Petiole borer (Coleoptera: Mordellidae) in Aralia

I located a young larva in August, in a tunnel in a leaf stalk of a living plant. I also found a second larva in late May; it had overwintered in the senesced plant material (the exact nature of which I did not record, but it was either a leaf stalk or a stem). The latter individual emerged as an adult in early June. As an adult, it was a rather uniform reddish-orange color overall, with very fine pubescence on the elytra.