The style–length of the female florets and their fate in two dioecious species of Xishuangbanna, China

Abstract

Constraints and evolution are central for the resolution of conflicts between mutualism species and for the stability of mutualisms. Dioecious fig species and their specific pollinators are also in conflict on the use of fig ovaries. Here, our experiments provided some data on the female florets allocation in two dioecious fig trees. The results showed that: (1) there is a bimodal distribution in the style-length of two fig trees' female florets, moreover, the style-lengths are fairly similar and narrowly distributed in gall figs and more variation seems to occur in seed figs;(2) the styles in seed figs are a little longer than those in gall figs; (3) the pollinator's ovipositor lengths are shorter than the style-lengths in seed figs, but they are very similar to those in gall figs so that pollinators can only lay their eggs into the ovaries of gall figs, but not in seed figs; (4) the stigmas stick together, and the style is curly and flexible in seed syconia of the two fig species studied, so it is very difficult for the pollinators to find suitable ovipositing sites and lay their eggs in seed figs; (5) the variations of stylelengths are bigger in seed figs than gall figs, but they are smaller in dioecious figs than monoecious figs; (6) for Ficus cyrtophylla, about 10% styles are shorter in seed figs than those in gall figs, even shorter than ovipositor. In contrast, about 2% styles in gall figs of Ficus hispida are longer than its corresponding pollinator's ovipositor. In a word, our study suggests that the female floret's fate in these two fig species is mainly dependent on its style-length, but not all. The stigma shape and the floral organization can both also attribute to their fate in the two fig species studied.

Style length variation in male and female figs: development, inheritance, and control of pollinator oviposition

“…Styles at receptivity in male figs were shorter than in female figs, as has been described for all other dioecious fig tree species (Weiblen, ; Shi et al., ; Ma et al., ). At the time of receptivity, styles in female figs are also much more variable in length than those in male figs.…”

Different Stimuli Reduce Attraction to Pollinators in Male and Female Figs in the Dioecious Fig Ficus hispida

“…were conducted at the Chinese Academy of Tropical Agricultural Sciences (CATAS), Danzhou, Hainan province, China (19°30.410′ S, 109°29.340′ E). Fig trees of F. hispida are free‐standing, usually 5–8 m in height, with spherical figs (Corlett 2006) and they are actively pollinated by Ceratosolen solmsi Mayr (Shi et al 2006). The fig fruit is ca 30–40 mm diam.…”

Ability to gall: the ultimate basis of host specificity in fig wasps?

“…Whereas galled ovules in F. montana figs rapidly expanded, there was no apparent response from the ovules of F. asperifolia and no successful development of fig wasp larvae. In contrast to this inability to generate galls, the lack of K. tentacularis offspring in female figs of its routine host species, F. montana , results from an almost total inability to deposit eggs in the ovules of female figs, reflecting their flowers' longer styles and different stigma structure (Shi et al ., ).…”