Rousettus aegyptiacus, E. Geoftroy Saint-Hilaire, 1810

Don E. Wilson & Russell A. Mittermeier, 2019, Pteropodidae, Handbook of the Mammals of the World – Volume 9 Bats, Barcelona: Lynx Edicions, pp. 16-162 : 87-88

46.

Egyptian Rousette

Rousettus aegyptiacus

French: Roussette d'Egypte / German: Nil-Flughund / Spanish: Rosetus de Egipto

Other common names: Egyptian Fruit Bat

Taxonomy. Pteropus aegyptiacus E. Geoffroy Saint-Hilaire, 1810 ,

Giza (Great Pyramid), Egypt.

Six subspecies are currently recognized.

Subspecies and Distribution. R.a.aegyptiacusE.GeoffroySaint-Hilaire,1810—MiddleEastinSTurkey,Cyprus,WSyria,Lebanon,Israel,WJordan,andEgypt(NcoastandNileValley).

R.a.arabicusJ.Anderson&deWinton,1902—ArabianPeninsula,SIran,andSWPakistan.

R.a.leachiiA.Smith,1829—E&SAfrica,fromEthiopiatoSouthAfrica.

R.a.princeps Juste &Ibanez,1993—-Principe1.

R.a.tomensis Juste &Ibanez,1993—SaoToméI.

R. a. unicolor]. E. Gray, 1870 — W Africa, from Senegal to WC Angola; also on Bioko I.

Introduced during the 2000s in the Canary Is (Tenerife), but probably successfully eradicated and no longer present.

Descriptive notes. Head—body 138-192 mm, tail 6- 6-25 mm, ear 18-27 mm, hindfoot 17-38 mm, forearm 82-106 mm; weight 81-171 g. The Egyptian Rousette is shortfurred has wingspan less or equal to 60 cm. Head is relatively large to contain a large brain—one of the highest brain to body weight ratios in bats. Eyes are large, with brown irises. Ears are of moderate size, round at apex, and dark. Sense of smell and vision are well developed, with adaptations for twilight vision. Facial fur is longer on forehead, covers face nearly to tip of muzzle, and is same color as dorsal fur. Dorsum varies from light ( Egypt) to dark brown ( South Africa) and grayish ( Cyprus and Tur key). Wings are dark brown in western and southern Africa, becoming lighter in the northern distribution. Venteris lighter than dorsum. Pale light yellow or orange is often present around neck. Stuff hairs are associated with sebaceous glands on throat of both sexes, although more developed in males. Fur extends dorsally and ventrally onto one-half of forearms and dorsally onto legs up to ankles and surface of uropatagium. Index claw is present; toes have perforated claws. Wing membrane (plagiopatagium) attaches to first toe. Tail is short. Skull is larger and more robust than in other species of Rousettus , with deeper and broader rostrum. Braincase is moderately deflected. Frontal region between postorbital processes is flattened, with width of interorbital constriction in adult specimens distinctly larger than width of postorbital constriction. Temporal crests unite into sagittal crest a short distance behind postorbital processes. Palate is usually broader posteriorly than between canines. Palatal ridge pattern is 4+ 4+ 1or4+3+ 1. Dental formula and tooth morphology are conservative. P! is much reduced, M, is shorter than other two molars combined, and upperincisors are almost equidistant. Tympanic bone does not extend into auditory meatus. Chromosomal complement has 2n = 36 and FN = 66-68, with twelve pairs of metacentric or submetacentric, four pairs of medium-sized subtelocentric, and one pair of small acrocentric autosomes. X-chromosome is medium-sized submetacentric, and Y-chromosome is the smallest acrocentric in the set.

Habitat. Arid to moist tropical biomes from sea level up to elevations of ¢. 4000 m. Populations of Egyptian Rousettes in arid areas of northern Africa and the Middle East have a patchy distribution in human-altered areas with increased roost and food availability.

Food and Feeding. The Egyptian Rousette feeds mostly on soft fruits from at least twelve genera of native species (e.g. Ficus , Moraceae ) in nine families and introduced species including cultivated Rosaceae (e.g. plum, loquat, and apple) and Rutaceae (Citrus) . After fruits have been collected from trees, individuals often use other trees as feeding roosts. Adults consume 50-150% of their body weight daily. Consumption increases for pregnant and lactating females to meet increased nutritional demands. Egyptian Rousettes forage in groups. They might also feed on flowers, occasionally leaves, and even insects. Feeding on insects has been inferred by analyses offeces,saliva, and stomach contents and with direct observation. Egyptian Rousettes deliberately forage for insects; in an urban setting in South Africa, they foraged for and consumed garden fruit chafers (Pachnoda sinuata, Coleoptera), alternating with consumption of figs that were also available in the same area. Efficient glucose absorption by the intestine happens mostly through passive paracellular absorption. Olfaction plays an important role in finding and selecting food. In its Mediterranean distribution, Egyptian Rousettes are viewed as agricultural pests in commercial orchards.

