Number and Structure of Anthers in Fig Syconia in Relation to Behaviour of the Pollen Vectors

Abstract

Structure and functioning of anthers have been studied in Ficus carica L., F. sycomorus L. and F. religiosa L. Polleniferous figs of F. carica produce numerous male flowers with plenty of pollen (multistaminate type). Mature anthers contain a normal fibrous layer and open spontaneously. On the other hand, figs of F. sycomorus produce a comparatively small number of male flowers, their anthers have a degenerated endothecium and do not dehisce normally. In pollination (pollen loading and unloading) the great differences occurring in the organization of the androecium of F. carica and F. sycomorus may be seen to be associated with different behaviour patterns of their specific pollen vectors, the agaonid wasps Blastophaga psenes and Ceratosolen arabicus, respectively. While the pollinators of F. carica become passively coated with pollen on their exit from the native fig (topocentric pollination), the pollen vectors of F. sycomorus help in opening of the anthers and load the pollen purposively, by direct lifting of the pollen from the anthers on to special pockets on the body of the insect (ethodynamic pollination). Thus, in the context of pollination, the complementary nature of the characteristics of the two participants of fig symbiosis is evident.

Fauna de Hymenoptera em Ficus spp. (Moraceae) na Amazônia Central, Brasil

“…Muitos insetos são polinizadores passivos, mas alguns grupos de vespas de figo adquiriram um mecanismo sofisticado de polinização ativa (COOK & RASPLUS, 2003). Algumas espécies de Agaonidae são polinizadoras passivas, dispersando o pólen que fica aderido ao corpo (sem nenhum comportamento especializado, GALIL & MEIRI, 1981;WEIBLEN, 2002). Estudos filogenéticos indicam que o mecanismo passivo de polinização é ancestral nas vespas de figo, mas em vários casos houve perdas secundárias do mecanismo ativo de polinização MACHADO et al, 2001).…”

“…não apresentam estruturas adaptativas para o transporte de grãos de pólen, sendo caracterizadas como polinizadoras passivas (GALIL & MEIRI, 1981;WEIBLEN, 2002). Nossos resultados apóiam a constatação de KJELLBERG et al (2001) de que o modo de polinização pode ser predito pelas características do sicônio.…”

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

“…In all passively pollinated figs (one-third of all fig species; Kjellberg et al 2001), the numerous stamens dehisce at wasp emergence so that pollen gets trapped on various parts of the wasps' bodies when they leave their natal fig (Ramirez 1969;Galil and Neeman 1977;Galil and Meiri 1981;Ramirez and Malavasi 1997;Kjellberg et al 2001). The pollen trapped on the wasps' bodies is then passively released in the fig cavity when wasps lay their eggs.…”

Speciation in fig wasps

“…Female wasps then emerge into the fig cavity and at this time the male fig flowers are mature and liberating pollen. In some species, the wasps actively collect pollen into thoracic pollen pockets and later deposit it deliberately onto flower styles (Galil & Meiri, 1981; Kjellberg et al , 2001; Jousselin et al , 2003a). In others, pollination is passive via transport on the wasp's body, as in most other insects (Waser & Ollerton, 2006).…”