Xishuangbanna is rich in local fig flora, with 81 native fig species (32 monoecious and 49 dioecious). Previous studies showed that pollinator activity of both monoecious and dioecious fig species occurred largely at the warmer times of the year. However, Ficus tinctoria, a hemiepiphytic dioecious fig species, showed peak pollinator dispersal in winter in Xishuangbanna. Dr. CHEN Huanhuan, together with her teachers of Xishuangbanna Tropical Botanical Garden (XTBG), made detailed phenology observations in order to understand the apparently anomalous phenological pattern.
The researchers conducted a phenological study of 28 male and 23 female plants of Ficus tinctoria. They visited the trees in Xishuangbanna at weekly intervals from August 2013 to January 2015.
The study found that both male and female trees of Ficus tinctoria produced their major fig crops at the coldest time of the year. By contrast, other figs had a winter low in fig production. Syconia were present on most of the F. tinctoria trees for much of the year, but there were single, annual crop peaks in both sexes and very few syconia for the rest of the year.
Male plants released pollinators during the period when most female trees were receptive and male syconia had a long wasp-producing (D) phase. Pollinator production in male syconia was greatest in the crops that preceded the peak crop and lowest after the peak crop. Conversely, non-pollinating wasps were lowest in the early crops and highest in the last crop, when they were more abundant than the pollinators.
During the rest of the year, few syconia were produced by either sex. However, the syconia produced in winter were sufficient to maintain local pollinator populations. The researchers explained the unique phenology of Ficus tinctoria as it has evolved to maximize female function.
  The study entitled “Winter cropping in Ficus tinctoria: an alternative strategy”has been published in Scientific Reports.