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Many bat-pollinated flowers begin their anthesis in the late afternoon, even before sunset, as illustrate by freshly opened Ceiba glaziovii (Malvaceae) flowers against the twilight sky (left panel). We present, for the first time, the spectral reflectance curves of bat-pollinated flowers using as model I Ceiba glaziovii i (Malvaceae), an impressive tree whose crown turns completely white during the reproductive season, and 13 other chiropterophilous species from Caatinga dry forest, Northeastern Brazil. These photographs illustrate the article "Shining bright in the dusk: How do bat-pollinated flowers reflect light?". [Extracted from the article]

In plant–pollination interactions, the antagonists collect the same set of resources offered to legitimate visitors, but their morphologies and behavioural approaches possibly make their effect on plant fitness negative rather than positive. Depending on the morphology of Malpighiaceae flowers, these small-bodied bees can adopt an upside-down position, biting and damaging the floral pedicel. Therefore, we hypothesized that small-bodied bees may reduce female reproductive fitness, due to increased floral abscission. We observed small Tetrapedia bees approaching bagged and unbagged flowers of Peixotoa tomentosa, and compared abscission rates associated with the upside-down behavior performance. When Tetrapedia bees exhibited the upside-down behaviour the floral abscission was about 1.7 times more frequent than without this behaviour. We observed that abscission frequency increased to 80% if upside-down behavior is performed at least three times per flower. Additionally, the frequency of upside-down behaviours were positively related to the number of flowers visited per plant. Overall, the upside-down behaviour of Tetrapedia compromised most flowers that were viable for fruit formation, potentially decreasing the female reproductive fitness of plant population. We emphasize that different roles of floral visitors, including the robbers, are associated with visitors' body size and behaviour. Such features of interactions determine whether floral visitors are pollinators, thieves or robbers and shape a continuum from mutualistic to antagonistic interactions. [ABSTRACT FROM AUTHOR]

Ovule characters have been shown to be informative at higher taxonomic levels and are therefore of interest in angiosperm systematics. In this study, we aimed to describe the evolution of the outer ovule integument thickness in Melastomataceae and to evaluate its systematic and biological significance. This character was investigated in 137 species, and data from the literature were compiled for 22 additional species, totalling 159 taxa. Integument origin was studied in selected species to clarify whether different conditions were associated with different ontogenetic origins. The most recent common ancestor of Melastomataceae probably had an ovule with a two-cell-layered outer integument. A multilayered outer integument evolved independently at least six times in the family. Moreover, reversals to the two-cell-layered plesiomorphic condition have also occurred more than once. The two-cell-layered and multilayered outer integuments have different ontogenetic origins, enhancing the taxonomic usefulness of this character. The thickness of the outer ovule integument is of systematic significance in Olisbeoideae, Rupestrea, Melastomateae and Miconieae. The multilayered outer integument may have some adaptive significance for Miconieae and Mouriri, groups with endozoochoric fleshy fruits. Evidence of a multiplicative testa was observed in a few species with both types of integuments and it may be associated with a massive seed coat found in large seeds. [ABSTRACT FROM AUTHOR]

• Flower colour change may have direct impacts on pollinator behaviour, affecting pollination. • Pollinators exhibited a strong preference for visiting young unchanged colour flowers. • Colour change directed pollinators to rewarding and receptive flowers. • The retention of colour-changed flowers was important to attract distant pollinators. Many flowers change colour as they age or after pollination, which can have direct effects on pollinator behaviour affecting both pollination (on the plant side) and foraging efficiency (on the insect side). The retention of colour-changed flowers might increase plant attractiveness to pollinators over long distances, while directing pollinators at short range towards flowers that still present rewards and are sexually receptive. In this study, we used Lantana undulata Schrank (Verbenaceae), which presents yellow-centered and white flowers within an inflorescence, as a model plant species to study the influence of floral colour change on pollinator visitation. We first show that colour change from yellow to white occurs over a 24 h period regardless of pollination, and is associated with reduced stigma receptivity and nectar reward availability. We then used pollinator visitor observations and experimental manipulations of inflorescence display patterns to investigate the effects of floral colour change on pollinator attraction, behavior and choices. Pollinators exhibited strong preference for visiting yellow-centered flowers, suggesting the colour change to white in older flowers is an honest signal directing pollinators to rewarding and receptive flowers within the inflorescence. In addition, the absence of white flowers on manipulated inflorescences significantly reduced their attractiveness to pollinators. Our results suggest that the retention of colour-changed white flowers is important to attract pollinators at long distances, while the yellow colour of young flowers guides pollinators to the sexually viable, rewarding flowers on inflorescences at short distances, maximizing both pollination and foraging efficiency. [Display omitted] [ABSTRACT FROM AUTHOR]