Yellow and Black Burrowing Bee Like Insect
February 8, 2010
I was doing yard work and picked up a broken branch there was a significant vibration and sound of swarming bees from the branch. I broke it open and there where these beetle like bee insects inside. I have attached a photo but unfortunately only got this one photo. They were quite large, larger then any large bee like insect here that I have ever seen.
It is difficult to distinguish details in your photo that would assist in the proper identification, but based on your description, we believe you discovered the nest of a Valley Carpenter Bee. The female creates a series of chambers in a burrowed tunnel in a branch, and she provisions each chamber with pollen and lays an egg. Female Valley Carpenter Bees are black and the males are a golden yellow. You subject line does not indicate if the insects are each yellow and black, or if there are different colored insects, and your photo has what appears to be a golden male Valley Carpenter Bee about to emerge.