A Novel Origin of Pteridivory among the New World Noctuoidea: Fern-Feeding “Litter Moths” (Erebidae: Herminiinae)

Surveys of the caterpillars of Area Conservacion de Guanacaste (ACG), northwestern Costa Rica, documented an array of litter moths (Erebidae: Herminiinae) feeding on ferns in at least 17 families. This represents the first documentation of extensive oligophagous fern-feeding among Herminiinae and possibly within New World Erebidae. Collectively, the taxonomic composition of foodplants of pteridivorous Herminiinae in ACG differs markedly from those of corresponding fern foodplants of sympatric Noctuidae: they are less concentrated in Polypodiales and tree ferns (Cyatheaceae) are among the primary foodplants of several herminiines. These have been recorded only rarely as foodplants of ACG noctuids. Pteridivorous herminiines also appear closely related to species variously recorded from dead leaves, algae, mosses (Bryophyta), spikemosses (Selaginaceae), palms (Arecaceae), and the exclusively New World family Cyclanthaceae. Feeding on monocots and mosses by caterpillars with pteridivorous congeners may even represent a more general pattern that is shared, for example, with certain sawflies (Tenthredinidae).