Fruit Bats in Borneo: Size matters (picture attached)

Researchers studying the Malaysian Short-Nosed Fruit Bat found that their body size and genetic makeup is determined by where they live.

Please download the attached picture of lesser short-nosed fruit bat (Cynopterus brachyotis) taken by Dr Mohd Tajuddin Abdullah from Universiti Malaysia Sarawak. His contact details are available from the link below.

Written by Dr Mohd Tajuddin Abdullah

Take any Malaysian Short-nosed Fruit Bat (or in Latin called ‘Cynopterus brachyotis’) from Borneo, Peninsular Malaysia and Thailand, place them side by side and they look similar in coloration and body forms. However, for about 100 years biologists and taxonomists working on the ‘Cynopterus’ group have argued that there are differences between the various populations due to geographical isolation.

In 1990, Dr Charles Francis who was working on the species noticed statistically major differences in the length of the fore arms between the ‘Cynopterus brachyotis’ living in the forest and outside of the tropical rain forest in Sabah, Malaysian Borneo. In 1991, Dr D.J. Kitchener and Maharadatunkamsi also observed significant differences in the body and skull measurements of ‘Cynopterus brachyotis’ populations on the Nusa Tenggara Island, Indonesia. That led them to describe a new species called ‘Cynopterus nusatenggara’ from the ‘Cynopterus brachyotis’ population collected from the area.

Armed with the idea that ‘Cynopterus brachyotis’ is a cryptic species (i.e. it looks alike but has enough major differences), we started a research on this species in 1995. We hypothesized that since after the last ice age, about 10,000 years ago when Borneo Island was separated from the Asian mainland due to the inundation and expansion of the South China Sea, the ‘Cynopterus brachyotis’ populations in Borneo has evolved, because there was no genetic exchange with those populations in the Asian Mainland.

We used both the body measurements and mitochondrial DNA cytochrome b gene to detect any changes in the ‘Cynopterus brachyotis’ populations from Borneo, Peninsular Malaysia and Thailand. Pooling the data into geographical regions failed to produce the results we expected. Instead, we found that by re-analysing the data and taking into account ecological factors, we discovered there were significant differences in the ‘Cynopterus brachyotis’ populations due to ecological habitats.

The smaller ‘Cynopterus brachyotis’ lives in the dense tropical rain forest while the larger ‘Cynopterus brachyotis’ is found in the open areas. Thus, there is a new species yet to be described from Borneo due to its major differences in the ecology, morphological characters and genetics.

Our recent findings are very important in three ways:
Firstly, by using advanced biotechnology and statistical tools, we were able to discover new species and create an inventory of the high biological diversity in Borneo’s tropical rain forest.

Secondly, any ecological study must be based on correctly identified species of animals so that the cryptic ones do not mask the actual results of the study leading to incorrect conclusions.

Thirdly, our results could generate another evolutionary hypothesis that the small-bodied ‘Cynopterus brachyotis’ evolved in order to adapt to greater agility and maneuverings in cluttered or dense vegetations of the forest, while the large-bodied evolved for fast and powerful flight to protect against nocturnal predators.

Field-testing of this evolutionary hypothesis posts a bigger challenge in terms of methods to observe and record biological and environmental variables.

Currently, our molecular ecology group are working on fishes, amphibians, birds and mammals to answer questions related to phylogenetics and biogeography of selected taxa using both classical and molecular genetics methods. We are also interested in collaborative field research in Southeast Asian region for detailed study on the wildlife and Wallace’s Line biogeography.


Acknowledgements: I would give credit to all my colleagues and students who had contributed to this research work.


Appendix 1: Output and major highlights from this research funded by the Malaysian Government: IRPA 09-02-09–1022-EA001 - Molecular ecology and evolution of fruit bats. RM180,000.00. ** denotes major papers

No Title Research status, paper & report
1 103 MtDNA sequences from 12S and 16S, and partial cytochrome b genes Accepted by the GenBank, NCBI, U.S.A. This is the major highlight of this research for the year 2005.

2 Jayaraj V. K., Faisal Ali Anwarali Khan, M. T. Abdullah. 2005. Bats Of Mount Penrisen, Padawan, Sarawak. Sarawak Museum Journal (in press)

3 Andy K.H.G., Yuzine E, Sallehin A A and Abdullah M T. 2005. Establishing Protocols for Phylogenetic Research on Megachiroptera. IRPA and Fundamental Research Paper Series, Universiti Malaysia Sarawak.

4 Besar Ketol, Andy K.H.G, Yuzine Esa and M.T. Abdullah. 2005. A Phylogenetic Relationship in the Genus Rhinolophus (Family: Rhinolophidae) From Borneo Inferred Using Partial Mtdna Cytochrome B Gene. Poster presentation in International Conference on Biodiversity and Biogeography “Wallace in Sarawak – 150 years later” at Sarawak Tourism Centre, Kuching, Sarawak.

5 Jayaraj V.K., C.J. Laman and M.T. Abdullah. 2005. Application of multivariate techniques in determining morphological variation in the genus Cynopterus of Peninsular Malaysia and Borneo. Poster presentation for The International Conference for Biography and Biodiversity – Wallace in Sarawak, 150 years later, 13 – 15 July 2005.

