Amblyomma Species Research Articles

Relationship of the occurrence and function of 2,6-dichlorophenol in two species of Amblyomma (Acari: Ixodidae).

Female Amblyomma americanum (Linnaeus) and A. maculatum Koch ticks contained approximately equal and maximum amounts of 2,6-dichlorophenol at 16 days after emergence. A. maculatum males also contained substantial amounts of the compound, but only traces of the chemical were detected in A. americanum males. There appeared to be no increase in the 2,6-dichlorophenol content of feeding ticks. Only male ticks of both species were attracted to local applications of the phenol. No behavioral response was observed in A. maculatum females to explain the presence of 2,6-dichlorophenol in males of this species or elucidate other investigators' observations on the aggregation of the sexes of this tick on hosts.

The Amblyomma (Acarina: Ixodidae) Parasitic on Giant Tortoises (Reptilia: Testudinidae) of the Galápagos Islands1

Study of ticks from giant tortoises, Geochelone elephantopus subspp., in the Galapagos Islands reveals 3 Amblyomma species parasitizing this host: A. usingeri , n. sp., A. macfarlandi , n. sp., and A. pilosum Neumann. Each active stage in the life cycle of these species is described and illustrated. Amblyomma boulengeri Hirst & Hirst, previously incorrectly considered to be synonymous with A. pilosum (sensu Robinson), is a distinct species parasitic on land iguanas and lava lizards.

The distribution of three species of reptile ticks, Aponomma hydrosauri (Denny), Amblyomma albolimbatum Neumann, and Amb. limbatum Neumann II. Water balance of nymphs and adults in relation to distribution

Three species of reptile ticks have abutting allopatric distributions in South Australia. Aponomma hydvosauri has a greater rate of water loss at normal temperatures than two Amblyomma species. Amb. albolimbatum and Amb. limbatum lose water at the same rate but the former is more resistant to desiccation because it is larger. The two Amblyomma species also have a higher critical temperature above which waterproofing properties of the cuticle break down, but there is no difference in the equilibrium humidities of the three species. There is a general correlation between physiological resistance to desiccation in a species and the aridity of the range of that species. But this correlation does not completely explain the distribution pattern.

Amblyomma (Acarina: Ixodidae) on white-tailed deer, Odocoileus virginianus (Zimmermann), from south Texas with implications for theileriasis.

A study was conducted during 1966–1968 to determine the tick and blood protozoan fauna of white-tailed deer from the Welder Refuge, south Texas. The prevalence, numbers, or both of several species of AMBLYOMMA and Theileria cervi were compared with host factors such as age, sex, and general behavior, and extrinsic factors including landscape density, and soil type. Three species of ticks, Amblyomma americanum, A. inornatum, and A. maculatum, were prevalent but not numerous on deer. Adult A. americanum were not found on neonatal fawns, adult A. inornatum preferred this age host, while A. maculatum were found on deer of all ages. A. maculatum preferred to attach to the developing antlers of males each summer. Conditions for development and activity of ticks were apparently most favorable in plant communities with vegetation characterized as “dense.” The potential of these species of Amblyomma to transmit Theileria cervi, a common infection of deer on Welder, is discussed.

A new species of Amblyomma from iguanas in the Caribbean (Acarina: Ixodidae).

Amblyomma antillorwn n. sp. resembling A. albopictum Neumann, is described from males and females from the iguana, Cyclura pinguis Barbour, from Anegada, British Virgin Islands. Males believed to be the same species are recorded from Iguana delicatissima Laurenti from Dominica in the Lesser Antilles.

THE LARVAE OF AUSTRALIAN IXODIDAE (ACARINA: IXODOIDEA)

AbstractThese studies are based on the larvae of 29 of the 52 species of Ixodidae recorded from Australia. The 29 species comprise 13 species of Ixodes, 6 species of Haemaphysalis, 1 species of Boophilus, 1 species of Rhipicephalus, 5 species of Amblyomma, and 3 species of Aponomma; larvae of 11 species are described for the first time.Descriptions, illustrations, and with the genera Ixodes and Haemaphysalis keys also, are given. The descriptions include the respective chaetotaxy patterns which are considered of value for generic and in many instances also for specific diagnosis.

