About Nematocampa resistaria (Herrich-Schäffer)
Nematocampa resistaria, commonly known as the filament bearer, bordered thorn, or horned spanworm moth, is a moth species belonging to the family Geometridae. This species was first formally described by Gottlieb August Wilhelm Herrich-Schäffer in 1856. It is distributed across North America, ranging from British Columbia to Nova Scotia, and extending south to Florida and California. Nematocampa resistaria was split from the Eurasian species Nematocampa limbata. The wingspan of adult individuals ranges from 19 to 25 mm. Adults can be seen in flight from May to August, with flight starting as early as April in the far southern parts of its range. The number of generations produced per year varies by location: there is one generation annually in the north, two generations in the middle United States, and multiple generations per year in the southern portion of the species' range. The larvae of this species feed on a wide variety of deciduous and coniferous trees and shrubs. Recorded host plants include Pseudotsuga, Tsuga, Abies, Picea, Salix, Betula papyrifera, Corylus, Fragaria, and carrot, which belongs to the genus Daucus.
