Integration of morphologic and genetic data clarifies the evolution and species boundaries within a Nychiodes Lederer, 1853 species complex (Lepidoptera, Geometridae)

TL;DR

This study uses a combination of physical traits, genetics, and ecology to clarify species boundaries in a complex group of moths.

Contribution

The integration of morphological, genetic, and ecological data resolves taxonomic uncertainties in a closely related moth species complex.

Findings

Ecological niche differentiation was found between morphologically and genetically distinct taxa in Iranian mountain ranges.

Multispecies coalescent analyses supported species distinction based on female genitalia characters despite conflicting gene tree results.

The study demonstrates the importance of combining multiple data types to clarify species boundaries in complex evolutionary contexts.

Abstract

Young species radiations are valuable from an evolutionary perspective, as they can reveal traits involved in species formation, but they are challenging for taxonomists due to discordance among independent lines of evidence. The present study integrates morphologic, ecological, and phylogenetic data to resolve delimitation of species within the geometrid moth genus Nychiodes Lederer, 1853, with a particular focus on the closely related species pair N.
divergaria Staudinger, 1892 and N.
subvirida Brandt, 1938. Our findings revealed significant ecological niche differentiation across the Iranian mountain ranges between the range of taxa distinguished by morphology and DNA barcodes. While individual gene trees from mtCOI and nuclear loci showed conflicting results regarding species boundaries, our multispecies coalescent analyses support the distinction of taxa with different female genitalia characters. Our study highlights how the combination of morphological, genetic, and ecological data helps to define the boundaries between closely related species, to solve taxonomic uncertainties in regions with a complex evolutionary background.

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