Between a rock and a hard place: Biologists unearth sandstone-excavating bees

Scientists describe the uncommon xeric bees that expend great effort to carve their nests in sandstone. Researchers discovered the bees nesting in sandstone nearly 40 years ago at two sites in Utah's San Rafael Desert, collected samples of the nests and reared the inhabitants to emergence. But this work was stored away and largely untouched until researchers examined the samples a few years ago and discovered five new nesting sites ranging from Ancestral Puebloan sandstone cliff dwellings at Col