Epomophorus wahlbergi, Sundevall, 1846

Don E. Wilson & Russell A. Mittermeier, 2019, Pteropodidae, Handbook of the Mammals of the World – Volume 9 Bats, Barcelona: Lynx Edicions, pp. 16-162 : 99-100

68.

Wahlberg's Epauletted Fruit Bat

Epomophorus wahlbergi

French: Epomophore de Wahlberg / German: Wahlberg-Epaulettenflughund / Spanish: Epomoforo de Wahlberg

Taxonomy. Pteropus wahlbergi Sundevall, 1846 ,

near Port Natal (= Durban), KwaZulu-Natal, South Africa.

Epomophorus wahlbergi is the only member of the wahlbergi species group. Monotypic.

Distribution. Widely distributed in C, E & S Africa, Gabon, Republic of the Congo, and Angola in W, coast of S Somalia S to S Tanzania (including Pemba, Unguja, and Maha Is) in E, also in Uganda, Kenya, Rwanda, N Tanzania, and E & SE DR Congo, and Malawi, Mozambique, Zambia, Zimbabwe, E South Africa, and Swaziland in S; possibly in Cameroon, Equatorial Guinea, and Namibia.

Descriptive notes. Head-body 106- 183 mm (males) and 113-171 mm (females), tail 0-4 mm (males) and 0-6 mm (females), ear 20-28 mm, hindfoot 20- 27 mm, forearm 72-95 mm (males) and 67-88 mm (females); weight 68-138 ¢ (males) and 69-140 g (females). Males are sometimes darker and on average larger than females, and their muzzles are broader. Males can be distinguished from a distance by their expansible cheeks with folded upper lip. Muzzle is relatively long, and tongue is elongated and muscular. Eyes are large;irises are brown. Ears are relatively short, rounded, naked, and brown, with dark rims and anterior and posterior light ear patches. Adult males have white epaulettes with 9-mm hairs, sometimes encircled by band of brown pelage. Dorsum is fawn or light sandy brown, paler on shoulders and sometimes with yellowish tinges on hindlimbs and around tail; hairs are fawn, with dark brown bases; pelage is soft and slightly fluffy, extending along forearm dorsally and ventrally; and mid-dorsal hairs are c¢. 10 mm. In breeding males, skin of testes and in neck region has brown discoloration. Venter is noticeably paler, sometimes grayish; band of brown pelage encircling epaulettes can also run across throat and can sometimes be found around testes of sexually active males. Wings have claw on second digits, and membranes are light brown, sparsely covered in hair, and attach to second toes. Skull is medium-sized and robust; rostrum is relatively short and broad, conspicuously dorso-ventrally flattened; braincase lacks posterior downward deflection;sagittal crest is low but generally clearly visible; lambdoid crestis fairly well developed; zygomatic width is comparatively large, with sturdy arches; palate is relatively short; and post-dental palate is obviously concave. There are six thick palatal ridges, of which sixth and rarely fifth are postdental, and ridges 2-4 not divided. Dental formula of neonate is 12/2, C1/1,M 1/1 (x2) = 16. At birth, teeth are lightly enameled, small, and sharp; during weeks two and three, second milk teeth premolars appear, resulting in 20 teeth. All permanent teeth are present between days 81 and 150; they are heavily enameled; and premolars and molars are heavily cusped. Exceptionally, an extra upper molar can be present. Lungs are relatively large: left one is unilobed and right one has two incompletely separated lobes and an accessory lobe. Thoracic cavity is large, and abdominal cavity is compressed toward narrow pelvic inlet. Gastrointestinal tract is small and short. Chromosomal complement has 2n = 36 and FNa = 68 or 72, with eleven pairs of metacentric and six pairs of submetacentric autosomes. X-chromosome is metacentric or submetacentric, and Y-chromosome is acrocentric. Another sample yielded six metacentric, eight submetacentric, and four subtelocentric autosomes.

Habitat. Primarily woodland savannas in Zambezian Woodland, Eastern Rainforest-Savanna Mosaic, Coastal Forest Mosaic, and Somalia-Masai Bushland biotic zones from sea level up to elevations of ¢. 2000 m. In South Africa, distribution of Wahlberg's Epauletted Fruit Bat is strongly associated with annual precipitation.

Food and Feeding. Wahlberg's Epauletted Fruit Bats eat soft fruits, pollen, and nectar, for which they can commute more than 13 km each night. Primary food sources are figs ( Ficus , Moraceae ); other food comes from at least 24 plant genera in 14 families. Cultivated fruits (sometimes from ornamental gardens) that are eaten are generally too ripe for commercial use. Wahlberg's Epauletted Fruit Bats feed while briefly hovering in front of fruits or flowers or after landing on a branch nearby. Fruitis often carried to a feeding perch where it is slowly chewed. Large pieces of fruit are held in one foot against the chest. Wahlberg's Epauletted Fruit Bats pollinate Adansonia (Malvaceae) and probably Parinari (Chrysobalanaceae) . Juices from leaves of Balanites (Zygophyllaceae) are swallowed, possibly for steroidal sapogenins and proteins. Beetles and other insects found in stomach contents might be eaten for protein, but accidental swallowing cannot be excluded. They do not seem to drink but were observed flying low over water and wetting ventral pelage.

Breeding. Litter size of Wahlberg's Epauletted Fruit Bat is one, exceptionally two. Reproductive cycle is aseasonal polyestry, although seasonal bimodal polyestry seems to occur at some localities. In inland Kenya, pregnant and lactating females and volant young were present in November—April. In coastal Kenya, lactating females were found in April-October. In South Africa, most females are seasonally monoestrous, but some are polyestrous. In KwaZulu-Natal, births occur year-round, with peaks in July and November—January. Females are not in close reproductive synchrony, and spermatogenesis is continuous. In Swaziland, young were found in a bimodal pattern, with peaks in January—May and August-October, and lactating females were present in December—May; postlactating females were found from February onward. Gestation lasts ¢.160 days. Parturition takes place at the roost in the presence of male and female group members. Females reach sexual maturity in their first year and males in their second year.

