Pollination Biology of Ficus hispida in the Tropical Rainforests of Xishuangbanna, China

摘要

Ficus hispida L. (Moraceae) is a remarkable species in the ecosystem of tropical rainforests in Xishuangbanna, China. The figs and fig-pollination wasps (Chalcidoidae: Agaonidae) are highly co-evolved mutualists that depend completely on each other for propagating descendants. Pollination of all fig species is done by fig wasps; their unique symbiotic associates, the fig wasps, cannot develop in anywhere except in the fig syconia. The present paper reports on the biology and flowering phenology of F. hispida, as well as the propagation character and pollination behavior of the fig wasps ( Ceratosolen solmsi marchali Mayr) based on our observations in the rainforests of Xishuangbanna, southern Yunnan of China. F. hispida is a dioecious tree that annually blossoms and bears fruits 6-8 times, with four to five fruit-bearing peaks. The male trees produce pollen and provide fig wasps with reproductive havens, while the female trees produce fig seeds after pollination by the female wasps. Pollen of F. hispida cannot escape from the dehiscent anthers until they are disturbed by fig wasps. The female wasps open the anthers and collect pollen with their antennal scrapes, mandibles and legs, and then carry pollen to the female receptive syconia where fertilization takes place. Meanwhile, some of the female wasps lay eggs in the male receptive syconia. It takes about 3-67 min to search for the receptive syconia for pollination, and 15 - 23 h to enter the female receptive syconia. The number of female wasps entering a syconium has close relation with the impregnation and seed-bearing rate of female flowers, as well as the oviposition and reproduction rate of the fig wasps themselves. F. hispida is endowed with a relatively high level of seed bearing (54.1% - 82.5% , average 73.8 %). The wasp oviposition rate on the male flowers is between 72.3% and 93.8% with a mean of 84.4% .