Reproductive success of two male morphs in a free-ranging population of Bornean orangutans
The reproductive success of male primates is not always associated with dominance status. For example, even though male orangutans exhibit intra-sexual dimorphism and clear dominance relationships exist among males, previous studies have reported that both morphs are able to sire offspring. The present study aimed to compare the reproductive success of two male morphs, and to determine whether unflanged males sired offspring in a free-ranging population of Bornean orangutans, using 12 microsatellite loci to determine the paternity of eight infants. A single flanged male sired most of the offspring from parous females, and an unflanged male sired a firstborn. This is consistent with our observation that the dominant flanged male showed little interest in nulliparous females, whereas the unflanged males frequently mated with them. This suggests that the dominant flanged male monopolizes the fertilization of parous females and that unflanged males take advantage of any mating opportunities that arise in the absence of the flanged male, even though the conception probability of nulliparous females is relatively low.
KeywordsPaternity analysis Male dominance Bimaturism Bornean orangutan Pongo pygmaeus Free-ranging population
We are grateful to Sabah Biodiversity Centre, Sabah Wildlife Department, and Economic Planning Unit of Malaysia Federal Government for permitting this study. We are also grateful to Dr. Noko Kuze, Dr. Henry Bernard, Dr. Vijay Kumar, Ms. Sylvia Alsisto, Mr. Sailun Aris, and all the staff of the Sepilok Orangutan Rehabilitation Centre for their kind support of our research activity in Sabah, Malaysia, and to Dr. Naofumi Nakagawa for helpful comments on our manuscript. The present study was supported by Grants-in-Aid for Japan Society for the Promotion of Science (JSPS) Research Fellow (Grant no. 10J01218 to Tomoyuki Tajima); JSPS Core-to-Core Program, Advanced Research Networks “Tropical Biodiversity Conservation” Wildlife Research Center, Kyoto University, Japan, and by the Ministry of Education, Culture, Sports, Science and Technology (MEXT), Leading Graduate School Program in Primatology and Wildlife Science, Kyoto University, Japan. We obtained appropriate permission from the Sabah Wildlife Department and Sabah Biodiversity Council before conducting our research, and the study complies with current Malaysian laws, as well as with the “Guidelines for Care and Use of Nonhuman Primates” and “Guideline for field research of non-human primates” provided by the Primate Research Institute of Kyoto University, Japan.
- Graham C (1988) Reproductive physiology. In: Schwartz JH (ed) Orang-utan biology. Oxford University Press, Oxford, pp 91–103Google Scholar
- Knott CD, Kahlenberg SM (2007) Orangutans in perspective: forced copulations and female mating resistance. In: MacKinnon KC, Panger M, Bearder SK (eds) Primates in perspective. Oxford University Press, New York, pp 290–305Google Scholar
- Kuze N (2005) Ethological study of semi-wild orangutans. In: Ph.D Thesis. Graduate School of Bioscience and Biotechnology, Tokyo Institute of TechnologyGoogle Scholar
- Trivers R (1972) Parental investment and sexual selection. Sexual selection and the descent of man. Aldine de Gruyter, New York, pp 136–179Google Scholar
- Utami Atmoko SS, Singleton I, van Noordwijk MA, van Schaik CP, Mitra Setia T (2009a) Male–male relationships in orangutans. In: Wich SA, Utami Atmoko SS, Mitra Setia T, van Schaik CP (eds) Orangutans: geographic variation in behavioral ecology and conservation. Oxford University Press, New York, pp 225–234Google Scholar
- Utami Atmoko SS, Setia TM, Goossens B, James SS, Knott CD, Morrogh-Bernard HC, van Noordwijk MA (2009b) Orangutan mating behavior and strategies. In: Wich SA, Utami Atmoko SS, Mitra Setia T, van Schaik CP (eds) Orangutans: geographic variation in behavioral ecology and conservation. Oxford University Press, New York, pp 235–244Google Scholar