In this review, we summarize experiments quantifying selection on continuous flower color variation in natural plant populations in the context of pollinator interactions. However, most of our current understanding of flower color evolution arises from variation between discrete color morphs and completed color shifts accompanying pollinator shifts, while pollinator-mediated selection on continuous variation in flower colors within populations is still scarce. Flower colors are very diverse, effect pollinator attraction and flower foraging behavior, and are hypothesized to be shaped through pollinator-mediated selection. The evolution of floral traits in animal-pollinated plants involves the interaction between flowers as signal senders and pollinators as signal receivers. This study emphasizes how essential the pre-zygotic and post-zygotic reproductive barriers are for rewarding orchids to avoid inbreeding depression. Moreover, nectar volume is reduced after pollination, but the sugar concentration is maintained. coriophora exhibits spatio-temporal variation in fitness that does not correlate with any plant feature. Furthermore, when self-pollination occurs, despite successful fructification, seed viability is significantly lower than that of cross-pollinated plants. We found that the species partially selects allogamous pollen if pollinia from the same stalk and other plants arrive to the stigma. corio-phora, and the spatio-temporal changes in its fitness as well as variation in nectar content after pollination. In this study, we assess the breeding system of the rewarding orchid A. In rewarding species, which receive a higher rate of visits per plant, geitonogamy is usually higher and therefore the risk of inbreeding increases. Pollination of deceptive orchids has enabled scientists to understand how these species avoid inbreeding depression by reducing the number of pollinator visits per inflorescence. Our results demonstrate the interest of field-captured pictures coupled with machine learning classification approaches to improve taxon identification and highlight candidate traits for further eco-evolutionary studies. Interestingly, the variables used by random forests to discriminate the groups were different from those suggested in the literature.
When combined, field- and image-based information provided identification accuracy of 95%. To assess whether these groups can be distinguished on the basis of their phenotypes, and to highlight the traits likely to be the most informative in supporting a putative differentiation, we (i) photographed and measured a set of 109 individuals in the field, (ii) extracted morphometric, colour, and colour pattern information from pictures, and (iii) used random forest algorithms for classification. We used image-based analyses coupled with a simple machine learning algorithm to test whether we could distinguish two vicariant population groups of an orchid species complex known to be difficult to tease apart based on morphological criteria. Species harbouring a disjunct spatial distribution or cryptic taxa suggest that scientists often fail to detect subtle phenotypic differentiation at first sight. coriophora subspecies.Ĭharacterising phenotypic differentiation is crucial to understand which traits are involved in population divergence and establish the evolutionary scenario underlying the speciation process. Our results suggest that selection could contribute to ongoing chemical divergence among A. This study is one of the first to document variation in phenotypic selection exerted on floral scents among conspecific populations. fragrans, whereas no selection was found on floral volatiles of A. We detected positive selection on several taxon‐specific compounds in A. Plant size was positively correlated with fruit set in most populations, while we found no apparent link between floral colour and female reproductive success.
We showed that the three studied subspecies were characterised by different floral colour and odour, with one of the two predominant floral volatiles emitted by each subspecies being taxon‐specific. We then quantified phenotypic selection exerted on these traits by regressing fruit set values on floral trait values. Colour was characterised using calibrated photographs and scents were sampled using dynamic headspace extraction and analysed using gas chromatography‐mass spectrometry. In this study, we compared floral colour and odour as well as selective pressures imposed upon these traits among seven populations belonging to three subspecies of the widespread, generalist orchid Anacamptis coriophora. However, whether this applies to complex traits such as colour or scents has been little studied, even though these traits often vary within species. Current divergent selection may promote floral trait differentiation among conspecific populations in flowering plants.
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