Identifying the proximal cue(s) for pupal color variation in the bordered patch butterfly, Chlosyne lacinia (Geyer 1837; Lepidoptera: Nymphalidae)

Color is a multifaceted trait with many functions such as predator
defense, thermoregulation, and immune response. We investigated pupal
color variation in Chlosyne lacinia pupae, focusing on identifying the cue
for increased melanization. Through laboratory experiments, we
demonstrated pupae reared on black backgrounds exhibited significantly
higher melanization compared to those on white backgrounds. Additionally,
black pupae experienced longer developmental periods, suggesting a
trade-off between defense and developmental time. Our findings support
crypsis as a likely evolutionary driver for increased melanization in
response to substrate color. We discuss potential implications for
predator avoidance, immune response, and developmental costs associated
with melanization. This study provides insights into the adaptive
significance of pupal melanization in response to environmental cues,
shedding light on the complex interplay between life history traits in
butterflies.