Papilio Niveus, Snow Swallowtail

Day 170: The larval stage of the uncommon-to-rare Papilio niveus is almost identical to that of P. zelicaon, but there can be no mistaking it due to its predilection for emerging in early spring at higher elevations, often while snow is still on the ground. This caterpillar feeds exclusively on bearberry (Arctostaphylos uva-ursi). In the third instar of the caterpillar's development, small red or red-brown warts containing a bitter and toxic alkaloid appear on the third and fourth segments, deterring attacks from Steller's Jays, the species' primary predator. These warts are also present during the pupal phase, but disappear in the mature butterfly. The adult is distinguished from other Swallowtails by purplish, fringed margins on the hind-wings. Additionally, if you've believed a word of this, you should be aware that you have been browsing an April Fools' Day field guide. This caterpillar is a plastic replica of a larval Anise Swallowtail.