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ARGAS (CHIROPTERARGAS) BOUETI Roubaud and Colas-Belcour, 1933.
(Figures 23,24,33, and 34)
These are the only records of this species from the Sudan.
Argas boueti is known from scattered localities in Africa as far south as Transvaal and is also present in the Near East. A tick apparently of drier areas, which has been widely spread by its chiropteran hosts, the long-legged bat argas is obviously more frequent than present meagre records indicate (Hoogstraal 1955B). Whether North Africa, the Near East, or the Ethiopian Faunal Region is its origin is difficult to determine from evidence at hand.
NORTH AFRICA: EGYPT
EGYPT (Hoogstraal 1952A,1954A ,1955B).
WEST AFRICA: FRENCH WEST AFRICA (Roubaud and Colas Belcour 1933. Hoogstraal 1955B).
CENTRAL AFRICA: FRENCH EQUATORIAL AFRICA
FRENCH EQUATORIAL AFRICA (Hoogstraal 1955B).
SUDAN (Hoogstraal 1952A,1954B,1955B).
KENYA (Heisch 1951B.
SOUTHERN AFRICA: ANGOLA (Hoogstraal 1955B). UNION OF SOUTH AFRICA (Hoogstraal 1955B. Subsequently, Dr. Zumpt has sent me additional specimens from Tzaneen, Transvaal).
NEAR EAST : Palestine (Hoogstraal 1954A, 1955B).
Asellia (= Hipposiderus) tridens and Taphozous perforatus (Roubaud and Colas_Belcour 1933. Taphozous p. perforatus, (Liponycteris) nudiventris, Rhiponoma hardwickei cystops, and otonycteris h. hemprichi are most heavily infested in Egypt. Less frequent hosts here are Rhino poma microphyllum, Asellia t. tridens, Rhinolophus clivosus brachygnathus, R. mehelyi, Roussetus a. aegypticus, Nycteris t. the baica, Tadarida a. aegyptiaca, T Eeniotis ruppelli, Pipistrellus k. kuhli and Plecotus auritus christei (Hoogstraal 1952A, 1955B). Megaderma cor (Heisch 1951B). Rhinolophus lobatus (Sudan record above). Eptesicus tenui pinnis (Hoogstraal 1955B).
Otonycteris h. hemprichi, a bat which roosts in small caves, crevices and niches, usually singly or with very few other of the same species, is most heavily infested in Egypt. Rhinopoma h. cystops, one of the most common cave-inhabiting bats near Cairo, is frequently heavily infested and probably represents the most important host in this area owing to its great abundance. All stages appear to feed on the same kinds of bats.
Nymphs and adults have bitten us in caves on a few occasions. They readily do so when allowed to in the laboratory (Hoogstraal 1952A,1954A, 1955B).
Rearing of A. boueti has been accomplished in our laboratories at temperatures of From 800F. to 90°F. with relative humidity ranging from 40% to 50%. Exceptionally large females may lay single egg batches of almost two hundred eggs over a two or three day period. An average size female deposits from 35 to 40 eggs in a single batch usually on a vertical surface. Afterwards, she
stands motionless over or next to the eggs for fifteen to 22 days until the larvae hatch. (Earlier, at unrecorded high summer room temperatures, we obtained hatching in eleven to fourteen days). Larvae attach to a host after twelve to fifteen days (earliest host offered), and feed from eight to 42 days, but mostly from sixteen to 25 days. Afterwards, larvae may require from four to thirteen days before molting to first instar nymphs, but they usually do so after four to seven days.
Nymphs molt two or, uncommonly, three times before reaching adulthood. In our laboratory, those nymphs that reach adulthood after two molts have never fed in the nymphal stage, even though bats were frequently offered. When a third instar nymph, which has not molted to an adult, feeds it does so for half an hour to an hour from seven to 26 days after the previous molt and becomes an adult from twenty to 32 days after feeding. The duration of each nymphal instar is seven to seventeen days for the first in star, with eleven to fourteen days the most common. The duration of the second instar is longer, from sixteen to 43 days, with 22 to 29 days average. The duration of the third stage, when it occurs, is erratic and lasts from 27 to 58 days. No significant data on sexual differentiation from the unusual third nymphs have been obtained.
