JI S. Afr. vet. med. Ass. 43 (3): 301-304 1972

STUDIES ON THE BIOLOGY OF COSMIOMMA HIPPOPOTAMENSIS DENNY, 1843 IN SOUTH WEST AFRICA

~. D. BEZUIDENHom* AND H. P. SCHNEIDER*~'

SUMMARY two males from the in the Cuando-Cubango Districts of Angola. A very rare African , first described in 1843 \ Cosmiomma hippopotamensis, has The intriguing fact that c. hippopota­ been found again, this time in relatively large mensis was once said to be common on goats 6 numbers, on vegetation in Kaokoland, South and had never been seen again, stimulated a West Africa. Studies on certain aspects of more thorough search for it in Kaokoland, a its ecology and on its reactions to various Bantu territory situated in the northwest potential hosts suggest that under natural corner of South West Africa. conditions it prefers to feed on the black rhinoceros, Diceros bicornis. MATERIAL AND METHODS Photographs of C. hippopotamensis were shown to stock inspectors working in Kaoko­ INTRODUCTION land and they were asked to be on the watch Cosmiomma hippopotamensis Denny, )843 for such . At the same time a survey has been found previously only in small num­ was conducted in the area and ticks were bers on a few occasions in south-western and collected from goats, cattle and black-faced eastern Africa. Little has been recorded impala, Aepyceros melampus petersi 9. 10. about its hosts and nothing about its ecology. After about 80 Cosmiomma ticks had been Nine adults, including the types of this found, the area was visited and its physical species, in the British Mueum (Natural His­ geography, vegetation and fauna were tory) are said to have been collected in the studied. The way in which the ticks awaited ) their host(s) was noted, special attention 1 'Interior of South Africa'. According to 1 being paid to the level to which they had 0 Hyatt 2, the original specimens (Accession 2 No. 43.19: 1 , 4 <¥ <¥) were obtained by a ascended on the vegetation. d 0 e t collector for the Earl of Derby, named Burke, The following attempts were made to feed a d at the 'parallel of Lalagor', a locality which Cosmiomma: (

r cannot be traced now. The male and one e a) Turtles (Pelomedusa subrufa) and tor­ h female bear labels stating that they were s (Testudo i toises spp.) were common in l found 'on '. Three of the re­ b parts where collections were made and

u maining four specimens (Accession No. 60.86:

P we suspected that they might be 1 0 ; 60.116: 2 <¥ ~) were collected by Anders­ e possible hosts. Five Cosmiomma ticks h son at Lake Ngami but no mention is made t (2 d' 0, 3 <¥ <¥) were therefore placed on y of their hosts. The ninth 'specimen, a male, b bears neither host nor locality data. a turtle with enough water to cover it in d

e a container. This experiment was repeat­ t n Later, a few specimens of C. hippopota­ ed twice. a r mensis g were recorded from East Africa by Similar experiments, but without

e Neumann 3, Hoogstraal 4 and Arthur S. also c water, were tried with turtles and also n without host data. The species was found e tortoises. c i again in South West Africa in 1959, over 100 l b) A monitor (Varanus exanthematicus) was r years after its original discovery there, when e put into a plastic container with some d three males and three females were obtained n ticks for a period of 8 hours. u at Ohopoho and Otjijanjasemo in Kaokoland,

y where they were said to be common on c) Habits were tried as hosts by confining a

w goats 6. '. In 1964 Serrano 8 recorded another the ticks on their ears in bags. e t a G

·State Veterinarian, Veterinary Diagnostic Centre, Windhoek, South West Africa. t e ··State Veterinarian, Kamanjab/Kaokoland, South West Africa. n i b a 301 S y b d e c u d o r p e R d) A goat was left for 18 hours tied to a e) A black rhinoceros (Diceros bicornis), bush which had about 20 Cosmiomma kindly provided by the Department of ticks on it. In another experiment a bag Nature Conservation and Tourism of con taining nine ticks (4 d" d", 5 ~ ~) was South West Africa, was challenged by secured on the ears of a goat for an hour. means to be described in another paper.

