Hello,
I am currently doing quite some research on Solenopsis invicta, mainly because ant keeping is an interesting hobby of mine (even though normally not my field of research) and I think that you cannot know enough and I have recognized several things that in my opinion don’t really fit into the invasive success of RIFA.
1.) most S. invicta colonies are monogynous and have a very high heterozygoty (I believe to have read 95%)
2.) polygynous S. invicta with the GP-9 allele can only exist in the Genotype Bb because bb and seemings BB wouldbe lethal, that means a highly polygynous mutated alate would have to mate with a “normal“ male to be able to reproduc.
Also 90-100% of the produced males in the highly polygynous mutation are sterile.
3.) fire ants were introduces to the US in the 1930s and their success started with very few colonies. Despite from this fact they still maintain a high heterozygosity.
Also many colonies found in their natural Habitat don’t have any queens at all.
So this suggests me that those ants have a unusual mode of reproduction, either worker reproduction, thelytokous parthenogenesis or similar. I really cannot imagine that this species could have been so invasive just because of their aggressiveness. Actually all invasive ant species I am aware of either have adaptive inbreeding, parthenogenesis or worker reproduction.
Maybe some of you have an explanation for this. Their success looks to me like very paradoxically
Best regards,
Andre
Hello Andre; S. invicta has been in my area (the Inland Valley of Southern Calif) for only a few years. It is the second highly invasive ant in the area. The argentine ant is the other. A little story about the argentine ant might be instructive. They are highly polygynous here but are monogynous in their native range. They are polydomous here but monodomous in the native range. Here they form massive "supercolonies" containing billions of workers and cover thousands of square kilometers. Within a super colony any worker is welcome in any nest. At the boundaries between supercolonies intense fighting occurs.
The colonies of S. invicta that I have played with here seem to be polygynous. At least I've seen more than one wingless queen in a single nest. Workers don't get attacked if they are moved from one nest to a neighboring one...whatever that means.
I've read about queenless ants (can't find the citation) but they are evidently rare. Queenless colonies of many ants may have reproducing workers but the product is only male offspring.
You might do some observations on S. invicta along these lines. Maybe you don't need such an unlikely interpretation. Best regards, Jim Des Lauriers.
I am well informed about Myrmecology so no explanation needed about the two social forms of Linepithema humile (former Iridomyrmex humilis).
The thing about the highly polygyne social form of invicta is that the males are mostly sterile and the queens have to mate with males from a non polygyne (not carrying the GP-9 allele) colony to produce viable offspring.
Also queenless ant species aren‘t even that uncommon if you mean by that, that workers can produce viable offspring if the queen dies.
Also there are several species that don‘t have any queens where the workers reproduce. For example multiple Ponerinae (f.e. Diacamma spp.) as well as Pristomyrmex pungens and Oocerea biroi.
In contrast to the highly polygyne social form of S. invicta, argentine ants can do inbreeding mostly without any effects of inbreeding depression. Solenopsis invicta mostly won’t. Also they greatly suffer from inbreed depression.
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