| Summary: | 碩士 === 國立臺灣大學 === 動物學研究所 === 91 === The role of dung beetles in determining the fate of seeds in the feces of the Formosan macaques (Macaca cyclopis) was studied at Fushan experimental forest from May 2001 to March 2003. Macaques’ feces were visited by 16 species of dung beetles belonging to 2 families (Scarabaeidae and Trogidae), including tunnelers, rollers and dwellers. Total numbers of species, individuals and large dung beetles collected at the forest site were higher than those at the grassland site. Time needed to process 20g of macaques’ feces and the ratio of seeds in feces buried by dung beetles varied with seasons and habitats. It took an average of 16.7 hrs for dung beetles to finish processing 20g of macaques’ feces in warm season, while more than 1 day was need in the cold season. Dung beetles processed the feces faster at the forest site than at the grassland site in cold season. Dung beetles buried more seeds in warm season (73.4%) than in cold season (55.4%). Regardless of the size of mimic seeds, a higher ratio of seeds were buried in the forest (2mm: 89.0%, 4mm beads: 80.8%) than in the grassland (2mm: 52.5%, 4mm: 47.7%). Furthermore, seed size would affect the ratio and depth of seeds being buried. Small seeds were buried more and deeper than large seeds. However, seeds would not germinate when they were buried deeper than 5cm. The results suggested that being processed and buried by dung beetles may be unfavorable for germination of small seeds. However, further studies on how handling by dung beetles may affect other selection pressure against seed survival and germination, e.g. predation by rodents or infection by fungi, are need to reveal the role of dung beetles on secondary seed dispersal.
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