Habitat suitability, not dispersal ability, limits the distribution of a group of Hawaiian moths (Lepidoptera: Xyloryctidae: Thyrocopa)

Thyrocopa are a group of generalist wood-feeding moths endemic to the Hawaiian islands.  Within the group, there are two major sub-clades, one restricted to wet forest, and the other restricted to dry, rocky, windy habitats (the “windswept” clade).  Here, we show that the windswept clade diversified in suitable habitats in the southeastern islands long after the emergence of the dry, rocky, windy northwestern Hawaiian islands.  Later, Thyrocopa back-colonized these northwestern islands despite having to cross long distances over open ocean.  Dates of diversification are independently supported by two methods of dating nodes (a molecular clock as well as estimates based on calibration points).  Our results suggest that for Thyrocopa, dispersal ability is not the limiting factor in terms of present distribution, and instead, the presence of suitable environmental conditions in a habitat is a strong predictor for the distribution of these moths.