Abstract:
 Abstract: 【Aim】 Ficus pumila var. awkeotsang, a special fruit tree, relies on Wiebesia sp. nr. pumilae for pollination. The aim of this study is to investigate the developmental dynamics of galls and W. sp. nr. pumilae, thus providing a foundation for further studies on the developmental biology of fig wasps. 【Methods】 By means of artificially releasing wasps-marking-regularly sampling-microscopic and electron microscopic observations, the synergistic development of W. sp. nr. pumilae with gall, and the source of nutrients and the position change of W. sp. nr. pumilae inside galls were observed, the developmental dynamics of the body length of W. sp. nr. pumilae and the diameter of gall was determined, and the developmental duration of W. sp. nr. pumilae in summer and winter was compared. 【Results】 The development of immature W. sp. nr. pumilae is generally divided into the egg, larval and pupal stages. The larval stage is divided into 5 instars, in which male and female are indistinguishable. The pupal stage is divided into three stages: early stage, middle stage and mature stage. Male and female pupae are differentiated and heteromorphic, and male pupae develop 1.34 d earlier than female pupae. The gall consists of epidermis, protective layer, endodermis and nutritive layer; both the epidermis and endodermis are colloidal and water-rich, providing good humidity guarantee for fig wasps. The protective layer, as the skeleton of the gall shell, protects the larval wasps. The nutritive layer secrets nutritive solution to feed larval wasps. A comparison with the structure of the lean fruit showed that the small wasp-galls changed their protective layer morphology with thickened protective layer, and the nutritive layer is capable to deliver nutritive solution to larval fig wasps. The position of immature fig wasps inside the gall is regularly varying. The body length of larval wasps increases synergistically with the diameter of the gall. Galls grow faster than wasp larvae to provide a bounteous growth space for them. The body length of the fig wasp stops increasing in the pupal stage, while the growth of galls stops after the 4th instar of the larva. In Fujian areas, W. sp. nr. pumilae has two generations a year, its generation time in winter and summer is 253 d and 112 d, respectively, and the duration of various developmental stages in winter is longer than that in summer. Especially, the duration of the 5th instar larva of W. sp. nr. pumilae in winter is 66 d longer than that in summer. W. sp. nr. pumilae overwinters in the form of the 5th instar larva, and a prolonged feeding period is beneficial for its overwintering. 【Conclusion】 The results clarified the nutritive connection between immature W. sp. nr. pumilae and its gall and their synergistic development dynamics, providing a theoretical basis for the study of fig-fig wasp coevolution.

Key words: Wiebesia sp. nr. pumilae, gall structure, developmental duration, nutrition, coevolution