Cleaner ants, as their name would hopefully suggest, are a number of species of Serinan ants, not always closely related to one another, which have adapted to feed partially or entirely on the dead tissue and ectoparasites of larger animals, mainly birds. Their evolutionary origins surely come from the behavior of many birds known as anting. Whereas anting in its primitive form involves the use of ants merely as tools for the bird in question and usually results in the harming or killing of many ants by the end of the process, the symbiosis adopted by cleaner ants and their patrons is a mutually beneficial affair. Depending on the species, cleaner ants may construct their nests on the ground or in tree hollows, but in both instances are usually easily discovered if you know what to look for, for they are almost always surrounded by groups of small birds queuing up for their turn to be looked over by the workers. To avoid being eaten, as well as to immediately identify their intent, they are colored brightly in unmistakable patterns of black, red, and yellow; their markings are not bluff, either, for they carry potent stings and will utilize them readily if the colony feels threatened. To demonstrate their willingness to be cleaned, and lack of ill intent, a bird thus also must provide a special signal before the ants will let down their guard; it will lean over to one side, point its bill skyward - showing that is has no interest in a meal - and raise a wing high over its head, allowing the insects to crawl up into its plumage. The ants then crawl through its feathers, searching for blood-sucking mites, dead skin cells and anything else edible that they can grab in their jaws and take back to the colony, while their partner waits patiently as the ants cleanse its troubles away, eventually turning to the other side to allow its cleaners to reach every part of it body. When the process is complete, the bird's skin will be exfoliated, any small wounds will be cleaned and disinfected of septic tissue, and most of its blood-sucking parasites will have been removed. As an added bonus, the waiting birds are also sure to leave plenty of droppings near the colony, which the generalistic ants will also pick through for additional edible pieces, such as seeds that may have passed through the birds' stomachs intact. A detente has thus been formed between the two natural enemies, each of which could harm its partner, but has far more to gain by getting along.
Some cleaner ants have interestingly lost their ability to fly entirely, with small vestigial wings even as sexually fertile adults. Instead, they rely on birds to disperse and form new colonies. Grabbing a hold onto a feather or the scales of its leg, newly-emerged fertile queens and drones stay with the bird for as long as a week before dropping off, sometimes many miles from their nest site. Knowing instinctively that wherever they have dropped off is likely a favorable spot for birds to rest and has a high chance of being visited by more birds again in the future, they will form a new colony right nearby to start the cycle anew.
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Cleaning behavior has evolved multiple times in ants upon Serina. Another group, only very distantly related to the colonial cleaner, specializes entirely in much larger animals. These ants are no longer social and belong to the group of flying, wasp-like predators known as vespers. Like the cleaner finches, they follow herds of large herbivores and feed mainly upon the large blood-sucking tickmites that plague them, without harming the birds themselves; while docile if unprovoked, except towards the small parasites upon which they feed, they do retain a painful sting as a defense against smaller flying birds. They exhibit a novel method of rearing their offspring which is also shared by some other flying ants; they carry their single larva in their middle pair of legs and raise it right there, rather than at a nest site, feeding it portions of every mite it subdues - the avian blood contained within is particularly nutritious for the developing young. To make up for their small brood size, young grow quickly and females are long enough lived to be able to rear a new larvae every three weeks for as long as two years.