Pteropus pelagicus, Kittlitz, 1836

Don E. Wilson & Russell A. Mittermeier, 2019, Pteropodidae, Handbook of the Mammals of the World – Volume 9 Bats, Barcelona: Lynx Edicions, pp. 16-162 : 139

143.

Chuuk Flying Fox

Pteropus pelagicus

French: Roussette de Chuuk / German: Mortlock-Flughund / Spanish: Zorro volador de Chuuk

Other common names: Seaside Flying Fox

Taxonomy. Pteropus pelagicus Kittlitz in Lutké, 1836,

Lukunor Atoll, Mortlock Islands, Chuuk State, Federate States of Micronesia.

Pteropus laniger and P. phaeocephalus are synonyms and the form insularis is included here as a subspecies. Pteropus pelagicus is in pelagicus species group. Two subspecies recognized.

Subspecies and Distribution.

P.p.pelagicusKittlitz,1836—C&SMortlockIs,possiblyextirpatedfromLosapAtollinNMortlocks(ChuukState,Micronesia).

P. p. insularisJacquinot & Pucheran, 1853 — Chuuk Lagoon, Namonuito Atoll (Chuuk State, Micronesia).

Descriptive notes. Head-body 150-186 mm (tailless), ear 20-24 mm, forearm 101- 105 mm; weight 142-203 g. Nominate subspecies ( pelagicus ) is mainly distinguished from insularis by its brighter color, more contrastingly colored (paler) mantle, larger white or pale buff mid-ventral patch, and larger cranial size. Muzzle of the Chuuk Flying Fox is moderately long and sparsely haired. Eyes are relatively large, and ears are small, with broadly rounded offtips. Head pelage is dark brown, blackish in some individuals, or grayish brown due to grizzled cap; mantle is creamy white to deep buff or tawny, medially divided by brown stripe, extending laterally to shoulders where it is often paler; and back is dark brown, with long hairs loosely adpressed, interspersed with rusty hairs especially toward rump. Tibia is naked dorsally and relatively long; uropatagium is narrow at center; and calcar is short. Throat, chest, and upper belly are rusty brown or reddish brown, with creamy white or pale buff patch. Lower belly is dark brown. Wing membranes are dark brown or black; index claw is present. Skull is typical pteropine, with moderate basicranial deflection. Laterally, rostrum is moderately long and wide, gently sloping into forehead; orbit is moderately large; braincase is domed; zygomatic roots are at level of upper alveolar line; and zygoma is moderately arched. Dorsally, rostrum is straight-sided, postorbital foramina are present, postorbital processes are thick at bases, relatively long postorbital constriction is well-marked, temporal lines join in thin low sagittal crest, nuchal crest is obvious, and braincase is oval or piriform (pear-shaped). Ventrally, palate is flat and long, premaxillae are small and arched, tooth rows are nearly parallel, post-dental extension of palate is relatively short, palate is deeply concave, pterygoids are large, ear bones are relatively small, and ectotympanic is ring-like. Mandible has sloping symphysis and moderately thick body; coronoid is inclined, with broad tip; condyle is almost level with lower alveolar line; and angle is rounded and indistinct. Eleven palatal ridges are arranged in the pattern b +4 + 2. Dentition is typical pteropine. Upper incisors are spatulated, with basal ledge on lingualside; C' is moderately long, with lingual cingulum showing laterally as basal cusp; P' is a spicule, often missing in adults; posterior cheekteeth decrease in height and are roughly rectangular in occlusal outline; and last molar is small, with poorly defined cusps. Lower inner incisors are smaller than outer incisors; C, is relatively short and slender, with large distal and lingual cingulum; P| is comparatively large and lowcrowned; posterior cheekteeth are relatively low and rectangular in occlusal outline; and last molar is comparatively large.

Habitat. Tropical moist forests with extensive coastal coconut ( Cocos nucifera, Arecaceae ) and breadfruit trees ( Artocarpus spp. , Moraceae ).

