A Review of Ixodid Ticks (Acari: Ixodidae) Associated with Lacerta spp. (Reptilia: Lacertidae) from the Caucasus and Adjacent Territory

: Based on a literature review, as well as on our own data, 14 ixodid tick species belonging to 5 genera were registered for the lizard hosts of the genus Lacerta ( L. agilis , L. media , and L. strigata ) in the Caucasus and the adjacent territories: Haemaphysalis sulcata , Haem. punctata , Haem. parva , Haem. caucasica , Haem. concinna , Haem. inermis , Ixodes ricinus , I. redikorzevi , Dermacentor marginatus , D. reticulatus , Hyalomma marginatum , Rhipicephalus bursa , Rh. rossicum , and Rh. turanicum . Tick species Haem. caucasica were recorded from Armenia for the ﬁrst time. Our ﬁndings of Haem. punctata represent the ﬁrst record of this species for Chechnya, Ingushetia (Russia), Armenia, and Azerbaijan. Most of the parasite species are associated with L. agilis (13) and L. strigata (12); L. media is a host of 6 tick species. Data on the infestation of Lacerta spp. by four tick species from our material ( I. ricinus , Haem. punctata , Haem. caucasica , and Hyal. marginatum ) are presented in the article. In addition, our article contains information on the range of infections associated with the above tick species. Castor bean tick I. ricinus (236 specimens), the most represented species in our collection, parasitizes all available terrestrial vertebrates including humans and can be vector of many various pathogens, so our study provides signiﬁcant epidemiological information.


Introduction
Parasitiform ticks and mites (Acari) are frequent ectoparasites of ecto-and endothermic terrestrial vertebrates.At least 242 species of Acari have been recorded as permanent parasites of reptiles [1], with hematophagic ticks (Ixodida) particularly common.Reptiles are even important reservoirs for tick-borne human pathogens, such as the spirochaete Borrelia burgdorferi, the cause of Lyme borreliosis [2,3], and hematophagic ticks are frequently found parasitizing lizards.
Ixodid or hard ticks (Acari: Ixodida: Ixodidae) are blood-feeding arthropods, with around 900 described species in 19 genera in three families, having a worldwide distribution and infesting virtually all terrestrial vertebrates.Ixodid ticks are capable of transmitting a broad range of human and animal pathogens.In the Palearctic region, the most wellrepresented genus is Ixodes (44 species), followed by Haemaphysalis (19 species), Dermacentor (13 species), Rhipicephalus, and Hyalomma (each with 7 species).
We chose three green lizard (genus Lacerta Linnaeus, 1758) species as objects of our study: three-lined lizard L. media Lantz et Cyrén, 1920, Caspian green lizard L. strigata Eichwald, 1831, and sand lizard L. agilis Linnaeus, 1758, since they are widespread in the Caucasus and one of the most common terrestrial vertebrates in the region.The parasite fauna of green lizards has been studied extremely unevenly.Information on the ectoparasites of L. media and L. strigata is fragmentary.At the same time, L. agilis Linnaeus, 1758 is one of the most complete and comprehensively studied reptile species in terms of parasitology.Extensive studies of this lizard have been carried out within the territory of the former Soviet Union and, above all, in its European part [4].Information about parasites in other parts of the above territory is mostly fragmentary.
Green lizards are included in the regional and national lists of protected animal taxa.For example, the Red Data Book of the Russian Federation includes L. agilis grusinica Peters, 1960 (subspecies declining in numbers and/or distribution), L. a. mzymtensis Tuniyev S. et Tuniyev B., 2008 (endangered subspecies) and the Black Sea population of L. media Lantz et Cyren, 1920 (declining population and/or distribution) [5][6][7].This underlines the relevance of this study from the perspective of studying and conserving biodiversity.
The issue of lizard species diagnostics also remains relevant.In particular, we noted numerous errors in the published articles and species distribution databases.Such oversights, if left uncorrected, may lead to errors in our collective understanding of parasite-host relationships and parasites' life cycle.
The aim of our article is to provide the first complete review of ixodid ticks (medically and veterinary significant species) parasitizing green lizards of the Caucasus and adjacent territories, forming one of the centers of their taxonomic diversity.We documented and curated previously published data including Russian-language non-digital (printed) sources, as well as previously unpublished records of ticks associated with lizards preserved at the Zoological Institute of the Russian Academy of Sciences (ZISP), which holds one of the largest collections of these animals in terms of diversity and specimen numbers.Also, we collected the most complete data on epidemiological significance of all tick species parasitizing lizard hosts under study.

