Why do mason bees generally lack the instinct to aggressively guard an area?

Answer

They do not live in a colony with a store of honey to defend.

Since mason bees are solitary and do not maintain a hive or stores of honey, they lack the instinct to aggressively guard a site.

Why do mason bees generally lack the instinct to aggressively guard an area?
insectbeestingreactionMason Bee