Data from: Mismatch in the distribution of floral ecotypes and pollinators: insights into the evolution of sexually deceptive orchids

Plants are predicted to show floral adaptation to geographic variation in
the most effective pollinator, potentially leading to reproductive
isolation and genetic divergence. Many sexually deceptive orchids attract
just a single pollinator species, limiting opportunities to experimentally
investigate pollinator switching. Here we investigate Drakaea concolor,
which attracts two pollinator species. Using pollinator choice tests, we
detected two morphologically similar ecotypes within D. concolor. The
common ecotype only attracted Zaspilothynnus gilesi, while the rare
ecotype also attracted an undescribed species of Pogonothynnus. The rare
ecotype occurred at populations nested within the distribution of the
common ecotype, with no evidence of ecotypes occurring sympatrically.
Surveying for pollinators at over 100 sites revealed that ecotype identity
was not correlated with wasp availability, with most orchid populations
only attracting the rare Z. gilesi. Using microsatellite markers, genetic
differentiation among populations was very low (GST = 0.011) regardless of
ecotype, suggestive of frequent gene flow. Taken together, these results
may indicate that the ability to attract Pogonothynnus has evolved
recently but this ecotype is yet to spread. The nested distribution of
ecotypes, rather than the more typical formation of ecotypes in allopatry,
illustrates that in sexually deceptive orchids pollinator switching could
occur throughout a species’ range, resulting from multiple potentially
suitable but unexploited pollinators occurring in sympatry. This unusual
case of sympatric pollinators highlights D. concolor as a promising study
system for further understanding the process of pollinator switching from
ecological, chemical and genetic perspectives.