Data from: Ophrys annae and Ophrys chestermanii: an impossible love between two orchid sister species

The biological concept of species is founded on the presence of barriers
that limit the gene flow and species delimitation represents a vivid topic
in orchids. Studies on the reproductive isolation in mediterranean orchids
often examine the gene flow between co-occuring species providing a
relevant understanding of how species boundaries are maintained. In
Ophrys, the role of post-mating boundaries are always been tought to be
weak and, despite the relevant morphological and ethological differences,
low phylogenetic diversity has been recorded. In contrast, not many
studies are focused on the relevance of each barriers in close related
species in island condition. Using a morphological approach and
experimental crosses to evaluate post-mating barriers, here, we clarify
the taxonomic position of two sardinian endemic orchid sister-species,
Ophrys annae and Ophrys chestermanii, currently ascribed in the
bornmuelleri group. In Ophrys, due their iper specialized pollination
syndrome, premating barriers are often considered more relevant than post
mating barriers. We found that the two endemisms differs sustantially in
16 functional traits adopted. We further detected asymmetric results in
manual crosses suggesting that post-mating barriers may act as
reinforcement of the pre-mating barriers. Our results suggest that in
close related orchid species of the genus Ophrys, gene flow is limited
also by post-mating barriers which have a relevant act in keeping the two
reproductively isolated.