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Population Dynamic Of Fig Wasps In Ficus Benjamina

Posted on:2010-02-23Degree:MasterType:Thesis
Country:ChinaCandidate:Z M WangFull Text:PDF
GTID:2120360278967195Subject:Agricultural Entomology and Pest Control
Abstract/Summary:PDF Full Text Request
Figs and their pollinating fig wasps constitute a unity of mutualism. It becomes a model system for studying origin and evolution of mutualism, resources conflicts, equilibrium mechanisms of mutualism and sex allocation. Figs (Ficus spp.) depend on wasps for transmission of their pollen, and fig wasps depend on fig inflorescences for the completion of their life cycles. There are also non-pollinating fig wasps living in figs besides the pollinators. Non-pollinating fig wasps have different influences on the unity, with multiple biological habits.Ficus benjamina is a monoecious popular cultivated tree for ornamental purpose worldwide. We collected 508 fruits of 19 crops from six trees in Danzhou, Hainan Province, dissected the figs, idendified the species and counted the wasp individuals. We found one pollinator (Eupristina koningsbergeri) and 15 non-pollinators belonging to 8 genera of Chalcidoidea, including 3 newly recorded species belonging to Sycoscapter and Sycophila genus.There were no significant changes in the community structure between dry and wet seasons. Galls in the syconium can be divided into 4 groups based on size and quality of galls. Each group of galls harbors specific species of wasps. 16 fig wasp species can be grouped into common species and rare species. Eupristina koningsbergeri, Sycoscapter sp.1, Philotrypesis sp. 1, Philotrypesis sp. 4, Philotrypesis sp. 5, Walkerella benjamini, Walkerella sp. 1, Sycophila sp. 2 and Sycobia sp. 2 were common species. The pollinator takes dominance and nearly as many as the non-pollinators. Sycoscapter sp. 1 occupies the largest proportion of non-pollinators, while Philotrypesis sp. 5 takes the smallest proportion. Rare species include Acophila sp. 1, Ormyrus sp. 1, Sycobia sp. 1, Sycophila sp. 1, Sycophila sp. 3, Sycophila sp. 4 and Sycoscapter sp. 2. The existence of these rare species usually does not distort the number of other common species. But when the resources are not enough, rare species have influence on the common non-pollinators.Non-pollinating fig wasps have a direct effect on distorting the sex ratio of pollinator. There is a positive relationship between the sex ratio of pollinator and the number of non-pollinating wasps. The number of non-pollinating wasps negatively correlates with the number of pollinating female offspring, but not significantly correlated to the number of pollinating male ones.We studied male polymorphism (dimorphism) taking Sycobia sp. 2 as an example. There are two types of male of Sycobia sp. 2., winged and wingless. The result showed that the winged ones only appeared at low population density, while two types co-existed at high population density. In addition, the number of Sycophila sp. 2 was negatively correlated with number of winged male of Sycobia sp. 2. However, there was no significant difference with seasons.
Keywords/Search Tags:Ficus benjamina, fig wasp, population dynamics, sex ratio, male dimorphism
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