This Post content is the research I have done previously for one of my YouTube videos (which will be linked down below). I thought it would relevant to make it available on written format for two reasons:

1 - Camponotus nicobarensis nuptial flights occur around this period in Macau, Hong Kong and South China region - Late February to Mid March, so it will help new and future ant keepers to be care for them properly.

2 - To share all the background reference papers, in case you are also interested in reading them for further information.

Carpenter ant is the common name for members of the genus Camponotus because their are known to excavate nests mainly in wood.

Most species in this genus, however, are not truthfully faithful to the name Carpenter ant because they can also nest on the soil.

Camponotus is an extremely large and complex, globally distributed genus. At present, more than 1000 species and it could well be the largest ant genus of all. These ants live in a variety of habitats and the sheer size of the genus makes any characterization of their biology challenging.

Nests are usually built in the ground (soil), between the interface of tree roots and soil, in rotten branches or twigs (rarely into living wood) and most species possess a highly generalist diet.

Camponotus nicobarensis Queen, workers and brood

Carpenter ants play a significant role in starting the degradation of tree cellulose. The ants do not consume wood but use their mandibles to excavate wood and transport the shavings to locations in the nest, where they can be stored, ejected through openings called windows, or packed into underground tunnels. The galleries and passageways are constructed continuously to accommodate the growing colony.

Workers in Camponotus are polymorphic and are commonly referred to by names that describe their size or function, such as majors or soldiers, medias, and minors.

Camponotus nicobarensis hunting in Macau forest

The shape and structure of the head vary depending on the caste and size of the ant. For example, the head of a minor worker is elongated, and the occipital region is greatly reduced in comparison to that of a major worker. The head of the queen is also elongated; however, it differs from that of the worker by possessing ocelli.

There are 45 subgenera of Camponotus, and let's introduce a couple of them.

Subgenus Camponotus - The majority of species in this subgenus nest in wood, hence their common name, carpenter ants. The species that cause the most damage to structures belong to this subgenus.

And this brings us to the subgenus to which C.nicobarensis belongs to, which is called Tanaemyrmex.

Subgenus Tanaemyrmex - are also known as Slim Carpenter Ants, they nest in dry, gravelly soil under rocks, or in buried wood. The head of minors can be classified under different forms:

(Alpha) sides of the head substantially parallel

(Beta) sides converging posteriorly from mouth

(Gamma) sides convergence is more and more pronounced

Nicobarensis is under Group VII: irritans-thraso, where the head of minors are of form Alpha.

The description is as follows - Medium to small species. Dimorphism is well marked, but majors neither stocky nor with a massively wide head.

Queens measure 12 to 15mm, minor workers vary between 5 to 8mm and majors vary from 8 to 12mm.

Within the species there is a quite significant color variation. They can have a very dark brown to red brown coloration, with majors a very noticeable large orange head. Queens may also present different colorations, in darker or lighter tones of red browns.

Although Camponotus species are normally regarded as monogynous, Camponotus nicobarensis can be polygynous at times, with several online references to multiple queens colonies at the hands of other ant keepers.

Camponotus nicobarensis worker from Thailand

Their colonies can grow to thousands, but initially like all Camponotus, they will take some time to develop, especially until the 2nd or 3rd year mark.

These ants prefer to forage at night, although they can be found quite active during the day as well. They are shy and not aggressive, but they will be very defensive regarding their territory, where they wont hold back from biting or spraying any intruder with their formic acid. So beware of vibrations on their nests because you can wipe off a whole colony, if you disturb them too much, as they will suffocate themselves with their own formic acid.

The nuptial flights occur depending on the region from late February to June.

Nicobarensis comes from the word Nicobar, which refers to a group of islands in the Indian Ocean. They can be found in India, Bangladesh, Myanmar, Thailand, Malaysia, Indonesia, Singapore, Vietnam, Laos, China and Taiwan.

Their climate variance goes from warm temperate to equatorial climate, these are referred to as tropical or subtropical regions. A tropical climate is a climate in which all twelve months have average temperatures warmer than 18 °C, whereas a subtropical climate features average temperature in the coldest month between 0 °C and 18 °C.

Camponotus nicobarensis worldwide distribution. Reference: Antmaps.org

They are usually referenced in the ant community for being a tropical carpenter ant species, but they also tolerate lower temperatures. In their natural habitat during the winter months, night temperatures often drop to the 0 to 10C range. And this brings up questions about their diapause.

