(2nd Place) Identifying the proximal cues for pupal color variation in Chlosyne lacinia Geyer (1837) (Lepidoptera: Nymphalidae)

Chlosyne lacinia, the bordered patch butterfly, has been described as one of the world’s most polymorphic butterflies with color variation at the larval, pupal, and adult stages. The basic mechanisms for adult and larval coloration are understood in C. lacinia, but we still do not know the processes associated with pupal color variation. The pupae range from white to black with varying levels of melanization, and the larvae are thought to receive the cue for coloration in the 5^th instar. To determine the proximal cue(s) for color variation in pupae, I placed C. lacinia larvae in Styrofoam cups painted white or black with nontoxic paint. I covered the cups in mesh of the corresponding color and placed the plastic lid of the cup with a hole cut out on top to securely hold the mesh in place. The cups were then placed in an incubator set at 30°C with a light cycle of 18h of light and 6h of darkness. Preliminary results show pupae formed in black cups have significantly more blackness than pupae from white cups (p-value = 0.005037). Pupae in black cups also took a significantly longer time to eclose than their white counterparts (p-value = < 0.0001). Given the sedentary nature of pupae, background matching provides an extra layer of defense against visual predators. The difference in time to eclosion could be contributed to melanin, a costly pigment to produce. Next, I plan to investigate gene expression associated with melanin production through the developmental stages.