Bats of Southern and Central Africa. Ara Monadjem

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Figure 14. Schematic comparison of the diversity of different daylight domiciles selected by representative species of African Chiroptera that roost in trees: A free-hanging from main boughs, Eidolon helvum; B clinging under exfoliating bark, Laephotis spp., Nycticeinops schlieffeni, and Pipistrellus spp.; C clinging within foliage, reliant on crypsis, Glauconycteris variegata; D clinging within cracks within an elephant-damaged branch, Chaerephon chapini; E clinging in hollow branches, Chaerephon pumilus; F free-hanging in large cavity of tree trunk, Nycteris grandis; G clinging on tree trunk, Taphozous mauritianus; H free-hanging under exposed roots, Nycteris spp.; I sheltering under elephant-stripped bark, Taphozous mauritianus; J deep in dense foliage, Scotoecus spp.; K free-hanging in shrubs, Lavia frons; L inside disused bird nests or spider nests, Kerivoula spp.; M in hollow boles high up in tree, Mops condylurus and M. niveiventer; N under exfoliating bark, Chaerephon nigeriae; O in narrow holes, small-bodied Molossidae (modified after Verschuren (1957a) and Brosset (1966a) with addition of unpublished data, F. P. D. Cotterill).

Foliage-roosting bats

      Most Pteropodidae, as well as Taphozous mauritianus, Neoromicia nana, Glauconycteris variegata and Myotis welwitschii, hang up or cling onto surfaces in trees or shrubs. Pteropodidae, G. variegata and M. welwitschii hang by their hind claws from the undersurface of leaves or branches, the last two hanging in a disguised manner among clumps of leaves. Taphozous mauritianus roosts face-down, anchored by its hind claws, but with its belly, thumb claws and hind claws in contact with the surface of a tree or wall. Neoromicia nana clings with its ventral surface in contact with the smooth surface of unfurling banana leaves (Taylor 2000). Crypsis of the pelage is a key adaptation for many foliage-roosting bats, such as Taphozous mauritianus and many species of Glauconycteris, Kerivoula and Myotis. Many of the fruit bats also rely on disruptive colouration, exemplified in the ear spots of Epomophorus species (Fenton 1992, Fenton and Simmons 2015).

Hollow-roosting bats

      Hollow-roosting bats occupy underground caves, hollows in trees, and anthropogenic hollows such as roofs and basements of houses, tunnels or cavities in dam walls, and abandoned mine shafts (Kunz and Lumsden 2003). Some members of Vespertilionidae, Emballonuridae and Molossidae roost in tree hollows. Radio-tracked Scotophilus viridis and S. dinganii occupied hollow Colophospermum mopane trees in the Kruger National Park and Combretum imberbe in Eswatini (Fenton et al. 1985, Monadjem et al. 2010a). The presence of mature trees in woodlands is essential for the persistence of tree-roosting bats, which are adversely affected by the removal of such trees (Fenton et al. 1998a). Similarly, ‘homogenisation’ of savanna landscapes through the impact of megaherbivores (particularly elephants) also acts to reduce bat diversity (McCleery et al. 2018). While a large amount of research has been carried out on tree-roosting microbats living in American forests, very little is known about such species in southern Africa.

      Scotophilus dinganii and S. viridis are frequently found roosting in hollow spaces in the attics of houses, as opposed to the crevice-like roosts used by many Molossidae. Occasionally, so-called ‘cave bats’, such as Nycteridae, Rhinolophidae and Hipposideridae, may be found in larger attics or basements (Voigt et al. 2016) (Figure 15), and also aardvark (Orycteropus afer) burrows in the case of Nycteris thebaica (Monadjem et al. 2009).