Herbivores are commonly classified as host specialists or generalists for various purposes, yet the definitions of these terms, and their intermediates, are often imprecise and ambiguous. We quantified host breadth for 240 non‐native, tree‐feeding insects in North America using phylogenetic diversity. We demonstrated that a partitioning of host breadth: (1) causes 67% of non‐native insects to shift from a generalist to special...

Aim The European gypsy moth, Lymantria dispar dispar (L.), (Lepidoptera: Erebidae) is an invasive defoliator that has been expanding its range in North America following its introduction in 1869. Here, we investigate recent range expansion into a region previously predicted to be climatically unsuitable. We examine whether winter severity is correlated with summer trap captures of male moths at the landscape scale, and quantif...

Range expansions are a function of population growth and dispersal, and nascent populations often must overcome demographic Allee effects (positive density dependence at low population densities) driven by factors such as mate‐finding failure. Given the importance of individual movement to mate finding, links between landscape structure and movement may be critical to range expansion; however, landscape effects on other factor...

Tall shrubs and trees are advancing into many tundra and wetland ecosystems but at a rate that often falls short of that predicted due to climate change. For forest, tall shrub, and tundra ecosystems in two pristine mountain ranges of Alaska, we apply a Bayesian, error‐propagated calculation of expected elevational rise (climate velocity), observed rise (biotic velocity), and their difference (biotic inertia). We show a sensit...

Climate change can cause major changes to the dynamics of individual species and to those communities in which they interact. One effect of increasing temperatures is on insect voltinism, with the logical assumption that increases in surface temperatures would permit multivoltine species to increase the number of generations per year. Though insect development is primarily driven by temperature, most multivoltine insect specie...