Phenotypic plasticity is aligned with phenological adaptation on micro- and macroevolutionary timescales

In seasonally-variable environments, phenotypic plasticity in phenology
may be critical for adaptation to fluctuating environmental
conditions.  Using an 18-generation longitudinal dataset
from natural damselfly populations, we show that phenology has strongly
advanced. Individual fitness data suggest this is likely an adaptive
response towards a temperature-dependent optimum. A laboratory experiment
revealed that developmental plasticity qualitatively matches the
temperature-dependence of selection, partially explaining
observed  advance in phenology. Expanding our analysis
to the macroevolutionary level, we use a database of over 1-million
occurrence records and spatiotemporally-matched temperature data from 49
Swedish Odonate species to infer macroevolutionary dynamics of
phenology.  Phenological plasticity was more closely
aligned with adaptation for species that have recently colonized northern
latitudes, but with higher phenological mismatch at lower latitudes. Our
results show that phenological plasticity plays a key role in
microevolutionary dynamics within a single species, and such plasticity
may have facilitated post-Pleistocene range expansion in this insect
clade.