Rousettus amplexicaudatus, E. Geoffroy 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 : 85

41.

Geoffroy’s Rousette

Rousettus amplexicaudatus

French: Roussette de Geoffroy / German: Geoffroy-Flughund / Spanish: Rosetus de Geoffroy

Other common names: Common Rousette

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

“L’ile de Timor [= Timor: Island],” Lesser Sunda Islands.

Subspecies of R. amplexicaudatus differ mainly in size, with amplexicaudatus being the largest and brachyotis the smallest. The form hedigeri from Bougainville Island ( Solomon Islands) is considered a synonym of brachyotis ; the form minor from Java is considered a synonym of infumatus. Taxonomic status ofthe recently described R. tangkokoensis by H. J. Lengkong and colleagues in 2016 from northern Sulawesi, similar to R. amplexicaudatus , needs additional investigation. Three subspecies recognized.

Subspecies and Distribution.

R.a.amplexicaudatusE.GeoffroySaint-Hilaire,1810—mainlandSEAsia(C&SEMyan-mar,SCChinainYunnan,NLaos,andNVietnamStoMalayPeninsula),Philippines,MentawaiIs(NorthPagai),EngganoI,Borneo,Moluccas,ELesserSundaIs(Flores,Sawu,Roti,Timor,andKisar),TanimbarIs,NewGuinea(includingWaigeo,Batanta,Salawati,andYapenIs),andLouisiadeArchipelago(SideiaI);SulawesianandnearbyIspopulations(Sangihe,Thulandang,Talisei,Lembeh,Batudaka,andPeleng)aretentativelyassignedtothissubspecies.

R.a.brachyotisDobson,1877—AdmiraltyIs(Manus),BagabagI,BismarckArchipelago(Mussau,Emirau,NewHanover,NewIreland,Dyaul,Tabar,Lihir,DukeofYork,andNewBritainIs),andSolomonIs(Buka,Bougainville,Fauro,Choiseul,VellaLavel-la,Kolombangara,NewGeorgia,Vangunu,SantaIsabel,Guadalcanal,NggelaSule,Malaita,andSanCristobal).

R. a. infumatus J. E. Gray, 1870 — Sumatra, Java, and W Lesser Sunda Is (Bali, Nusa Penida, and Lombok; possibly also on Alor).

Descriptive notes. Head—body 128-154 mm, tail 13-24 mm, ear 16- 5-24 mm, hindfoot 19-21 mm, forearm 70-92 mm; weight 64-106 g. Males are always larger on average than females. Geoffroy’s Rousette is similar to Leschenault’s Rousette ( R. leschenaultii ), distinguished by subcircular (as opposed to elliptical) occlusal outline of M,, narrower ears, and proportionally more slender and shorter rostrum. Ears are narrow, tips are not attenuated, and antitragus is small and round. Fur coloris similar to that of other species of Rousettus : generally brown and grayish drab on chest, breast, and belly. It has been suggested that darker hue might be useful to distinguish Geoffroy’s Rousette from other eastern species of Rousettus . Head, back, and rump range from dark brown to dark olive or sepia-brown; nape is wood-brown to greenish brown; sides of neck and fore neck are more or less suffused with wood-brown or tawny olive in males and greenish brown in females. Distinct band of dorsal fur, 15-35- 5 mm wide, occurs between both plagiopatagium insertions. Furis rather short and sparse. Neck region is almost naked. Uropatagium and tibia are almost bare. Adults of both sexes can have two bright-colored and bristly hair tufts, one at either side of neck; these tufts occur especially in older specimens and are often absent, without geographical regularity. Wing membranes are dark brown but are nearly translucent over bones giving appearance of white stripes. Claw is present on index finger. Palatal ridges are variable depending on subspecies: 3+4+1,4+3+1,0or4+4 +1 (less commonly). Dental formula for all species of Rousettusis12/2, C1/1,P 3/3, M 2/3 (x2) = 34. Dentition is conservative in tooth number and structure of dental pieces. There is a tendency in Geoffroy’s Rousette for reduction of interspace between C' and P?%P! in some individuals is closely wedged between those two teeth (absent in a few individuals); this characteristic is variable, without correlation to geography. Premolars and molars vary in size but are similar to those of Leschenault’s Rousette. Chromosomal complement has 2n = 36 and FN = 68.

Habitat. Primary and secondary forests, mixed agricultural land (orchard), and open areas, from sea level up to elevations of ¢. 2200 m. Geoftroy’s Rousette also occurs in residential areas up to elevations of ¢. 500 m.

