Journal of the Bombay Natural History Society, 107(3), Sep-Dec 2010 183-188 SUMMER DIET OF INDIAN GIANT FLYING SQUIRREL PETAURISTA PHILIPPENSIS (ELLIOT) IN SITAMATA WILDLIFE SANCTUARY, RAJASTHAN, INDIA Chhaya Bhatnagar1'3, Vijay Kumar Koli14 and Satish Kumar Sharma2 ‘Aquatic Toxicology and Wildlife Research Laboratory, Department of Zoology, Mohanlal Sukhadia University, Udaipur 313 001, Rajasthan, India. 2Sajjangarh Wildlife Sanctuary, Udaipur 313 001, Rajasthan, India. Email: [email protected] 3Email: [email protected] 4Email: [email protected] Summer feeding habit of the Indian Giant Flying Squirrel Petaurista philippensis was studied from March 2009 to June 2009 in Sitamata Wildlife Sanctuary. These squirrels are arboreal and entirely depend on plant material. Of 2,157 feeding records, 13 plant species from 10 families were identified in their feeding behaviour. Used food items were piths (58.59%), twigs (16.87%), leaves (5.09%), bark (2.64%), flowers (5.23%), buds (4.82%), fruits (6.44%) and seeds (0.27%). Mahuwa Madhuca longifolia was a predominant species in their feeding. They are early rising and use their early active time in feeding after which their activity lowers during night. Key words: Petaurista philippensis, arboreal, feeding behaviour, Madhuca longifolia INTRODUCTION the rainfall is very low and erratic. During summer, the sun shines directly upon Tropic of Cancer, which increases the Food is one of the most important resources for growth, temperature (32°C to 40°C) in southern Rajasthan; the reproduction and survival of animals. Consequently, animals subtropical forest replaces the tropical deciduous forest, and that are generally herbivores, respond to spatial and temporal water and food availability becomes low. Summer, therefore, variability of food availability by selecting specific feeding is a very critical time for Petaurista philippensis for survival. habitats (McNaughton 1990; Wilmshurst et al. 1999; Ball et This study was carried out to understand how P. philippensis al. 2000) and diet (Hanley 1997; Dumont et al. 2002). Dietary copes with unfavourable situations and was confined to its variation occurs in response to plant phenology and changes food availability, food preference and diet during summer. in availability of resources (Poulsen et al. 2001). Impact of plant phenology on primary consumers has gained much STUDY AREA attention in recent years (Van Schaik etal. 1993; White 1998; Curran and Leighton 2000). The study was carried out in the Sitamata Wildlife Flying squirrels (Rodentia: Sciuridae: Petauristainae) Sanctuary (Fig. 1), which is situated between 24° 04'-24° 23' N are nocturnal gliding mammals, comprising of 12 genera and and 74° 25'-74° 40' E. The Sanctuary covers an area of 422.95 43 species (Eisenberg 1981). Only one species of flying sq. km. It is situated in the south-eastern region of Rajasthan squirrel is found in Europe and north Asia, and two species where three very ancient mountain ranges of India meet in North America. Species richness peaks in the South-east forming a teak forest. The configuration of land is hilly and Asian countries (Lee and Liao 1998; Nandini 2001). Eleven rugged with altitude varying from 280 to 600 m. The general species are found in India, most of which are concentrated in slope of the land is from North-West to South-East. Forest the Himalayan, the North-east regions and the Western Ghats with subtropical feature is characterized by distinct winter, (Nandini 2001). summer and rainy seasons. Average rainfall is 756 mm and Petaurista philippensis has a wide distribution and the temperature ranges between 6°C in winter and 45°C occurs in most forests of peninsular India (Prater 1971; in summer. The Sanctuary harbours nearly 50 species of Agarwal and Chakraborty 1979; Wilson and Reeder 1993). mammals, 275 species of birds, 40 species of reptiles, Southern Rajasthan is a distinct patch for the occurrence of 9 species of amphibians, 30 species of fishes and more than P. philippensis. Tehsin (1980) and