Is Carebara Diversa Polygynous?

The author resides in Singapore, where Diversa, Affinis and many sub-variants of the 2 are present.

There are coloration, size and behavioural differences between Diversa, Affinis, and Cf Affinis, cf Diversa, etc. More discussion on the various Carebara subspecies Here.

Some difference in queen sizes.

Another sub species which I understand to be commonly exported from China. Note the slimmer thorax and the longer gaster. They measure 18 to 20mm.

It appears that the minors of some sub species will tend to entirely engulf their queens when the queens are exposed:

In other sub species, minors will swam their queens too, albeit not as much:

The author has personally succeeded in getting sister queens of certain Affinis subspecies (caught from the same nest during the same nuptial flight) to pleometrotically establish young colonies together. Picture and video proof can be found here. However, these colonies inevitably killed off the weaker (and perhaps infertile) queens over time, leaving only one (dominant) and egg-laying queen within the colony. The killing was observed to have started when the minor worker population hits around 500-800. This illustrates secondary monogyny.

Notwithstanding, I’ve heard of ant hobbyists whose Affinis colonies demonstrated secondary polygyny- which means that the colony produced alates; the alates inbred and mated in the nest, shed their wings, and became egg mating queens in the colony. As I have not yet kept Affinis to an extent where they have produced alates, so I’m unable to verify this personally.

Some who conducted field studies in Thailand claimed that established colonies of C. Diversa which were dug up contained only a single fertile egg-laying queen, which was most likely also the founding queen, given the degree of ovarian development observed as well as the extent of depleted thorax muscles and metabolized fats in the gaster. This would be consistent with some form of monogyny (albeit founding method uncertain).

The author’s personal experience has been that C Diversa is primary monogyny.

The author has not managed to get more than 1 C. Diversa queen to found a colony. In addition, from his experience, it appears almost impossible to get an already founded colony (whether a young colony or an established colony) of C. Diversa to adopt newly mated queens.

Perhaps the author has mis-ID his own ants, and/or the author’s method of queen introduction needs to be re-evaluated?

Pictures and videos of newly mated queens being pinned down and “torn apart” – a clear sign of rejection. Don’t worry I saved these queens shortly after I took the video.

 

A friend of the author, Quah, has suggested a hypothesis for possible monogyny in C. Diversa:

“My general observation of polygyny in ants are that it is primary a survival strategy, meaning the weaker species adopt polygynous attribute to be more effective.”

I tend to agree with this hypothesis, as in Singapore, C. Diversa appears to be the dominant species; occurring in both urban areas and man-made parks. Whereas Affinis, cf Affinis and other smaller subspecies of Carebara tend to occur in fringes of forests and densely forested areas.

 

Conclusion: C. Affinis is reportedly highly polygynous (primary). But, is C Diversa polygynous too? I’m still not sure…

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