Lepidoptera Survey


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Taxonomic Report of the International Lepidoptera Survey (November 17, 2022) 10(9): 1-16

Also available at the archival TTR website, Internet Archive, Biodiversity Heritage Library, Zobodata, and Zenodo


Copyright 2022, International Lepidoptera Survey. Open access material

License: Creative Commons Attribution-ShareAlike-NonCommercial 4.0 International (CC BY-SA-NC 4.0 International)


The San Emigdio blue butterfly, Plebulina emigdionis (Grinnell, 1905), occurs in small, scattered colonies in and near the southwestern Mojave Desert of California. Colonies depend on a symbiotic relationship with the ant Formica francoueri (Bolton), and occur only where the ant’s range (primarily in more mesic cis-montane habitats) narrowly overlaps that of the butterfly’s more widely distributed Atriplex larval hosts in more xeric habitats. Colonies of P. emigdionis are often localized around a few host plants and, therefore, sensitive to habitat changes due to anthropocentric causes and environmental stochasticity. The biology, ecology, and status of known colonies of P emigdionis are presented with intent to offer insights into the species’ conservation. The status of all P. emigdionis colony sites known from museum records, published accounts, and the personal records of other lepidopterists is assessed.