Data from: Floral trait differentiation in Anacamptis coriophora: phenotypic selection on scents, but not on colour

Current divergent selection may promote floral trait differentiation among
conspecific populations in flowering plants. However, whether this applies
to complex traits such as colour or scents has been little studied, even
though these traits often vary within species. 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. Colour was
characterised using calibrated photographs and scents were sampled using
dynamic headspace extraction and analysed using gas chromatography-mass
spectrometry. We then quantified phenotypic selection exerted on these
traits by regressing fruit set values on floral trait values. 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. 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 detected
positive selection on several taxon-specific compounds in A. coriophora
subsp. fragrans, whereas no selection was found on floral volatiles of A.
coriophora subsp. coriophora and A. coriophora subsp. martrinii. This
study is one of the first to document variation in phenotypic selection
exerted on floral scents among conspecific populations. Our results
suggest that selection could contribute to ongoing chemical divergence
among A. coriophora subspecies.