This green sweat bee or "peridot bee" is described as eusocial, meaning it exhibits some level of social organization where a single female or group of females produce the offspring, and non-reproductive individuals help care for the young. In this case, these bees are only primitively eusocial and nest underground. These generalist pollen foragers are widespread in the western U.S. and much of western/southern Mexico.

Credit: K. James Hung, UC San Diego

This worker Sonoran bumblebee, worker is also eusocial, nests underground and is known to be a generalist pollen forager. As of fall 2016, the International Union for Conservation of Nature listed this species as threatened. It used to be widespread in the American Southwest but is now less common. Interestingly, it also was observed to be the dominant bumblebee species in San Diego in 2016.

Credit: K. James Hung, UC San Diego

Male cuckoo bee. These bees are cleptoparasites, meaning they steal the food that another species collects. In this case, they generally steal from mining bees in the genus Andrena, but there are exceptions.

Credit: K. James Hung, UC San Diego

The mason bee is known to be solitary, partial to nesting in wooden cavities and a generalist pollen forager. They are mostly found in Western North America, but researchers are still studying their range.

Credit: K.James Hung, UC San Diego

A bumblebee forages on blueberry flowers.

Credit: Molly MacLeod, Winfree Lab, Rutgers University

An augochlorine bee harvests pollen from a tomato flower.

Credit: Lisa Mandle