The foundation of the visitor’s center is being redone at the arboretum. Holes are being dug to pour concrete to support new beams. On one of the corners, there was a stump of an oak tree. While digging out the stump, Connor came across this huge larva boring through the middle of one of the roots, and it looks like a California Root Borer Beetle.
The California prionus beetle is 1¾ - 2¼ inches long (45-60 mm) and reddish-brown with long, deeply notched antennae. The larvae can be 4¼ inches (108 mm) and approximately ¾ inch (18 mm) at the widest point of their body.
The larva can spend from three to five years underground eating roots before reaching maturity. Based on the size of this larva, it appears to be getting close to maturity. So we found a small terrarium that wasn’t being used and set it up with soil and chunks of oak tree roots. We covered it with leaves and put a screened lid on top.
Of course, my hope is that the larva will pupate and turn into an adult beetle. I’m not sure of the survival rate of this beetle after being plucked from its home inside an oak root two feet underground. I’ll certainly let you know what happens.
