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NYASALAND (Neave 1912. De Meza 1918A. Absent in northern area: Wilson 1945,1953).

SOUTHWEST AFRICA (Dönitz 1905. Howard 1908. Tromsdorff 1913,1914. Warburton 1922. Bedford 1926,1927,1932B).

UNION OF SOUTH AFRICA (Neumann 1897,1901,1911. Dixon and Spruell 1898. Lounsbury 1899,1900A,1904A,B,1905B,1906B,C. A. Theiler 1905B,1906,1909A,B,C,19118,19128,1921. Howard 1908. A. Theiler and Christy 1910. Dönitz 1910B. Moore 1912. Van Saceghem 1914. Bedford 1920,1926,1927,1929,19328,1934. Cowdry 1923,1925B,C,1926A,1927. Curson 1928. Bedford note in Cooley 1929. Cooley 1934. Clark 1938. McIntyre 1939. Bedford and Graf 1939. R. du Toit, Graf, and Bekker 1941. R. du Toit 1942B,C,1947. De Meillon 1942. Zumpt 1942B. Cluver 1944. Bekker and Graf 1946. Thorburn 1947,1952. Schreuder and Wright 1948. Graf and Bekker 1949. Whitnall and Bradford 1949. Bekker, Graf, Malan, and Van der Merwe 1949. Theiler 1950B. Meeser 1952. J. Gear 1954).

OUTLYING ISLANDS:

ZANZIBAR (Neave 1912.

Aders 1917). MAURI TIUS (De Charmoy 1915. Moutia and Mamet 1947). CANARY ISLANDS (Nuttall lot 3226 in BMNH; H.H. det.). See also IMPORTED SPECIMENS below.

stated specimens had been Our experience here indi

ARABIA: YEMEN: Franchini (1930) found at the seacoast town of Hodeida. cates that if this locality record is correct, the ticks were from cattle imported from the Yemen highlands. Sanborn and Hoogstraal (1953), Hoogstraal (ms.).

IMPORTED SPECIMENS: MADAGASCAR: MADAGASCAR: R. e. evertsi arrives at quarantine but is not established on the island (Buck 1940,1948A, Hoogstraal 1953E). EGYPT: Mason (1915,1916) reported specimens on cattle imported from the Sudan. Nowadays at the Cairo abattoir we find a few specimens on Sudan cattle and sometimes many specimens on Somali or Ethiopian cattle that occasionally reach here. Specimens from cattle and donkeys were reported by Mason (1916) without mention of source. The species is not established in Egypt. BRAZIL: Specimens "were found on angora goats in the animal hospital in Rio de Janeiro. If they had not been found they would certainly have been scattered throughout our country like R. sanguineus" (de Beaurepaire Aragao 1936).

HOSTS

Adult red ticks most commonly occur on domestic cattle, equines, goats, and sheep, and on wild antelopes, zebras and a few other large game animals. If a comparative host-predilection study of this species could be undertaken, it is likely that domestic horses, miles, and donkeys and wild zebras might rank highest as preferred hosts. Although Lewis (1931B) considered it peculiar that horses in the Rift Valley of Kenya yielded no red ticks, I have subsequent ly collected many specimens from horses there 7. Immature stages normally feed on the same type of large-size host as do the adults, though their feeding sites on the animal differ markedly. Under some conditions, larvae and nymphs attack hares, elephant shrews, tree rats, and baboons, but the factors causing these presumably atypical infestations are not known.

Domestic animals: Cattle are mentioned as hosts by all authors noted above and equines, sheep, and goats are also commonly listed by the same persons. A single record from camel is known (Wiley 1953). Dogs are seldom infested (Theiler 1953), as are pigs (Theiler, correspondence), although a few specimens from each of these animals have been taken in the Sudan. Dogs have been reported as hosts by Mettam (1932) in Uganda.

Wild antelopes: In one of the earliest host-lists of African ticks, Howard (1908) noted the eland and reedbuck. Bedford (1932B) listed the blue wildebeest, sable antelope, blesbok, roan antelope, Cape kudu, impala, steenbuck, Cape duiker, springbok, bushbuck, waterbuck, and (for nymphs) the bontebok, steenbok, and grysbok. In the Sudan, King (1926) noted specimens from the Isabella gazelle, while we have found others on the teltel (Roosevelt's hartebeest), eland, Baker's roan antelope, and oribi. Mettam (1932) reported duiker and kob from Uganda, and Weber (1948) took specimens from the eland, Grant's gazelle, duiker, hartebeest, and impala. The impala has also been reported by Meeser (1952; see ecology below), Santos Dias (1953B), and Tendeiro (1951A,B), while Jack (1942) added the tsessebe. In the Masai Reserve of Kenya, Lewis (1934) found the roan antelope, wildebeest, and hartebeest infested. The sable antelope, eland, wildebeest, and kudu were reported as hosts in Northern Rhodesia by Matthysse (1954). These records are rep resentative of others relating to wild antelopes as hosts.

