There has been several major transitions (John Maynard Smith and Eors Szathmary) and systematically there is opportunity for conflict to arise…. and it does! There is conflict along genes within a chromosome (example the Psr gene of Nasonia vitripennis, see R. Trivers and A. Burt Genes in conflict), along chromosome within an individual and along individual within a colony.
Ants has been much studies (see E.O. Wilson, L. Keller, M. Chapuisat) and it has been found that there are tons of different reproduction system in those species. There are conflict between queens, between workers and between queen and workers to reproduce. In some species, a colony have several queens, in others, there are several queens fighting early in life for the right of being the unique queen. In some species, workers can fight to take over the queen and take her function. In some species, workers reproduce sometimes even if there is a queen. There is conflict over who will survive depending on how much related one is to the other one. For example, there is conflict over sex-ratio, the queen is as much related to her sons than to her daughters but the workers are more related to their sisters than to their brothers (because of haplo-diploidy, see Robert Trivers).
There are various factors limiting the conflicts: high relatedness (Hamilton, Trivers), Cost of a fight, absence of information, power asymmetries. Ants evolved various strategy. There is a "police" who kill worker's spawn. We might as well consider lineage selection that select for cooperative colonies (note that L. Lehmann and L. Keller argue that group selection and kin selection are the same concept!)
I basically repeated some stuff I read (or learned in class) but I am personally not sure that all that makes sense! I don't know if really the frequency of conflicts is not simply related to the mutation-selection balance. Criticisms are welcome!
In reaction to your comment:
Conflicts always have to do with reproduction or survival in evolutionary biology. One might make three categories of conflict:
1)Those involving the right of reproducing
2)those involving the probability of dying (I prefer not to be a forager because forager have a very high mortality)
3) Those that concern the survival of kin individuals. The "purpose" (if I might use this agency way of speaking) of any one to to increase its inclusive fitness (Hamilton, but don't read Hamilton, there is lots of easy source of information on kin selection). Therefore, one will rather help its brother to survive rather than his cousin as it is more closely related to its brother. Similarly, beccause of the haplo-diploidy nature of sex determination system in hymenoptera, workers are more closely related to other workers than to the males while the queen is as much closely related to her daughters and sons. Therefore, we would expect a conflict over the sex ratio, queen trying to have a sex-ratio of 1:1 while the workers are trying to have a sex-ratio of 75:25 (if there is only one father).
Hope this helps!
If you want more specific information about sex-ratio in ants, kin selection, group selection please ask it in another post. Note that there is already some discussions one these subjects on Biology.SE.