Cave nectar bat
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|Cave Nectar Bat|
|Cave Nectar Bat range|
Cave Nectar Bat (Eonycteris spelaea), common names also include Dawn Bat, Common Dawn Bat, Common Nectar Bat and Lesser Dawn Bat , is a species of megabat within the genus Eonycteris. Its natural habitats are subtropical or tropical moist montane forests and caves, and it is threatened by habitat loss. E. spelaea is the sole pollinator of the durian fruit, a crop that contributes $120 million US dollars to the economies of Southeast Asia each year.
E. spelaea is found in India, China, Southeast Asia, Philippines, Sumatra, Java and Borneo. It had been previously recorded from Gomantong, Sukau, Segama and Madai in Sabah; Niah, Sungai Tinjar and Kuching in Sarawak; and Sungai Tengah and Kutai in Kalimantan .
Biology and ecology
This species were caught near fruiting Ficus in forest fringe in Wang Pinang and in regenerated habitat at Gunong Gading National Park. The regenerated area was used for agriculture and contained banana plots. There were ten males, ten females and three could not be sexed. Sixteen were adults, four subadults, two immatures and one was not aged before release. Females banded in March 1997 at Wang Pinang were lactating. At the same date a male from Wang Pinang had enlarged testes during that period. A female from Sungai Dusun was in postlactation in May 1997. The presence of subadults and immatures between March and May at Wang Pinang, Sungai Dusun and Taleban suggesting of births occurred a few months before.
In Batu Caves, in Peninsular Malaysia, Beck and Lim observed that there was no evidence that E. spelaea had a regular reproductive pattern . More than 50% of the adult females were pregnant or lactating every month during the study period 1966 to 1968. Peak pregnancy rates occurred in May - June and October - November in 1966 and in April - May and September 1967. Parturition and lactation periods occurred during heavy and low rainfalls. High rates of parturition were recorded in June and November 1966 and June and September 1967. The weaning period finished approximately eight weeks after birth. Gestation period was estimated between 6 to 6.5 months in Malaysia  and three to four months in India . By using four months gestation, Heideman  projected that parturition in Negros occurred in January, May, July, September, November and December. In north-east India, E. spelaea lactate for five to eight weeks . On Leyte Island, the Philippines, females carrying neonates or juveniles suggested a seasonal and synchronous pattern of reproduction . Tidemann et al.  reported that two pregnant females and 60% juveniles were collected on Lombok Island in September. In May, seven individuals were pregnant and one was a juvenile. Their data indicated that birthings for the species occurred before the on-set of the rainy season in October and most immatures from the recent parturient season were flying.
E. spelaea usually roosts in small colonies in caves . The bat flies long distances in search of flowering trees; feeds on pollen and nectar . Ecologically, the cave nectar bat is found to be a major pollinator of many forest trees including the commercially important durians (Durio) in Malaysia . An adult female (forearm length 67 millimetres or 2.6 inches, weight 53.5 grams or 1.89 ounces) from Gading was netted with a Ficus species fruit weighing 13 grams (0.46 oz).
- C. Francis, G. Rosell-Ambal, B. Tabaranza, P. Carino, K. Helgen, S. Molur & C. Srinivasulu (2008). "Eonycteris spelaea". IUCN Red List of Threatened Species. Version 2009.1. International Union for Conservation of Nature. Retrieved February 2, 2010.
- J. Payne, C. M. Francis & K. Phillipps (1985). A field guide to the mammals of Borneo. Kota Kinabalu, Sabah: The Sabah Society. ISBN 978-967-99947-1-1.
- A. J. Beck & B. L. Lim (1973). "Reproductive biology of Eonycteris spelaea in West Malaysia". Acta Tropica 30 (3): 251–260. PMID 4147874.
- H. R. Bhat, M. A. Sreenivasan & P. G. Jacobs (1980). "Breeding cycle of Eonycteris spelaea (Dobson, 1871) (Chiroptera, Pteropodidae, Macroglossinae) in India". Mammalia 44 (3): 343–347.
- Lawrence R. Heaney & Paul D. Heideman (1987). "Philippine fruit bats, endangered and extinct". Bats 5: 3–5.
- C. R. Tidemann, D. J. Kitchener, R. A. Zann & I. W. B. Thornton (1990). "Recolonisation of the Krakatau Islands and adjacent areas of West Java, Indonesia, by bats (Chiroptera) 1883-1986". Philosophical Transactions of the Royal Society B 328 (1245): 123–130. doi:10.1098/rstb.1990.0111.
- A. N. Start & A. G. Marshall (1976). "Nectarivorous bats as pollinators of trees in West Malaysia". In J. Burley & B. T. Styles. Tropical trees, variation, breeding and conservation. London: Academic Press. ISBN 978-0-12-145150-9.