In two recent publications (Dellinger et al. 2025: Does the abiotic environment influence the distribution of flower and fruit colors? https://doi.org/10.1002/ajb2.70044; Kopper et al. 2025: Mountain colonization precedes shifts away from bee pollination in Melastomataceae. https://doi.org/10.1111/nph.70273) we could show that there is a non-random association between abiotic environmental variables and flower traits. Although enviornment-trait links are not unsurprising and actually very well researched for vegetative plant traits, flower traits are commonly studied mostly studied in the context of pollination, but rarely both in relation to abiotic (climatic) and biotic (pollination) contexts.
In a large assessment of pollination biology and environment evolution of the plant family Melastomataceae, we could show that across the family, bee-pollinated species occur at significantly lower elevations than species which have shifted away from bee pollination. Importantly, these environment and pollinator shifts have not happened independently of each other, but reconstructing the evolutionary history of both, we could show that environment shifts very likely preceded, and hence triggered pollinator shifts. Thus, Melastomataceae likely colonized the uplifiting tropical mountains within the past 30-15 million years, and only within these mountain environments, shifted from bee to vertebrate pollinators (usually less than 5 million years ago). The likely driver of these pollinator shifts is the fact that bee pollinator availability is much lower in tropical montane environments (e.g., cloud forests) than the availability of vertebrate pollinators.
Similarly, our assessment of the global distribution of flower and fruit colors across 51 plant clades (>2800 species) revealed that flower and fruit colors are not randomly distributed across the globe, but actually show significant associations with distinct abiotic environmental variables. While white is the most common flower color, non-white flowers are more common in environments of high abiotic stress, with pink and red flowers more common in cold environments, and yellow and purple flowers being more common in dry and sun-exposed environments. These findings hint to an important role of color pigments in flowers as mediating abiotic stress, besides being attractive to pollinators (and humans). Similarly, in fruits, red and black are the most common colors, with red fruits being particularly common in cold environments, while black fruits are most common in tropical forests. Dull-colored fruits (green, yellow, brown, orange) are more common in warm environments with high sun exposure. These lighter colors may function as desiccation avoidance in hot, dry environments.
