This week, the question was: What is on this citrus leaf?
This looks a lot like bird poop, however, it’s just a camouflage tactic of the giant swallowtail caterpillar. This species is often called the “orangedog” as they feed on members of the citrus family throughout their larval stage. They can be a pest to young citrus trees, though mature trees can tolerate a fair amount of feeding. Sacrificing a few leaves is well worth it to see the beautiful butterfly this caterpillar will become. See photos and read more here.