Comparison of feeding ecology of two endemic species of langurs, Himalayan grey langur (Semnopithecus ajax) and tufted grey langur(Semnopithecus priam)

Abstract

A field study was conducted to study the feeding ecology of two endemic species of the langurs viz., the Himalayan grey langur (Semnopithecus ajax) and Tufted grey langur (Semnopithecus priam). The study was conducted from August 2018 to April 2019 in Dachigam National Park, Srinagar and Wayanad Wildlife Sanctuary, Kerala. The Himalayan grey langur showed typical preference towards a particular feeding item during different seasons. Although the Himalayan grey langur is folivorous yet consumes a variety of food items such as fruits, roots, flowers, buds, bark and twigs. The Himalayan grey langur spent a considerable amount of time in searching and feeding of insects to maintain the ionic balance. The overall maximum feeding was reported in case of Rosa webbiana (9.54 %), followed by Populas deltiodes (8.11 %), Salix alba (7.63 %), Hedera nepalensis (7.63 %) and Aseculas indica (6.9 %). Rosaceae family was most preferred followed by Salicaceae. The most preferred food item was leaves (27.18 %) followed by fruits (22.75 %) and seeds (10.49 %). Average height of feeding was reported to be 5.68 m, which was maximum, in case of Aseculas indica and Pinus wallichiana (11 m), followed by Ulmus villosa (9.8 m) and Ulmus wallichiana (9.7 m). The Tufted grey langur was reported to be feeding on 12 tree species belonging to seven different families. The maximum duration of feeding in case of Anogeissus latifolia and Samanea saman (18.87 %) followed Dalbergia lanceolaria and Gmelia tillifolia (9.43 %), Terminalia bellarica (7.55 %). The Tufted grey langur diet mainly comprised of leaves, twigs and fruits. The leaves comprised of 60.38 %, twigs 20.75 % and fruits 18.87 %. The average height of feeding was 8.8 m, which was maximum in case of Hydnocarpus pentandra (12 m) followed by T. bellarica (10.5 m). The Himalayan grey langur spent maximum time in feeding followed by resting and grooming. The Himalayan grey langur spent 41 % of the time budget activity on feeding, followed by moving (21 %), resting (16%) and grooming (15%). Vegetation studies using quadrant survey showed a total of 26 species belonging to 16 different families. The species such as P. wallichiana, P. jacquemontiana, Q. robur and M. alba as dominant. The IVI was computed to show quantitative relationship among vegetation and highlight the importance of trees. The IVI values show that most important family of trees is Panacea, Hamamelidaceae, Ulmeace, Fagaceae, Cannabeacae and Rosaceae. Although major population areas of S. ajax and S. priam are protected areas yet special efforts are required for conservation of these valuable species which have been categorized as ‘Endangered’ and Near threatened’ by IUCN.