acarology, held in České Budĕjovice, Czechoslovakia, 6–11 August 1990 vol. 1 pp. 59–68. SPB Academic Publishing: The Hague.

[E-PAG91] Estrada-Peña, A., A. Albó & J. Gutiérrez. 1991. Phenotypic variation of larval Argas (Carios) vespertilionis (Argasidae) in Spain and northern Africa. In: Dusbábek, F., & V. Bukva (eds) Modern Acarology: Proceedings of the VIII International Congress of Acarology, held in České Budĕjovice, Czechoslovakia, 6–11 August 1990 vol. 2 pp. 147–153. SPB Academic Publishing: The Hague.

[E12] Evenhuis, N. L. 2012. Publication and dating of the Exploration Scientifique de l’Algérie: Histoire Naturelle des Animaux Articulés (1846–1849) by Pierre Hippolyte Lucas. Zootaxa 3448: 1–61.

[F-M91] Feldman-Muhsam, B. 1991. The role of Adlerocystis sp. in the reproduction of argasid ticks. In: Schuster, R., & P. W. Murphy (eds) The Acari: Reproduction, development and life-history strategies pp. 179–190. Chapman & Hall: London.

[G20] Goldfuss, G. A. 1820. Handbuch der Naturgeschichte vol. 3. Handbuch der Zoologie pt 1. Johann Leonhard Schrag: Nürnberg.

[GE05] Grimaldi, D., & M. S. Engel. 2005. Evolution of the Insects. Cambridge University Press: New York.

[H98] Halliday, R. B. 1998. Mites of Australia: A checklist and bibliography. CSIRO Publishing: Collingwood.

[H07] Hoffmann, A. 2007. Acarology in Mexico: prehispanic to modern times. In: Morales-Malacara, J. B., V. M. Behan-Pelletier, E. Ueckermann, T. M. Pérez, E. G. Estrada-Venegas & M. Badii (eds) Acarology XI: Proceedings of the International Congress pp. 21–26. Instituto de Biología and Faculdad de Ciencias, Universidad Nacional Autónoma de México, Sociedad Latinoamericana de Acarología: México.

Horak, I. G., J.-L. Camicas & J. E. Keirans. 2002. The Argasidae, Ixodidae and Nuttalliellidae (Acari: Ixodida): a world list of valid tick names. Experimental and Applied Acarology 28: 27–54.

[JO99] James, A. M., & J. H. Oliver Jr. 1999. Vitellogenesis and its hormonal regulation in Ixodida. In: Needham, G. R., R. Mitchell, D. J. Horn & W. C. Welbourn (eds) Acarology IX vol. 2. Symposia pp. 471–476. Ohio Biological Survey: Columbus (Ohio).

[JR91] Jaworski, D. C., R. Rosell, L B. Coons & G. R. Needham. 1991. Evidence that a 90 kDa tick salivary gland polypeptide is a cement component. In: Dusbábek, F., & V. Bukva (eds) Modern Acarology: Proceedings of the VIII International Congress of Acarology, held in České Budĕjovice, Czechoslovakia, 6–11 August 1990 vol. 1 pp. 335–340. SPB Academic Publishing: The Hague.

[KH75] Kaiser, M. N., & H. Hoogstraal. 1975. Observations on the subgenus Argas (Ixodoidea: Argasidae: Argas). A. (A.) lowryae, new species, parasitizing cave-dwelling kestrels in the Nullarbor region of Western Australia. Annals of the Entomological Society of America 68 (3): 585–590.

[Ke09] Keirans, J. E. 2009. Order Ixodida. In: Krantz, G. W., & D. E. Walter (eds) A Manual of Acarology 3rd ed. pp. 111–123. Texas Tech University Press.

[K99] Klompen, J. S. H. 1999. Phylogenetic relationships in the family Ixodidae with emphasis on the genus Ixodes (Parasitiformes: Ixodidae). In: Needham, G. R., R. Mitchell, D. J. Horn & W. C. Welbourn (eds) Acarology IX vol. 2. Symposia pp. 349–354. Ohio Biological Survey: Columbus (Ohio).

[KDB02] Klompen, H., S. J. Dobson & S. C. Barker. 2002. A new subfamily, Bothriocrotoninae n. subfam., for the genus Bothriocroton Keirans, King & Sharrad, 1994 status amend. (Ixodida: Ixodidae), and the synonymy of Aponomma Neumann, 1899 with Amblyomma Koch, 1844. Systematic Parasitology 53: 101–107.

[Kr09] Krantz, G. W. 2009. Form and function. In: Krantz, G. W., & D. E. Walter (eds) A Manual of Acarology 3rd ed. pp. 5–53. Texas Tech University Press.

