Greater Long Toothed or Greater Long Tongued Fruit Bat (Macroglossus sobrinus)

Distribution

M. sobrinus were mist-netted from Doi Suthep, Sungai Enam, Kuala Gandah, Wang Pinang Malaysia to Taleban on the Asia Mainland. This species is distributed in Burma, Thailand, Vietnam and Peninsular, Sumatra, Java and Bali (Lekagul and McNeely 1977, Medway 1978). This species is commonly found in hilly areas in Malaysia (Lim 1966).Range Description: This species ranges from north-eastern South Asia and Southern China, to much of Southeast Asia. In South Asia it is found in India (Arunachal Pradesh, Meghalaya, Tripura and West Bengal) (Molur et al. 2002). In Southern China, it is found in Mengla, Xishuangbanna and Yunnan (Smith and Xie 2008). In Southeast Asia, it ranges from Myanmar in the West, through Thailand, Lao PDR, Vietnam, possibly Cambodia (reports of this species from Cambodia cannot be confirmed [Kock 2000]) and Peninsular Malaysia, and from here occurs in Indonesia (the Mentawi Islands, Sumatra and Java). It has been recorded from elevations of up to 2,000 m asl.greater long-tongued fruit bats occupy a variety of habitats, including mangrove swamps, montane forests, and lowland forests. When range overlaps occur between Macroglossus sobrinus and Macroglossus minimus, it appears that M. minimus is restricted to coastal mangrove swamps while M. sobrinus is found in montane and lowland forests. A separate study in Thailand found the species in evergreen forests below 1918 m, where pollen is available year round. (Bates and Harrison, 1997; Lekagul and McNeely, 1988)

Population:

This is generally a locally common species. Nothing much is known of its population in South Asia (Molur et al. 2002).
Population Trend: Stable

Biology and ecology and Description

This species is found to prefer lowland and montane forest. It occurs in secondary habitats and also in old fruit orchards, villages, and banana plantations, rarely recorded in mangroves also common in association with humans, particularly under roofs of houses. Roosts singly or as a few animals, commonly in rolled up banana leaves. Not recorded roosting in caves (Bates and Harrison 1997).
Systems: Terrestrial
Five adult males and five adult females were recorded. On 25 March 1997, a full term foetus was aborted by a full term pregnant female (MTA97347) taken from Wang Pinang. Males with enlarged testes suggested that they were of sexually active state at Taleban in March 1997, Kuala Gandah in July 1997 and Doi Suthep in May 1997. M. sobrinus that were netted were all associated with banana plants in most sites and with flowering trees in Doi Suthep.
External measurements
FA = 46.12±1.25, TL = 3.81±1.07 (6), EL = 15.38±1.00, HD = 30.22±1.39, TB = 18.29±0.61, WT = 20.22±3.23, HB = 73.92±4.45, HF = 9.29±0.89, D5 = 58.50±1.73.
M. sobrinus can be isolated from M. minimus by using external morphological measurements. Comparatively, M. sobranus is than M. minimus in the forearm length (43.35 to 46.95 mm vs 40 to 43 mm) and head length (30.05 to 30.54 mm vs 26 to 28 mm) and heavier body weight (17 to 23 g vs 13 to19 g) (Medway 1978). However, the tail length (0-2 mm versus 0-5 mm) and hind foot (8 - 9 mm versus 15-18 mm) disagreed to that of Lekagul and McNeely (1977).Greater long-tongued fruit bats have slender, delicate skulls with long rostra. Length of skull is at least 30 mm. The skull has a low occipital crest, a palate ending beyond the last molar, and weakly developed postorbital processes. The braincase is deflected downward. Males have larger skulls than females. The mandible has low processes and is long and slender with a groove for the tongue at the front. The highly protrusible tongue has a feathery tip made of filiform papillae and is used in feeding on pollen. (Bates and Harrison, 1997; Lekagul and McNeely, 1988)
Greater long-tongued fruit bats have reduced dentition: cheek teeth are narrow and low-crowned. All teeth are well spaced linearly along the jaw. The incisor tooth row is elliptical with a large gap between both the upper and lower incisors through which the tongue protrudes. The gap between the lower incisors is larger relative to the upper gap. The incisors are forward-sloping and small, and the canines are short and sharp. (Bates and Harrison, 1997; Lekagul and McNeely, 1988)
The long pelage of Macroglossus sobrinus lacks markings. It is soft, fine, and light reddish-brown, with the chest coloured lighter than the head. On the dorsal surface, the pelage is uniformly clay-brown. Hairs are present the inner wing membranes, forearms, and upper surface of the tibiae. Members of this species exhibit no sexual dimorphism in fur colour. The ears are medium-sized with small antitragal lobes. Both ear and wing skin is dark brown. Short hairs thickly cover the upper and lower surfaces of the interfemoral membrane. These bats lack an external tail and have reduced calcars. (Bates and Harrison, 1997; Lekagul and McNeely, 1988)
Basal metabolic rate has not been documented, but in their close relative Macroglossus minimus, it falls around 0.88 and 1.48 cm^3 of oxygen/g/hr for lower range bats and highland bats, respectively. Macroglossus sobrinus closely resemble Macroglossus minimus, but the paler under parts and longer muzzle are distinguishing characteristics of the former species. (Bates and Harrison, 1997; Bonaccorso and McNab, 1997; Lekagul and McNeely, 1988)Little or no information exists on the mating systems of the species. However, male Macroglossus sobrinus have smaller testes relative to other mega chiropteran bats. Across species, testes size has a positive relationship with body size, but also correlates positively to group size, suggesting that members of this species do not live in large groups. Lower intraspecific sexual competition resulting from small or no group-living may be the cause of their reduced testes. (Hosken, 1998)
Breeding interval
Breeding interval is not known.

