CENTRAL AFRICA: CAMEROONS (Unsworth 1952). FRENCH EQUATORIAL AFRICA (Rousselot 1951; not repeated 1953B). BELGIAN CONGO (TonelliRondelli 1930A. Bequaert 1931. Theiler and Robinson 1954). NOTE: According to Theiler (correspondence), the record for Ruanda Urundi by Santos Dias (1954D) is in error. EAST AFRICA: SUDAN (Weber 1948. Hoogstraal 1954B). KENYA (Lewis 1931C,1932A,1934. Theiler 1945C). UGANDA (Warburton 1913. Tonelli-Rondelli 1930A. Mettam 1932. Theiler 1945C. Wilson 1950A,C). TANGANYIKA (J. B. Walker, unpublished; see HOSTS below). SOUTHERN AFRICA: MOZAMBIQUE (Santos Dias 1953B). UNION OF SOUTH AFRICA (Bedford 1932B,1934. R. du Toit 19428,1947A. duced from East Africa: Theiler 1945C). Intro NOTE: H. aciculifer does not occur on Madagascar (Hoogstraal 1953E). HOSTS Antelopes are the most common hosts of adult H. aciculifer. Other wild animals and domestic animals are rarely attacked. Rodents, small antelopes, and possibly hares appear to be the chief hosts of the immature stages. Domestic cattle have been reported as hosts in Uganda (Wilson 1950A,C), Kenya (Lewis 1934 and Theiler 1945C), and the Union of South Africa (Theiler 1945C). Lewis (19324) noted a single specimen from a domestic goat in a Somali village between Karati Forest and Naivasha. Rousselot (1951) reported a female from a domestic dog in French Equatorial Africa. Antelopes hosts of adult ticks are the Uganda kob (Warburton 1913), reedbuck (Simpson 1914, Nuttall and Warburton 1915, Bed ford 1932B, Theiler 1945C), bushbuck (Lewis 1931C,1932A, Mettam 1932, Theiler 1945C), waterbuck (Lewis 1931C,1932A, Mettam 1932), various duikers (Mettam 1932, Lewis 1932A), Thomson's gazelle (Lewis 1934), oribi and Roosevelt's hartebeest (Equatoria Province records above), and tiang (Bahr El Ghazal Province record above). Miscellaneous hosts of adults are buffalo (Lewis 1931C), serval cat (Bedford 1936, Theiler 1945C), mongoose (Theiler 1945C), and wild cat (Felis lybica group) (Hoogstraal, Kenya collecting). The probability that Mettam's (1932) records of this species from unidentified birds refer to H. hoodi hoodi should be considered. Nymphs have been found on the bushbuck, waterbuck, duiker, buffalo, warthog, and hare according to Lewis (1932A), but these records need checking for accuracy of identification. Lewis (1932A) reared H. aciculifer on hares. Examination of 49 Thom son's gazelles In Tanganyika yielded only a single nymph and no further specimens of this tick were found on many other game animals examined there (J. B. Walker, unpublished). Our Equatoria Province collections contain nymphs from a striped grassmouse, Lemniscomys striatus massaicus, and from an oribi, Ourebia ourebi aequatoria. A larva from a forest rat, Praeomys tullbergi sudanensis, in Lotti Forest (listed above) is apparently the only record extant for this stage in nature. BIOLOGY Life Cycle Lewis (1932A) reared the three host H. aciculifer on laboratory hares in a minimum of 107 days. His data, are as follows: Ecology In Kenya, H. aciculifer is found usually in forested areas at about 7500 feet elevation (Lewis 1932A). The writer's experience in Kenya and Sudan confirm that this is mostly a highland species (4500 to 8000 feet elevation) but that it is also present at lower altitudes (Torit, 2000 feet elevation). Records tend to indicate that where this species occurs at lower altitudes it is in more humid habitats but this subject requires further field study. Theiler (1945C) discussed the distribution of H. aciculifer on cattle in localized areas of northern and eastern Transvaal where it sometimes occurs on neighboring farms and at other times on distant isolated farms. The scattered distribution is believed to be due largely to the incidence of cattle importation from East Africa and to the ability of introduced ticks to maintain themselves in new areas. In South Africa, H. aciculifer survives in regions with from fifteen to fifty inches of annual rainfall but especially where thirty or more inches fall each year. These include subtropical evergreen and deciduous tree and thorn forest areas, open parkland areas in highlands, subtropical parkland areas, tall grass areas, and rarely short grasslands adjacent to highveld. H. aciculifer ranges from lowlands to highveld at 4500 feet elevation and is present only where winters are not severe, though it may survive where occasional light frosts occur. Unstudied. DISEASE RELATIONS IDENTIFICATION Males: Measure from 1.8 mm. to 1.9 mm. long, and from 1.1 mm. to 1.3 mm. wide. They may be recognized among the African fauna by the long, needlelike spur of coxa IV. The basis capituli is rectangular with well developed cornua; the palpal outline (Fig ures 128 and 129) is unique in the African fauna. The smooth scutum has small, shallow punctations; the lateral grooves may reach only the scutal midlength or they may be much longer. Certain variations in material at hand suggest the need for more specimens from various parts of Africa for further morpho logical study. Females: Engorged specimens measure from 6.0 mm. to 6.5 mm. long, and from 4.0 mm. to 4.5 mm. wide; unengorged, they are about 2.5 mm. long and 1.5 mm. wide. The scutal length equals or only slightly exceeds the width (0.8 mm. to 0.9 mm. long, 0.7 mm. to 0.9 mm. wide); the posterior margin is broadly rounded; cervical grooves are long, deep, and converging; punctations are small and inconspicuous. Palpal features are most distinctive (Figures 130 and 131). There is no dorsal projection on palpal segment 3. Coxae I to IV each have a small posterior spur and, in addition, coxa I has a small outer posterior spur; the spur of IV is short and wide thus differing greatly from that of the male. Palpal and scutal characters easily separate females from all other African species. The larva and nymph have been described and illustrated by Theiler (1945C). |