MYRMICINAE: the Double-waisted ants

The species in this very large sub-family all have narrow, ‘double-jointed’ waists or petioles, as a result of which some can raise their abdomens over their heads when danger threatens. Many South African species are not armed with stings although many overseas species can sting viciously. The pupae of this sub-family are always naked, i.e. the larvae do not spin cocoons. Apart from these common features, however, there is a huge variety of shape, size, habit, etc etc within the sub-family, although none of the species are as large as some ponerine or formicine ants. Some are harvesters, some are fungus-growers, some may be purely carnivorous hunters. Many live in tunnels in the soil, while others build carton-like nests in bushes and trees, or live in thorns, or rotting wood. Sizes range from tiny, less than 1.5 mm, to large ants up to 10 mm; some are blind, some are monomorphic [one size of workers] while others have major workers with the most disproportionally-large heads in the business.
Several myrmicines have become world-wide invaders, forming super-colonies by budding; in our area these include ants from the genera Monomorium, Pheidole and Solenopsis.

The following are the more important myrmicine genera that occur in Southern Africa. There are several others and some will be added to this site in due course.  Click on the genus name for more info about its particular species.

Crematogaster [Cocktail ants]
There are about 43 species in Southern Africa, of which the most common are the Black Cocktail ant (Crematogaster peringueyi),the Brown Cocktail ant (Crematogaster melanogaster) and the Red Cocktail ant (Crematogaster castanea), which occurs along the south and east coasts and up into the northern interior of South Africa.
Two characteristics make them easy to identify:
[a] they ‘cock’ their ‘tails’, raising their heart-shaped gasters above their heads and releasing a deterrent fluid, when disturbed or in attack mode;
[b] many species [but not all] build ‘carton’ nests of chewed vegetable matter in bushes and shrubs.

Melissotarsus [Bee-legged ants]
Uncommon and bizarre little ants that live permanently under the bark or in the heartwood of the protea Leucospermum praemorsum, and other shrubs. There are two species in our area, but these may turn out to be one after all. 
Western and Northern Cape, KZN, Mpumalanga and Zimbabwe.

Meranoplus [Hairy cautious ants]

These ants superficially resemble Crematogaster until you realise that they are much too hairy. They’re slow-moving, related to the heavily-sculpted genus Cataulacus, but Meranoplus are always much hairier. There are seven species in SA, but they are all very shy, and seldom seen.

Messor [Harvester ants]

There are seven species in Southern Africa, of which the Cape Harvester, Messor capensis, is the most widespread in the drier parts of the country. Slow, bumbling ants that run in rough trails, they are most commonly seen on warm evenings gathering vegetable detritus which they carry to their nests. There it is chewed up and used to grow the fungus which the ants eat.

Monomorium [Timid ants]
These are mostly fairly obscure, tiny ants that are seldom noticed. However, at least one species, Monomorium pharaonis (Pharoah ant) is a serious invader around the world, and has been found in the Cape, too [more below]. There are about 82 species in our region, many of which are quite obscure and seldom encountered. They all have tiny, ineffective stings [from a human point of view!] and, apart from the Pharaoh ant, live in tiny colonies that are seldom noticed.

Myrmicaria [Droptail ants]

There are twelve species in Southern Africa, but only a handful of these are at all common. With their characteristic drooping abdomens they cannot be easily mistaken for any other ants; the genus is unique in that the antennae consist of just 7 segments [scape + 6], fewer than any other ants.

Ocymyrmex [Hotrod ants]

There are thirty species in Southern Africa, many of which are very obscure. The true Hotrod ant, Ocymyrmex barbiger, is the most common. The ants run around at great speed and, as the scientific name of this species implies, they have a ‘beard’ or basket of bristly hairs beneath their heads, which seems to be solely used for removing sand grains from their nests. They are most active on very hot days and so are not often seen, although in some arid areas they are quite common.

Pheidole [House ants or Big-headed ants]
There are about 25 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.

Solenopsis [Fire ants]

There are four species in Southern Africa, of which one is a dangerous invader. The ants are polymorphic, living in large colonies in rotten wood, etc. The venom in their painful stings can cause anaphylactic shock in sensitive individuals.

Tetramorium [Fierce or Garden ants]
This is the largest genus in Southern Africa with some 97 species, many of them obscure and uncommon and all of them small to medium in size. All the species have spines on the propodeum [last segment of the thorax] and distinct creases or ‘wrinkles’ on their heads – you may need a good magnifier to see these.

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