Megachilids include leaf cutter, mason and resin bees.
Resin bees use plant resins to glue sand and pebbles together to produce their nests, typically located on the underside of plant stems or under ledges.
Leafcutter bees shear oval or circular pieces from leaves to produce individual cells that comprise their nests, typically located in wood or underground.
Mason bees, a major group of native pollinators, nest in pre-existing tunnels within wood. They partition the tunnel into cells and then seal the entrance with mud, effectively protecting their developing offspring from an array of predators and parasites.

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