Other wild animals: Zebras, various kinds (Neumann 1907C, 1910B,1922, Loveridge 1923A, Lewis 19318,1934, Bedford 1932B, Mettam 1932, Weber 1948, Matthysse 1954). Giraffe (Howard 1908, Neumann 1901,19070,1910B, Moore 1912). Warthog (Neumann 1922, 1954; other specimens in MCZ). Cane rat (Bedford 1932B. These somewhat larger than ordinary rodents appear to harbor an un usual number of stray ticks that do not normally infest rodents).

Noninfestation of young antelopes: Mettam (1933) made the interesting observation that newly born kob, duiker, bushbuck, and reedbuck in an Entebbe paddock heavily infested with R. appendiculatus and R. evertsi were in no instance affected by these ticks. Wild adults of these antelopes are commonly attacked.

Immature stages: As already stated, larvae and nymphs com monly infest the same kinds of hosts as adults. Sometimes, however, they do attach to other animals, especially hares, for reasons not yet understood. Hares have been reported as im mature stage hosts by Moore (1912), Bedford (1932B), Sanborn and Hoogstraal (1953), Matthysse 1954; and others; see also BIOLOGY below. Some specimens are found in ears of elephant shrews (Sudan records above) and Theiler (correspondence) has a single record from another genus, Nasilio, of these insectivores, as well as another from a tree rat, Thallomys. Bedford (1932B) reported nymphs from various antelopes, and Lewis (1932B) found both immature stages common in the ears of hartebeests. Dogs are satisfactory hosts for laboratory rearing of the im mature stages (Lounsbury 1904A).

BIOLOGY

Life Cycle

R. evertsi is one of the few rhipicephalid ticks with a twohost type of life cycle. Both immature stages occupy the same hosts, but engorged nymphs drop and molt on the ground. As adults they seek a new host. All stages normally infest domestic or wild herbivores, but under some conditions immature stages may attack insectivores, rodents, and hares. Theiler (correspondence) has observed that this may be due to unusual or local factors: "For

years my records did not show R. evertsi immatures on any hosts (other than herbivores), except as an incidental infestation perhaps; then last year (1950) we recorded heavy infestations among all species of hares in the East London district,"

Details of the life cycle and periods of survival have been frequently reported by various South African workers beginning with Dixon and Spruell (1898). As noted by Theiler (1943B) these periods are:

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The periods between larval hatching and feeding and between adult emergence and feeding and oviposition are not stated.

When larvae molt, they loosen their hold on the host. Nymphs reattach nearby on the same animal. Nymphs drop from the host when engorged and molt to adults on the ground. Adults mate on the host.

Unfed larvae survive for seven months and unfed adults sur vive twice as long.

Ecology

Adults attach almost invariably in the perianal region under the base of the tail, less commonly on the teats, at the base of the legs, or on the scrotum. Larvae and nymphs cluster deep in the depressions of the inner ear surface especially at the base of the auricula; rarely on the host's flanks. (For comparison, immature B. decoloratus and R. appendiculatus usually attach along the edge of the ear). All authors and our own observations are in agreement on these feeding-site predilections. It appears

that the messy area in which adults usually feed influences to some extent the numbers of red ticks represented in collections made by Europeans though this is seldom a deterrent to "unspoiled" African assistants. An exception to the above statements, however, was made by Meeser (1952), who noted that red ticks on the impala antelope of southeastern Transvaal is infested on the genitalia and shanks and almost nowhere else on the body. R. e. evertsi, together with B. decoloratus, are the chief tick parasites of this common antelope there.

Theiler's (1950B) study of the distribution of the red tick in South Africa shows that it is present in all types of forest, in all parklands except dry ones, and in all types of grasslands. It maintains itself with difficulty in shortgrass country and is generally absent from desert-shrub areas, but may persist in thorn country and in mixed desert shrub grassland. Altitude and low temperature do not limit the red tick, but rainfall below ten or fifteen inches per annum seems to be a limiting factor. There appears to be no seasonal variation in the activities of this spe cies.

In parts of Africa warmer than South Africa, a somewhat higher critical level of annual rainfall is probably necessary for the red tick to maintain itself, but definite limits have not yet been as certained.

As already noted, another subspecies (mimeticus) takes over from this subspecies in the arid areas of southwestern Africa but both are found together in the savannahs of western equatorial Africa. Such evolution of a rhipicephalid species in Africa is as unusual as the red tick's morphology and as its life cycle.

In Kenya, the red tick appears to be somewhat more adaptable than in South and West Africa. There it occurs in the deserts of Northern Province, in coastal areas and open plains, as well as in forests above 8000 feet altitude; "in fact almost anywhere" (Wiley 1953).

Wilson (1953) noted that the red tick occurs in both the same areas as the R. pravus A. gemma association (cf. page 681) and the R. appendiculatus A. variegatum association (cf. page 274). While absent from wet zones of Nyasaland and Tanganyika, it is the dominant species in the Masai grasslands and occurs seasonally

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