One generalist or several specialists? Comparative analysis of the polyphagous butterfly Adelpha serpa celerio and its serpa-group relatives

Patterns of larval food plant use and immature stage morphology help clarify Neotropical butterfly species diversity, and, in many cases, lineages identified with molecular data are corroborated by morphology and ecology of immature stages. Here, we investigate cryptic species in Adelpha butterflies (Nymphalidae), a group known for challenging adult wing similarity coupled with mimicry, and for its remarkably wide larval food plant breadth. We focus on the Adelpha serpa-group and in particular Adelpha serpa celerio, whose immatures have been documented feeding on 11 plant families. Our analyses of A. serpa, and among serpa-group species across the Neotropics, revealed evidence of cryptic species, but the pattern within A. serpa celerio showed relatively weak mtDNA and morphological differences, and no differentiation in food plant use. We conclude that A. serpa should be revised and recognize A. serpa to include the nominate subspecies and recognize A. celerio (revised status) as a geographically widespread species and a larval food plant generalist that contains A. c. celerio (revised status), A. c. duiliae (revised status) and A. c. diadochus (revised status). Four additional species within the serpa-group show strong evidence of harbouring allopatric cryptic species, and further research should be done to clarify their species limits.