Wind pollination and propagule formation in Rhizophora mangle L. (Rhizophoraceae): resource or pollination limitation?

Abstract

Rhizophora mangle is considered as a self-compatible mangrove, and is pollinated by wind and insects. However, there is no information about fruit production by autogamy and agamospermy and on the foraging behavior of its flower visitors. Hence, the present study analyzed the pollination and reproductive systems of R. mangle in a mangrove community in northern Pernambuco, Brazil. Floral morphology, sequence of anthesis, and behavior of flower visitors were described; the proportion of flowers that resulted in mature propagules was also recorded. Autogamy, agamospermy, and wind pollination tests were performed, and a new anemophily index is proposed. The flowers of R. mangle are hermaphrodite, protandric, and have high P/O rate. Flies were observed on flowers only during the male phase, probably feeding on mites that consume pollen. Rhizophora mangle is not agamospermic and its fruit production rate by spontaneous self-pollination is low (2.56%) compared to wind pollination (19.44%). The anemophily index was high 0.98, and thus it was considered as a good indicator. Only 13.79% of the flowers formed mature propagules. The early stages of fruit development are the most critical and susceptible to predation. Rhizophora mangle is, therefore, exclusively anemophilous in the study area and the propagule dispersal seems to be limited by herbivory.

Phenology and floral synchrony of Rhizophora mangle along a natural salinity gradient

“…In many species, flowering and fruiting are influenced by biotic interactions such as pollination and seed dispersal (Staggemeier, Diniz‐Filho, & Morellato, ; Wheelwright, ). Plants of the genus Rhizophora are mainly wind pollinated (Tomlinson, ; Tomlinson et al., ) and believed to be self‐compatible (Menezes, de Oliveira, & de Mello, ; Nadia & Machado, ). The success of wind pollination is likely determined by several conditions, including level of synchrony (within season and even day) in pollen release among conspecifics, low levels of humidity or probability of rainfall, and other unambiguous environmental cues to coordinate flowering (Real, ).…”

Terrestrial species adapted to sea dispersal: Differences in propagule dispersal of two Caribbean mangroves

“…Wind pollination, which typically moves pollen greater distances than transport via insects, characterizes red mangroves, in contrast to white mangroves, which are insect‐pollinated (Tomlinson, ). Both species are self‐compatible, and red mangroves have been documented to produce fruit from self‐pollination at approximately one tenth of the frequency of wind pollination (Nadia & Machado, ). White mangrove flowers have been observed to self‐pollinate when not visited by insects (Landry, ).…”

Contrasting Effects of Historical Sea Level Rise and Contemporary Ocean Currents on Regional Gene Flow of Rhizophora racemosa in Eastern Atlantic Mangroves

“…This is in accordance with the observed patterns of contemporary migration rates and modeled propagule dispersal trajectories and suggests that post-glacial SLR has established the genetic connectivity between populations of the Rio Del Rey Estuary and those of the CEC via the Inter-Bioko-Cameroon (IBC) corridor. Rhizophora racemosa is wind pollinated, with occasional insect pollination [ 83 , 84 ]. Pollen dispersal by wind covers certain distances, but unlikely over the entire studied area.…”