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Rewardless orchid species are pollinated by deception and have reduced reproductive success. Those species that present self‐compatibility followed by alternative mechanisms of autogamy may compensate for such episodic allogamy events. This is the case for rain‐assisted self‐pollination, a rare mechanism in Orchidaceae. In this study, we investigated the reproductive biology of two terrestrial species: Cyrtopodium hatschbachii and C. paludicolum. We studied their reproductive systems, examined pollinators and male and female successes, and ascertained if rain promotes self‐pollination. Both species are allogamous but self‐compatible. However, natural fruit set is low, not exceeding 1.40% during 4 years of observation. This may result from the reduced frequency of pollinator visitation followed by a high pollinator specificity, because each species was pollinated by a single specialist bee. Although spontaneous selfing did not occur, we verified fruits formed by rain action. The evaporation of the water droplet that accumulates on stigma helps the pollinarium to slip back, promoting selfing. This occurred in approximately 10% of C. hatschbachii fruits, but in C. paludicolum it was recorded only once during three observation years. This indicates that the phenomenon happens at random and may vary temporally. Nevertheless, rain may confer additional fruit set, especially under circumstances of pollinator limitation. Overall, we confirmed deception as a strategy for this understudied genus. In addition, we report a further two cases of rain‐assisted self‐pollination for Cyrtopodium, for species from the center of diversity of the genus, indicating that it may be more widespread than previously thought.

A consolidação em uma área do conhecimento acontece principalmente quando as informações acerca de um determinado fato ou fenômeno são sistematizadas na forma de uma teoria explicativa, capaz de gerar novas hipóteses testáveis. Na biologia da polinização, o teste de diversas hipóteses ecológicas permitiu ampliar o entendimento sobre os processos que originam, mantêm, alteram ou ainda excluem as interações entre plantas e visitantes florais, gerando os padrões observados na natureza. Visando sintetizar esse panorama teórico e oferecer condições para que novas questões relacionadas ao funcionamento de interações de polinização sejam geradas, compilamos aqui um conjunto de 25 hipóteses, ideias e teorias ecológicas que fornecem aporte conceitual para a área. Essas ideias estão relacionadas a aspectos reprodutivos, morfológicos, cognitivos, macroecológicos e de coexistência, de acordo com a especialização das interações entre as plantas e seus polinizadores. Ao apresentarmos essas ideias principais, esperamos promover a utilização de uma abordagem teórico-conceitual explícita no planejamento e desenvolvimento de estudos em biologia da polinização. Concluímos com a expectativa de que essa contribuição direcione os estudos em biologia da polinização no Brasil e contribua para o avanço e internacionalização das pesquisas desenvolvidas no país. Palavras-chave: Fundamentação teórica, interação planta-polinizador, sucesso reprodutivo, ecologia cognitiva. AbstractA particular research area can be significantly improved when information is systematized in explanatory theories able to generate testable hypotheses. In pollination biology, such systematization contributed to several ecological theories and expanded the understanding of the patterns and processes that originated, maintain, or exclude ecological interactions. Here, we compiled a set of 25 ecological ideas that have already received conceptual contribution from pollination biology. These ideas are related to reproduction, morphology, cognition, macroecology and species coexistence. We hope to promote the use of an explicit conceptual and theoretical approach when planning and developing studies in this research field by presenting these main ideas. We conclude that this contribution will boost studies in pollination biology in Brazil and contribute to the advancement and internationalization of such research developed in the country.

Flower color has been studied in different ecological levels of organization, from individuals to communities. However, it is unclear how color is structured at the intrafloral level. In bee-pollinated flowers, the unidirectional gradient in color purity and pollen mimicry are two common processes to explain intrafloral color patterns. Considering that floral traits are often integrated, usually reflecting evolutionary modules under pollinator-mediated selection, we hypothesize that such intrafloral color patterns are structured by intrafloral color modules as perceived by bee color vision system. Here, we studied the tropical bee-pollinated orchid Cattleya walkeriana , given its intrafloral color complexity and variation among individuals. Considering bee color vision, we investigated if intrafloral color modules arose among intrafloral patches (tip or base of the sepals, petals, and labellum). We expected a separate color module between the labellum patches (the main attractive structure in orchids) and petals and sepals. We measured the color reflectance and calculated the photoreceptor excitation, spectral purity, hue, and the chromatic contrast of the floral structures in the hexagon color model. Spectral purity (saturation) was higher in the labellum tip in comparison to petals and sepals, generating a unidirectional gradient. Labellum base presented a less saturated yellow UV-absorbing color, which may reflect a pollen mimicry strategy. C. walkeriana presented three intrafloral color modules corresponding to the color of petals and sepals, the color of the labellum tip, and the color of labellum base. These color modules were unrelated to the development of floral structures. Given the importance of intrafloral color patterns in bee attraction and guidance, our results suggest that intrafloral patterns could be the outcome of evolutionary color modularization under pollinator-mediated selection.

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Agradeço, primeiramente à Deus, pela saúde e pela oportunidade de poder lutar pelas pessoas e razões as quais acredito. Aos meu pais, Júlio Cesar e Sandra, pela educação, caráter, amor e o apoio incondicional em todas as fases da minha vida. Aos meus irmãos, Maxwell e Túlio, pelas risadas, aprendizados, conversas e brigas que me fizeram crescer. Ao professor Paulo Eugênio e ao Vinícius Brito, pela confiança, paciência e aprendizado ao longo desses anos. Ao Senhor Milton de Almeida Magalhães Junior, proprietário da Fazenda Preciosa, pela confiança, apoio e gentileza em permitir a realização dessa pesquisa em uma das áreas do estudo. À toda equipe do LECA pela ajuda na preparação e identificação das abelhas e ao professor Hamilton Kikuti por ceder a estufa para realizar o trabalho. Ao João Custódio, pela imensurável colaboração em todas as etapas dessa pesquisa. Às instituições que apoiaram ao longo de todo o trabalho CAPES, CNPq e UFU. E por fim, gostaria de agradecer à minha segunda família, os meus amigos, que de várias formas me ajudaram a construir os caminhos para que eu alcançasse esse objetivo. "Sozinho se chega mais rápido, mas em grupo se chega mais longe"