Abstract:
This survey of ixodid ticks was the first to compare the species composition and population
dynamics of free-living ticks in intensive, sable antelope breeding enclosures, now
commonplace in commercial wildlife ranching in South Africa, with those of multi-herbivore
enclosures. The species composition, abundance and seasonal abundance of questing ixodid
ticks on the vegetation in intensive breeding enclosures for sable antelope (Hippotragus
niger), on which strategic tick control is practised, were compared with those of ticks in a
multi-species herbivore enclosure surrounding the breeding enclosures in which no tick
control is practised. A total of eight ixodid tick species were collected by drag-sampling the
woodland and grassland habitats in each enclosure type monthly from July 2011 to July 2013.
Rhipicephalus decoloratus, a potential vector of fatal tick-borne disease in sable antelopes, was
the most abundant, accounting for 65.4% of the total number of ticks collected in the sable
enclosures, whilst representing only 25.4% of number of ticks collected in the multi-species
herbivore enclosure. Rhipicephalus decoloratus and R. evertsi evertsi were more abundant than
R. appendiculatus (both p < 0.05) and Amblyomma hebraeum (p < 0.001 and p < 0.01, respectively).
Rhipicephalus decoloratus larvae were collected throughout the year, with peak collections in
November 2012 and October to December 2013 in the sable enclosures; and in April/May
2012 and February/April 2013 in the multi-species herbivore enclosure. More R. decoloratus
were recovered in the second year than in the first year in the grassland habitat of the sable
enclosures (V = 7.0, p < 0.05) possibly as a result of acaricide resistance. The apparent temporal
over-abundance of R. decoloratus in sable antelope breeding enclosures, in the face of strategic
tick control, is of concern and requires further investigation.
