Bats of Southern and Central Africa. Ara Monadjem
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1 Specimens measured by the authors
Epomophorus wahlbergi roosts singly or in small groups in the dense foliage of a large, leafy tree and may travel several kilometres each night to reach fruiting trees (Fenton et al. 1985). They may also roost under the eaves of buildings in urban environments (Rollinson et al. 2014). Roost switching is normal and may be partially explained by ambient temperature, since the basal metabolic rate of this species increases under colder conditions, for example, in winter (Downs et al. 2012a). The ability to sleep is also affected by ambient temperature in E. wahlbergi, with bats sleeping far less on hot summer nights than on cool winter nights (Downs et al. 2015). It is associated with forest and forest-edge habitats, including riparian forests that extensively incise savannas in the eastern part of the region. It may also penetrate peri-urban areas with extensive wooded gardens. It occurs sympatrically with E. crypturus in Mozambique, Malawi, northern South Africa (upper Levuvhu River, Limpopo Province), and eastern Zimbabwe. However, E. crypturus appears to prefer drier situations. For example, in Mozambique, E. wahlbergi is captured at high rates in the south, while the capture rate of E. crypturus increases in the north.
Figure 57. Skull and teeth of Epomophorus wahlbergi: (a) dorsal view, (b) ventral view, (c) lateral view, and (d) lateral view of mandible (DM 8627).
Extralimital: Epomophorus wahlbergi has also been recorded from Burundi, Cameroon, Congo, Equatorial Guinea, Ethiopia, Gabon, Kenya and Tanzania.
Foraging ecology: Epomophorus wahlbergi feeds on fruit, nectar, pollen and flowers, with a preference for low protein content (Mqokeli and Downs 2014); they do not show a specific preference for sugar concentration (Coleman and Downs 2012). The bats use both sucrose and glucose efficiently by varying total consumption depending on sugar concentration (Downs et al. 2012b). Furthermore, buccal morphology in the form of palatal ridges, an elongated papillate tongue, and wide flat molars appears well suited for feeding on fleshy fruit that are crushed in the mouth, after which the pulp is discarded (Mqokeli and Downs 2013). Fruits include a variety of cultivated and indigenous tree species, but figs appear to be favoured. At Mtunzini, KwaZulu-Natal, the following trees were recorded from ‘spit-outs’ collected from under feeding stations (C. Sapsford, personal communication): Ficus sur, F. trichopoda, F. natalensis, Voacanga thouarsii, Tabernaemontana ventricosa, Syzygium cordatum, Bridelia micrantha, Euclea natalensis, Eugenia capensis, Ekebergia capensis, Annona senegalensis, Podocarpus latifolius, P. falcatus, Sideroxylon inerme, Rauvolfia caffra, Halleria lucida, Sclerocarya birrea, Trichilia emetica, Harpephyllum caffrum and Mimusops caffra. In the Kruger National Park, this species specialises on the fruits of Ficus sycomorus (Bonaccorso et al. 2014). These bats also feed on exotic plants, particularly in urban environments (Rollinson et al. 2013), and may be effective dispersers of invasive species (Jordaan et al. 2012). They pollinate Adansonia digitata flowers. They feed while hovering in front of the fruit or flower, or after landing on a suitable branch alongside it (Fenton et al. 1985).
Recent telemetry work in the Kruger National Park, South Africa, has shown that Epomophorus wahlbergi individuals may travel over 13 km between roosting and feeding sites in a single night and that the same fruiting tree may be visited on subsequent nights (Bonaccorso et al. 2014). However, most flight activity was within 400 m of a Ficus sycomorus tree with ripe fruits, and home ranges averaged ∼16 hectares. By comparison, bats radio-tracked in the urban environment of Pietermaritzburg, Kwazulu-Natal, had home ranges that varied by sex and season, with females and males ranging between 18–61 hectares and 13–54 hectares, respectively (Rollinson et al. 2013). Mean maximum distances between roosting sites and foraging areas were 1.45 km and 0.88 km for winter and spring, respectively. These bats fed predominantly on exotic and invasive fruit growing in gardens, including Melia azedarach, Psidium guajava and Eriobotrya japonica, although between 20% and 30% of observations were of bats consuming the fruit of indigenous Ficus species (Rollinson et al. 2013).
Reproduction: Births occur throughout the year, but with peaks in July (winter) and the summer months (Monadjem and Reside 2012). Breeding males have particularly long epaulette hairs, as well as a brown discolouration of the skin in the vicinity of the testes and in the neck region. These males will sing from traditional lekking sites to attract females. One, or rarely two, young are born after a gestation period of five to six months.
Figure 58. Epomophorus wahlbergi: (a) female roosting showing white ear tufts, and (b) male showing covered epaulettes (a: © P. J. Taylor; b: © L. Lumsden).
SYSTEMATIC NOTES
1846.Pteropus wahlbergi Sundevall, Öfversigt af Kongl. Svenska Vetenskaps-akademiens Förhandlingar, Stockholm 3(4): 118.
The names unicolor (Gray 1870), neumanni Matschie 1899, stuhlmanni Matschie 1988 and zenkeri Matschie 1899 are synonyms. The putative subspecies haldemani (Halowell 1846) is cranially similar to wahlbergi, with which it is sympatric in Angola and Zambia (Bergmans 1988), and is therefore not recognised as a valid taxon.
The diploid number in E. wahlbergi is 2n = 36 and aFN = 68 (Peterson and Nagorsen 1975).
1 Specimens measured by the authors
Epomops franqueti (Tomes 1860)
Franquet’s epauletted fruit bat Least Concern
Description: Epomops franqueti is a large bat with a mass over 150 g in adult males and around