Materials and Methods
Host specimens were collected in the Caucasian part of Russia, Armenia, Azerbaijan, Georgia (including Abkhazia), Turkey, Iran, and Iraq between 1871 and 2022, fixed in alcohol, and deposited at the ZISP.In 2021-2022, we carefully examined 1189 specimens belonging to three species of the genus Lacerta, including 814, 112, and 263 specimens of L. agilis, L. media, and L. strigata, respectively.Ticks were attached to their lizard hosts, so potential museum cross-contamination was excluded.Lizards of the genus Lacerta were determined according to a key by Bannikov et al. [8].The morphological identification of ixodid ticks was performed based on a key by Estrada-Peña et al. [9].Parasite specimens were mounted on permanent microscopic slides in Faure-Berlese's mounting medium.Specimens were examined under a compound microscope (AxioImager A2, Zeiss, Germany).Slide-mounted specimens were deposited at ZISP.
In this study, the prevalence and mean intensity of ticks were determined according to these definitions: Prevalence (P) is the number of host specimens infected by at least one tick divided by the number of specimens examined.Mean intensity (MI) is the total number of ticks of particular species divided by the number of specimens infected with ticks of those species.Indexes P and MI were calculated for each species (I.ricinus, Haemaphysalis punctata, Haem.caucasica, Hyalomma marginatum).Alphabet designations: L means larva; N means nymph.

Results
Ticks have been found on 94 host specimens (prevalence 7.9%).Total 389 ticks have been removed from lizards (mean intensity 4.1).
List of ticks associated with green lizards in Caucasus and adjacent territories is present below.
Other hosts: Reptiles and birds are hosts for immature ticks, while large mammals, including cattle and sheep, are the major hosts for adults of Haem.sulcata [17].
Other hosts: Reptiles and birds are hosts for immature ticks, while large mammals, including cattle and sheep, are the major hosts for adults of Haem.sulcata [17].
Remark: our finding of Haem.punctata is the first record of this species for Chechnya and Ingushetia (Russia), Armenia, and Azerbaijan.
Other hosts: small mammals (hares, hedgehogs), birds, and lizards are hosts for immature stages; adults mainly feed on wild and domestic ungulates, particularly cattle, ships, and goats.H. parva can attack humans [9].
Other hosts: hares are the most common hosts of all life history stages, also occurs on bears, jackals and foxes.Nymphs can also feed on lizards [23].
Pathogen transmission: unknown.Remark: Haem.caucasica has been recorded for Armenia for the first time.
Other hosts: domestic and wild ungulates, small mammals, birds.These ticks can parasitize a range of mammals including cattle, horses, sheep, deer, dogs, foxes and hedgehogs.Human infestation has also been reported [12,16].
Other hosts: domestic and wild ungulates, small mammals, birds.These ticks can parasitize a range of mammals including cattle, horses, sheep, deer, dogs, foxes and hedgehogs.Human infestation has also been reported [12,16].
Green lizard hosts: L. agilis [23], L. strigata [11].strain of the Crimean-Congo haemorrhagic fever virus [108] was isolated from Rh. bursa collected from goats, but the vectorial capacity of this tick still needs to be proven.
Other hosts: all stages feed on a large variety of hosts.At least nine families of birds and 17 families of mammals have been reported as hosts [109].Amphibians and reptiles are exceptionally rare hosts [10].There seems to be no differences in host preference between adults and the immature stages.This tick has been reported on humans several times [109].
Pathogen transmission: experimental proof for the vectorial capacity of Rh. rossicus is available for Francisella tularensis, Crimean-Congo hemorrhagic fever virus, and West Nile virus (for a complete review, see Mihalca et al. [109]).Other pathogens have been detected in Rh. rossicus by various laboratory methods, but there is no experimental evidence for its vectorial ability.These include: Theileria equi, Babesia bigemina, and Coxiella burnetii [109].
Rhipicephalus turanicus Pomerantzev, 1940 Distribution: Palearctic.Many records of Rh. turanicus from around the world are currently only speculative.It is heavily suspected that what has been classically described as "Rh.turanicus" in Europe west to Turkey might, in fact, represent another entity.It is important to note that molecular sequences available in GenBank are expected to have the same degree of unreliability as mentioned for the records or the knowledge of the ecology of this species.
Pathogen transmission: since the taxonomic status of Rh. turanicus is under discussion, its role as a vector of human pathogens, including Rickettsia massiliae, R. conorii, and other microorganisms molecularly detected in ticks designated as this species, needs confirmation.