Chundawat et al. (2002) 800 species of plants (Kartikeya 2005). reported the presence of Large Brown Flying Squirrel in Phulwari Wildlife Sanctuary in Udaipur district of Rajasthan. MATERIAL AND METHODS Sitamata Wildlife Sanctuary is also a prominent area of distribution of P. philippensis in southern Rajasthan. The present study was carried out during summer In Rajasthan, climate ranges from arid to semiarid and between March and June 2009. Four flying squirrel sites, SUMMER DIET OF INDIAN GIANT FLYING SQUIRREL IN SITAMATA WILDLIFE SANCTUARY Behaviour of individual flying squirrel was recorded using Focal Animal Sampling Method (Altmann 1974). In this method occurrence of specified actions (feeding) of an individual were recorded during each sample period. A record was made of the length of each period and for each focal individual. The amount of time during the sample was actually in view. Once chosen, a focal individual was followed to whatever extent possible during each of the sample periods. The data was recorded at five second intervals from the time the squirrel started feeding, Phenological data were also collected monthly during the study period. The data was taken to assess the association between abundance of plant parts and composition of the diet of the flying squirrel. Phenology of plant species was categorized into two phases: vegetative phase and reproductive phase. Vegetative phase was further sub¬ categorized into piths, twigs, leaves and bark, while reproductive phase was sub-categorized into buds, flowers, fruits and seeds. RESULTS A total of 2,153 feeding records were collected during 304 hrs of field observation with a mean (± SE) of 538 ±97.94 records/month (Range = 0-467). The flying squirrel consumed 8 plant parts from 13 species belonging which they inhabited permanently, were identified and marked to 10 families (Table 2). Most feeding records were (Table 1). Identification of sites where squirrels were present from Sapotaceae (33.14%), Combretaceae (33.14%), was done using two procedures. Initially the area was Anacardiaceae (8.71%), Moraceae (7.27%), Ebenaceae thoroughly explored to locate the squirrel inhabited trees and (7.09%), whereas other families contributed a smaller amount. sites. These were later continued by the forest personnel and Three families, namely Moraceae, Combretaceae and by exploring the area at regular time intervals. The sites were Anacardiaceae include two species each, while other families visited fortnightly with a minimum of five days stay in the had one species each. field during each visit in fifteen days and eight nights in one Six species of trees including Mangifera indica, month. Being nocturnal and arboreal, the flying squirrel is Mitragyna par\>iflora, Alvizia odoratissima, Cordia myxa, hard to locate during night. They were detected by eyeshine Tectona grandis and Sarcopetalum tomentosa contributed and calls, and occasionally by their movement on or between < 5% (range 0.27-3.29%) and 2 species of trees including trees. Every night around dusk, vigilant move was carried Madhuca longifolia and Terminalia bellirica contributed along a trail, which meandered through the study area. >20% (range 510-715 of the 2,157 feeding records). Binocular and spotlight (NS-8300DX) with a Swiss handle Remaining species contributed between 5 to 10% of feeding and stand were used to observe the flying squirrel. records. Madhuca longifolia was a predominant species for Table 1: Location of Flying squirrel sites in Sitamata Wildlife Sanctuary S. No. Site Location Nesting tree 1 Arampura naka 1 24°13' 19" N, 74°25' 54" E Madhuca longifolia 2 Arampura naka 2 24°13' 21" N, 74°25' 53" E Madhuca longifolia 3 Lambi samel 24°13' 07" N, 74°25' 36" E Madhuca longifolia 4 Kunda nala 24°13' 39" N, 74°25' 55" E Terminalia bellirica 184 J. Bombay Nat. Hist. Soc., 107 (3), Sep-Dec 2010 SUMMER DIET OF INDIAN GIANT FLYING SQUIRREL IN SITAMATA WILDLIFE SANCTUARY Fig. 3: Monthly diet composition of the flying squirrel Eight food items were consumed