Roosting ecology and morphometric analysis of Pteropus medius (Indian flying fox) in Lower Dir, district, Pakistan

The present study was conducted to explore morphometric variations of Pteropus medius (the Indian flying fox) and the roosting trees in Lower Dir, Pakistan. The bats were captured from Morus alba, Morus nigra, Brousonetia papyrifera, Pinus raxburghii, Hevea brasiliensis, Platanus orientalis, Populous nigra, Melia azedarach, Eucalyptus camaldulensis and Grevillea robusta through sling shot and mess net methods. A total of 12 bats were studied for the differential morphological features based on age and sex. Male bats were recorded higher in weight than females. The variations were found in body mass (821.1+34.65gm), circumference of body with wings (25.43+0.39cm), wingspan (112.58+1.90cm), Body length (20.73+0.68cm), Snout length (3.42+0.04cm), Eye length (1.45+0.033cm), Length of ear (3.56+0.05cm), Width of ear (2.46+0.04cm), Length b/w ear (5.51+0.11cm), Circumference of neck (12.23+0.24cm), Circumference of body without wings (18.68+0.31cm), Arm wing length (23.2+1.03cm), Length of thumb (5.43+0.1cm), Length of nail (1.89+0.05cm), Hand wing length (29.1+0.51cm), Maximum width of wing (21.03+0.68cm), Length b/w tip of wing to 5 th digit (29.39+0.30cm), Length b/w 5 th digit to foot (22.97+1.09cm), Length b/w feet (18.31+0.74cm) and Length of foot claw (4.23+0.05cm). This study was designed for analysis of external morphological variations for P.medius (the Indian flying fox) that may help in identification of these bats and their roosting sites.


Study area
Lower Dir is located at North of Malakand and about 130 km from Peshawar (capital of the province) and 40 km away from Mingora, Swat. This area lies at 34, 6500 (3438'60.000"N), Latitude; 72, 0333 (721'59.880"E) longitude and 687m altitude. The annual rainfall range from (600mm-1100mm) and average maximum and minimum temperature are about 29C 0 and 12C 0 , respectively.

Data collection
Pteropus medius (Indian flying fox) were captured with the aid of net and slingshots. The samples were safely brought to the Laboratory of Parasitology, Department of Zoology, University of Malakand for morphometric analysis.

Morphometric analysis
The collected animals werekilled in a vacuum chamber by using cotton wetted with chloroform. All the specimens were measured with the aid of plastic ruler

Roosting site analysis
The bats colonies were counted through the direct roost count method (Herrera et al., 2008) on different trees and the data was saved in written form. The research area was periodically visited and bats were counted on different species of trees.

Statistical analysis
The recorded data were put in excel for statistical analysis and their corresponding results were mentioned in this paper.

Morphological characteristics (average) of Pteropus medius.
Morphological observations shows that Indian flying fox is dark brown in colour with body weight 821.1+34.65gm, body length: 20.73+0.68cm, snout is elongated and hairy:3.42+0.04cm, ears are tall, black and pointed at tips: 3.56+0.05cm, width of ear: 2.46+0.04cm, length b/w ears: 5.51+0.11cm, eye length: 1.45+0.033cm, circumference of neck: 12.23+0.24cm, the wings are massive, long and pointed, circumference of body without wings: 18.68+0.31cm, arm wing length: 23.2+1.03cm, wingspan length: 112.58+1.90cm and Circumference of body with wings: 25.43+0.39cm, width of wing:21.03+0.68cm, hand wing length: 29.1+0.51cm, length of thumb is 5.43+0.1cm, the thumb or first digit has greater claw, while the claw of the second digit is small, length b/w tip of wing to 5 th digit: 29.39+0.30cm, length of nail: 1.89+0.05cm, the feet are large with blunt claws, length b/w 5 th digit to foot: 22.97+1.09cm, length b/w feet:18.31+0.74cm, length of foot claw length:4.23+0.05cm.The males bats were calculated larger in size then females bats and measurements of external parameters were observed variable because of differences in age and sex.

