Disjunct distributions and evolutionary diversification of Australasian geometrid moths: subfamilies Epidesmiinae, Desmobathrinae and Oenochrominae (Lepidoptera)

Disjunct distribution patterns have long intrigued biogeographers, sparking ongoing debates about the mechanisms driving the current distribution of biodiversity. Among the most discussed patterns are long-distance dispersal and vicariance. While these patterns have been extensively studied in plants, marine taxa, mammals, and some invertebrates, they remain less explored in groups like moths. In this study, we use the Epidesmiinae + Oenochrominae + Desmobathrinae complex-three closely related subfamilies within the Geometridae family-as a model to examine disjunct distribution patterns in Australasian moths. Epidesmiinae + Oenochrominae moths are primarily distributed within the Australasian region, with some taxa being endemic to New Zealand. In contrast, their sister group, Desmobathrinae, exhibits a trans-continental and mainly pantropical distribution. The biogeography and evolution of these subfamilies, which currently have different distribution areas, have not been analysed in an evolutionary context before. To investigate this, we inferred phylogenetic trees using a Maximum-Likelihood approach and used the topology to estimate time-calibrated trees and reconstruct ancestral biogeographical areas using a Bayesian method. Additionally, we explored the diversification rates of these lineages. Our results suggest that the ancestor of the three subfamilies most likely originated in Australasia during the Eocene (∼58 Ma). Bayesian biogeographical analyses suggested dispersal events of the Desmobathrinae into the Indo-Malayan region and other areas, with an important jump to the Neotropics, while Epidesmiinae and Oenochrominae dispersed mainly within Australasia. Diversification analysis revealed no significant shifts in diversification rates, with the phylogeny showing a pattern of declining speciation rates over time. Our study exemplifies how phylogenetics in combination with biogeographical reconstruction uncovers macroevolutionary patterns in moths.