Breeding. Reproductive seasonality of the Egyptian Rousette varies geographically. In some regions, it reproduces year-round, and in other regions, reproduction can be biannual (e.g. DR Congo) or concentrated in one breeding season that lasts one to several months (e.g. South Africa). In areas where births are seasonal, they tend to occur during rainy seasons. Although females usually give birth to one young, twins seem to occur frequently. Gestation lasts 105-107 days in captivity. Lactation lasts 60-70 days. Testes of subadult males are abdominal and scrotal in adult males. Testes are ovoid or round and during mating are c. 13 mm long; seminal vesicles increase in size during mating. Uterus is duplex and symmetrical, and two uterine horns are externally united. There is evidence to suggest that ovaries function alternately from one pregnancy to the next. Pregnancy rates are 80-96%. Neonatal crown-rump length is ¢. 56 mm, and weights at birth are 18-24 g. Neonates are born with folded ears and closed eyes. They are naked except for thin, downy covering on head and dorsum. At ten days of age, ears become erect and mobile, and eyes open. In ¢.9 months of age, both sexes have attained adult size and weight.

Activity patterns. Egyptian Rousettes leave their roosts to feed every night. Activity initiates after sunset and ends before sunrise. A study in South Africa showed that the period of activity in summeris longer than in winter when start of activity is a little delayed and individuals return earlier to roosts. The Egyptian Rousette typically roosts in caves but also uses different types of holes and crevices including artificial ones (tombs, temples, mines, tunnels, etc.). This habit is facilitated by its echolocation abilities. Species of Rousettus are able to use echolocation, accomplished by tongue clicking. Egyptian Rousette calls last 140-250 microseconds and allow individuals to detect and avoid, experimentally, 6-mm wires. Echolocation is used in light and dark conditions.

Movements, Home range and Social organization. Colonies of Egyptian Rousettes have from 100 to several thousand individuals (up to 40,000 -50,000). Colonysize fluctuates seasonally, and during breeding season (summer), sexes segregate, with females forming nursery colonies. Roosts are often shared with other bat species. Individuals cluster together forming clusters in dark corners and crevices, whose availabilities can limit population sizes. Seasonal migration follows fruit abundance, especially in Mediterranean populations. Individuals in a colony interact with vocalizations and grooming. A study suggested that individuals spend about one-half of their nights in grooming activity, during which body, head, and wings are thoroughly combed and cleaned. Fights seem to be frequent and include bites, strikes, and loud screams. Because of their cave roosting habit, Egyptian Rousettes might travel long distances to food sources. Tracking and genetic studies indicate relatively high gene flow among populations.

Status and Conservation. Classified as Least Concern on The IUCN Red List. The Egyptian Rousette has a wide distribution and large overall population and is adaptable to human-modified environments. It is hunted for food in some parts of Africa. In its Mediterranean distribution, fruit farmers considerit a pest leading to destruction and fumigation of caves, although these practices have stopped in some countries (e.g. Israel).

Bibliography. Andersen (1912b), Barclay et al. (2006), Bergmans (1979a, 1994), Bernard (1988a), Centeno-Cuadros et al. (2017), Del Vaglio et al. (2011), Herzig-Straschil & Robinson (1978), Holland et al. (2004), Jacobsen & DuPlessis (1976), Jones (1971), Korine (2016), Korine et al. (2004), Kwiecinski & Griffiths (1999), Penzhorn & Rautenbach (1988), Tracy et al. (2007), Waters & Vollrath (2003).

Figures

32. Zenker’s Fruit Bat (Scotonycteris zenkeri), 33. Hayman’s Fruit Bat (Scotonycteris occidentalis), 34. Bergmans’s Fruit Bat (Scotonycteris bergmansi), 35. Short-palated Fruit Bat (Casinycteris argynnas), 36. Pohle’s Fruit Bat (Casinycteris ophiodon), 37. Campo-Ma’an Fruit Bat (Casinycteris campomaanensis), 38. Lesser Dawn Bat (Eonycteris spelaea), 39. Greater Dawn Bat (Eonycteris major), 40. Philippine Dawn Bat (Eonycteris robusta), 41. Geoffroy’s Rousette (Rousettus amplexicaudatus), 42. Bare-backed Rousette (Rousettus spinalatus), 43. Leschenault’s Rousette (Rousettus leschenaultin), 44. Linduan Rousette (Rousettus linduensis), 45. Sulawesi Rousette (Rousettus celebensis), 46. Egyptian Rousette (Rousettus aegyptiacus), 47. Malagasy Rousette (Rousettus madagascariensis), 48. Comoro Rousette (Rousettus obliviosus), 49. Long-haired Fruit Bat (Stenonycteris lanosus)

Subspecies and Distribution. R.a.aegyptiacusE.GeoffroySaint-Hilaire,1810—MiddleEastinSTurkey,Cyprus,WSyria,Lebanon,Israel,WJordan,andEgypt(NcoastandNileValley). R.a.arabicusJ.Anderson&deWinton,1902—ArabianPeninsula,SIran,andSWPakistan. R.a.leachiiA.Smith,1829—E&SAfrica,fromEthiopiatoSouthAfrica. R.a.princeps Juste &Ibanez,1993—-Principe1. R.a.tomensis Juste &Ibanez,1993—SaoToméI. R. a. unicolor]. E. Gray, 1870 — W Africa, from Senegal to WC Angola ; also on Bioko I. Introduced during the 2000s in the Canary Is (Tenerife), but probably successfully eradicated and no longer present.