We were in Rohnert Park picking up a burrito tonight (29 June 2024) and noticed several of these long-horned beetles on the outer walls of a building. I couldn't help saying "Whoa!" out loud when I saw the first one.
The black-and-white coloration with blue tints was eye-popping, but so was the size of this beetle. Here's one with a standard key for scale:
Meet the Banded Alder Borer (Rosalia funebris)!
Up close this beetle is even more impressive. Such beautiful coloration!
I'm curious about those large mandibles. Although the larvae eat decaying wood, the adults are said to eat nectar and pollen. Are the mandibles used for jousting?
Banded Alder Borers are native to western North America, but it appears that they are less common along the coast in this area.
