288.

African Yellow Bat

Scotophilus dinganii

French: Scotophile de Dingane / German: Gelbbauch-Hausfledermaus / Spanish: Scotofilo de Dingane

Other common names: African Yellow House Bat, Dingan’s Bat, Yellow-bellied House Bat

Taxonomy. Vespertilio dinganii A. Smith, 1833,

“ South Africa,—between Natal [= Durban] and Delagoa Bay [= Maputo].”

See SS. wigritn. Several divergent cy tochrome-b lineages of S. dinganii suggest that cryptic species might be present, and the name colias was tentatively suggested for East African populations because they clearly differ from typical dinganii in southern Africa. Monotypic.

Distribution. Widely distributed in subSaharan Africa, from Senegal and Gambia E to Eritrea, Djibouti, and Ethiopia, and S through much of E & S Africa as far S as E South Africa, Lesotho, and Swaziland.

Descriptive notes. Head—body ¢. 74-90 mm, tail 46-65 mm, ear 11-22 mm, hindfoot 10-14 mm, forearm 47-60 mm; weight 15-36 g. Femalesare slightly larger than males in body measurements. Pelage is smooth,soft, and sleek. Dorsal pelage is sepia-brown, greenish brown, grayish brown, or reddish brown; dorsal hairs are paler at bases. Middorsal hairs are 6-7 mm. Ventral pelage is pale yellow, bright yellow, or orange yellow, not tinged with brown. Wings and uropatagium are dark brown and semi-translucent. Ears are comparatively short, widely separated, with strongly convex inner margin and almost straight outer margin. Tragus is moderately long, with rounded tip and concave anterior margin. Eyes are small. Testes are posterior to anus. Young of both sexes have two pairs of rudimentary nipples, but only one pair of functional nipplesis present in adult females. Skull is medium to large (greatest skull lengths 18-3-23- 5 mm) for Scotophilus; profile of skull is mostly a gentle slope from front to back, with very shallow concavity in forehead region; and sagittal crest and occipital helmet are well developed. I? is unicuspid; M' and M* have concave surfaces and indistinct ridges and appear worn; and M” is very short and has two ridges. Chromosomal complement has 2n = 36 and FNa = 52, with small acrocentric X-chromosome and small metacentric Y-chromosome in South Africa, or 2n = 36 and FNa = 50, with medium submetacentric X-chromosome and small telocentric Y-chromosome in Somalia.

Habitat. Most habitats south of the Sahara, including woodland savannas and various bushland and thicket savannas; rainforests (but not Congolese rainforest); rainforestsavanna mosaics; and riverine, coastal, and montane forests.

Food and Feeding. The African Yellow Bat forages by moderate fast hawking in moderately uncluttered spaces above canopies, in clearings, and over fields. It has been observed foraging near lights and drinking in streams, pools, and dams. It forages close to trees and as low as c. 2 m aboveground. Foraging is characterized by long, straight, or gently banked flights and abrupt acrobatic swerves and spectacular dives in pursuit of prey. African Yellow Bats seem to feed on beetles and other flying insects taken opportunistically. In Kenya, three stomachs contained Coleoptera, Hemiptera, Orthoptera, and Lepidoptera .

Breeding. The African Yellow Bat commonly has twins, sometimes one and occasionally triplets. Based on serially sectioned reproductive tracts of females from Kruger National Park, it is seasonally monoestrous. Insemination, ovulation, and fertilization take place in April-May. Early embryonic development of normally two embryos (one in each uterine horn) was retarded, and implantation was delayed until mid-winter July) when blastocysts implanted. During the first week post-partum, a captive female licked her two young, sheltered them with one wing, and sometimes squeaked. Young stayed attached to nipples until the third night, after which they occasionally roosted beside their mother or climbed over her.