Activity patterns. Wahlberg's Epauletted Fruit Bats hang from one or both feet and remain motionless for long periods. Following a grooming session of ¢.30 minutes, they generally leave their roosts at dusk one by one, often in different directions. They fly during the entire night, but flight intensity drops to one-half peak level after 20:00 h. At dawn, they return to their roosts where theystart nose-to-nose sniffing and sometimes licking, probably enabling mutual recognition. In KwaZulu-Natal, theyslept/rested longer and more often in winter than summer, and no individuals slept when ambient temperatures were over 35°C. During the first hoursafter nightly activity ends, they slept with both eyes closed, but this changed to one eye open later on, reaching a peak at ¢.10:00 h. Courting males generally use perches near roosts, 2-20 m aboveground, and at least 50 m from competing males, where they make moderately loud gong-like calls with fundamental frequency at 7-9 kHz and several harmonics, with durations of 200- 300 milliseconds, repeated about once a second. Call frequency of males increases in presence of females; males show off their epaulettes, quiver, and beat their half-opened wings once or twice with each call. After 15 minutes to more than one hour, they move to another perch.

Movements, Home range and Social organization. Wahlberg's Epauletted Fruit Bat generally roosts alone or in small mixed-sex groups in foliage of trees with dense canopies,living or dead fronds of palms (e.g. Borassus sp. and Roystonea elata, both Arecaceae ), and occasionally thatched ceilings or eaves ofbuildings. Individuals roost an average of 16- 5 cm from each another (except mother-child pairs). If a neighbor comes too close, they become aggressive, strike out their thumbs, wave their wings, squeal, and sometimes bite. A roost in Kenya was occupied for more than five years and had 40-400 individuals of mixed sex. Nomadic individuals might return to familiar roosts in various localities they visit. Some switch between multiple roosts in one area every 5-6 days in winter, more often than in summer. Male home ranges are smaller than those of females (0-46 km? vs. 0-78 km?). Mean foraging distances were 1-4 km in winter and 0-88 km in spring. Sex ratios in large groups are generally equal, but individual males will roost with up to three females and their young.

Status and Conservation. Classified as Least Concern on The IUCN Red List. Wahlberg's Epauletted Fruit Bat has a wide distribution and large population. It is probably not declining fast enough to be assigned to a higher category. It faces no major threats overall, but in KwaZulu-Natal ( South Africa), coastal populations have declined because of loss of coastal forests from dune mining. Fatalities as a result of encounters with wind turbine blades have been reported. Viral infections (e.g. Lagos bat virus) might affect certain populations.

Bibliography. Acharya (1992), Adams & Snode (2015), Babiker Salata (2012), Downs et al. (2015), Duli¢ & Mutere (1973, 1977), Happold, M. (2013g), Lanza et al. (2008), MacEwan (2016), Mickleburgh et al. (1992), Monadjem & Reside (2012), Monadjem, Taylor et al. (2010), Pienaar et al. (1980), Rollinson et al. (2013), Schoeman (2016), Taylor (2000), Wickler & Seibt (1976).

Figures

50. Western Woermann’s Fruit Bat (Megaloglossus azagnyi), 51. Eastern Woermann’s Fruit Bat (Megaloglossus woermanni), 52. Angolan Soft-furred Fruit Bat (Lissonycteris angolensis), 53. Little Collared Fruit Bat (Myonycteris torquata), 54. Sao Tome Collared Fruit Bat (Myonycteris brachycephala), 55. Sierra Leone Collared Fruit Bat (Myonycteris leptodon), 56. Bergmans’s Collared Fruit Bat (Myonycteris relicta), 57. Broad-faced Fruit Bat (Plerotes anchietae), 58. Hammer-headed Fruit Bat (Hypsignathus monstrosus), 59. Franquet’s Epauletted Fruit Bat (Epomops franqueti), 60. Buttikofer’s Epauletted Fruit Bat (Epomops buettikoferi), 61. Veldkamp’s Epauletted Fruit Bat (Nanonycteris veldkampr), 62. Gambian Epauletted Fruit Bat (Epomophorus gambianus), 63. Peters’s Epauletted Fruit Bat (Epomophorus erypturus), 64. Angolan Epauletted Fruit Bat (Epomophorus angolensis), 65. Little Epauletted Fruit Bat (Epomophorus labiatus), 66. Minor Epauletted Fruit Bat (Epomophorus minor), 67. Ansell’s Epauletted Fruit Bat (Epomophorus anselli), 68. Wahlberg's Epauletted Fruit Bat (Epomophorus wahlbergi), 69. Dobson’s Epauletted Fruit Bat (Epomophorus dobsonu), 70. Sanborn’s Epauletted Fruit Bat (Epomophorus grands), 71. Lesser Epauletted Fruit Bat (Epomophorus pusillus), 72. Hayman’s Epauletted Fruit Bat (Epomophorus intermedius)

Distribution. Widely distributed in C, E & S Africa, Gabon , Republic of the Congo , and Angola in W, coast of S Somalia S to S Tanzania (including Pemba, Unguja, and Maha Is) in E, also in Uganda , Kenya , Rwanda , N Tanzania , and E & SE DR Congo , and Malawi , Mozambique , Zambia , Zimbabwe , E South Africa , and Swaziland in S; possibly in Cameroon , Equatorial Guinea , and Namibia .