Pérez-Barrales Rocío, Sá Túlio, Matias Raphael, Furtado Marco Túlio, Rodríguez Ebenezer, González Julio Rabadán, Consolaro Hélder, Castro Cibele Cardoso
Botany Department, Faculty of Science, University of Granada, Avenida de Fuente Nueva s/n, 18071 Granada, Spain.
Graduate Program in Biodiversity, Federal Rural University of Pernambuco, Rua Dom Manoel de Medeiros, s/n, Recife 52171-900, Pernambuco, Brazil.
AoB Plants. 2025 Mar 13;17(3):plaf014. doi: 10.1093/aobpla/plaf014. eCollection 2025 Jun.
The flowering phenology of many closely related species in the Brazilian Cerrado coincides with the onset of the rainy season, where sequential flowering often occurs with some overlap. Transitioning from solitary flowering to coflowering with congeneric species may alter the pollination environment, affecting pollen delivery and deposition patterns. Coflowering among conspecifics concurrently requires pollination niche differentiation to minimize reproductive costs. This study tested these concepts in the distylous during two flowering periods: early in the season when it flowered alone, and later with conspecific , also distylous. Pollination syndromes were assessed by measuring corolla length, nectar volume and sugar concentration, and reproductive organ height. shows yellow and shorter corollas with higher sugar concentration in the nectar, while presents yellow to orange longer corollas with more diluted nectar, aligning with bee and hummingbird pollination syndromes, respectively, as reported in the literature. However, the species exhibited significant overlap in stigma and anthers height. The main floral visitor in the two species during the study was Visitation increased through the season, particularly in conspecific patches of , resulting in higher pollen delivery. In contrast, pollen deposition was similar or higher in congeneric patches with during the coflowering period. Visits to were higher than in , suggesting a bumblebee preference for the former. The study highlights the complex interplay between flowering phenology, floral traits, and pollinator behaviour in shaping reproductive outcomes and potential niche differentiation. While differences in flowering and flower morphology may prevent potential costs of pollinator sharing, the risk of reproductive interference remains significant. Future research should focus on comprehensive pollination dynamics throughout the entire flowering season, measuring pollinator behaviour, pollen dynamics and plant fitness, to further elucidate the mechanisms driving floral evolution and niche differentiation in sympatric species.
巴西塞拉多地区许多近缘物种的花期与雨季开始时间一致，通常会出现连续开花且有部分重叠的情况。从单花开花转变为与同属物种同时开花可能会改变授粉环境，影响花粉传递和沉积模式。同种植物同时开花则需要授粉生态位分化，以尽量减少繁殖成本。本研究在两个花期对异型花柱植物进行了这些概念的测试：在季节早期它单独开花时，以及后期与同种植物（也是异型花柱）同时开花时。通过测量花冠长度、花蜜体积和糖浓度以及生殖器官高度来评估授粉综合征。研究表明，[一种类型]呈现黄色且较短的花冠，花蜜中糖浓度较高，而[另一种类型]呈现黄色至橙色的较长花冠，花蜜更稀释，分别与文献报道的蜜蜂和蜂鸟授粉综合征相符。然而，该物种在柱头和花药高度上存在显著重叠。研究期间这两个物种的主要访花者是[访花者名称]。访花次数在整个季节中增加，特别是在[某种植物]的同种斑块中，导致更高的花粉传递。相比之下，在同时开花期，与[另一种植物]的同属斑块中的花粉沉积相似或更高。对[一种植物]的访问高于对[另一种植物]的访问，表明大黄蜂更喜欢前者。该研究强调了花期物候、花部特征和传粉者行为在塑造繁殖结果和潜在生态位分化方面的复杂相互作用。虽然开花和花形态的差异可能会防止传粉者共享的潜在成本，但生殖干扰的风险仍然很大。未来的研究应专注于整个开花季节的综合授粉动态，测量传粉者行为、花粉动态和植物适合度，以进一步阐明驱动同域物种花部进化和生态位分化的机制。