Activity patterns. Aspect ratio and wing loading are medium; flight is fast and agile, with poor maneuverability. The African Yellow Bat can take off from the ground. It turns by banking and stalling-and-twisting. Scuttling, headfirst, up and down, over horizontal, sloping, and vertical surfaces has been reported. Day roosts include small holes in trees and wooden lampposts, crevices in hollow trees, narrow crevices and crannies in buildings, under eaves and roofs of corrugated iron, and in thatch. It prefers to rest on sloping or horizontal surfaces but also clings to vertical surfaces. Foraging activity begins soon after sunset, and individuals have full stomachs before dark. The African Yellow Bat tolerates high temperatures under iron roofs. In Malawi at 20-21°C, it does not become torpid during the day. Seasonal fluctuation in abundance was observed in Sudan and East Africa. In Malawi, it was more abundant in the wet season (November—February) than the rest of the year (data not available in July-August). In Zimbabwe, the African Yellow Bat is absent above elevations of 1200 m during colder months. It does not hibernate in South Africa. Average peak echolocation frequency was 33-4 kHz in St. Lucia, KwaZulu-Natal, eastern South Africa. Average peak frequency of 33-9 kHz and average duration of 4-1 milliseconds was recorded in Durban, eastern South Africa. Averages of seven calls in Soutpansberg, north-eastern South Africa, had maximum frequency of 51-6 kHz (42-1-65-2 kHz), minimum frequency of 33-1 kHz (31-6-34-1 kHz), frequency of the knee of 36-4 kHz (34-4-37-4 kHz), characteristic frequency of 33-8 kHz (31-9-35-3 kHz), and duration of 3-4 milliseconds (2-7—4-6 milliseconds). At Maroua, northern Cameroon, 19 calls were FM/QCF and had maximum frequency of 58-5 kHz (49-4-84-8 kHz), minimum frequency of 52-6 kHz (46-7-69-5 kHz), mean frequency of 55-6 kHz (48-1-77 kHz), frequency of the knee of 58-5 kHz (49-4-84 kHz), characteristic frequency of 52-7 kHz (46-8—-69-5 kHz), and duration of 0-88 milliseconds (0-73—1 milliseconds). In Swaziland, minimum frequency was 33-2 kHz (30-3-34-7 kHz), frequency of the knee was 36-4 kHz (32-1-38-6 kHz), characteristic frequency was 33-7 kHz (30-3-35-6 kHz), and duration was 3-8 milliseconds (2:6-6-1 milliseconds). Calls were detectable up to 20 m. Diurnal avian predators include bat hawks (Macheiramphus alcinus) and African harrier-hawks (Polyboroides typus).

Movements, Home range and Social organization. African Yellow Bats are mostly gregarious, roosting in groups of up to 20 individuals. In KwaZulu-Natal, some roosts were occupied for at least eight years. In Zimbabwe, aggregations of hundreds of individuals foraged where termites swarmed. Of 93 African Yellow Bats mist-netted in Malawi, 66 were caught alone, six were in pairs, 14 were with another individual of the same sex, and six were in groups of two males and one female. Endoparasites include the bacteria Rickettsia and the kinetoplastid Leishmania. Ectoparasites include bedbugs Cacodmus sparsilis, Aphrania ct. barys, and Stricticimex transversus ( Hemiptera, Cimicidae), the flea Charopteropsylla brockmani ( Siphonaptera, Ischnopsyllidae), bat flies Basilia glabra and B. bouvieri ( Diptera, Nycteribiidae), and the mite Spinturnix walkerae (Acari, Spinturnicidae).

Status and Conservation. Classified as Least Concern on The IUCN Red Lust.

Bibliography. Eisenring et al. (2016), Fenton (1975), Fenton & Bell (1981), Happold, M. (2013bi), Jacobs et al. (2007), Kingdon (1974), Koopman (1994), Linden et al. (2014), Manga Mongombe (2012), van der Merwe & Rautenbach (1990), van der Merwe et al. (2006), Monadjem, Shapiro et al. (2017), O'Shea & Vaughan (1980), Robbins (1978), Robbins et al. (1985), Schoeman & Waddington (2011), Simmons (2005), Smithers & Wilson (1979), Taylor, Sowler et al. (2013), Trujillo et al. (2009), Vallo, Benda & Reiter (2011).