Study On The Phenology And Reproductive Biology Of The Symbiosis System Of Banyan Trees In Dinghu Mountain

The mutualism of figspollinating figwasps is a highly species specific system.In this system,figs provide breeding place for pollinating wasps,while wasps help figs to pollinate.Both of figs and fig wasps obtain the benefits from each other.The above characteristics of the specific mutualism of figs-fig wasps makes it a typical example for us to study the coevolution of organisms.Dinghu Mountain is located in Zhaoqing City,Guangdong Province.Dinghu Mountain National Nature Reserve is the first National Nature Reserve in China.It has dense plants,complete community and more than ten kinds of wild fig species.It is an ideal site for studying the interation of figs and figwasps.In this study,the phenology and reproductive biology of six species of figs(Ficus hirta,F.esquiroliana,F.fistulosa,F.hispida,F.variegate var.chlorocarpa,and F.variolosa)that growing in the Reserve have been investigated from August 2017 to July 2018.Phenological investigation showed that the climate of the Reserve was a typical humid subtropical monsoon climate,characterized by hot and humid summers and mild winters.Affected by the climate,the stagnation period of inflorescence flowering of the six figs in the sample plot was relatively short.One species,F.hirta,could bloom throughout the observation period.In addition,microhabitats have obvious effects on F.fistulosa and F.variolosa.Low temperature can cause rapid death of F.fistulosa,and insufficient light can also cause the stagnation of inflorescence occurrence of F.variolosa.Morphological comparison of syconia showed that the shapes of syconia are different at female flower phase,especially between male(fig wasps reproducing)and femal(seed-producing)Ficus trees.The number of female flowers and length of the stigma within syconia between male and female trees are different.At male flower phase,the shapes of syconia are different among six species.For the wasps,the number of galls and hatching rate of fig wasps at male flower phase are significantly different among different sample plants.The sex ratio of male to female of the pollinating wasps ranged from 3 to 4.Surveying of reproductive biology showed that characteristics of flowering time are different among six fig species.The occurrence of syconia in F.hirta and F.hispida are asynchronism within and among trees;whereas the appearances of syconia in F.esquiroliana,F.fistulosa,F.variegata,and F.variolosa are synchronism in same trees,but asynchronism among different trees.Shapes of syconia in six species are different at post-floral phase,and seed productions of syconia are different too.Detections of species-specific mutualism of Ficus showed that the species F.hirta and F.fistulosa were highly species-specific "one-to-one" mutualisms,only a single pollinating wasp,Blastophaga javana and Ceratosolen constrictus were found in F.hirta and F.fistulosa,respectively.However,two pollinating wasps,B.esquirolianae and B.javana(which originally coexisted with F.hirta)were both found in syconia of F.esquiroliana.