Formica pacifica

Formica pacifica is a brightly coloured, aggressive species of Formica occupying the west coast of the United States and Canada. This species is a host for the temporary social parasite Formica obscuripes, and potentially more temporarily parasitic and slave raiding Formica species (J. Roth, pers. comm., 2019).

Distribution based on Regional Taxon Lists
Nearctic Region: United States.

Reproduction
Alate brood is produced after hibernation, and, in British Columbia, nuptial flights occur from July to late August (on particularly warm days). Male sexuals are released first, in the early afternoon. Female alates fly soon after. Dealate queens often overwinter before laying their first eggs.

Nesting Habits
Unlike most species from the F. fusca group, Formica pacifica colonies prefer their nests moderately dry. Pupae are stored at the top of the nest, often underneath a rock or another solid surface. Larvae and eggs are usually stored deeper underground, in the additionally moistened parts of the nest.

Foraging/Diet
Formica pacifica collects honeydew. These ants are also scavengers, primarily collecting dead arthropods. Dead, dried out worms are collected in particularly high numbers. Foraging activity primarily occurs in the daytime, with the peak amount of workers dispatched in the afternoon. These ants generally forage alone, but will form trails to plants containing aphids. Once food is found, workers will often recruit others to help feed, or pull food back to the nest.

Association with Other Organisms
This species is a host for the temporary parasite in British Columbia, Canada (J. Roth, pers. comm., 2019) and is enslaved by.

Nomenclature

 *  pacifica. Formica pacifica Francoeur, 1973: 131, figs. 190-197 (w.q.) U.S.A.