of H. rufipes and of H. truncatum (= H. transiens) could be dif- Kratz (1940) records the finding of a nymph, which molted into a male rufipes, on a female comorant caught on the high seas between the northern trip of Madagascar and the Comores Archipelago. The Onderstepoort collection (Theiler, correspondence) has larvae (L) and/or nymphs (N) from the following South African birds: N Namaqua thrush, Afrocichla smithi LN Cape thrush, Afrocichla o. olivacea (2 collections) N White-throated seed eater, Crithagra a. albogularis LN Mocking chat, Thamnolaea c. cinnamomeiventris (3 collections) N N N N N Starling (Southwest Africa) Boubou shrike, Lanjarius f. ferrugineus Fiscal flycatcher, Sigelus silens N Cape barn owl, Tyto alba affinis The same collection contains nymphs from a hare and a rock hare (Pronolagus randensis) in South Africa and from a hare in Uganda. In Egypt, nymphs (reared to adults in the laboratory) have been found only on birds (Hoogstraal, ms.) although adults are locally common on domestic animals. The hosts have been: Wheatear (European form), Oenanthe o. oenanthe Blackeared wheatear (Eastern form), Oenanthe hispanica melanoleuca The former bird breeds throughout most of Europe east to Central and northern Asia and to northern Alaska; it winters in Arabia and tropical Africa, also in Asia to India. The latter "breeds in the Crimea, Bulgaria, and almost throughout the Balkan peninsula, Asia Minor, Palestine, and western Persia, etc.; winters in Egypt and Sinai to the Sudan, Ethiopia, the Red Sea coast, and has straggled to the southern Sahara, British Islands, Malta, and northwest Africa" (Meinertzagen 1930). Possibilities for the wide dis persal of this tick are easily recognized. BIOLOGY Life Cycle Under laboratory conditions, H. rufipes is a two host tick although it possibly may also undergo a three host type of life cycle. Theiler (1943B and 1955 correspondence) has summarized the developmental stages as follows: It appears that the minimum time for completing the life cycle is between four and five months but double this period may be required under local conditions. "The life cycle of H. aegyptium (= ?H. rufipes, possibly mixed with H. truncatum: HH) Is of particular value in that it illus trates the influence of vermin in the distribution of the species. On sheep, cattle, and domestic fowl it behaves as a three host tick, requiring a separate host for the larval, nymphal, and adult stages. On the hare, H. aegyptium will feed as a larva, become engorged, molt as a nymph without leaving the host, feed as a nymph on the same individual host, and then drop off the host for molting. Thus on the hare the life cycle requires only two hosts" (Brassey-Edwards 1932). This interesting phenomenon should be re investigated. The long oviposition period is especially noteworthy. Unfed larvae may survive a year, unfed nymphs three months, and unfed adults for longer than a year (Theiler 1943B). Enigk (1953) ob served unfed adults surviving up to two years. Howard (1908) considered H. rufipes as a two-host tick with one generation a year in South Africa. He described, illustrated, and discussed the immature stages but did not differentiate them from those of H. truncatum which he apparently did not rear. Jack (1928) noted a two-host and a three-host type of life cycle for this tick. Ecology Thorburn (1952) states that on cattle the chief site of in festation of this tick is in the tail region. Specimens in the present collection are from the flanks, genitalia, udders, and perianal regions. The anal area is mentioned by Matthysse (1954). Nymphs are always, in our experience, on the crown of the head of their avian hosts. du Toit and Monnig (1942) record the finding of a male at tached to the hard palate of the mouth of a cow, and indicated that on the farm where this occurred this phenomenon had been ob served on several occasions. H. rufipes ranges through the more arid areas of tropical and southern Africa but only localized populations maintain themselves in the severely arid conditions of northern Africa. It exists where annual rainfall is from ten to thirty inches a year. It may also thrive in irrigated areas with diminished rainfall or where a long, severe dry season occurs between an annual rainy season of approximately forty inches. In the Sudan, it is more common in the drier savannah and semiarid central areas than in the southern forest and savannah areas; it occurs in the Nile Valley, but is not known in extreme desert conditions. In Egypt, H. rufipes is found only in the Nile Valley, never in extreme desert areas. The hairy hyalomma is included in Wilson's (1953) Amblyomma gemma R. pravus (= R. neavi) association (see page , which is found in areas where rainfall rarely exceeds 25 inches annually. The only ecological survey of this tick is that of Theiler (1956) who lists the areas of its occurrence and absence in south ern Africa. It occurs in all desert and semidesert areas with rainfall up to thirty inches annually, but at higher altitudes or in semitropical conditions, where the relative humidity is higher, it is absent even though annual rainfall is little or no greater than in some of the hotter, drier areas. It does not occur in winter rainfall areas, where rain falls throughout the year, or in coastal areas with high relative humidity as a result of proximity to the sea. Temperature appears to be a limiting factor of lesser importance since H. rufipes ranges from hot deserts into areas with up to 120 days of frost annually. Increase in temperature associated with increase in relative humidity restricts the tick's range. Other factors being equal, the hairy hyalomma occurs in most vegetational types except forested areas of central Africa. In many regions it is active the year around, but in others more so in summer than in winter. In Russia, H. rufipes has been reported (as H. impressum) from the western deserts of Transcaucasia (Pomerantzev, Matikash vily, and Lototsky 1940) and, in western Tadzhikistan, from mountain pastures but not in the valleys (as H. aequipunctatum) (Galuzo and Bespalov 1935). DISEASE RELATIONS MAN: Nymphs infected with boutonneuse fever (Rickettsia conorii) have been taken from a hare in South Africa. CATTLE: H. rufipes causes abscesses and sloughing of the host skin. These areas often serve as points of penetration of the screwworm Chrysomia bezziana Villem. This tick may also be associated with footrot of sheep, a secondary infection by bacteria, and lesions from its bites may also lead to lameness in sheep. The possibility that the hairy tick may be a vector of sweating sickness (virus) of cattle has been mentioned. IDENTIFICATION Male: H. rufipes, almost without exception, is a large, robust, shiny black tick with a comparatively broad body outline. Its scutum is densely and rather uniformly punctate, so much so that the lateral grooves are obscured. The punctations are close together and while they give the impression of being rather uniform, they usually grade imperceptibly from large posteriorly to smaller anteriorly. There is little differentiation of the caudal area. Ventrally, the subanal shields are directly pos terior of the adanals and the circumspiracular area is more or less hirsute, but a fair to dense accumulation of hairs always occurs in this area. The ventral integument is usually somewhat more hirsute than in other species. The legs are reddish brown with bright, paler rings. The posterior body margin is typically broadly rounded but not infrequently may be somewhat constricted and thus tend to approach the form of that in H. impressum. Newly molted specimens are reddish brown and rare preserved individ uals show this color. The body shape of some specimens is more narrowly elongate than is typical for this species, but such individuals always appear to be rather weak and poorly nourished. Females: This sex often reaches considerable size. Cir cumspiracular pilosity and color are like those of the male; scutal punctations are like those of the anterior part of the male scutum. The genital apron is a wide shield that bulges strongly from a deep anterior and posterior indentation. The outline of the apron is much like that of H. marginatum and H. impressum; however the division of the apron of the latter spe cies into an anterior ridge and a posterior button readily separates this from H. rufipes. The larva has been sketched by Bedford (1934) and Theiler (1943B). |