Data on life history traits
We used data on four key life history traits to potentially explain
shifts in phenology and NRB, and in population trends. The trait
variables used included: body size (continuous variable), overwintering
stage (factor with four levels: Adult, Larvae, Pupa, Egg), specificity
of larval host plant use (factor with two levels: Generalist,
Specialist), and voltinism (factor with two levels: Univoltine,
Multivoltine). These traits were chosen as they were linked to variation
in responses to climate and environmental change in previous empirical
studies on Lepidoptera (Pöyry et al. 2009, 2017; Betzholtzet al. 2013; WallisDeVries 2014), and because information on
these traits is available for both moths and butterflies. See Fig. S3
for further details and data sources.