Alkali Bee
Nomia poss. melanderi
This aggregation of alkali bees was found on a road shoulder adjacent to an alkali desert spot west of Arlington, Maricopa Co., Arizona in March 2008. Notice the chimneys around most tunnels which may keep a rare but devastating rainstorm from flooding the chambers. Also several of the grayish bees can be seen in mid-flight.
Apidae -- Bee Family
Although this great number of Alkali Bees are all nesting in close proximity they are in fact solitary bees. Each female bee digs and provisions her own tunnel in the soil and will defend it from any neighboring bee that invades it. It so happens that this spot meets the specific soil conditions - a partially damp saline soil below that developes a hardened crust at the surface - that the bees require.
Besides the alkali desert agricultural operations nearby offer fields of alfalfa - the flowers of which are an important nectar and pollen source for this species. Indeed with declines in European Honey Bees growers requiring pollination services have turned to this bee among others. There are quite a number of alkali bee species that require some magnification and expertise to identify.