Further observations on the Australian species of Aponomma and Amblyomma with descriptions of the nymphs of Amblyomma moreliae (L.Koch) and Amb. loculosum Neumann (Acarina: Ixodidae).

The taxonomy of the species of Aponomma and Amblyomma listed by Roberts (1953) from Australia has been examined. Ap. trachysauri (Lucas) is now considered synonymous with Ap. hydrosauri (Denny) and the species previously determined as Ap. hydrosauri is now Ap. concolor Neumann. Other synonymy noted includes Ap. tropicum Roberts with Ap. concolor, Ap. simplex Cooper & Robinson, and Ap. ecinctum Neumann with Ap. jimbriatum (C. L. Koch), Ap. decorosum (L. Koch) with Ap. undatum (Fabricius), and Amblyomma sternae Roberts with Amb. loculosum Neumann. Further information is given on the host range and geographical distribution of the species of both genera, and the nymphs of Amb. moreliae (L. Koch) and Amb. loculosum are described.

Ecology and host-relationships of ticks (Ixodoidea) infesting domestic animals in Kassala Province, Sudan, with special reference to Amblyomma lepidum Dönitz.

Amblyomma lepidum Dön., previously incriminated as a vector of heartwater (caused by Rickettsia ruminantium) among sheep and goats, and possibly camels, in southern Kassala Province, Sudan, is apparently the only Amblyomma species in this area. Systematic collections of all ticks infesting domestic animals were carried out in November 1959, just after the rains, in five ecologically differing areas in the region most severely infected with heartwater. Though rare in desert scrub (north of 16°N. latitude) and only moderately numerous in semidesert grassland (Butana area), incidence of A. lepidum is high in wooded savannah (River Atbara) and in the cultivated Gash Delta, and highest (15·5 per host) in the Acacia seyal savannah of the River Gash. Chief hosts of adults are cattle. Sheep are secondary hosts, and camels, donkeys, and goats are less heavily infested. Two males were taken feeding on humans. Mating (breeding) activity is only slight following the rains (November). Few larvae and nymphs were found during this period; those present were mainly on sheep and goats, with a few on cattle, and these were usually feeding on the hoofs of their hosts.Rhipicephalus s. sanguineus (Latr.), the most numerous and widely distributed tick here, infests chiefly sheep and goats, is common on cattle, and also occurs on camels and donkeys. Mating activity of this species is high in November. Hyalomma dromedarii Koch is equally widely distributed and follows R. s. sanguineus in numbers, but is most frequent on camels, common on cattle, and rare on donkeys and sheep; goats were uninfested. Mating is moderately active at this season. The incidence of H. impeltatum Schulze & Schlottke, which occurs in each zone, equalled that of A. lepidum. Cattle are the chief hosts and camels are secondary hosts; donkeys, sheep, and goats are less frequently infested. Mating activity is moderate in November.Other more or less common tick species on these domestic animals are Boophilus decoloratus (Koch), R. e. evertsi Neum., R. simus Koch, H. anatolicum excavatum Koch, H. truncatum Koch and H. marginatum rufipes Koch, evidence for the status of which as a subspecies of H. marginatum Koch is to be presented in a subsequent paper. Several other rare species are also recorded.

Amblyomma calabyi n.sp. from Western Australia (Acarina: Ixodidae)

The new species of Amblyomma described in this paper was collected and forwarded to the author for identification by Mr J. H. Calaby, Wildlife Section, C.S.I.R.O. This is the fourth species of the genus to be recorded from Western Australia, the others being A. australiense Neumann, A. albolimbatum Neumann, and A. triguttatum Koch (Roberts, 1953).

