Data from: Evolution of ontogenic change in color defenses of swallowtail butterflies

Natural selection by visually-hunting predators has led to evolution of
color defense strategies such as masquerade, crypsis and aposematism that
reduce the risk of predation in prey species. These color defenses are not
mutually exclusive, and switches between strategies with ontogenic
development are widespread across taxa. However, the evolutionary dynamics
of ontogenic color change are poorly understood. Using comparative
phylogenetics, we studied the evolution of color defenses in the complex
lifecycles of swallowtail butterflies (Family: Papilionidae). We also
tested the relative importance of life history traits, chemical and visual
backgrounds, and ancestry on the evolution of protective coloration. We
found that vulnerable early and late instar caterpillars of species that
feed on sparsely-vegetated, toxic plants were aposematic, whereas species
that feed on densely-vegetated, non-toxic plants had masquerading and
cryptic caterpillars. Masquerading caterpillars resembled bird droppings
at early instars, and transitioned to crypsis with an increase in body
size at late instars. The immobile pupae – safe from motion-detecting,
visually hunting predators – retained the ancestral cryptic coloration in
all lineages irrespective of the toxic nature of the host plant. Thus,
color defense strategy (masquerade, crypsis or aposematism) at a
particular lifestage in the lifecycle of swallowtail butterflies was
determined by the interaction between life history traits such as body
size and motion levels, phytochemical and visual backgrounds, and
ancestry. We show that ontogenic color change in swallowtail butterflies
is an adaptive response to age-dependent vulnerability to predation.