I was very excited to find this larva of Papilio canadensis (Canada Tiger Swallowtail Butterfly) in late August last year preparing to form a chrysalis thinking I could photo its progression day-by-day. Maybe I might even see it emerge as a butterfly the following spring. As the days wore on there was no change to the larva. After two weeks I began to think something was wrong here. Shortly after that it was gone from the leaf. Whether it died and fell off or was eaten I don’t know.
This caterpillar is on an aspen leaf one of the species’ larval host plants. Other preferred larval foods are willow, cherry, and ash. The eye-spots on the larva’s thoracic segments presumably deter some predators. Interestingly, the young larva resemble bird droppings.