Patterns of Lepidoptera herbivory on conifers in the New World

Five families of conifers are native to the New World: Pinaceae (104 species), Cupressaceae (73 species), Podocarpaceae (40 species), Araucariaceae (2 species), and Taxaceae (6 species). Pinaceae and Cupressaceae both serve as larval hosts to many specialist and generalist lepidopterans. In contrast, Podocarpaceae, Araucariaceae, and Taxaceae support exceedingly few lepidopteran herbivores. This pattern can be explained primarily by the comparatively low species richness (taxonomic diversity) and relictual distributions (host plant distribution and density) of the last three families, resulting in a lower apparency or exposure to potential herbivores. However, it is likely that secondary plant compounds also play a role in deterring insect feeding. A total of 794 species of Lepidoptera have been recorded feeding on conifers, with 503 specialists (i.e. restricted or nearly so to a single conifers family) and 291 generalists (i.e. feeding on conifers and angiosperms). Tortricoidea (n = 198) include the greatest number of conifer feeders, followed by Geometroidea (n = 196) and Noctuoidea (n = 156). Whereas the majority of species of macrolepidoptera (e.g. Lasiocampoidea, Bombycoidea, Geometroidea, Noctuoidea) that feed on conifers are generalist herbivores that feed on a variety of plant families (angiosperms and conifers), most microlepidopterans (e.g. Gracillarioidea, Yponomeutoidea, Gelechioidea, Pyraloidea) that feed on conifers are restricted to conifers (i.e. exceedingly few feed on angiosperms).