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1 : : '.:~':': 0 ~: " 2 .. d e t a d ( r e h s i l b u P e h t y b d e t n a r g e c n e ." .. c i l r e d n u J r'l_ • CW"',,", II .. : t. ,.,,,,,.,,.,.,,..,..,. y a --- AII'II.,..· ,...". w e t a G t e n i b 302 a S y b d e c u d o r p e R RESULTS water and decreased as one moved away from it; they were never found more than 1. Description of the collecting area about 40 metres away. Kaokoland is bounded on the north by the Kunene River, which separates it from C. hippopotamensis was usually collected Angola, eastwards by OWanlbo, southwards from the tips of leaves or branches of bushes by Kamanjab District and westwards by the and from grasses at heights between 50 and Atlantic Ocean. 150 cm. Only two specimens were found at different levels. One was sitting 200 cm high Relatively high mountains, the Baynes, in a C. imberbe tree and the other on the Zebra and Otjihipa, lie on the north, represent seed head of a grass, C. ciliaris, at a level of east and west sides of the collection sites and 17 em. rise in places to a height of over 2 000 metres. The rest of the area is covered mainly by Some bushes contained only one specimen rocky hills. Scattered throughout are nume­ but most carried more; from one a total of rous dry, sandy river beds, where water flows 56 ticks was collected. They sat on the side for a few hours after storms; as well as adjacent to the footpath, waiting for a host springs, which only dry up during severe to pass by. They were only found on both droughts. sides of a bush when it was growing in the middle of a footpath. These ticks clumped The vegetation differs from place to place, together on top of each other, sometimes as depending on whether the area is moun­ many as seven being found at the tip of a tainous or relatively flat. In general, however, leaf. Questing was pronounced when they the veld-type is savannah with abundant were approached, but stopped immediately Colophospermum mopane. It is further the observer got close to them, especially characterized by the presence of various when they were touched. They made no Commiphora spp. and Terminalia prunioides. attempt to climb on to the observers' hands Game is still very prevalent, the common­ or clothing. est species being kudu, impala, zebra and black rhinoceros. 3. Experimental hosts

) a) In one of the three experiments with 1

1 2. Ecology of C. hippopotamensis turtles in water, all nine of the females 0 2

attached within about 20 minutes but

d During March, 1971, C. hippopolamensis e only two of the six males. In the first t was found at Ondjarrakagha, Otjiboronbonga, a experiment the ticks remained attached d Otjipembe and Ekoto, in the north-eastern (

for 7 days but were then found to be r quarter of Kaokoland between about 17° to e dead when closely examined. In the h 18°E and 13° to 14°S. s i second and third experiments they were l b dead by the third day. In the experiments u These areas are at altitudes between 1000

P conducted without water similar results and 1500 metres, with a mean annual rainfall e were obtained. h of about 250 mm. Specimens of the tick were t

y collected from the following species of plant: b In the case of tortoises a lower per­ the trees Acacia reficiens; Colophospermum d centage of ticks attached and they also e t mopane; Combretum apiculatum, C. imberbe

n died after a day or two.

a and C. hereroense; Dichrostachys cinerea r g subsp. africana and Securinega virosa; the b) Cosmiomma did not attach to the monitor. e c shrubs Catophractes alexandri; Euclea divino­ c) Rabbits are possible experimental hosts n e rum, E. pseudebenus; Grewia flavescens, because C. hippopotamensis attached and c i l G. bicolor and Ximenia americana; the grass engorged on their ears, though only after r e Cenchrus ciliaris and the sedge Cyperus mar­ these had been shaved. Not all the ticks d ginatus .. n attached, and those that did, took nearly u 2 weeks to engorge partially. Whether y Infested vegetation was found along some a these ticks will produce fertile eggs re­ w of the footpaths leading to springs; they were e t mostly rhino paths where relatively fresh mains tci)e seen. a

G d) None of the Cosmiomma attached to the

tracks and dung deposits could be seen. The t e concentration of ticks was greatest near the goat. n i b a

