Data from: Adaptive developmental plasticity in a butterfly: mechanisms for size and time at pupation differ between diapause and direct development

Diapause (overwintering) and direct development are
alternative developmental pathways in temperate insects. Diapause
necessitates physiological preparations for dormancy, while direct
development is associated with strong time constraints, resulting in
selection for fast development under the direct development pathway.
Physiological and behavioural preparations for pupation contribute to
development time, so divergent selection in them is expected between
the alternative developmental pathways. Critical mass for pupation
induction is a central physiological parameter for the pupation
process. Here, we compare the critical masses and the characteristics
of the wandering stage – wandering taking place after the cessation of
growth and before pupation – between diapausing and directly
developing larvae in the butterfly Pieris napi. Critical mass
estimation succeeded only for diapausing individuals, among which it
was lower in females than in males, indicating an inter-pathway
difference in the physiology of critical mass. Directly developing
individuals wandered for a shorter time and distance and lost less
mass before pupation than diapausing individuals. These physiological
and behavioural differences represent adaptive phenotypic plasticity
and contribute to fast development under direct development. Thus, the
observed developmental plasticity in physiology offers a mechanistic
explanation for adaptive life history variation between alternative
developmental pathways and sexual dimorphism.