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HOSTS*

Most prominently listed as hosts of all stages of R. a ndicu. latus by most authors are cattle, but domestic goats, sheep, rses, mfiies, donkeys, and dogs are also commonly listed. The comparative incidence on these animals has seldom been carefully observed. The brown ear.tick appears to feed more readily on cattle than it does on sheep, according to Wbrsley (1950). A single male has been reported from a domestic chicken (Lucas l95L).

Wild antelopes and buffalo are frequently reported, and nu. merous other animals are infested on occasion. Wild carnivores appear to be parasitized only rarely.

Larvae and sometimes nymphs feed on modium_small animals such as hares and cane rats, and may also attack man. Mostly, however, they are known from the same larger size hosts as adults. The question of why some larvae and nymphs choose smaller hosts deserves further investigation.

In connection with the account of noninfestation of young antelopes (below), it is of interest that Binns (1951) has reported that calves tied to trees in the Lela District of Kenya were attacked within two days after birth. Although these calves harbored only one or two ticks duing the first week, four to ten ticks infested them after a fortnight. At the end of the month, over twenty brown ear_ticks were feeding on some calves. Afterwards, the count fluctuated considerably but averagd weekly 12.9 adult ticks per animal for six calves for three months. This was a lower average than for freely grazing older animals (but ‘adequate to provide a reasonable exposure to East Coast fever‘).

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Antelo s: Death of waterbuck due to heavy infestation (Hutchins 1917). Most of the following antelope hosts have been reported by several authors. Uganda kob (Warbuton 1913). Nyala, kudu (Bed. ford 1932B, Santos Dias l952D). Impala (Bedford 1932B. Santos Dias 1952D. Meeser 1952). Bushbuck, waterbuck (Bedford 1932B). Sable antelope, Livingstone's suni, steenbuck, klipspringer (Jack 1942).

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*The matter of domestic animal hosts will be treated in the forthcoming volume on disease relations of African ticks. Nuerous addi_

tional host records are provided in the APPENDIX.

White_bearded gnu (Loveridge 1928). Dik-dik (Loveridge 1928, Stella 1939B). Kobus ellipsiprflnus and Adenota vardoni (Schwetz

and Collart 1929). Hi r s niger roosevelti (Santos Dias 1952D). Hartebeest ang lecgwe (flatthysse .

Mettam (1933) reported the interesting observation that newly..born kob, duiker, bushbuck, and reedbuck in an Entebbe

paddock heavily infested with R. appendiculatus and R. evertsi t ese 1c s.

were in no instance affected by

Buffalo: (Howard 1908, Richardson 1930, Lewis 1931C ,19l.3, we.1ke_I§3'2"r , Jack 1942, Santos Dias l950B,1952D).

Carnivores: Hunting dog (Lycaon sp.) (Howard 1908). Lion
P

(Zmp~mtos Dias 1953 hysse 1951.). Felis ca nsis hindei (Allen and Loveridge 1933). Jackal (Santos llias 1955165,

I9'55E7. Leopard (Santos Dias l952H,l953B, Matthysse 1951.).
Min: (Howard 1908).

Miscellaneous: "All game animals in Kenya" (Lewis 1939A) but "rare on game in Masai Reserve" (Lewis 1934). Warthog and elephant (Zumpt 19428). Zebra (Lewis 1931,1932, Santos Dias 19521), Matthysse 1954). Giraffe (Santos Dias 195313).

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Hares and rock rabbits (Pronola s sp.) (Theiler, unpublished). Large cane rat (Wilson 1950B). Bush squirrel (Santos Dias 19521)). Duiker (Lewis 19316). Zebra, hartebeest, lechwe, kudu, hares (large numbers), and jackals (Matthysse 1951.). Men (Equatoria Province record above. Pijper and Dau 1934). '_

[graphic]

Tick identification "probable": elephant_shrews (Rhinonax

%~ and Petrodromus s. sultani) and Peter's gazelle
Lums en 55). Farasi ti sm of eIepF1Tnt shrews by nymphs of this

species is probably rare or questionable.

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Hares (Lewis 1934). 1433 (Pijper and Dau 1931.). see Avrmmix.

BIOLOGY

R. appendiculatus is a three host tick. In Nyasaland, where there_is a sing a rainy season each year, the brown ear_tick produces one generation a year (Wilson l946,l950B) but in South Africa it may produce one or two generations a year (Lounsbury 1904). In Kenya and Uganda, where two rainy seasons occu each year, multi_ plication is faster and two or three generations breed within a twelve months‘ period (Wilson 1953). As stated in the section on HOSTS above, adults feed on large animals, nymphs attack large or medium size hosts, and larvae appear to prefer small to medium size animals above the size of usual rodents. Varia. tion in size and structure of this species, as influenced by hosts and environment, are discussed under REMARKS below.

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In Nyasaland, Wilson (19508) found that under optimum condi. tions of high huidity, from 110 to 129 days are necessary to complete the life cycle. In South Africa, Lounsbuy reared the brown ear.tick through its life cycle in from 61 to 146 days depending on the season. Nuttall (19138), working in an English laboratory, reared this species in a minimum of 115 days, from preoviposition to preoviposition period, when maintained at between 17°c. and 2o°c.

Nuttall (l9l3B) summarized his life cycle studies about as follows: R. a ndiculatus requires three hosts upon which to feed in its larvzl, nymphal, and adult stages. Larvae usually remain on the host for from three days to a week; when they remain considerably longer they either do not imbibe blood freely or they may not actually attach on the day on which placed on the host. Engorged larvae drop off up to fifteen days after having been placed on the host. Nymphs remain on the host for five to eleven days. Fertilized, replete females abandon the host after six to fouteen days. Males attach to the animal for longer periods, and unfertilized females may remain on the host up to 24 days.

The temperature at which the host is maintained, within the limits observed, exerts no apparent influence on the time that different stages remain attached. Postfeeding metamorphosis re. quires the following time: from e to larva, 32 to 65 days at 17°C. to 19pC.; from larva to n , Thur to six das at 30qC., or 2.1 to 41 days at 13°C“. tol ., or 60 to 75 days at 13°c. to 1490.; from n to adult, ten days at 37°C., or 21 to 38 days at 2090., or 64 ays FE I190: Away from the host, therefore, ten; perature markedly influences the rateof development.

Once the female abandons the host, oviposition commences after six to 23 days at 17°C. to 19°C., or after fifty to sixty days at 12°C. Oviposition continues for from fifteen to 56 days, during which period the female lays from 3000 to 5770 eggs.

Nuttall's average minimum tines and Thei1er's minimum and maximum times for various periods of the life cycle are summarized as follows:

PERIOD nus
Nuttall (19133) Theiler (191.33)

[graphic]

Preoviposition 6 5.40
Oviposition to hatching 32 (17.19°c.) *28
Larval prefeeding period 7 -
Larva feeds 3 3-7
Premolting period 21 (17°C.) 10.49
Nymphal prefeeding period 7 -
Nymph feeds 5 3-7
Premolting period 21 (20qC.) 10.61
Adult prefeeding period 7 ' -
Female feeds 6 4.10
Total 115 63.202

Field observation indicates the extreme importance of knowing not only the temperature but also relative humidity at which all rearing experiments such as these are accomplished.

[graphic]

*Eggs require three months for hatching in wintertime, South Africa.

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