by the flying squirrel Plant part iring the study period. Pith was most frequently (58.59%) Fig. 2: Percentage observation of plant parts in the diet consumed, followed by twigs (16.87%), fruits (6.44%), of the Flying squirrel during summer season flowers (5.23%), leaves (5.09%),buds (4.82%). bark (2.64%) and seeds (0.27%) (Fig. 2). Pith was obtained from 10 plant feeding and it contributed 33.14% of feeding records and species, twigs from 7 plant species, leaves and fruits from Tectona grandis contributed only 0.27% and ranked 13 in 2 plant species, bark, flowers and buds were obtained from the list. Both Madhuca longifolia and Terminalia bellirica only Madhuca longifolia. Seeds were least preferred and species contributed more than half of the feeding records. obtained from Tectona grandis (Table 2). Table 2: Plant species and part consumed by Petaurista philippensis at Sitamata Wildlife Sanctuary (Rajasthan) during summer in 2009 S.No. Family Species Part Phenophase* % Feeding time Rank 1 Ebenaceae Diospyros melanoxylon Twig imm 7.09 5 Pith - 2 Sapotaceae Madhuca longifolia Bark imm 33.14 1 Buds - Pith - Fruit r, sr, ur Flower m, imm Twig imm 3 Combretaceae Terminalia tomentosa Leaf imm 9.50 3 Pith - Terminalia bellirica Twig imm 23.64 2 Leaf imm Pith - 4 Anacardiaceae Lannea coromandelica Pith - 5.42 6 Mangifera indica Pith - 3.29 8 5 Moraceae Ficus religiosa Twig imm 7.27 4 Pith - Ficus bengalensis Pith - 5.33 7 6 Rubiaceae Mitragyna parviflora Twig imm 2.41 9 Pith - 7 Fabaceae Alvizia odoratissima Twig imm 0.92 11 8 Boraginaceae Cordia myxa Fruit m 0.69 12 9 Lamiaceae Tectona grandis Seed m 0.27 13 10 Menispermaceae Sarcopetalum tomentosa Twig imm 1.20 10 Pith - 'Codes for phenological phase of plant parts consumed. imm = immature; m = mature; ur = unripe; sr = partly ripe; r = ripe 1 Bombay Nat. Hist. Soc., 107 (3), Sep-Dec 2010 185 SUMMER DIET OF INDIAN GIANT FLYING SQUIRREL IN SITAMATA WILDLIFE SANCTUARY DISCUSSION The flying squirrel fed primarily on pith in summer besides twigs, leaves, bark, flowers, buds, fruits and seeds. Other studies on the diet of the flying squirrel also show that they are largelyfolivorous (Lee etal. 1986; Kawamichi 1997; Kuo and Lee 2003; Nandini and Parthasarathy 2008). The flying squirrel is a selective forager and only 13 plant species and 8 plant parts were consumed in their summer diet. Besides § 52 5 o o O*O7 ^Om they consumed the part only from a few plant species in each month. Some species of plants were used more whereas others Timing of feeding were used sporadically emphasizing its preference. Kuo and Fig. 4: Feeding time of the Flying squirrel during their active Lee (2003) showed that the flying squirrel consumed at least period (7.30 pm-5.00 am) 79 species-specific parts of plants belonging to 30 families, It was also observed that in March only 5 food parts and Nandini and Parthasarathy (2008) reported that were used in 508 feeding records. The most preferred feeding 25 different plant parts of 10 tree species were recorded in plant part was twigs, which comprised 27.95% of the monthly the feeding of the flying squirrel. lapanese Giant Flying feeding records. This was followed by leaves (21.65%), buds Squirrels P leucogenys were also found to be highly selective (20.47%) and pith (18.70%) (Fig. 3, Table 3). In April, 4 food feeders (Ando et al. 1985; Kawamichi 1997). ianzen (1978) items were used in 817 feeding records and the percentage of and Kuo and Lee (2003) stated that, relative to terrestrial pith increased and reached 50.30% which was followed by animals, arboreal species are unable to store large amounts twigs (19.95%), fruits (15.91%) and flowers (13.83%). Use of fat, which would restrict their movements and increase the of pith further increased in May reaching 80.60% with risk of falling. Furthermore, because arboreal folivores rely 361 feeding records. Except pith other food parts were twigs on relatively poor quality food, they may be constrained by (15.78%), fruits (1.93%) and seeds (1.66%). In lune, the