Giant Resin Bee: Carpenter Bee Hole Squatters from Asia

The large, burnt-orange-thorax bees using your carpenter bee holes are giant resin bees (Megachile sculpturalis), native to Asia, established in the U.S. since 1994. They partition holes with resin and wood bits, provision with pollen, and lay eggs. Females can sting but are non-aggressive; males lack stingers. They don't damage wood—leave them alone as interesting pollinators.