Unfortunately we have to introduce some new concepts, and this may be a bit boring, but if you hold on, you may find it interesting when we start drawing some conclusions,

Homodynamic - a continuous all-year round development of the colony without the obligatory periods of dormancy.

Homodynamic species often have a certain seasonal structure of the annual cycle, on a general background of continuous development. It is well known that typically tropical insects cannot survive for a long time at temperatures well below the optimum and, especially, below the developmental threshold, therefore, it can be argued that the tropical ants in their majority are not adapted to survive during the cold periods of the year. However, some ant species can demonstrate continuous all-year round development even in subtropical environments.

Heterodynamic - An annual developmental cycle of ant colonies, in which a diapause arises naturally.

They have a distinct seasonal structure, the period of diapause is regularly replaced by the period of development, after which a new period of diapause occurs, and so on. It is characterized by a lack of larval development and of queen oviposition and the presence in the nests of only certain brood categories.

Quasi-heterodynamic - Tropical species, adapted to live in regions with cold winters without forming real diapause, they are characterized by the potential for unlimitedly long development under favorable conditions inherent in homodynamic species.

As an example, several scientists have shown that in southern United States, the invasive fire ant species remain essentially homodynamic: eggs, larvae and pupae of workers are present in their nests all-year round. However, the number of brood stages varies considerably during the year, and in winter, it is very small, as the development of the brood ceases at temperature below the developmental threshold and so, the ants spend the winter in a cold coma state suffering from more or less strong mortality, but in general the colonies overwinter successfully.

And this is the main question with Camponotus nicobarensis, how are they classified under these terms?

So are they a homodynamic species or a heterodynamic species?

Normally Camponotus are known to be heterodynamic, and to make things a little bit more complicated, heterodynamic species are divided into two groups.

The exogenous-heterodynamic characterized by the possibility of continuous and unlimited development under optimal conditions. The diapause is optional and occurs only when the temperature is lowered. At temperatures above 25°C, as well as at diurnal thermal periods 20/30°C, they all behave like true homodynamic species.

And the endogenous-heterodynamic where the diapause arises due to internal factors (internal biological clock) and no external conditions can prevent it.

I personally believe that Camponotus nicobarensis falls into the heterodynamic category and the exogenous group. Of course this is simply my assumption, and I hope that you all can chip in with your own experiences and conclusions on this topic down on the comment section.

The reason why I think they are heterodynamic and not homodynamic is because under less optimum conditions as they are occurring right now since its winter, I am observing my colony with only eggs and larvae, a very indicative sign of a heterdynamic behavior. If they were homodynamic, under the same conditions, pupae would be expected (probably with smaller numbers, but still visible, as it occurs with fire ants and other truly homodynamic species)

Camponotus nicobarensis Queen with brood (Pupae and Larvae)

Most ant keepers in our community who keep this ant species as an exotic, mainly in Europe, having been referenced and told that this species doesn’t require diapause because it is tropical, as such, they immediately assume that a heat mat or other temperature control method is necessary, to avoid the ants from dying. In my case, I am keeping my colony without any additional heat, and subjected to normal room temperature varying from 16C to 21C during this winter time. And they seem to be doing just fine. And mind you, that in the wild, further north, in Henan and Shandong temperatures can drop to minus 2C.

Of course, scientific studies are necessary to validate any further conclusion, but I would say that this ant species does have diapause under adverse conditions. The discussion is open !

This species is probably the most recommended species for those starting to keep tropical or exotic ant species and now I think we can see why. A very forgiving Camponotus species regarding diapause, that are very easily kept in captivity, can grow to large sizes, eats almost everything that they are offered, will be active throughout the year and are not too aggressive, which also makes them suitable for any beginner ant keeper.

Let me know what you think about the research!

References:

Response to vibrations of substrate and reactions to speciﬁc drumming in colonies of carpenter ants;
Structure, diversity and adaptive traits of seasonal cycles and strategies in ants;
The kin recognition system of carpenter ants;
The life history of the carpenter ant;
Time allocation in carpenter ants;
Carpenter ants: Their biology and control;
Le genre Camponotus Mayr et les genres voisins;
Le genre Camponotus Mayr, nouvelle essai de sa subdivision en sous-genres

Camponotus nicobarensis Diapause / Hibernation

Camponotus nicobarensis - Care Guide and Ecology

Polyrhachis - The Spiny Ants