Pieris brassicae geometric morphometric data

By adopting a longitudinal study design and through geometric
morphometrics methods, we investigated size and shape regulation in the
head capsule during the larval development of the cabbage butterfly Pieris
brassicae under laboratory conditions. We found evidence of size
regulation by compensatory growth, although not equally effective in all
larval stages. Size compensation is not attained through the regulation of
developmental timing, but rather through the modulation of per-time growth
rate. As for the shape, neither the variance of the symmetric component of
shape, nor the level of fluctuating asymmetry show any evidence of
increase across stages, either at the population or individual level,
which is interpreted as a mark of ontogenetic shape regulation. In
addition, also the geometry of individual asymmetry is basically conserved
across stages. While providing specific documentation on the ontogeny of
size and shape variation in this insect, this study may contribute to a
more general understanding of developmental regulation and its influence
on phenotypic evolution.