How does tiger moth (Erebidae, Arctiinae) functional diversity respond to environmental and spatial variables?

Abstract Deterministic and stochastic processes are of great importance in influencing the composition of communities. Here, we tested if deterministic and stochastic processes have the same force of influence on functional traits of tiger moth communities. Specifically, we hypothesised that the functional traits of the tribe Arctiini would be more strongly influenced by stochastic processes (associated with spatial variables), given that these moths are primarily diet and habitat generalists within a highly diverse clade. They also exhibit high morphological trait dissimilarity and are capable of occupying a wide range of vegetation habitats. On the other hand, we hypothesised that the functional traits of the tribe Lithosiini would be more influenced by deterministic processes (associated with environmental variables), given that these moths are primarily diet and habitat specialist moths and tend to occur in more specific vegetation types. In agreement with our hypotheses, the functional traits of Arctiini species were better explained by variables related to stochasticity, while the functional traits of Lithosiini were explained by deterministic processes only. Thus, the processes shaping moth distributions across communities may vary according to species’ functional traits and interspecific relationships.