only their ability to convert energy (Eisenberg 1978; Kuo and Lee feeding part was pith which comprised 100% of the monthly 2003). feeding records. In this study, the flying squirrel preferred to feed on The feeding time of the flying squirrel is shown in pith, as it comprised 58.59% of its diet. Pith is the central Fig. 4. The most active time of feeding was when flying part of stem or twig which is rich in water content and squirrels emerged from their holes. After emerging, they nutrition. This content fulfils the requirement of water for started feeding. Feeding became less around 00:30 hrs. flying squirrel in summer. Immature leaves were used during Between 00:30 hrs and 02:00 hrs, the feeding activity ceased. March. Coley (1983) showed that young and mature leaves Feeding resumed after 02:00 hrs, but the frequency was low. of pioneer species contain fewer digestion reducers such as Thus, the peak time of feeding was 19:30 to 21:30 hrs while cellulose, tannins, and lignin and are relatively palatable to 24:00 to 02:00 hrs was resting time. herbivores. Table 3: Data on different plant parts consumed each month and their monthly percentages Plant part March April May June No. of % No. of % No. of % No. of % observations observations observations observations Pith 95 18.70 411 50.30 291 80.60 467 100 Twigs 142 27.95 163 19.95 57 15.78 - - Leaves 110 21.65 - - - - - - Bark 57 11.22 - - - - - - Flowers - - 113 13.83 - - - - Buds 104 20.47 - - - - - Fruits - - 130 15.91 7 1.93 - - Seeds - - - - 6 1.66 - - Total 508 - 817 - 361 - 467 - 186 J. Bombay Nat. Hist. Soc., 107 (3), Sep-Dec 2010 SUMMER DIET OF INDIAN GIANT FLYING SQUIRREL IN SITAMATA WILDLIFE SANCTUARY Nandini and Parthasarathy (2008) revealed that fruit from one species of oak to another in search of new leaves was most usable plant part for the flying squirrel, in the or acorns due to their slightly different periods of leaf out Western Ghats, which constituted 48.42% of all plant parts. and seed production (Kawamichi 1997). No significant The difference in feeding parts of plants may be because, relationship was found between availability of parts of the habitat of the flying squirrel in the Western Ghats has plants and feeding frequency, implying that Indian Giant more humid area and the squirrel does not require to conserve Flying squirrels did not select food on the basis of total water. In the present study, water conservation by the animal availability. Similar observations were reported by Kuo and is much required as the forest is of dry deciduous type. Thus, Lee (2003). During the present study, no occasion was the flying squirrel consumed a wide variety of plant parts. witnessed when the flying squirrel fed on food of animal The diet of the flying squirrel changed in relation to plant origin. Similar observations were also noted by Kawamichi phenology. This habit is related to availability of food and (1997), Nandini and Parthasarathy (2008) and Kuo and Lee composition of forest. For example, reproductive phase of (2003). Madhuca longifolia is fixed in annual time period, so, flying According to Nandini (2001), flying squirrels begin squirrel used their phase parts (bud, flower and fruit) in feeding around 18:30 hrs, while in this case both feeding and March and April; bark was used in March. Thin bark is often calling began around 19:00 hrs. Feeding dropped around removed to the depth of the cambium, but thicker bark may 22:00 hrs. At 22:00 hrs most individuals were noticed either not be (MacKinnon 1978). Some seeds or fruits are produced calling or sitting. The present study also showed that most relatively early in summer, which may contribute to the food active feeding time was from 19:30 to 21:30 hrs that reduced available for young squirrels (Thompson and Thompson till 24:00 hrs, while after 02:00 hrs some feeding was 1980). Giant flying squirrels also shifted to other food items, observed. even when a previously known food item was still available. 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