About Polyergus rufescens (Latreille, 1798)
Workers of Polyergus rufescens from western and southwestern Europe are dark red, while specimens from eastern parts of the range are more orange-red. Darker individuals often have a purplish or brownish tinge on their gasters and appendages. Morphologically, this species is similar to the Mexican species Polyergus topoffi, but P. rufescens has narrower heads, narrower petioles, and more hairs on the first tergite of the gaster. Adult P. rufescens ants measure 4.7 to 7 mm (0.19 to 0.28 in) in total length. P. rufescens is native to parts of Europe, including Spain, France, the Netherlands, Germany, Switzerland, Austria, Bulgaria, Italy, Croatia, Serbia, and Slovenia. Its range extends into Asia, reaching as far east as the mountains of Kyrgyzstan, Kazakhstan, and western China. It typically inhabits open, sparse grassland, occurring wherever its host species are found. Host species differ across P. rufescens' range and include Formica cunicularia, F. fusca, F. rufibarbis, F. clara, F. gagates, and F. cinerea. The main host species in the eastern part of the range is F. clara; generally, P. rufescens uses the local Formica species that is most abundant, or can be raided with the lowest mortality.