A Preliminary Survey of the Distribution and Host-specificity of Ticks (Ixodoidea) in the Bechuanaland Protectorate

SummaryTwenty one species of ticks (Ixodoidea), one of which is represented by two subspecies, are recorded from the Bechuanaland Protectorate. Localities, dates and the hosts are given; general distribution and medical and veterinary importance are discussed under each species.The shrub desert formations of the Kalahari are shown to be unsuitable habitats for most species of ticks; only a few are able to survive under severe desert conditions.In medical respects, Ornithodoros moubata (Murr.), as the transmitter of relapsing fever, is the most important tick in the Protectorate. It has been found in the eastern part up to Francistown and in Ngamiland and near Tsane; its further distribution has not yet been established. Larvae and nymphs of various members of the Ixodidae infesting domestic and wild rodents are potential transmitters of tick-bite fever.Cattle in the eastern area and in Ngamiland were found to be infested by ten species, of which Amblyomma hebraeum Koch, Hyalomma rufipes Koch, H. truncatum Koch, Rhipicephalus appendiculatus Neumann, R. evertsi evertsi Neumann, R. simus simus Koch and Boophilus decoloratus (Koch) are the most important ones, both in respect of the numbers infesting cattle, and of their significance as transmitters of redwater, anaplasmosis, heartwater and sweating sickness.Sheep, goats, pigs and horses were found to be infested by nine of the species listed above as occurring on cattle.Dogs were mainly parasitised by Rhipicephalus simus which outnumbered by far the two recognised dog-ticks, Rhipicephalus sanguineus sanguineus (Latr.) and Haemaphysalis leachii leachii (Aud.).Wild Bovids and zebra are infested by species which also live on domestic ruminants, but the percentage of the different species present varies according to the host and to the locality.Wild carnivores are infested by the same species as are dogs, but in this group, too, there are differences in the relative abundance of the various tick species.Small birds are hosts of immature stages of Amblyomma and Hyalomma species. Their importance as carriers for the dispersal of cattle-infesting ticks is noticed.

Notas de ixodologia: V - A propósito da validade de algumas espécies do gênero Amblyomma do continente americano (Acari: Ixodídoe)

a) The species Amblyomma tapiri Tonelli Rondelli, 1937 and Amblyomma finitimum Tonelli Rondelli, 1937 are synonymous with Amblyomma cajennense Fabricius, 1787. Both species are based in differences of size, colour, punctations and form of the dorsal shield, presence or absence of ventral plates, size, form and direction of the spine of coxa IV. Such differences prouved to be only variations frequently observed in large lots or in cultures of Amblyomma cajennense. The revalidation of Koch's species Amblyomma tenellum Koch, 1844 and Amblyomma mixtum Koch, 1844 proposed by TONELLI RONDELLI as also of Amblyomma sculptum Berlese, 1888 and Amblyomma versicolor Nuttal et Warburton, 1908 cannot be accepted by the same reasons. b) Amblyomma beccari Tonelli Rondelli, 1939 and Amblyomma latepunctatum Tonelli Rondelli, 1939 are cospecific with Amblyomma scalpturatum Neumann, 1899 the same being true for Amblyomma myrmecophagium Schulze, 1935 and for Amblyomma brasiliense var. guianense Floch et Abonnenc, 1940, as previously stated. c) Amblyomma tasquei Floch et Abonnenc, 1940 is a good species but synonym with Amblyomma romitii Tonelli Rondelli, 1939 which has priority. d) Amblyomma curruca Schulze, 1936 is a synonym of Amblyomma parvum Aragao, 1908. e) Amblyomma deminutivum Neumann, 1899 represents a variation of Amblyomma dissimile Koch, 1844, a species whose internal spine of coxa IV may be poorly developed or even absent. f) Amblyomma nigrum Tonelli Rondelli, 1939 prouved to be synonym with Amblyomma paccae Aragao, 1911 the type representing a blackish specimen of the later species. g) Amblyomma brimonti Neumann, 1913 is a synonym of Amblyomma humerale Koch, 1844.

The Australian species of Aponomma and Amblyomma (Ixodoidea).

