Abstract: Ficus semicordata Buch.-Ham. ex J. E. Sm. is a common species of Ficus. It is also a pioneer species in the tropical rainforest eco-system. After tropical rainforest has been disturbed this species will establish and grow rapidly in valleys and on roadsides. It is, therefore, an important species in the preliminary stages of forestry ecosystem rehabilitation in the tropics and semi-tropics. This paper describes the pollination behavior and propagation of fig wasps. Individual sample trees were observed at regular intervals at different sites and syconia were dissected and examined at different phases of development. The results indicate that F. semicordata is dioecious and bears 2-3 crops year round in Xishuangbanna. Florets of the syconia on female trees are pollinated by pollinating fig wasps, and develop into seeds afterwards. Female trees only produce staminate flowers and intermediate flowers, the latter are specially provided to pollinating fig wasps for their oviposition and proliferation. Ceratosolen gravelyi Grandi is the only insect pollinator of F. semicordata. Its males emerge from pupae 30-60 min before the females. Some males crawl over the layer of gall flowers searching for those that contain a female. After finding one they then bite a hole in it and copulate with the female inside. Other males will chew a hole in the pulp; after copulation females will crawl out of the mating hole, collect pollen in the staminate area, then fly out to look for receptive young syconia to enter and pollinate or oviposit. Females that pollinate female trees can fly for 300-500 m; the time interval of pollination in the fig cavity is as long as 5-14 h. After 3-5 h of pollination females die; females that search for male trees to reproduce typically fly 20-100 m. After finding a tree they will enter into the fig cavity and oviposit; each female can lay more than 400 eggs if undisturbed. Non-pollinating fig wasp species include phytophagous fig wasps, gall-makers, inquilines, etc.; these have a great impact on the propagation of pollinating fig wasps, often reducing the population of the latter by 25%-70%. The number of pollinating fig wasps that enter into fig cavities affects both the propagation of F. emicordata and themselves, the optimum is 3, more or less will reduce the reproductive success of both the pollinating fig wasps and their host fig trees.

Key words: Xishuangbanna, Ficus semicordata, pioneer tree species, pollinating fig wasp, behavior, pollination, propagation