S 303 y b d e c u d o r p e R e) The black rhinoceros proved to be an Also, rhino deposit dung on certain foot­ excellent host. When the ticks were re­ paths leading to waterholes, the distances leased on its back they attached in the between these deposits becoming shorter the perianal area within 5-15 minutes. nearer one gets to the water. Cosmiomma After engorgement, the females laid ticks were also found along these footpaths, fertile eggs from which larvae hatched increasing in numbers nearer the water. successfully. The rearing of these larvae will be described later. Subsequently the suitability of the black rhinoceros as a host was proved by infesta­ tion experiments with -c. hippopotamensis. It DISCUSSION AND CONCLUSIONS was found afterwards that this already The writers' initial observations, based on had been listed as a natural host in the circumstantial evidence, suggested the black Cuando-Cubango District of Angola B. rhinoceros as the most likely host of C. hippo­ Although cattle, goats and black-faced potamensis in Kaokoland. The hippopotamus, impala 9.10 are known to visit infested springs, the first recorded host of this tick, does not no C. hippopotamensis could be found on occur in the area where the present collec­ them. tions were made. A few hippopotami are present in the Kunene River about 90 km up­ The way Cosmiomma ticks clump together stream from the one collecting site, and they on top of each other on leaf tips and twigs may therefore play a role as hosts along the might be interpreted as a method of moisture river, but they definitely do not reach the conservation. other collecting sites. These sites, however, do correspond with part of the recorded dis­ ACKNOWLEDGEMENTS tribution of the rhinoceros in this area (Fig. 1) 12. We have pleasure in thanking the Direc­ tor of Veterinary Services, S.W.A., for his The feeding habits of the rhinoceros are permission to publish this report and Dr. G. such that the ticks would be able to infest Theiler for inspiring us to undertake this it readily 13. It usually stands next to the ,. study and for translating certain papers. shrub or tree on which it is browsing and

) sometimes pushes its head right in among Thanks are due to Mr. W. Giess of the 1

1 the branches, slowly cropping the twigs. The Herbarium, Windhoek, for identifying all the 0 2

optimum browsing height is between 60 and plants collected, and to Miss Jane B. Walker d e 108 cm, which corresponds closely with '-the and Dr. A. Schmidt-Dumont for their h~lpful t a heights at which the ticks were found. criticism of the manuscript. d ( r e h

s REFERENCES i l b u 1. Denny M. 1843 Ann. Mag. nat. Rist. 6. Theiler G. 1962 The Ixodoidea parasites P XII: 312 of vertebrates in Africa south of the e

h ,

t 2. Hyatt K. H. 1968 Personal communication , Sahara (Ethiopian Region). Project

y to Jane B. Walker S.9958. Report to the Director of Vete- b 3. Neumann G. 1899 Soc. zool. d L. Mem. Fr. rinary Services, Onderstepoort e t 12: 107 .

n 7. Triebner S. 1971 Personal communication

a 4. Hoogstraal H. 1956 African Ixodoidea. 1. r

g 8. Serrano F. M. H. 1964 Pecuaria, Loanda

Ticks of the Sudan (with special refer­ e c ence to Equatorial Province and with 22: 37 n e preliminary reviews of the genera

c 3. Ebedes H. 1971 Personal communication i l Boophilus, Margaropus & ).

r 10. Hofmeyr J. M. 1971 Personal communica­ e Res. Rep. NM 005 050.29. 07, 1, 101 pp. d tion

n Washington D.C., Dep. Navy, Bur. Med. u Surg. 11. Bezuidenhout J. D: & Schneider H. P. Un­ y a 5. Arthur D. R. 1960 Ticks. A monograph of published data w

e the Ixodoidea. Part V. On the genera t 12. Joubert E. 1971 Madoqua 1: 33 a , Anocentor, Cosmiomma, G Boophilus & Margaropus. 251 PP. Cam­ 13. Joubert E. & Eloff F. C. 1971 Madoqua t e bridge Univ. Press 1: 5 n i b a S

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