Data from: A cross-seasonal perspective on local adaptation: metabolic plasticity mediates responses to winter in a thermal-generalist moth

The physiological and ecological impact of the thermal environment across
life-stages can result in trade-offs that determine fitness and population
dynamics. Understanding mechanisms and consequences of local adaptation
for any organism that overwinters requires taking a cross-seasonal
perspective. We used a trait-based approach to distinguish variation among
ecotypes in ecological and physiological responses to overwintering
conditions. We used fall webworms (Hyphantria cunea; Lepidoptera:
Arctiidae) from Ottawa, Ontario and Columbus Ohio, representing the centre
and periphery of the native range. We hypothesised that populations would
be locally adapted to their overwintering environments, with fitness
maximised under natal overwintering conditions. We predicted that this
local adaptation would result from modulation of rates of energy use,
growth and development. Each ecotype had higher overwinter survival in
their natal compared to non-natal winter environment, and this was
associated with larger pupal mass, size and carbohydrate reserves at the
end of winter. This suggests that the ecotypes are locally adapted to
winter conditions. Larger adults laid more eggs, but there was no effect
of ecotype or environment on fecundity. Pupae overwintering at warm,
energetically demanding southern temperatures suppressed metabolic rates
in autumn, and developed more quickly in the spring, compensating for
energetic demands of warmer winters. Northern ecotypes had lower thermal
sensitivity of metabolism, leading to higher metabolic rates at cool
temperatures that correlated with faster post-winter development. Local
adaptation to winter conditions suggests performance of peripheral
populations may not be enhanced by warming winters. Decoupling of winter
and growing season temperatures may negatively impact ectotherms.