榕果與榕果小蜂系統為榕屬植物與其授粉蜂間的互利共生。除了授粉蜂外，也有許多非授粉蜂利用榕果資源，並和授粉蜂競爭產卵空間。此複雜的系統如何維持平衡一直是研究榕果與榕小蜂系統的核心問題。寄生蜂寄生壓力假說指出授粉蜂為了避免被寄生蜂寄生，產生偏好產卵在內層胚珠的行為，因而不過度剝削榕果。棲位分化假說認為授粉蜂與非授粉蜂會藉由空間或時間上的分化來維持共存。此研究的目的是為了檢驗寄生蜂寄生壓力假說能否解釋種子與授粉蜂間的分層現象，並檢驗授粉蜂與造癭蜂之間是否存在棲位分化的現象。我的結果發現授粉蜂在內層與外層的寄生率有顯著差別，此結果符合寄生蜂寄生壓力假說。授粉蜂和造癭蜂間在產卵位置上有空間分化的現象，授粉蜂偏好在短花柱雌花、榕果的中間部位產卵;而造癭蜂偏好產卵在長花柱雌花、榕果底部或無偏好。在研究期間，我將文理大道上的正榕族群依照其開花物候分成四個開花季，觀察小蜂族群在四個開花季間的族群動態有無變化。我的結果顯示授粉蜂與造癭蜂的族群動態在不同開花季間上有差異，但還需要更長的研究時間才能證明小蜂間的確存在時間上的分化。 Fig-fig wasp mutualism is a symbiotic interaction between Ficus and its pollinating fig wasps. In addition, many non-pollinating fig wasps also utilize the same figs and compete with pollinating wasps for breeding sites and plant resources. How does this complicated system maintain its stability has intrigued ecologists for a long time. The parasite pressure hypothesis indicates that parasitoids contribute in stabilizing mutualism by forcing pollinators to oviposit in inner ovules and do not over-exploit fig. The niche partitioning hypothesis proposes that parasites and pollinators can coexist through spatial or temporal separation. The aims of my study were to examine whether parasite pressure hypothesis can explain the stratification of seeds and pollinators, and to test if niche partitioning between pollinators and gallers do exist in fig-fig wasps system of F. microcarpa. My results indicated there were significant differences in parasitism between inner and outer ovules, which are consistent with the parasite pressure hypothesis. My results also suggested there was spatial separation in oviposit sites between pollinator and non-pollinator wasps. Pollinators prefer to oviposit in inner ovules and the central region of a fig. In contrast, gallers prefer to oviposit in outer ovules and the basal or randomly in different fig regions. In my investigation period, I defined four crops of F. microcarpa in Campus mall according to their flowering phenology, and investigated whether wasps’ population dynamics varied between crops. I found population of pollinators and galler Odontofroggatia fluctuated between crops. Although abundance of pollinators and gallers differed significantly between crops, the observation period was not long enough to have concrete evidences to support temporal partitioning hypothesis.
