Intrafloral Color Modularity in a Bee-Pollinated Orchid.

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.

Genetic correlations and ecological networks shape coevolving mutualisms.

Ecological interactions shape the evolution of multiple species traits in populations. These traits are often linked to each other through genetic correlations, affecting how each trait evolves through selection imposed by interacting partners. Here, we integrate quantitative genetics, coevolutionary theory and network science to explore how trait correlations affect the coevolution of mutualistic species not only in pairs of species but also in species-rich networks across space. We show that genetic correlations may determine the pace of coevolutionary change, affect species abundances and fuel divergence among populations of the same species. However, this trait divergence promoted by genetic correlations is partially buffered by the nested structure of species-rich mutualisms. Our study, therefore, highlights how coevolution and its ecological consequences may result from conflicting processes at different levels of organisation, ranging from genes to communities.

Análise comparativa de duas formações vegetacionais e de seu ecótono, Miranda - MS / Comparative analysis of two vegetation types and its ecotone, Miranda - MS

O Pantanal é constituído por diferentes formações vegetacionais, entre elas o Paratudal e a Mata Ciliar. Este trabalho objetivou analisar comparativamente essas duas formações, e o ecótono entre elas, quanto à diversidade e similaridade. O estudo foi desenvolvido na região do Passo do Lontra, às margens do rio Miranda, MS. Foram estabelecidas cinco parcelas de 10 x 10m em cada área e nelas todos osindivíduos acima de 1m de altura foram contados e identificados. Foram registrados 913 indivíduos, distribuídos em 70 taxa, dos quais 60 foram identificados em nível de espécie. O índice de diversidade de Shannon (H’) foi 2,715 com equidade de Pielou (J’) de 0,806 no Paratudal; 3,010 e 0,835 na Mata Ciliar; e 2,739 e 0,797 no ecótono, respectivamente. Esses resultados demonstram maior diversidade na Mata Ciliar, como esperado, já que as condições do ambiente do Paratudal são mais seletivas. A similaridade florística entre o Paratudal e a Mata Ciliar, de acordo com o índice de Sorensen, foi de 0,2o que distingue ambos os ambientes. Portanto, este trabalho evidencia a distinção entre Mata Ciliar e Paratudal, bem como os valores intermediários do ecótono.

The Pantanal consists of different vegetation types, including the Paratudal, a monodominat floodablesavanna, and Riparian vegetation. This study aimed to analyze diversity and similarity in samples of these two vegetations, and its ecotone. The study was developed in the region of Passo do Lontra, at the Miranda river margins. Five plots 10 x 10m, were allocated in each area, where all individuals above 1m height were counted and identified. Nine hundred and thirteen individuals were registered, distributed in 70 taxa, of which 60 were identified in species level. The Shannon diversity index (H’) was 2.715 with Pielou Eveness (J’) of 0.806 in Paratudal, 3.010 and 0.835 in Riparian vegetation, and 2.739 and 0.797 in ecotone, respectively. These results show highest diversity in the Riparian vegetation, as expected, since the Paratudal’s ambient conditions are more restrictive. The floristic similarity between the Paratudal and the Riparian vegetation, according to the Sorensen index, was of 0.2, what distinguishboth environments. Therefore, this study evidences the distinction among Riparian vegetation and Paratudal, as well the existence of an intermediary values with ecotone.