Rover Ants
Brachymyrmex sp.
These ants were found on Annual Sunflower -- Helianthus annuus. They are gathered on the undersurface of a bract below the inflorescence flower head. Nov. 2012, Glendale, Arizona, USA.
Formicidae -- Ant Family
Among the smallest ants in the Sonoran Desert, Brachymyrmex
are very common in the urban and agricultural settings in the Sonoran Desert -
there are several introduced species and this could be one of them. They are
barely longer than a millimeter and move quickly over plant and other surfaces.
A microscope and considerable expertise is required for specific
identification. The sunflower may benefit by the presence of the ants in that
they can deliver acidic gas in minute spray that could deter herbivores. The
nectar secretions from the bract may thus be an enticement for the ants to help
in protection.