Introduction
The bats exhibit a remarkable diversity and broad geographic range (Simmons, 2005). Bats are found everywhere in the world except Arctic, Antarctica and some islands (Hutson et al., 2001) and comprising 1,232 species representing a quarter of the total 5,487 mammal species (Schipper et al., 2008;Simmons 2010;Kunz et al., 2011). However, about 119 bat species found in the subcontinent including Pakistan (Bates and Harrison, 1997).
The roosting sites in Pakistan provides natural habitats for the survival of bat fauna (Perveen and Jamal, 2012;Perveen and Rahman, 2012). In Pakistan bats comprise about one fourth of the known mammalian species which comprise 50 species with 26 genera and 8 families (Roberts, 1997). Three genera and four species of Pteropodids bats including short nosed fruit bat (Cynopterus sphinx), the Indian flying fox (Pteropus giganteus), the Egyptian fruit bat (Rousettus aegyptiacus), and the fulvous fruit bat (Rousettus leshenaulti) are found in Pakistan (Roberts, 1997;Mahmood-ul-Hassan et al., 2009).
Pteropus giganteus is generally a colonial species and roost in large trees often in area with topographic features offer protection from strong winds, assist in thermoregulation and provide access to updrafts for easier flight (Cheke and Dahl, 1981;Pierson and Rainey, 1992;Richmond et al., 1998). Flying foxes acquire shelter and energy from plants and in turn disperse the pollen and seeds of the plants ( Ganesh and Davidar, 2001). Roosts of Indian flying fox were also observed in forest plantations of Casurina species, Acacia species, and indigenous tree species like Ficus, Bauhinia, rain tree (Samanea saman) and Indian date (Tamarindus indica) (Chakravarthy and Yeshwanth Hm, 2008). Roosting site selection depends on their abundance, risk of predation, availability and distribution of food resources, body size and physical environment (Kunz, 1982).
Body measurements of the P. giganteus have been recorded by Roberts (1997), bates and Harrison (1997), Aziz et al. (2007) and Molur et al. (2007). Characters like body mass, wing morphology and forearm length may be designated important parameters for autecological considerations (Aeshita et al., 2006).
Flying foxes are declining word-wide Stier and Mildenstein, 2005) due to growing human populations and consequent demands for food and housing that cause destruction of bat habitat (Fujita and Tuttle, 1991;Mickleburgh et al., 2002). Farmers and biologists of Pakistan considered them as non-significant animal, therefore, less research has been conducted on bat fauna in Pakistan (Butt and Beg, 2001).This research was aimed to gather information on differential morphology and roosting trees of the Indian flying fox.
The pelage of this species is long, varies in color at the shoulder and ventral surface, independent of age, sex and climate variations. Its body weight and fore-arm length are the greatest than all collected bats. It is frugivorous or nectarivorous, i.e., it eat fruits or lick nectar from flowers. At dusk, it forages on ripe fruits, while ingesting pulp of fruits, it expels waste that pollinates and disperses seeds. It is gregarious and roosts in nature. The further details of morphometric variations are given in Table 1.

Roosting trees
The total number of bats (2844) were counted and roosting trees in this area observed were Grevillea robusta (n=3), Populous nigra (n=73), Platanus orientalis (n=8), Hevea brasiliensis (rubber tree, n=1), Pinus raxburghii (n=9), Brousonetia papyrifera (n=13), Orus nigra (n=8) and Morus alba (n=5), Melia azedarach (3), and Eucalyptus camaldulensis (12). The maximum average number of bats was counted on platanus orietalis (26.5) and minimum average number of bats was counted on melia azedarach (5). The seasonal changes in place and separate roosting and feeding sits (persimmon gardens) were observed. There were thousands of trees of populous nigra and even hundered of the other trees but in this paper those trees mentioned in which bat was observed and the number of trees and bats counting are given in Table 2.

Discussion
The bats were identified on the basis of external morphology and measurements of different skull parameters (Hill and Smith, 1985;Vaughan et al., 2000;Jacobs et al., 2006) are still a highly reliable technique in most instances. The measurement of body mass of this species is large compared to other species and our result is similar to Simmons (2005) who stated that among all the bat species, P. giganteus is the world largest bat due to their largest body size and weight. Our results about average body weight of Pteropus medius (821.1+34.65gm), body length (20.73+0.68cm), wingspan (112.58+1.90cm) and males were larger than females are similar to (Marimuthu, 1998;Nowak, 1999;Thatcher, 2004;"Greater Indian Fruit Bat (Indian Flying Fox)", 2002) body mass of this species ranges from 600 to1600 and males are generally larger than females, wingspan may ranges from 1.2 to 1.5 m and body length average 23cm. In our collections some bats were exactly 23cm body length but the slightly difference is due to age and sex. Thumbs were observed for hanging to trees in this species in study area and the same view was given by Bennett (1993) that the pendent postures of mega chiropteran are hanging from one or both feet facilitated by locking mechanism.
In Pakistan P.giganteus was reported by Murray (1884) and Eates (1968) from Malir in Karachi. However, we were observed P.medius in Dir district. Moreover, it was reported from Mohlandar Mango Garden, Governor House, Jhelum in Multan, Mailsi in Punjab and Malakand in Pakistan by Roberts (1997). Khan (1985) claims the largest colony of Indian Flying fox in Bangladesh with 2500 individual of bats while we were observed 2844 individual in the roosting trees: Grevillea robusta, Populous nigra, Platanus orientalis, Hevea brasiliensis, Pinus raxburghii, Brousonetia papyrifera, Morus nigra, Morus alba,Melia azedarach, and Eucalyptus camaldulensis.
Over 6000 individuals of Indian flying fox colony was reported in Nallur near Chennai, Tamil Nadu (Smith, 1998). In present study all the roosting sites were located near water sources like rivers and streams of Lower Dir district, Pakistan. Most of the authors have been reported the same view that roosts commonly are found close to water (Fenton and Barclay, 1980;Kunz, 1982;Herd and Fenton, 1983;Thomas, 1988;Brigham et al., 1992).
Bats generally prefer to roost during daytime in diversified roosting habitats. Roosting site selection depends on their abundance, risk of predation, availability and distribution of food resources, body size and physical environment (Kunz, 1982). Bates and Harrison (1997) Richardson (1990).
The trees that provided great protection from environmental hazardous were more populated; help in flights and the same view were given by (Pierson & Rainey, 1992;Richmond et al., 1998). These bats use near fruits gardens for food during night time that are separated from their roosting sits and the same behavior selecting feeding and roosting sits separate has noted for other pteropus species (Pierson & Rainey 1992). P.giganteus were migrated to other place in winter for food and according to (Pierson & Rainey 1992) seasonal migration of Pteropus tend to be related to birthing season and (Nelson, 1965) migration is due to food abundance.

Conclusions
P.medius show variation in external morphological features due to age and sex differences, use separate feeding and roosting sits as well as diverse roost.