Acta Entomologica Sinica ›› 2020, Vol. 63 ›› Issue (7): 861-869.doi: 10.16380/j.kcxb.2020.07.010

• RESEARCH PAPERS • Previous Articles     Next Articles

Trade-off between pollination and oviposition of the pollinator Ceratosolen sp. (Hymenoptera: Agaonidae) in monoecious Ficus racemosa

WANG Xue-Min1,2, MIAO Bai-Ge2, PENG Yan-Qiong2,*   

  1. (1. College of Ecology and Environmental Science, Yunnan University, Kunming 650091, China; 2. Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Mengla, Yunnan 666303, China)
  • Online:2020-07-20 Published:2020-07-29

Abstract: 【Aim】 Ficus relies on the pollination of obligate wasps (Agaonidae) and provides the breeding place for the pollinator, which forms a classic coevolutionary relationship between plants and animals. In the receptive female figs, the wasp needs to pollinate and lay eggs within the limited survival time, and the balance between pollination and oviposition of wasp remains an open question. This study aims to ascertain the behavior and reproductive pattern of active pollinator Ceratosolen sp. in the receptive female figs of monoecious Ficus racemosa. 【Methods】 The style length of female flowers of F. racemosa and the ovipositor length of its pollinating fig wasps (Ceratosolen sp.) were measured under the microscope with micrometer, and the searching, oviposition and pollination behaviors of pollinating fig wasps were observed and recorded by video combined with the controlled experiments. After the pollinator was introduced to enter receptive female figs, the body sizes, egg loads, and pollen loads were measured at different stages. Finally, the numbers of fig wasp offspring and seeds in controlled figs were counted in male floral phase. 【Results】 The style length of female flowers of F. racemosa had variation between trees, but the ovipositor length of fig wasps was longer than the style length of most female flowers, indicating that the fig wasps can lay eggs in the ovaries of most female flowers. In general, larger pollinators had more egg loads, but the correlation between body size and pollen load was not significant. Behavioral observation showed that fig wasps mainly laid eggs in the first 6 h that they entered receptive female figs, laying about 95% of eggs in the ovaries. In receptive female figs, fig wasps averagely spent 27 s to search appropriate female flowers, and the oviposition time was averagely 46 s. During this period, the pollination behavior was rarely observed, and the number of pollen grains in pollen pockets did not vary significantly. After fig wasps entered the figs for 6-24 h, they mainly performed active pollination consistently and efficiently pollinated female flowers. The average time for pollination was 2 s, and at last 80% of the pollen loads were pollinated. The controlled experiment also confirmed that fig wasps mainly oviposited and produced their offspring in the first 6 h after entering fig, and then pollinated female flowers to produce fig seeds in the next 6-24 h. 【Conclusion】 In the receptive female figs of monoecious F. racemosa, fig wasps firstly lay eggs and then actively pollinate female flowers. The oviposition and pollination behaviors of fig wasps were exhibited for the first time, and the number of eggs laid and seed production matching the behaviors were determined, reflecting that the actively pollinated fig wasps have the tradeoff between pollination and oviposition about time and quantity.

Key words: Fig wasps; Ceratosolen sp.; Ficus, Ficus racemosa, pollination, oviposition, coevolution, mutualism