Legume Genomics and Genetics 2024, Vol.15, No.5, 210-220 http://cropscipublisher.com/index.php/lgg 212 2.2 Phylogenetic relationships Within the Fabaceae family, several major clades exhibit distinct evolutionary traits. The Dipterygeae clade, for example, is characterized by its unique winged papilionate floral architecture and comprises genera such as Dipteryx, Monopteryx, Pterodon, and Taralea (Carvalho et al., 2023a). Another significant clade is the Cladrastis clade, which includes species with compressed, winged fruits and displays an amphi-Pacific distribution. The Bowdichia clade, with fossil evidence from the Paleogene of North America, further illustrates the diversity and evolutionary history within the Fabaceae family (Herendeen et al., 2022). Genetic evidence supports the evolution of winged flowers through comprehensive phylogenetic analyses. Studies on the Dipterygeae clade using nuclear ribosomal ITS/5.8S and plastid matK and trnL intron sequences have strongly supported the monophyly of each genus and the conservatism of winged floral traits. Similarly, the Cladrastis clade’s phylogenetic relationships and divergence times have been reconstructed using nuclear and plastid regions, revealing the evolution of winged fruits and their biogeographic history (Duan et al., 2019). 2.3 Co-evolution with pollinators Winged papilionate flowers have evolved specific adaptations to attract and interact with specialized pollinators. The unique floral architecture of the Dipterygeae clade, including zygomorphy and petal differentiation, has facilitated effective ecological interactions with pollinators, ensuring the protection of young flower buds and developing fruits. The presence of glandular wing petals in Petaladenium urceoliferum also highlights the evolutionary adaptations for pollinator attraction and interaction (Prenner et al., 2015). Case studies of co-evolutionary relationships between winged papilionate flowers and their pollinators provide valuable insights into their evolutionary history. For instance, the ancient winged papilionate floral conservatism in the Dipterygeae clade has maintained effective ecological interactions with specialized pollinators, contributing to the clade’s evolutionary and ecological persistence (Carvalho et al., 2023a). Additionally, the mid-Mesozoic kalligrammatid lacewings, which exhibited convergent evolution with Cenozoic butterflies, demonstrate the complex co-evolutionary dynamics between flowers and their pollinators (Labandeira et al., 2016; López-Martínez et al., 2023). 3 Ecological Roles and Adaptations 3.1 Habitat preferences Winged papilionate flowers, particularly those within the Dipterygeae clade, are predominantly found across tropical forests in Central America and the Amazon. They also exhibit ecological dominance in the savannas of the Brazilian Central Plateau (Carvalho et al., 2023a). This wide geographic distribution highlights their adaptability to diverse environmental conditions and their ability to thrive in both forested and savanna ecosystems. The Dipterygeae clade has shown remarkable conservatism in floral architecture over 30 million years, which has likely contributed to their successful adaptation to various environmental conditions. The unique winged papilionate floral structure, characterized by a highly differentiated calyx, has enabled these species to maintain effective ecological interactions with specialized pollinators and protect developing fruits, ensuring their persistence across different biomes. Additionally, the ability of Vigna caracalla to adapt its mating system to varying ecological contexts, such as higher elevations with reduced pollinator diversity, further demonstrates the adaptive strategies of papilionate flowers (Etcheverry et al., 2008). 3.2 Pollination mechanisms Papilionate legume flowers exhibit structural adaptations that facilitate pollination by filtering pollinators based on their ability to exert the necessary strength to access floral rewards. Morphometric traits, particularly those of the keel and wings, are strongly correlated with the operative strength required to open the flowers. This structural complexity forms an intrafloral functional module that ensures only suitable pollinators can access the rewards, thereby enhancing pollination efficiency (Córdoba and Cocucci, 2011). The specialized floral architecture of winged papilionate flowers has fostered symbiotic relationships with specific pollinators. For instance, Vigna caracalla relies on pollinators such as Bombus morio, Centris bicolor, Eufriesea mariana, and Xylocopa eximia to trigger its pollination mechanism. These relationships are crucial for the reproductive success of these plants, as
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