Flower Specialization in a Passively Pollinated Monoecious Fig: A Question of Style and Stigma?

Abstract

JSTOR is a not-for-profit service that helps scholars, researchers, and students discover, use, and build upon a wide range of content in a trusted digital archive. We use information technology and tools to increase productivity and facilitate new forms of scholarship. For more information about JSTOR, please contact support@jstor.org.. The University of Chicago Press is collaborating with JSTOR to digitize, preserve and extend access to International Journal of Plant Sciences.The stability of the mutualism between figs and their pollinator wasps depends on the patterns of seed and wasp production. In Ficus maxima, a passively pollinated monoecious fig, we estimated the correlations among different flower characteristics and determined their relationships with pollination success and pollinator oviposition. Across flowers, stigma length shows an allometric relationship with style length, and style length correlates negatively with style width. Longer-styled flowers are more likely to be pollinated and receive higher pollen loads. This is probably explained by their larger stigmatic surface that increases their chance of receiving the passively dispersed pollen. Consistent with findings in other species, flowers with longer styles are less likely to receive a pollinator's egg. This oviposition pattern is probably explained by a combination of factors: (1) wasps ovipositor are too short to reach flowers with extremely long styles, and 17% of flowers are inaccessible;(2) sometimes, there are too few pollinators to use all accessible flowers; (3) oviposition is more difficult through the long stigmas and thin styles associated with long-styled flowers. Given the patterns of pollinator egg distribution, the style/stigma size relationship in F. maxima appears advantageous for the fig since it leads to preferential pollination of flowers that are not used by wasps. It might reflect flower functional specialization and contribute to the mutualism stability.

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

“…Compared with some previous reports on the seed-wasp conflict in some monoecious species (Galil and Eisikowitch 1968;Bronstein 1988;Kathuria et al 1995;Anstett 1996Anstett , 2001Nefdt and Compton 1996;Herre 1999;Otero and James 2002;Douglas et al 2004;Jousselin et al 2004), we found that dioecious species and monoecious species may adopt different mechanisms to resolve the conflict. The monoecious species control seed loss through increasing the style-length variation which can increase the probing and handling time for the pollinator's oviposition, but the dioecious ones decrease the style-length variation and only produce short-styled flowers in gall figs to facilitate the pollinator's oviposition, and the seed figs mainly inhibit the pollinator's oviposition through almost only bearing longstyled florets.…”

The Subdivision of Ficus Subgenus Pharmacosycea Section Pharmacosycea (Moraceae)

“…This partly explains the features of figure 1 in the paper by Jousselin & Kjellberg (2004) dealing with pollination in Ficus maxima. The illustration presents a general picture of a monoecious fig rather than that of the actual species at anthesis.…”

Spatial Stratification of Internally and Externally Non-Pollinating Fig Wasps and Their Effects on Pollinator and Seed Abundance in Ficus burkei

“…About half (300+) of Ficus species are monoecious, where both male flowers and ovules are present in the same syconium (enclosed inflorescence or " fig"). Within monoecious syconia, ovules are highly variable in length [7][8][9][10]. Long (inner) ovules have short styles and mature near the centre of the syconium, whereas short (outer), long-styled ovules mature nearer the outer wall (see Figure 1).…”

“…Female pollinating wasps (foundresses) lay their eggs by inserting their ovipositors down the flower styles. At maturation, wasp galls are clustered at the syconium's centre [4,6,[9][10][11][12][13] with seeds at the outer wall. This spatial stratification of pollinating wasps and seeds enables mutualism stability, although the mechanisms preventing the wasps from galling all ovules are unclear.…”

“…[13][14][15]). Ovipositing foundress wasps may favour inner ovules because of shorter handling times offered by the short styles [10,12]. Interference competition between foundresses, which further slows oviposition [16], and limited longevity [13,16] means that wasps die before all ovules are galled.…”