Rethinking the pollination syndromes in Hymenaea (Leguminosae): the role of anthesis in the diversification.

Isys M Souza,Ligia S Funch,Frederic M Hughes,Luciano P De Queiroz

doi:10.1590/0001-3765202120191446

Isys M Souza, Ligia S Funch + Show 2 more

Open Access

https://doi.org/10.1590/0001-3765202120191446

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Abstract

Floral traits associated with functional groups of pollinators have been largely employed to understand mechanisms of floral diversification. Hymenaea is a monophyletic legume genus widely recognized to being bat-pollinated, with nocturnal anthesis and copious nectar. The most of species has short-paniculate inflorescences, white and robust flowers, congruent with a bat-pollination syndrome. However, other Hymenaea species show a different floral pattern (e.g., long-paniculate inflorescences and smaller flowers) which we report here as being bird pollinated. We examined the floral traits and visitors of Hymenaea oblongifolia var. latifolia and identified evolutionary shifts in floral traits associated with potential pollinators of Hymenaea species. Floral traits of H. oblongifolia var. latifolia differ from those expected for bat-pollinated flowers in species of sect. Hymenaea, and we observed hummingbirds collecting nectar legitimately. Our phylogenetic analysis did not support the monophyly of the taxonomic sections and suggests that bat pollination is ancestral in Hymenaea, with bird pollination evolving later. The transition coupling with shifts in the timing of anthesis and other floral traits. Pollinator-mediated evolutionary divergence hypothesis partially explains the Hymenaea diversification in the Neotropics. It is congruent with those species shifting from traits linked traditionally to bat pollination to hummingbird pollination.

Highlights

Pollination syndrome concept is based on the notion that suites of floral traits reflect adaptations to a specific pollinator or group of most effective pollinators (Stebbins 1970, Faegri & van der Pijl 1979, Grant 1994)
The conservatism of floral traits is intuitively understood as a direct result of the evolutionary history in the context of sharing of the common ancestry without selective pressures exerted by pollinators
We examined the floral traits and potential pollinators of Hymenaea oblongifolia var. latifolia Lee & Langenh

Summary

Introduction

Pollination syndrome concept is based on the notion that suites of floral traits reflect adaptations to a specific pollinator or group of most effective pollinators (Stebbins 1970, Faegri & van der Pijl 1979, Grant 1994). It is a proxy for understanding floral trait diversification and evolution towards specialized pollination systems (Fenster et al 2004, Armbruster et al 2014, Rosas-Guerrero et al 2014). The conservatism of floral traits is intuitively understood as a direct result of the evolutionary history in the context of sharing of the common ancestry without selective pressures exerted by pollinators (i.e., phylogenetic inertia; Sakazono et al 2012, Papadopoulos et al 2013).

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