A study has been made of the Australian species of Aponomma and Amblyomma (Ixodoidea). Nine species of Aponomma were determined, namely A. trachysauri, A. hydrosauri, A. auruginans, A. decorosum, A. simplex, A. trimuculatum, A. tachyglossi, A, tropicum, and A. pulchrum, the last three species being new. Two previously described species, namely A. quadratum and A. ecinctum, were recognized among the material available for study. A detailed description given of each species together with essential figures. Keys to the males, females, and nymphs are included. Twelve species of Amblyomma were seen. Species previously described included A. moreliae, A. limbatum, A. albolimbatum, A. triguttatum, A. australiense, and A. papuanu. A. postoculatum and A. helvolum were not recognized among the material available for study. A. papuana is recorded from Australia for the first time. Four new species, namely A. sternne, A. echidnae, A. macropi, and A. moyi, are described. Keys to the males and females are given.

Notes on ticks. IV. Nomenclature of various species of the genus Amblyoma of Brazil and neighboring countries (Acari: Ixodidae)

An attempt is made to clear the nomenclature of some netropical species of the genus Amblyomma. Amblyomma myrmecophagium Schulze, 1933 and Amblyomma brasiliense guyanense Floch et Abonnenc, 1933, are synonyms of Amblyoma scalpturatum Neumann, 1906. Amblyomma superbrasiliense Schulze, 1941, is cospecific with Amblyomma incisum Neumann, 1906. Amblyomma ypsilophorum Schulze, 1941, is a synonym of Amblyomma cooperi Nuttal et Warburton, 1907.

Parthenogenesis in the Argasid Tick Ornithodoros moubata (Murray, 1877)

Agamic reproduction in ticks was first reported by Aragio (1912) in a species of Amblyomma which he named agamum but which later was placed in synonymy with A. rotundatum C. L. Koch, 1844. He observed thousands of females which laid fertile eggs in the absence of males. The male of this species is still unknown. Nuttall (1913) observed the same phenomenon in Rhipicephalus bursa. Unmated females remained longer on the host than mated females, they did not become completely engorged, and the number of eggs produced was much smaller than in mated females. None of the larvae were reared to the adult stage. However, in later experiments with R. bursa, Nuttall (1915) considered that parthenogenesis was artificially induced by manipulation accompanying the enumeration of the eggs immersed in normal salt solution and rubbed gently with a camel's-hair brush. Bodkin (1918) reported parthenogenesis in Amblyomma dissimile. Sixty-five ticks of the first generation reared to adults were all females. Parthenogenesis was subsequently observed to the fourth generation. Brumpt (1934), Schulze (1937), and Floch and Abonnenc (1940) have expressed doubt as to the identity of the tick with which Bodkin worked. If the species of tick was A. rotundatum instead of A. dissimile, as has been suggested, the results are in complete agreement with the original report of Aragio for this The fact that the 65 ticks reared to adults in the first generation were exclusively females gives credence to their parthenogenetic origin. Only one reference has been found to parthenogenesis in argasid ticks. Cunliffe (1921) reported that one of ten 0. moubata females held for observation deposited 183 fertile eggs. However, he concluded that this female was probably fertilized unobserved and suggested that further evidence is necessary before parthenogenesis can be considered to be even of rare occurrence in this species. During a study of the quantitative transovarial transmission of Borrelia duttonii in Ornithodoros moubata, 600 ticks were reared from the first nymphal stage to adults by feeding individually at each nymphal stage and as adults on white mice. During the interfeeding periods, the ticks were stored individually in serially-num

