Common names: 'The Little Marauder Ant' or 'Asian Red Army Ant'.
This species is often confused with C. diversa.
There are noticeable differences in behaviour, but unless you have both species to study - it is difficult to tell them apart.
The following information is from observations of colonies in their natural habitat and colonies I have kept in captivity conducted over the past ten years.
First and most notable is that diversa only ever has one queen in a colony. I have excavated many colonies of this species and only ever found a single queen. The queen is kept in a chamber at the very base of the colony which is often over 60 cm down. Even in young newly formed colonies the queens chamber can be 30 cm down. In comparison affinis has multiple queens in each colony, frequently in the region of 10 -20 and sometimes even more. These queens are found in the surface chambers along with the brood and are very easy to collect.
If newly mated queens of diversa are placed together they will fight each other until only one remains. Affinis queens will agreeably cluster together to form a new colony.
Diversa queens are larger and often 2.0-2.2 cm in size while affinis varies from about 1.6 to 1.8 cm in size and frequently the smaller queens are a comparable size to the largest majors.
When disturbed the queens of affinis seem to attract great attention from their workers and will be covered by a seething mass, to the point that it is difficult to see them. Although diversa queens are also heavily protected the attraction is not as great.
Colonies of diversa are larger and much more aggressive. On average probably two – three times the size of affinis colonies. Where both species occur in the same area diversa seems dominant with far fewer colonies of affinis being present.
The minor workers of affinis are also fractionally smaller than diversa and slightly more reddish in colour. Both species have large super majors of a similar size although diversa colonies seem to maintain a larger number of majors.
In captivity affinis seems to be more difficult to establish but once stabilised will respond well.
One of the main problems in differentiation is that the Chinese wholesalers have been selling affinis under the name of diversa for many years. This is probably because it is much easier for them to collect multiple queens from an affinis colony than the single queen of diversa. Hence many observations and records by hobbyists about diversa are actually about affinis. This may have resulted in the belief amongst hobbyists that diversa is a difficult species to keep in captivity.