Food and Feeding. Geoffroy’s Rousette is frugivorous but also eats nectar. It often feeds on overripe fruits, minimizing their damage in commercial orchards. On Panay Island ( Philippines), diets included native and exotic fruits from at least 14 genera and eleven families. Ficus was very important on Panay Island, with eleven species included in diets. Flowers from Erythrina (Fabaceae) and Barringtonia (Lecythidaceae) are used.

Breeding. On Negros Island ( Philippines), multiparous Geoffroy’s Rousettes gave birth in March-April and usually August-September, a pattern of seasonal bimodal polyestry. Exact timing of these birth periods probably varies from year to year, but births coincide with beginning of dry season and early wet season. Females were lactating and pregnant when captured in April-May, indicating that most females have young in both birthing periods and postpartum estrus. Females become pregnant in their first year oflife; first births occurred in broad peak from June to late August. Gestation is ¢.150 days, and lactation lasts ¢.60 days. Crown—rump length of neonates is ¢. 47 mm. A similar reproductive pattern was observed in New Guinean populations, with females producing two litters of one young annually. Geoffroy’s Rousettes might have a harem-type of mating system; adult males are less abundant than females.

Activity patterns. On Mindanao, Geoffroy’s Rousette roosted in caves with large openings and close to water, and it might use rock crevices and old tombs. It is docile when handled, rarely calling or biting.

Movements, Home range and Social organization. Geoffroy’s Rousette roosts in large colonies of2000-100,000 individuals. On the Island of Samal ( Philippines), the world’s largest colony of Geoffroy’s Rousette was estimated at ¢.883,000 individuals in the first 100 m of a 150 m-long cave (Monfort Cave). It often roosts in association with other fruit bats such as the Lesser Dawn Bat ( Eonycteris spelaea ). A capture-recapture study suggested that individuals have large home ranges. Geoftroy’s Rousettes regularly fly long distances (more than 20 km /night) to forage. Genetic studies based on allozymes showed little genetic differentiation among populations in the Philippines, indicating high dispersal ability.

Status and Conservation. Classified as Least Concern on The IUCN Red List. Geoffroy’s Rousette is widespread, with common and abundant populations, and seemingly not declining at a fast rate. Nevertheless,it is heavily hunted in South-east Asia, Borneo, and the Philippines and regarded as a pest in parts ofits distribution.

Bibliography. Bergmans & Hill (1980), Bergmans & Rozendaal (1988), Carpenter, E.S. et al. (2014), Csorba, Rosell-Ambal & Ingle (2008), Francis (1989), Galorio & Nuneza (2014), Heaney, Dolar et al. (2010), Heaney, Walsh & Peterson (2005), Heideman & Heaney (1989), Heideman & Utzurrum (2003), Hill (1983), Hodgkison et al. (2004b), Hood et al. (1988), Lengkong etal. (2016), Rookmaaker & Bergmans (1981), Tanalgo & Hughes (2018), Tanalgo & Tabora (2015).

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.amplexicaudatusE.GeoffroySaint-Hilaire,1810—mainlandSEAsia(C&SEMyan-mar,SCChinainYunnan,NLaos,andNVietnamStoMalayPeninsula),Philippines,MentawaiIs(NorthPagai),EngganoI,Borneo,Moluccas,ELesserSundaIs(Flores,Sawu,Roti,Timor,andKisar),TanimbarIs,NewGuinea(includingWaigeo,Batanta,Salawati,andYapenIs),andLouisiadeArchipelago(SideiaI);SulawesianandnearbyIspopulations(Sangihe,Thulandang,Talisei,Lembeh,Batudaka,andPeleng)aretentativelyassignedtothissubspecies. R.a.brachyotisDobson,1877—AdmiraltyIs(Manus),BagabagI,BismarckArchipelago(Mussau,Emirau,NewHanover,NewIreland,Dyaul,Tabar,Lihir,DukeofYork,andNewBritainIs),andSolomonIs(Buka,Bougainville,Fauro,Choiseul,VellaLavel-la,Kolombangara,NewGeorgia,Vangunu,SantaIsabel,Guadalcanal,NggelaSule,Malaita,andSanCristobal). R. a. infumatus J. E. Gray, 1870 — Sumatra, Java, and W Lesser Sunda Is (Bali, Nusa Penida, and Lombok; possibly also on Alor).