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Four nymphal instars are invariable in our numerous observations. Nymphs, like adults, feed for from 25 to fifty minutes. The first nymphal instar, however, never feeds; it molts to the second instar usually in ten to thirteen days (range eight to 21 days). One to three weeks later the second instar nymph feeds and molts to the third instar some two weeks later (range eight to 23 days). The third instar nymph takes food between three and 35 days afterwards and molts three or four weeks later (range fifteen to 59 days). The fourth instar nymph feeds between five and 36 days afterwards and molts to the adult stage three or four weeks later (range seventeen to forty days).

Note that although there are many morphological similarities between A. confusus and A. boueti, the biology of the nymphal stage of each is distinct.

In this species, the observed period between nymphal molting and feeding is quite variable. Some accept food within five to seven days although two to three weeks, or longer, is more common for this and for other bat-parasitizing argasids. Also noteworthy is (1) the average two week postfeeding period of second instar nymphs in contrast to the three or four week average postfeeding period of the two subsequent instars, and (2) the nonfeeding first instar.

Adults placed together shortly after molting have been observed to mate only after feeding which may occur from eight to sixteen days after molting. The feeding period varies from forty minutes to two hours. No egg batches have been deposited before three and a half to four months after molting. Further studies on the F1 generation are in progress.

Ecology

We have collected, with considerable and strenuous effort, . several hundred specimens of A. confusus in Egypt. This species, together with A. transgariepinus, is the most secretive of bat infesting argasids." It wedges itself deeply into the narrowest crevices of caves and of hillside crannies in which bats rest. It is never found easily or in groups of more than two to a maximum of twelve specimens. We know of only a single exceedingly small population in Cairo, where bats roost in buildings that are more humid than desert caves. In the environs of Cairo, A.

confusus is scattered throughout desert and desert-edge retreats, arid, such as antiquities structures, caves, and hillside crannies.

Records from northern Sudan and from the Protectorates of South Africa indicate a more or less similar tolerance of aridity, but those from various regions of South Africa, Torit, and the crater of Mt. Menengai in Kenya indicate also that certain populations exist in markedly humid environments where they tolerate lower temperatures and higher relative humidity than they do in

Egypt.

DISEASE RELATIONS

BATS: A small number of specimens thus far studied in NAMRU-3 laboratories have been negative for blood protozoa, spirochetes, viruses and rickettsiae, and Shigella organisms.

REMARKS

Further studies on the habits and ecology of this species are presently under way and will be reported when completed. For a definition of the subgenus Chiropterargas and for criteria to distinguish this species from A. boueti, see page 95.

IDENTIFICATION

A. confusus adults have an extremely wide body outline, and, in common TEET. boueti, are characterized by the absence of a sutural line dividing dorsal and ventral surfaces, and by the presence of a conspicuous hood over the mouthparts. In A. confusus the dorsal integumental protuberances are fine, shiny-tipped," tapering points which on the lateral margin are more closely spaced and more regular. The posterior discs are arranged radially; the legs are shorter than the body length; and the hypostome has only a single pair of denticle files. The tarsi have no dorsal protuberances. A pair of grooved organs of unknown function is present just posterior of the anus on the ventral surface.

Except when greatly engorged, the peripheral flange of the body remains partly unfilled. In partially engorged individuals this flange is folat, and in dry specimens it may be turned up like a rim. The body color is reddish yellow with a central, darker area of varying extent.

Males measure from 5.9 mm. to 6.4 mm. long, and from 7.4 mm. to 7.2 mm. wide (average 6.1 mm. long and 7.5 mm. wide). The genital aperture forms a wide arc. Females are larger, and measure up to 8.0 mm. long and 9.5 mm. wide. The female genital aperture is a transverse groove with thick, rugose lips.

The h and larva have been described by Hoogstraal (1955B). The larva first instar nymph are quite similar to those of A. boueti but the successive instars of each resemble the associated 3 *

Figures 37 and 38, d, dorsal and ventral views

ARGAS (CARIOS) VESPERTILIONIS Egyptian specimen

- 103

[graphic]

ARGAS (CARIOS) VESPERTILIONIS (Latreille, 1802).
(Figures 21,22,37, and 38)

THE ROUND BAT-ARGAS

L N 9 d. EQUATORIA PROVINCE RECORDS 2 Lokwi Rousettus aegyptiacus June (CNHM) 4. Katire *Mimetellus "moloneyi Sep 9 Sunat Taphozous perforatus haedinus Feb DISTRIBUTION IN THE SUDAN Northern: One larva from an undetermined species of bat at Dongola, 12 April 1917, Bedford legit; Sudan Government collections.

Khartoum: Several larvae from an undetermined species of

bat(s?) at Khartoum, 20 September 1914, R. Cottam legit; in Sudan Government collections, one retained in Hoogstraal collection.

DISTRIBUTION

The Argas vespertilionis group, consisting of A. vespertilionis (Latreille,T362) in Europe and Africa, A. Fusillus Kohl's, T550, on Palwan Island in the Philippines, and of numerous closely related forms of yet uncertain species status, ranges throughout the continents and island groups of the world, except in the Americas. It is possible that certain African populations presently identified as A. vespertilionis will prove to be separate, closely related species. # fuller study of this group is under way.

African Records Only

Eventually, the round bat-argas most likely will be found in many more territories of Africa.

*Field identification of host; specimen not seen by a specialist in bat taxonomy.

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