Discussion
Fourteen ixodid tick species belonging to 5 genera (Table 1) parasitize lizards of the genus Lacerta in the Caucasus and the adjacent countries: 6 species of the genus Haemaphysalis, 3 species of Rhipicephalus, 2 species of the genus Ixodes, 2 species of the genus Dermacentor, 1 species of the genus Hyalomma.Most of the findings belong to the following 3 species (Table 2): I. ricinus (the vast majority of findings), Haem.punctata, and Hyalomma marginatum.Some of our findings are the first records for the countries.In particular, Haem.punctata has been recorded from both Armenia and Azerbaijan for the first time.Haem.caucasica also has been recorded from Armenia for the first time.Our findings are represented mostly by immature stages (larvae and nymphs).
Total infestation of sand lizards by all ixodid tick species in our material is much lower than that in the data on Dagestan (P 6.6 vs. P 36.5)[11] and Poland (P 6.6 vs. P 13.8-58.1)[127].It is difficult to explain the reason for the low infestation of lizards in our material; it is possible that ticks left their hosts during transportation, and in some cases, the acquired individuals were kept in captivity for some time, which also led to the loss of some of the ticks.
Analyzing the ecological niches of ticks (Table 3) and their hosts, it should be noted that the territory of the Caucasus has a high degree of mosaic landscapes.Probably, this explains the findings of ticks with different ecological niches on the same host species.In particular, the medium lizards, which prefers dry biotopes [128,129]

Ixodes ricinus
Commonly found in deciduous and coniferous woodland and mixed forests.
Requires a relative humidity of at least 80% to survive during its off-host period, being therefore restricted to areas of moderate-to-high rainfall with vegetation that retains a high humidity. [23]

Haemaphysalis punctata
A wide variety of habitats from cold to mild.It inhabits pastures, forest margins, forest steppes, brush areas, limestone pastures, artificial conifer forests, oak forests with scarce undercover and, rarely, even evergreen oak forests.
It can be found in a very wide variety of habitats from humid climates to drier biotopes.[15] Haem.caucasica This is a rare species.It occurs in steppe areas, either on the plains or more commonly in foothills and mountainous regions.

Haem. concinna
It can occur in a variety of different habitats, including deciduous forests, mixed forests, mixed hornbeam-oak forests with bush undergrowth, forest clearings and the margin of oak forests, lake coasts, river basins, and in shoreline vegetation.
Prefers humid habitats.[26] Haem.sulcata It occurs mostly in steppe with a semi-desert character and is usually not present in areas with high humidity.It is widespread mostly in wormwood foothills, mountain steppe, dry steppe, and semi-desert habitats.It has been recorded in mountain valleys up to 2200-2500 m a.s.l.
It is usually absent in areas with high humidity.[12] Haem.inermis Generally found in temperate broadleaf and mixed forests.Prefers humid habitats.
[29] From humid Mediterranean climates to the arid environments of steppe regions. [128]

Dermacentor marginatus
Typical open country tick species, preferring meadows and pastures, where it may be sympatric with D. reticulatus.

D. reticulatus
Typical open country tick species, preferring meadows and pastures.Frequently found in river basins or along lake shores.Dermacentor reticulatus occurs up to 1000 m a.s.l.

Rhipicephalus bursa
It is closely associated with sheep breeding and is distributed mostly in areas with a humid winter and long dry summer.It can be found at altitudes up to 1950 m a.s.l.

Rh. rossicus
Habitat preference is attributed mainly to host abundance and availability rather than to abiotic factors.The tick has been found at various altitudes, ranging from 0 to 1500 m a.s.l.
Prefers several habitats (from river basin valleys to dry forests and xeric shrublands from steppic regions).
[ 29,109] Rh. turanicus It prefers grasslands and pastures.Prefers dry habitats.[23] Our study demonstrates the need for parasitological surveys of herpetological collections, which could undoubtedly provide interesting data on the diversity, distribution, and vector role of ectoparasites.Further molecular studies of the collected material are needed to investigate the spectrum of pathogens associated with ixodid ticks in the Caucasus region.

Table 3 .
Infestation ecological niches of studied ticks.