Breeding season
Greater long-tongued fruit bats may breed throughout the year.

Average number of offspring
One.
Greater long-tongued fruit bats probably breed year round. Other information on the reproduction of Macroglossus sobrinus is either limited or not available. The closely related Macroglossus minimus is better known. Gestation time of that species in Malaysia ranges from 110 to 130 days, followed by a lactation period of 60 to 70 days. On average, the length between pregnancies ranges from 140 to 160 days, so that Macroglossus minimus likely produces 2 to 2.5 offspring per year. Like most other bats, they give birth to a single young. The degree of seasonality present in reproduction of M. minimus varies with location. For example, reproduction on the island of Maripipi was not seasonal, while 9 km away on Biliran reproduction was more synchronous. (Bates and Harrison, 1997; Lekagul and McNeely, 1988)

Behaviour
Range territory size
1 to 2 km^2
Greater long-tongued fruit bats typically forage alone, with pairs found rarely. Individuals tend to roost alone, although small groups are also found. In Malaysia, these groups ranged from 5 to 10 individuals, most commonly found in palm trees, roofs, and banana plants. Macroglossus sobrinus, along with Macroglossus minimus, are responsible for the first peak feeding activity by Chiroptera each night. (Bates and Harrison, 1997; Gould, 1978)

Information on the behaviour of Macroglossus sobrinus is scarce, but more research has been done on the behaviour of its close relative, Macroglossus minimus. During the day, when inactive, Macroglossus minimus of Papua New Guinea roost individually. They have home ranges of around 5.8 hectare with very little overlap. This, along with prominent sternal scent glands, suggests territoriality, although this has not been definitively shown. In addition, Macroglossus minimus engages in “probing forays," potentially to scout new habitat. When temperatures reach 11-29 degrees Celsius, Macroglossus minimus enter a torpid state, maintaining a body temperature of 2-5 degrees Celsius above the ambient temperature. (Bonaccorso and McNab, 1997; Winkelmann, et al., 2003)

Communication and Perception

Like most members of Pteropodidae, greater long-tongued fruit bats do not use echolocation. These bats emit audible calls of less than 9 kHz with a duration of about 15 milliseconds and inter-call intervals around 128 milliseconds. Macroglossus sobrinus occasionally emits double pulses or clicks. The purpose of these double pulses is not yet known. In stressful disturbance situations, these bats emit harsh broadband signals as distress calls. The call is a large series of clicks with duration greater than 100 milliseconds. (Funakoshi, et al., 1995)