The Genus Amblyomma (Ixodidae) in the United States

The publication of a review of the genus Amblyomma in the United States has become desirable because of the increasing interest in the members of this genus as known or suspected carriers of diseases and especially because of the need for criteria for the specific differentiation of the larvae and nymphs. This genus, which is far richer in species than any other, is geographically limited to that portion of the world which is between the 40th parallels of latitude, that is, to the warmer countries. In the United States it is essentially limited to the Southeastern and Southcentral States. C. L. Koch (1844) was the first to publish a comprehensive account of the ticks. He described many new species and the genus Amblyomma. Though he laid the foundation for the systematic classification of ticks, he failed in many instances to select adequate characters. G. Neumann in 1896 began his Revision de la Famille des Ixodes which included Amblyomma and he was the first to use satisfactory morphological characters and thereby made a definite contribution to the classification of genera and species. Donitz (1909) urged the importance of the ornamentation as an aid in recognizing the species and his plan of giving names to the constituent spots and stripes brought order into the terminology of the ornate pattern which most species of Amblyomma display. However, the species of Amblyomma in the United States are readily separated by morphological characters, hence the ornate color patterns are not described in this paper. They are shown in the figures. L. E. Robinson (1926) gives excellent descriptions and figures of the 86 species then known and also summarizes their geographical distribution, hosts, economic aspects, and relation to disease. The more important later writings include Sharif (1928), Dunn (1934), Aragao (1936) and Osorno-Mesa (1941). Other contributions have been made by Warburton (1927), Schulze (1932, 1933, 1936), Kishida (1935) and Cooley and Kohls (1942). The collection of the Rocky Mountain Laboratory now contains 65 described species of Amblyomma from various parts of the world. A study of these and of other available species has led to a fuller understanding of critical morphological and color characters as well as of variation. Variation occurs, particularly in the color patterns, but is less confusing than in some other genera. A single male specimen of Amblyomma ovale (Koch, 1844) taken from a dog, Sept. 8, 1941, Tama Indian Reservation, west of Tama, Iowa, was sent to us for

Amblyomma philipi: A New Tick from Texas and Mexico, with a Key to Known Species of Amblyomma in the United States (Acarina: Ixodidae)

Amblyomma philipi: A New Tick from Texas and Mexico, with a Key to Known Species of Amblyomma in the United States (Acarina: Ixodidae)

On Coloration in Ticks. II

The coloration of Amblyomma hebraeum, A. gemma, Dermacentor venustus, D. variabilis and D. reticulatus niveus, as seen in living examples, is depicted for the first time, and the desirability of recording the colours of ornate ticks when alive is indicated.A remarkable change in colour in living specimens of A. hebraeum is described and figured, this change taking place after a prolonged sojourn (74–141 days) upon the host. Such a colour change has not hitherto been observed in ticks. The difference in colour is seen in dead dried specimens but is not appreciable in those preserved in alcohol.Since the immature stages of ornate ticks are inornate, and the colours change in adults of some species during prolonged periods of parasitism, it is evident that the coloration in adults must depend upon the accumulated products of metabolism beneath the chitinous exoskeleton, the regional distribution of colour depending upon special metabolic functions taking place in corresponding parts of the tick. The ornamental colour-producing layer can be scraped away from the underside of the scutum in most ornate ticks and it is removable from such ticks by the use of caustic potash.The whitish or creamy coloration that is so characteristic of most species of Dermacentor and the three ornate species of Rhipicephalus that are known to science, appears on the other hand to depend largely upon inclusions or structural changes within the chitin itself, whence the persistence of the creaminess seen by reflected light in the caustic-treated ticks. Similar, but less distinct, appearances may be seen in ticks belonging to other genera. Dermacentor rhinocerotis, which does not exhibit creamy coloration but only dull yellowish spots when dry, is totally decolorized by caustic potash, whilst contrary to most species of its genus it shows metallic coloration in well-preserved specimens in alcohol.The examination of caustic-treated specimens was carried out upon 31 species of ornate ticks, i.e. Dermacentor (8), Rhipicephalus (3), Amblyomma (15), Aponomma (4) and Hyalomma (1 species).The coloration and creamy ornamentation, herein distinguished, appear to be confined to the thinner portions of the exoskeleton. That the characteristic dark markings correspond to thicker and more darkly chitinised portions of the scutum is demonstrable by dissections, caustic-treated, or sectioned specimens; this being especially evident for instance in Amblyomma. The orange spot on the scutum of A. splendidum offers an exception.The optical and chemical study of coloration in ticks deserves further investigation.

Notes on Ticks. II.

The following descriptions relate to a new species of Amblyomma in all its stages, to two species of Haemaphysalis of which diagnoses of the males and females are given, and to the hitherto unknown larva of Ixodes putus:

New Species of Ticks (Ixodes, Amblyomma, Rhipicephalus)

The following descriptions relate to a new species of Ixodes, to a new variety of Ixodes loricatus, to new species of Amblyomma and Rhipicephalus