Abstract
Aim We model the ecological niches and geographic distributions of 22 of 23 Megalagrion damselfly species and explore ecological and evolutionary hypotheses that may explain patterns of diversity. Location The Hawaiian Archipelago (Kaua‘i, O‘ahu, Moloka‘i, Lāna‘i, Maui, Hawai‘i). Taxon Megalagrion damselflies (Odonata: Coenagrionidae) are an endemic Hawaiian radiation of 23 species. Methods We gathered occurrence data from GBIF, iNaturalist, museum collections, and field surveys. Species distribution models were constructed using generalized linear models (GLM) and MaxNet with 10 environmental variables. Models were evaluated using AUC and TSS. Species richness, corrected weighted endemism, and phylogenetic diversity were calculated from stacked SDMs. Results MaxNet models generally outperformed GLMs. Species richness, endemism, and phylogenetic diversity increase with island age from Hawai‘i to Kaua‘i, with highest values at mid‐to‐high elevations. Most species showed positive relationships with slope and elevation and negative relationships with solar radiation. Notable exceptions include M. xanthomelas and M. pacificum , which prefer low‐elevation lotic habitats. Three closely related seep‐breeding Kaua‘i endemics ( M. adytum , M. eudytum , M. vagabundum ) exhibit distinct modelled environmental niches and distributions that may reflect ecological diversification within the clade. Main Conclusions Habitat suitability patterns are consistent with the island progression rule, with older islands supporting higher endemism due to greater habitat diversity and longer isolation. Ecological niche models provide a quantitative assessment of breeding habitat classifications and ecological diversity among species that breed in seep habitats on Kaua‘i. This study highlights how SDMs can inform conservation strategies and enhance understanding of adaptive radiations in island systems.