Food and Feeding. The Chuuk Flying Fox is frugivorous; ripe breadfruit ( Artocarpus spp. ) is preferred. Other foods include fruit from Musa (Musaceae) , Carica (Caricaceae) , Calophyllum (Calophyllaceae) , Crataeva ( Capparaceae ), Pandanus (Pandanaceae) , and Ficus (Moraceae) . Coconut trees are visited and likely flowers and unripe fruit are eaten. Foraging behavior has been recorded only once on a Pandanus tree where individuals flew in and out of foliage taking ripe fruit and carrying pieces in flight, presumably to a feeding roost.

Breeding. Unlike most species of Pteropus , the Chuuk Flying Fox probably breeds continuously because births and females with dependent young are recorded in many months of the year. Litter size is one. Newborn clings to ventral side of its mother and is carried in flight. Young remain in close contact with their presumed mothers long after they are able to fly.

Activity patterns. The Chuuk Flying Fox is active at all times of day, with peaks after sunset and before sunrise while moving between day roost and foraging areas. It roosts in crowns of coconut and breadfruit trees.

Movements, Home range and Social organization. The Chuuk Flying Fox roosts alone or in small groups of 5-10 individuals, with two observations of loose aggregations of 27 and 50 individuals. It is frequently observed flying between islands near sunset.

Status and Conservation. CITES Appendix I (as Pteropus insularis). Not assessed on The IUCN Red List. The Chuuk Flying Fox probably merits classification as Endangered given its restricted distribution, vulnerability to large-scale stochastic events (cyclones) and rising sea level due to global climate change, and relatively small, fragmented, formerly declining population. According to island residents, population of subspecies pelagicus was larger in the past and has remained stable in recent years; it was estimated in 2004 to be 925-1200 individuals in four atolls where it is known to occur, with 75% of the population in two atolls with the largest land area (Satawan and Lukunor); total extent of occurrence is only 10- 1 km *. Data are lacking on subspecies insularis, but commercial hunting in the 1980s reduced its population in Chuuk Lagoon. Main threats to existing populations of the Chuuk Flying Fox include severe mortality in the aftermath of the devastating cyclones that might increase in frequency and sea levelrise associated with global climate change with the potential to submerge atolls. High tides flood islets and resulting salty soils cause considerable damage to plants heavily used by Chuuk Flying Foxes. Overhunting has been important in the past; bats harvested in Chuuk State were exported to the Guam market in the late 1980s, but inclusion of the Chuuk Flying Fox in the CITES Appendix I has halted or greatly reduced impact of international commerce on existing populations. Locally, Chuuk Flying Foxes are not hunted for food but are perceived as a pest of cultivated fruit, although they are not killed to avoid crop damage. They are not known to occur in any protected area.

Bibliography. Allen (1890a), Almeida et al. (2014), Andersen (1912b), Buden et al. (2013), Flannery (1995a), Thomas (1883).

Figures

127. Wallace's Stripe-faced Fruit Bat (Styloctenium wallacei), 128. Mindoro Stripe-faced Fruit Bat (Styloctenium mindorensis), 129. Small-toothed Fruit Bat (Neopteryx frosti), 130. Sulawesi Flying Fox (Acerodon celebensis), 131. Talaud Flying Fox (Acerodon humilis), 132. Golden-capped Flying Fox (Acerodon jubatus), 133. Palawan Flying Fox (Acerodon leucotis), 134. Sunda Flying Fox (Acerodon macklotii), 135. Moluccan Masked Flying Fox (Pleropus personatus), 136. Lombok Flying Fox (Pteropus lombocensus), 137. Little Red Flying Fox (Pteropus scapulatus), 138. Big-eared Flying Fox (Pteropus macrotis), 139. Gilliard’s Flying Fox (Pteropus gilliardorum), 140. Sanborn’s Flying Fox (Pleropus mahaganus), 141. Dwarf Flying Fox (Pteropus woodfordi), 142. Pohnpei Flying Fox (Pteropus molossinus), 143. Chuuk Flying Fox (Pteropus pelagicus)

Subspecies and Distribution. P.p.pelagicusKittlitz,1836—C&SMortlockIs,possiblyextirpatedfromLosapAtollinNMortlocks(ChuukState,Micronesia). P. p. insularisJacquinot & Pucheran, 1853 — Chuuk Lagoon, Namonuito Atoll (Chuuk State, Micronesia ).