Pteropodidae Author Don E. Wilson Author Russell A. Mittermeier text 2019 2019-10-31 Lynx Edicions Barcelona Handbook of the Mammals of the World – Volume 9 Bats 16 162 book chapter 88683 10.5281/zenodo.6448815 bbbf94d9-a910-4cda-97df-7eca124163ed 978-84-16728-19-0 6448815 82. Lesser Naked-backed Fruit Bat Dobsonia minor French: Petite Roussette / German: Kleiner Nacktrickenflughund / Spanish: Dobsonia pequeno Other common names: Lesser Bare-backed Fruit Bat Taxonomy. Cephalotes minor Dobson, 1879 , “Amberbaki, [north-west] New Guinea .” A record from Sulawesi , attributed to D. minor by Boeadi and W. Bergmans in 1987, might represent an incidental vagrant, an undescribed subspecies, or species based on generally larger teeth and longer lower tooth row. Monotypic. Distribution. New Guinea including Yapen I, also on tiny Bagabag I offshore NE coast based on three skulls. Descriptive notes. Head-body 102-135 mm , tail 5-28 mm , ear 13-22 mm , hindfoot 16-24 mm , forearm 78-92 mm ; weight 63-90 g . The Lesser Naked-backed Fruit Batis the smallest species of Dobsonia . Fur is uniform dark brown. Semi-transparent brown flight membranes meet at midline of lower back. Fur underlies naked-backed part of wing membranes. Claws on thumbs and feet are dark brown. Index claw (second digit of wing) is absent. Ears are narrow and moderately long, and tips just barely touch if adpressed together. Nostrils are divergent and shortly tubular and extend slightly beyond snout. A shorttail is present and free of uropatagium. Uropatagium is narrow and runs length of legs, terminating at supporting calcar. Eyes are large, with brown irises. Dental formula for all species of Dobsoniais11/1,C1/1,P 2/3, M 2/3 (x2) = 28. Incisors are minute, and I, (I, missing) require hand lens to see clearly. Canines are slender. P,, M, and M,, and P? are reduced in size. Premolars and molars are simple, lacking well-marked anterointernal and posterior basal ledges or surface ridges. Habitat. Primary and secondary forests, swamp forests, and village gardens from sea level up to elevations of ¢. 600 m . Roosting habitat usually is in forest understories. Food and Feeding. The Lesser Naked-backed Fruit Bat is frugivorous, and fig species including Ficus bernaysii and F hispidioides ( Moraceae ) are important dietary items. It regularly feeds on infructesences of the introduced invasive shrub Piper aduncum ( Piperaceae ), which since its World War II accidental introduction overgrows abandoned village gardens and along riverbanks in many areas of Papua New Guinea . It also eats papaya ( Carica papaya, Caricaceae ) in active village gardens. Breeding. Female Lesser Naked-backed Fruit Bats have one young per pregnancy. In northern New Guinea , pregnancy is not highly synchronized and has been recorded in January, April-June, and September; lactation in February and April; and volant young in August and December. Males with epididymides containing sperm have been found in June. This information suggests either asynchronous timing of reproduction or that there might be two annual birth periods in dry and wet seasons. Activity patterns. The Lesser Naked-backed Fruit Bat is nocturnal, with foraging activity confined to hours of darkness. During daylight, it roosts in foliage in closed-canopy forests, usually alone or females with dependent young. Basal metabolic rate (BMR) for adults averages 101% of that expected for a mammal with its body weight; however, volant young (mean body mass 49- 7 g ) have very low BMR, representing only 58% of that expected from body weight. A single, audible call note, described as a “high-pitched bleat,” is periodically made during flight, perhaps acting as a contact note to conspecifics. Movements, Home range and Social organization. Lesser Naked-backed Fruit Bats roost alone. Individual bats used 1-3 roost trees/month during a radio-tracking study, none of which were more than 300 m apart. Males and females occupied home ranges of 1-4-9-4 ha (mean 5-1 ha, no significant difference by sex) when tracked up to a month. Maximum movements observed across home ranges was 1150 m . Individuals that were radio-tracked two or more times for up to 19 months during different seasons expanded or contracted foraging movements in response to spatialtemporal distribution of fruiting fig trees; however, these individuals continued to feed in core areas that included P. aduncum concentrations over their long seasonal fruiting periods. Physiological responses to environmental temperatures likely to be encountered in its foliage roosts include regulation of constant body temperature at a mean of 36-5°C, BMR near mammalian mass-specific standard (101% ofexpected), and minimal thermal conductance (103% of expected from body weight for a resting mammal) also near the mammalian standard. Maintenance of high body temperature should be important to foliage roosting Lesser Naked-backed Fruit Bats to allow instantaneous flight in response to many potential predators, notably a large number of arboreal pythons, tree boas, and brown tree snakes. Status and Conservation. Classified as Least Concern on The IUCN Red List. While Lesser Naked-backed Fruit Bats occur at low densities throughout their large distribution, they are adaptable to disturbance and forest fragmentation of primary forest habitats in New Guinea due to logging and forage in secondary forests and patchwork subsistence gardens. Bibliography. Bartholomew et al. (1970), Bergmans & Sarbini (1985), Boeadi & Bergmans (1987), Bonaccorso (1998), Bonaccorso et al. (2002), Flannery (1995a, 1995b), Hutson, Suyanto, Helgen & Bonaccorso (2008d), Koopman (1979), McNab & Bonaccorso (2001).