Strongylognathus
This is one of 2 ant genera that is parasitic on Tetramorium in this country. Its workers are about the same size as the Tetra.workers; while its queens are not much bigger and contrast notably with the large, black queen of Tetramoruim. It seems to exist mainly in Hampshire and Dorset with a few infestations along the South coast into Devon; but not as far West as Cornwall or East into Sussex.
Anergates
This is the other ant, which is a parasite of Tetramorium nests. It has no workers of its own, only queens and curiously shaped, wingless males. Again, it only appears in central southern England. The Anergates queens enter the host nest, with little, or no opposition; they just walk in. These queens are then fed by the Tetra.workers and they lay many eggs; all of which produce more sexuals and no workers of their own. It seems that the workers of Tetramorium then neglect to feed their own queen, resulting in her starving to death; if in fact, she is not actually killed by her own daughters. This leads to the death of the host colony after a year or two.
In contrast, this ant is less effective as a social parasite than Strongylognathus, which does have workers of its own to help it survive for a much longer time.
Sifolinia
A parasitic ant that invades the nests of Myrmica species. It has none of the defects of the preceeding 2 parasitic species, as it does without its own workers and allows the host queen(s) to continue producing workers, but inhibits any sexual brood to be born into the host nest. The Myrmica workers rear winged sexual males and female Sifolinia however, which are then free to fly off and mate and to parasitize other Myrmica nests. Fortunately only a few nests succumb to the parasitic invasion of this ant, so most live out their lives as normal Myrmica only colonies.
Ants have the ability to pass on their genes via the production of young male and female sexuals, which in most cases are capable of winged flight; and so can spread the species over a wide range of territory like the dispersed seeds of a dandelion flower. A queen ant has some control over the development of eggs, and therefore can determine whether to produce males, females or both; as these will become alates (winged sexually mature ants). It is the workers however that exert control over whether larvae become young queens or turn into workers.
It would appear that the workers in a mature, more established nest, move the larvae to areas where the humidity and temperature are more suited to the development of sexuals; and that they also feed these "sexual larvae" on a different diet to that given to worker larvae. Thus, although worker ants do not themselves have the means to pass on their genes, being completely sterile and having under-developed ovaries; the genetic code of the species is carried by their sisters who hatch out as young queens. Male ants also pass on the code by inseminating virgin queens, either from their own nest via brother/sister matings, or from mating with virgin queens from other nests of the same species.
The reason ant nests send out such a high number of sexuals each year is, that the rate of success for young queens to mate and then start their own nesting colony, is unfortunately for them, extremely low! Something like 97% will die, either during, or shortly after their mating flight; more often than not from predation by birds, spiders and even other ants. Despite suffering such heavy losses however, enough young queens are successful enough to ensure the continued survival of the species. So, even when an old queen dies, her gene pool lives on in the resulting "daughter colonies" and their decendants, which makes an ant genus or species virtually indestructable and immortal; as in theory a colony could survive forever. While I seriously doubt this, I can imagine that some polygynous (multiple queens) species could maintain a nesting colony for many years, even a century or more. Who can say?
Monomorium
This ant, commonly known as the "Pharaoh's ant" , is really an invader to our country. It cannot live outdoors, apart from when the summers here are hot and dry; but survives in heated buildings such as hotels and hospitals. I remember when I was training to be a nurse, it was Christmas and I was on night duty. The nurse in charge told me to have a box of dates which was in the ward office and I am extremely fond of eating. Late that night, I opened them; only to find a seething mass of tiny, red ants; so small, you could only just see them.
The ward was infested with this little critter. These ants live in crevices, usually near a source of heat like a radiator. They have dozens of queens which mate in the nest, then they spread their numbers by using the 'budding' system mentioned in the wood ants page. There are so many queens, that they only need a few dozen or so workers each to form large colonies in a very short time. As each queen can lay many hundreds of eggs per day, it does not take long for a major infestation to happen. They make up a vast 'super colony', which can eat almost anything and never has disputes over territory, as the colonies are all related to each other. As long as they have constant warmth and plenty of food, they 'live long and prosper', to qoute Mr Spock, the Vulcan Officer friend of Captain James T. Kirk from Star Trek fame. So, as you can see, ants are extremely adaptable; no wonder they have survived for millions of years.
