Pheidole species: the House or Big-headed ants

MYRMICINAE

The Genus Pheidole (House ants)

Typical detritus cone of sand grains and other debris around a Pheidole nest entrance

There are about 26 species in Southern Africa, but the genus as a whole is in urgent need of revision and it is in practice extremely difficult to be certain about many of the species without microscopic examination.
All Pheidoles are easily recognized by the huge-headed major workers. The minor workers can be easily confused with Argentine ants (Linepithema humile) , but when in doubt look for [a] the huge-headed major workers, and [b] the narrow, double-jointed petiole (waist).

The most important species, economically speaking, is Pheidole megacephala. Although considered to be indigenous in South Africa, the species has become invasive world-wide, and has similarly become invasive here too. It spreads by colony-budding, leading to huge, interconnected nests that overwhelm most other ant species. Even Argentine ants can be driven out by this species if conditions are right.
The slightly smaller Pheidole capensis does not form super-colonies and is not as often found in houses.

Other characteristics: Nest in tunnels underground; in gardens, dwellings, fynbos, and karoo. These ants are diurnal and are not particularly aggressive when disturbed. They are harvesters and seed-eaters and may play a role in the distribution of some small-seeded fynbos plants.

 Pheidole megacephala, although indigenous, is a world-wide INVADER. Although the genus is in a taxonomic mess, P. megacephala is normally a bit bigger than P. capensis; the colour can vary from red-yellow to dark brown

There are some very good photos of P. megacephala at these links:

www.ispotnature.org/node/698347

www.ispotnature.org/node/487630

www.ispotnature.org/node/657922

www.ispotnature.org/node/658189

Survive invasive species:
Linepithema humile       : Argentine ants       : Probably
Lepisiota sp.                  : Small Black ants    : Yes
Technomyrmex albipes : White-footed ants  : unknown
Anoplolepis gracilipes   : Yellow Crazy ants  : unknown