Food Habits

The diet of the greater long-tongued fruit bats varies among localities, but it appears to consist primarily of pollen and nectar, although soft fruit may be taken as well. In Malaysia, Macroglossus sobrinus was found to feed on the pollen and nectar of three species of wild banana, Dubanga grandiflora flowers, and soft fruit. Start (1974) estimated that an adult Macroglossus sobrinus could survive solely off two to three wild banana plants; due to the flowering habits of the banana, food would be available year-long. Generally, Macroglossus sobrinus is considered a banana specialist, although secondary food sources are also used. (Bates and Harrison, 1997; Lekagul and McNeely, 1988; Winkelmann, et al., 2003)

Greater long-tongued fruit bats move around 1 to 2 km per night while feeding, although this range may be significantly smaller in areas with higher densities of wild banana plants. It has been hypothesized (Gould, 1978) that individuals may follow set routes as they travel from plant to plant each night. (Bates and Harrison, 1997; Gould, 1978; Lekagul and McNeely, 1988)

Plant Foods
fruit; nectar; pollen; flowers

Major Threat(s):

There are no major threats to this widespread and adaptable species as a whole. In South Asia, this species is inferred to be locally threatened by habitat loss, largely through commercial extraction of bamboo and the conversion of land to agricultural use (Molur et al. 2002).

Ecosystem Roles

One of the major roles that Macroglossus sobrinus fills is that of a pollinator to a variety of ecologically important plant species. A study in 2002 found that Macroglossus sobrinus serves as an effective pollinator for Musa itinerans, an important pioneer species in the rain forests of south-western China. A separate study found that Macroglossus sobrinus serves an important role in the pollination of a wild banana, Musa acuminata. (Gould, 1978; Itino, et al., 1991)

Macroglossus sobrinus populations in Cambodia serves as a potential host for a variety of viruses in the Lyssavirus family. This is evidenced by the presence of anti-lyssavirus neutralizing antibodies in serum samples. (Reynes, et al., 2004)

Economic Importance for Humans: Negative

Greater long-tongued fruit bats have antigens for the Lyssavirus – a family of viruses containing rabies. It indicates that they may be carriers for the Lyssavirus, and could infect humans with rabies. Their large localized population density results in their being classified as vermin in India, although they do not harm people and are beneficial through pollination services. (Reynes, et al., 2004)

Predation

Predators specific to Macroglossus sobrinus are unknown, but Old World fruit bats generally have few predators. Snakes, birds of prey, and carnivorous mammals occasional prey on them. Of these, snakes are most common predators of bats in roosts. While predation influences behaviour and feeding habits, it does not significantly affect population size. (Mickleburg, et al., 1992)

Conservation Actions:

This species is present in many protected areas, and no direct conservation measures are needed as a whole. Within India, it is considered to be vermin under Schedule V of the Indian Wildlife (Protection) Act. The species has been recorded from protected area in India namely Namdapha Wildlife Sanctuary in Arunachal Pradesh. Survey, population monitoring, habitat management and awareness to policy makers are critical recommendations for India (Molur et al. 2002).

Conservation Status

IUCN Red List of Threatened Species [Link]
Least Concern
More Information

US Federal List [Link]
No special status

CITES [Link]
No special status

State of Michigan List [Link]
No special status

Due to the large range of Macroglossus sobrinus, the species is considered stable. The lack of endemic subspecies coupled with the locally common nature of Macroglossus sobrinus contributes to this assessment. In addition, the species is present in multiple protected areas across South Asia, minimizing the need for conservation measures. Although the species is generally “safe," it may be locally threatened as a result of habitat loss due to bamboo extraction and the conversion of land for agricultural use. Molur et. al. (2008) recommend survey, population monitoring, and habitat management to the Indian government. (Bates and Harrison, 1997; Hutson, et al., 2008)


Other Comments

Macroglossus sobrinus was considered to be a subspecies of Macroglossus minimus, from the works of E. Geoffrey in 1810 until the more recent research done by Hill in 1983. Currently, a variety of different authors consider M. sobrinus to be a distinct species, including Corbet and Hill (1992), Koopman (1993), Bates and Harrison (1997) and Simmons (2005). All Indian specimens are referred to by the subspecies name of Macroglossus sobrinus sobrinus. The species name Macroglossus sobrinus is also synonymous with Macroglossus fraternus. The common name is variable, although most sources use either “hill long-tongued fruit bats” or “greater long-tongued fruit bats”. (Bates and Harrison, 1997; Lekagul and McNeely, 1988; Hutson, et al., 2008; Wilson and Reeder, 1993)

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