[K91] Kryuchechnikov, V. N. 1991. Protective responses of Ixodoidea hemocytes. In: Dusbábek, F., & V. Bukva (eds) Modern Acarology: Proceedings of the VIII International Congress of Acarology, held in České Budĕjovice, Czechoslovakia, 6–11 August 1990 vol. 1 pp. 331–334. SPB Academic Publishing: The Hague.

[LD91] Leonovich, S. A., & F. Dusbábek. 1991. Pheromone sensory subsystem in ticks: correlation between structure of sensilla and evolution of behaviour. In: Dusbábek, F., & V. Bukva (eds) Modern Acarology: Proceedings of the VIII International Congress of Acarology, held in České Budĕjovice, Czechoslovakia, 6–11 August 1990 vol. 1 pp. 53–58. SPB Academic Publishing: The Hague.

[LL07] Liu, J., L. Liu, Y. Zhang, Z. Wei & J. Liu. 2007. Preliminary studies on the juvenile hormone of Haemaphysalis longicornis Neumann (Acari: Ixodidae). In: Morales-Malacara, J. B., V. M. Behan-Pelletier, E. Ueckermann, T. M. Pérez, E. G. Estrada-Venegas & M. Badii (eds) Acarology XI: Proceedings of the International Congress pp. 205–208. Instituto de Biología and Faculdad de Ciencias, Universidad Nacional Autónoma de México, Sociedad Latinoamericana de Acarología: México.

[M-PV-G01] Montiel-Parra, G., G. A. Villegas-Guzman, M. Vargas & O. J. Polaco. 2001. Mites associated with nests of Neotoma albigula Hartley, 1894 (Rodentia: Muridae) in Durango, México. In: Halliday, R. B., D. E. Walter, H. C. Proctor, R. A. Norton & M. J. Colloff (eds) Acarology: Proceedings of the 10th International Congress pp. 586–593. CSIRO Publishing: Melbourne.

Murrell, A., N. J. H. Campbell & S. C. Barker. 2003. The value of idiosyncratic markers and changes to conserved tRNA sequences from the mitochondrial genome of hard ticks (Acari: Ixodida: Ixodidae) for phylogenetic inference. Systematic Biology 52 (3): 296–310.

Nicholson, W. L., D. E. Sonenshine, R. S. Lane & G. Uilenberg. 2009. Ticks (Ixodida). In: Mullen, G. R., & L. A. Durden (eds) Medical and Veterinary Entomology 2nd ed. pp. 483–532. Academic Press.

[NJ91] Nuttall, P. A., & L. D. Jones. 1991. Non-viraemic tick-borne virus transmission: mechanism and significance. In: Dusbábek, F., & V. Bukva (eds) Modern Acarology: Proceedings of the VIII International Congress of Acarology, held in České Budĕjovice, Czechoslovakia, 6–11 August 1990 vol. 2 pp. 3–6. SPB Academic Publishing: The Hague.

[OW01] Otto, J. C., & K. J. Wilson. 2001. Assessment of the usefulness of ribosomal 18S and mitochondrial COI sequences in Prostigmata phylogeny. In: Halliday, R. B., D. E. Walter, H. C. Proctor, R. A. Norton & M. J. Colloff (eds) Acarology: Proceedings of the 10th International Congress pp. 100–109. CSIRO Publishing: Melbourne.

[P91] Podboronov, V. M. 1991. Antibacterial protective mechanisms of ixodoid ticks. In: Dusbábek, F., & V. Bukva (eds) Modern Acarology: Proceedings of the VIII International Congress of Acarology, held in České Budĕjovice, Czechoslovakia, 6–11 August 1990 vol. 2 pp. 375–380. SPB Academic Publishing: The Hague.

[TYM08] Tennent, W. J., M. Yasuda & K. Morimoto. 2008. Lansania Journal of arachnology and zoology—a rare and obscure Japanese natural history journal. Archives of Natural History 35 (2): 252–280.

[WP99] Walter, D. E., & H. C. Proctor. 1999. Mites: Ecology, Evolution and Behaviour. CABI Publishing: Wallingford (UK).

[WN01] Wang, H., & P. A. Nuttall. 2001. Characterisation of immunoglobulin G binding proteins in male Rhipicephalus appendiculatus ticks. In: Halliday, R. B., D. E. Walter, H. C. Proctor, R. A. Norton & M. J. Colloff (eds) Acarology: Proceedings of the 10th International Congress pp. 618–621. CSIRO Publishing: Melbourne.

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