Generalist-specialist continuum and life history traits of Central European butterflies (Lepidoptera) - are we missing a part of the picture?

In this paper, the authors analyzed ten life history traits for 136 species of butterflies currently occurring in the Czech Republic, using principal correspondence analysis (PCA) and controlling for phylogeny. The main gradient extracted indeed revealed a generalist-specialist continuum, while the gradient perpendicular to the main axis distinguished between small-bodied polyvoltine species feeding on small herbaceous plants and large-bodied monovoltine species feeding on grasses or woody plants. The authors coin "constrained voltinism continuum" for the second gradient and argue that it reflects the effect of anti-herbivore strategies of larval host plants on butterfly development. The position of the butterflies in the PCA ordination mirrors the C-S-R (Competitors-Stress tolerators-Ruderals) strategies of their host plants. Butterflies that feed on C- and R-selected plants tend to be generalists, but differ in voltinism, whereas specialists tend to feed on S-selected plants.