摘要
榕树（Ficus）及其传粉榕小蜂（Agaonidae）构成了高度专一的互惠共生体系。榕树的果实（以下简称榕果）内也寄生着一些非传粉小蜂。绝大多数非传粉小蜂在榕果外把产卵器刺入果壁产卵到果腔内，只有极少数种类能够进入果腔内产卵。在西双版纳地区，钝叶榕（Ficus curtipes）上的杨氏榕树金小蜂（Diaziella yangi）类似于传粉者钝叶榕小蜂（Eupristina sp．），它也是进入榕果内产卵繁殖后代的，这就为比较研究榕果内产卵小蜂与寄主榕树间的关系提供了材料。该文从形态学、行为学和生态学角度比较研究了这两种进入榕果内产卵的小蜂与寄主钝叶榕之间的作用关系，研究结果显示：1）杨氏榕树金小蜂与钝叶榕小蜂的雌蜂头部形状存在趋同进化；2）两种小蜂的产卵器的平均长度都比雌花花柱长，因而能把卵产在子房里；3）钝叶榕小蜂从瘿花出来需要3～5h，交配需要17～19min，杨氏榕树金小蜂从瘿花出来只需18～20min，交配时间为20～30s；4）在自然群落中，大约90％的雌花期榕果里都只进一只杨氏榕树金小蜂和一只钝叶榕小蜂，杨氏榕树金小蜂能通过传粉来增加榕树种子数量，但对钝叶榕小蜂种群的繁衍造成了极显著的负面影响；5）两种小蜂于同一时期进入榕果内繁殖，子代同期成熟羽化，发育期与榕树雄花的发育期同步。研究表明：进入榕果内繁殖的两种小蜂与寄主榕树之间存在着协同进化关系，杨氏榕树金小蜂为榕树有效地传粉，这可能是一个由寄生者向互惠方向进化的实例。
Aims Fig trees （Ficus） and their pollinating wasps （Chalcidoidea, Agaonidae） form a highly obligated mutualism. In addition, Ficus species also host some non-pollinating fig wasps, most of which oviposit from the outside of figs, and only a few have evolved fig-entry behavior. Ficus curtipes hosts an internal ovipositing non-ollinating fig wasp, Diaziella yangi, in Xishuangbanna, and it is similar to the pollinating fig wasp （Eupristina sp.）. Our objective was to investigate whether there was coevolution between D. yangi and host F. curtipes in aspects of morphology, behavior and ecology.
Methods Head length and width of the fig wasps, along with length of the ovipositors and styles, were measured using dissecting microscopy. In the field, the behavior of wasp＇s entry in female floral phase was observed, and the mating and emerging behavior in male floral phase were observed in the laboratory. Moreover, we recorded a number of foundress in the fig female floral phase, and counted the number of wasps and seeds in the male floral phase. Important findings The head shape （length：width） of female D. yangi was strongly correlated with that of the female pollinator Eupristina sp., while there was no corresponding correlation in male head shape. The style-length of figs was in the reach ofEupristina sp. and D. yangi. The emergence time for each Eupristina sp. from a gall was usually for 3-5 h, and the mating time lasted 17-19 rain. The emergence time for each D. yangi was usually for 18-20 min, and the mating time lasted 20-30 s. In nature, almost 90% of figs at female floral phase averaged only one D. yangi and one Eupristina sp. In the natural community, D. yangi has a significant negative effect on the pollinator, but a positive effect on the number of viable seeds. Both internal ovipositing species entered fig in the same day of female rioral phase and left the fig at the same time （figs＇ male floral phase）. Results suggested that D. yangi can pollinate the figs, similar to the pollinator Eupristina sp. It has high degree of co-adaptation with the host F. curtipes. This is possibly an example of evolving from parasitism to mutualism.
出处
《植物生态学报》
CAS
CSCD
北大核心
2008年第4期768-775,共8页
Chinese Journal of Plant Ecology
基金
国家自然科学基金(30571507和30670358)
中国科学院植物园与生物分类研究项目(KSCX2-YW-Z-003)
中国科学院知识创新工程青年人才领域前沿项目
