jwb, I put forward your question to other biologists I know in Norway through a facebook group we have. It's not yet brimming with replies, but there's some which has led to some interesting insights for me.
About Wilson, he did put forth an argument that eusociality had evolved by some form of group selection. I have not yet dug into what exactly the mechanisms were supposed to be, but this was countered by the aforementioned haplodiploid argument that I got into and which was published in Dawkins' 1973 The Selfish Gene.
Wilson argued that it was not sufficient to explain eusociality because a requirement, which I admittedly didn't get into, is monogamy. Once a queen ant has sex with several males and not just one, the relatedness between worker ants drops. There are non-monogamous species of hymenopterans that are eusocial. However, it seems that monogamy was an ancestral traits even in these lineages so that at the time eusociality evolved in hymenoptera, diplohaploidity and kin selection coupld with monogamy is indeed a likely explanation.
Source:
https://science.sciencemag.org/content/320/5880/1213
HOWEVER there are other things that are needed to explain eusociality as well, especially when found outside hymenoptera. Ecological factors and things like inbreeding can play important part, as well as the way genetics works for the various lineages (like the diplohaploid sex determination system or chromosomal linkage in termites).
Some things I found interesting are a couple of pre-conditions that seem important:
- Offspring that require a lot of parental care
- Low reproductive success rates for solitary pairs that attempt to reproduce
There are more things, but these two coupled with some kind of circumstance that might increase relatedness between siblings seem like important factors that will help drive evolution of eusociality.
I'm told this is not bad ->
https://en.wikipedia.org/wiki/Evolution_of_eusociality
I'll keep reading because it's highly interesting so may comment more.. But right now, my wife tells me I need to get out and have ice in the sun with the kids.