6** Jayaraj, V.K., C.J. Laman and M.T. Abdullah. Morphological variation in the genus Cynopterus of Peninsular Malaysia and Borneo. Regional Conference on Environmental and Ecological Modeling, School of Mathematical Sciences and School of Biological Sciences, Universiti Sains Malaysia on the 15-16 September 2004.

7** Ryan, J.R., K.H.G. Andy, V.K. Jayaraj, Y. Esa, A.A. Sallehin and M.T. Abdullah. 2005. DNA taxonomy of the Malaysian fruit bats (Family: Pteropodidae) inferred from the 12S and 16S rRNA gene segment. Oral presentation for The International Conference for Biography and Biodiversity – Wallace in Sarawak, 150 years later, 13 – 15 July 2005.

8 Note on rapid survey of bats in Gomantong and Madai forest, Sabah. Imelda Vivian Paul, Les Hall & M. T. Abdullah Report Submitted to Sabah Wildlife Department, Kota Kinabalu

9 Great Caves of Borneo: Gomantong, Sabah
M.T. Abdullah, Imelda Vivian Paul and Les Hall BATS 2005. published by BCI, USA.

Other Selected Published Papers by group members;

No Title
1 Abdullah MT, Abang Arabi Abang Aimran and Andrew Alek Tuen. 2005. Biodiversity and conservation of chiroptera in the Gunung Berumput-Pueh mountainous complex, Sarawak. In A.A. Tuen (ed) Diversity and Conservation of Biological Resources in Western Sarawak, Universiti Malaysia Sarawak (in preparation).

2 Jayaraj V. K., Faisal Ali Anwarali Khan and M. T. Abdullah. 2005. Bats Of Mount Penrisen, Padawan, Sarawak. Sarawak Museum Journal 81 (in press).

3** Hall LS, Gordon G. Grigg, Craig Moritz, Besar Ketol, Isa Sait, Wahab Marni and M.T. Abdullah. 2004. Biogeography of fruit bats in Southeast Asia. Sarawak Museum Journal 81: 191-284.

4 Karim, C., A.A. Tuen and M.T. Abdullah. 2004. Mammals. Sarawak Museum Journal Special Issue No. 6. 80: 221—234.

5 Mohd. Azlan J., Ibnu Maryanto , Agus P. Kartono and M.T. Abdullah. 2003. Diversity, Relative Abundance and Conservation of Chiropterans in Kayan Mentarang National Park, East Kalimantan, Indonesia. Sarawak Museum Journal 79: 251-265.

6 Abdullah, M.T. 2003. Short notes on a colony of thick-thumbed pipistrelle near Mulu National Park. Sarawak Museum Journal 79: 268-269.

7 Abdullah MT, Neuchlos Jub and Norhayani Jalaweh. 2003. First Record of Hipposideros ater in Sarawak, Malaysian Borneo. Sarawak Museum Journal 79: 271-274.

8 Rahman, M. A., Abdullah, M. T., and Noweg, G. T. 2003. Hunting, uses, and trade of wildlife by Orang Ulu in the upper reaches of Batang Rajang, Sarawak, Malaysia. Pp 91-102 in Mertz, O., Wadley, R. L., & Christensen, A. E. (eds.) Local Land Use Strategies in a Globalizing World: Shaping Sustainable Social and Natural Environments. Proceedings of the International Conference, August 21-23, 2003. Volume 3. Institute of Geography, University of Copenhagen, Copenhagen.

9 Hall LS, Richards GC, and Abdullah MT. 2002. The bats of Niah National Park, Sarawak. Sarawak Museum Journal 78: 255-282.

10 Rahman MA, Abdullah MT. 2002. The avifauna of Upper Rejang Sarawak, Malaysia. Sarawak Museum Journal 78: 237-253.

11 Tuen, AA. Abdullah MT, Laman CJ, Rahman MA, Hang ESU, Ketol B, Sait I and Marni W. 2002. Mammals of Balambangan Island, Sabah. Journal of Wildlife and Parks 20:75-82.

12 Zainal-Zahari Z, Abdullah MT, Daim MS, and Yasak MN. 2001. Introduction of the green peafowl (Pavo muticus muticus) in the vicinity of Melaka Zoo, Malaysia – a preliminary observation. Journal of Wildlife and Parks 19: 1-5.

13 Abdullah MT. 2001. Report on the ecology of fruit bats. Tigerpaper 28(2):14-17.

14** Abdullah MT, Moritz C, Grigg GC., and Hall LS. 2000. Evidence of cryptic species within Cynopterus brachyotis by using mtDNA sequence. In Yaacob Z, Moo-Tan S, Yorath S (eds) In situ and ex situ Biodiversity Conservation. Yayasan Sabah, Kota Kinabalu.

15 Abdullah MT, Hall LS, Rahman, MA, Besar Ketol, and Wahap Marni, Isa Sait. 2000. A note on the rare Pipistrellus vordermanni in Sarawak, Malaysian Borneo. Malayan Nature Journal 54(4): 375-376.

**Abdullah, MT . 2003. Biogeography and variation of ‘Cynopterus brachyotis’ in Southeast Asia. PhD Thesis. Department of Zoology and Entomology, The University of Queensland, St Lucia 4072, Australia.

Published: 18 Mar 2006

Contact details:

Universiti Malaysia Sarawak94300 Kota SamarahanSarawak, Malaysia

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Websites: Contact details of Dr Mohd Tajuddin Abdullah Universiti Malaysia Sarawak