Adults feed for thirty to 35 minutes beginning some five days after molting. Further studies on the life cycle of progeny are under way
A biting tick remains motionless during feeding. It often stands the full length of its anterior legs away from the point of insertion of mouthparts that are extended by a pendulous tube from the basis capituli. Once the hypostome is inserted, the host's hand or arm (or the bat) may be moved freely till the tick is satiated without causing it to remove its mouthparts. When blood is rapidly engorged a large drop of clear coxal fluid appears beneath the body, but none is emitted during slow feeding. Repletion from the human hand or arm requires from 25 to 35 minutes but full engorgement from the membrane of a bat's wing may require three or four hours. Individuals that feed slowly become very lethargic and one may remove them, even though fully fed, after seven to 24 hours with the mouthparts still inserted in the wing membrane. Itching at the site of the bite on man may persist for several weeks.
When disturbed the long-legged bat argas is much more active and moves with greater speed that either A. confuşus or A. vespertilionis. The long anterior legs wave up and down while walking and tap objects antenna fashion. This tapping is especially active just before the mouthparts are inserted. During feeding the anterio: legs may or may not touch the host skin but they seldom function as a support for the tick. These ticks will feed in light or in dark ness but prefer darkness,
The original authors of A. boueti described this species from material collected about 1910 in hollow trees inhabited by the two species of bats listed above. In the generally arid Northern Province of Kenya, Heisch found adults on walls of an underground con crete shelter and larvae on Megaderma cor in the same structure, Those South African specimens with collecting data are from houses.
In Egypt we commonly find the long-legged batu argas thriving under the most severe desert conditions. It is less common in more humid buildings inhabited by bats in Cairo. A. boueti is the most numerous bate parasitizing argasid in Egypt and the same ecological observations noted for Egypt under A. vespertilionis apply to this species.
The frequency with which these long-legged ticks fall from rough surfaces in the laboratory is surprising in view of their usual habitat on walls and on ceilings of caves and chambers. A number of specimens exhibit a body tremor that causes them to flip over on their dorsal surface with every few steps. Righting move ments require considerable effort.
MAN. Attacks on our laboratory personnel have caused mild itching persisting for several weeks in warm weather.
BATS. We have been unable to find spirochetes in Egyptian material. Collections of local specimens injected into laboratory animals have resulted in negative findings for viruses and rickett siae. Other material from the Cairo area has not yielded Shigella organisms. The hosts from which the type series was collected in French West Africa showed a trypanosome infection but research to ascertain the relationship of ticks and trypanosomes was not undertaken.
For a discussion of long-legged parasites of bats, see REMARKS under Ixodes vespertilionis.
A. boueti populations consist of two size groups, the larger about 6,8 mm. long and 6.9 mm, wide and the smaller about 5.0 mm. long and 4.5 mm. wide (Hoogstraal 1955B, figure 125). The significance of these "races is at present being studied.
The subgenus Chiropterargas Hoogstraal, 1955 (B), of which A. boueti is the type species, contains one other species, A. confusus. This subgenus is defined as follows:
"Parasites of which bats are hosts of predilection, Morpho. logical characters intermediate between those of typical Argas and typical Ornithodoros; with a general Argas facies but lacking a sutural line; with a flattened body flange but lacking 'cells and with exceedingly slight integumental differentiation at periphery; body shape circular to transversely elliptical. Integument with fine, close granular projections; discs mostly small, conspicuous, radially distributed, ventral "paired organ present. Definite hood over mouthparts; mouthparts about level with anterior body margin. Logs of variable length, arising from anterior half of body; tarsal humps lacking."
The remarks above include the outstanding characters for iden tifying this species and A. confusus.
The male of A. boueti is somewhat smaller than the female and has a semicircular genital aperture while the female has a narrow, transversely elongate genital aperture bounded by two rugose lips. In both sexes, the body outline is subcircular to pearshaped (definitely wider than long in A. confusus), leg IV extends far beyond posterior margin of body (only slightly beyond in A. confusus), basis capituli and palpal segments comparatively narrow and elon gate (globose in A. confusus), minute integumental protuberances are mostly flat (mostly tapered in A. confusus), etc. The dental formula of both species is 1/1, the apex of the hypostome is slight ly indented, and a corona is lacking.