薜荔和爱玉及其传粉昆虫繁殖特性

THE REPRODUCTIVE CHARACTER OF FICUS PUMILA VAR. PUMILAR, F.PUMILA VAR. AWKEOTSANG AND THEIR POLLINATORS

薜荔 (FicuspumilaL .var.pumila)隶属桑科榕属 ,爱玉 (F .pumilaL .var.awkeotsangCorner)为其变种 ,它们的花是单性的 ,雌雄异株。雌花序中着生雌花 ,雄花序中有瘿花和雄花 ,每个花序中花的数量极多 ,达 40 0 0～ 6 0 0 0朵。薜荔榕小蜂是唯一能进入薜荔和爱玉的隐头花序中产卵或传粉的共生昆虫 ,自然状态下雌花的结实率分别为82 %、83.5 2 %;瘿花的成虫瘿率分别为 5 8.71%、5 1.32 %,因此可形成大量的果实和虫瘿。物候观察表明薜荔和爱玉花期不遇 ,它们花序中的榕小蜂种群已经生殖隔离。人为的放蜂实验表明 ,生活于爱玉花序中的榕小蜂 ,已无法在薜荔花序中繁殖 ,生殖隔离进一步得到证实 ;实验同时表明爱玉的花粉亦不能使薜荔雌花结实 ,宿主两变种间生理上已不亲和。本文从共生双方协同进化的角度出发 ,探讨了榕树 2变种间与传粉昆虫繁殖特性的差异 ,以及变种产生的主要原因。

Ficus pumila var. pumila and F.pumila var.awkeotsang are dioecious.In the female syconia exist female flowers while in the male syconia are gall flowers and male flowers.And in every syconium, there are many flowers,about 4,000 to 6,000 in number.Blastophaga pumilae is the only mutualism insect that can enter the syconia of F.pumila and its variety to produce eggs and pollinate.Naturally, the production rate of the female flowers is 82.00% and 83.52% respectively.And the gall_turning rate of gall flowers is 58.71% and 51.32% respectively. Therefore, lot of fruits and galls can be produced.According to the phenological observation, the blooming of F.pumila and its variety are at different stages,and the fig wasps living in their syconia are already of reproductive isolation.Artificial fig wasps introduction indicated that the fig wasps living in the syconia of F.pumila var.awkeotsang can not reproduce in the syconia of F.pumila,which further proves the reproductive isolation.Experiments also showed that the pollen of F.pumila var.awkeotsang can not make the female flowers of F.pumila produce fruits.The two varieties of host are no longer congenial physiologically.This paper,from the point of co_evolution of the mutualism insects,discusses the differences of reproductive character between the varieties of figs and their pollinating insects.It also discusses the possible reasons how the varieties come into being.