西双版纳榕树-榕小蜂互惠系统中线虫多样性的初步研究

Research on Biodiversity of Nematodes in Fig-Fig Wasp Mutualism in Xishuangbanna

西双版纳热带雨林具有极高的榕树种类多样性,榕树与其专一传粉榕小蜂互惠共生,在这个互惠系统中除寄生非传粉榕小蜂外,线虫伴随榕树和榕小蜂的繁殖周期有规律地生存和繁衍,这些线虫与榕树及其传粉榕小蜂关系密切,且存在明显种的专化性.选择分布于西双版纳热带地区的32种榕树,包括雌雄同株14种和雌雄异株18种,对自然寄生于榕树隐头果内的线虫物种多样性进行调查,结果显示:在32种榕树中,有19种榕树的隐头果内寄生了24种线虫,其中7种线虫为已知种,17种是尚未描述的新种,在雌雄异株榕树上,线虫寄生雄果是成功的选择,寄生雌果则由于缺乏传粉榕小蜂携带传播,繁殖适合度为零.但仍发现6种榕树的雌果内寄生有线虫,这说明线虫能准确定位传粉榕小蜂雌蜂,但没法选择雌雄果.首次调查了西双版纳热带地区榕树寄生线虫多样性,结果很好地丰富了我国乃至亚洲热带地区榕树寄生线虫的物种数及多样性.

Fig trees（Ficus）are high biodiversity in the tropical rainforest of Xishuangbanna.The fig tree and its species-specific pollinating fig wasp constitute a classic mutualism.Except for the pollinating fig wasp,syconia（figs）are exploited by non-pollinating fig wasps,and it is known that nematodes are associated with figs and pollinating fig wasps to develop and complete life cycle regularly,which the nematodes have co-evolved with the fig tree and pollinating fig wasp to show specialization obviously.In this study,32 species of fig trees distributed in Xishuangbanna tropical region were selected to investigate the biodiversity of nematodes,which included 14 species of monoecious fig trees and 18 species of dioecious fig trees.The inter-floral phase figs were used to collect nematodes inside figs.The results showed that 24 species of nematodes were found from 19 species of fig trees.Only 7 species of nematodes were known,and 17 species were new species of nematodes.In dioecious fig trees,the nematodes in male figs were able to infect female pollinating fig wasps so that they had chance to reach receptive figs,and successfully reproduced.While the nematodes in female figs were difficult to escape their natal figs because there was no any fig wasp to transfer them,so the reproductive fitness of nematodes was zero in female figs.However,some nematodes still happened in the female figs of 6 Ficus species.It suggests that the nematodes can correctly infest female pollinating fig wasps,but they can not choose male or female figs.This is the first study about fig nematode species and diversity in Xishuangbanna tropical region,which will enrich fig nematode diversity in China,as well as in tropical Asia.