The authors convincingly show that the application of the histone acetyltransferase inhibitor C646 via sucrose feeding to Temnothorax ant workers shifts their activities in a condition-sensitive manner, when colony composition was drastically altered. in young worker colonies, C646 feeding enhanced the transition from brood care to foraging was found enhanced, while in old worker colonies it inhibited the reversal to brood care. This said, I have the following questions and comments, all for minor revision.

1) Although the authors have used C646 in prior experiments as a tool to pharmacologically manipulate histone acetylation in ant species, has HAT activity actually ever been assayed in these ants? Especially, has an inhibition of HAT activity by C646 ever been demonstrated? I am asking because C646 has been shown to not only inhibit HAT (writer) activity, but also histone deacetylase (eraser) activity in inflammatory responses in mice (van den Bosch et al., 2016, Biochem Pharmacol).
Though I do not request that the authors would have to show via an enzymatic activity assay that C646 does inhibit HAT activity in the ants. Yet, in case this has not been previously shown, certain statements may have to be toned down.

2) I had certain difficulties in following the experimental design, and I would find it helpful if the authors could provide a flowchart graph representing the experiment.

3) In Material and Methods, the authors state that 69 colonies were collected in 2016 in the US and then established in Mainz, but were all these colonies actually used in the current experiment. The number of colonies per experimental group is not clearly stated, at least, I could not find this information. This has consequences on the sample sizes presented in the two figures. Especially, it is not mentioned in the text or the legend what the actual sample sizes (N) were in the treatments. Though this can be fund in raw data in the supplementary material, this should be informed to future readers who may not have access to the supplementary material (made available to reviewers only). I was also wondering whether violin plots would not be a better way to present the data – but this will depend on the actual sample sizes.

4) I also have a question concerning the dose of C646 that was fed to the ants. The authors say that the sucrose solution was supplemented with 100 uM of C646 dissolved in DMSO or 100 uM DMSO as control. Is 100 uM C646 or DMSO the actual final concentration in sucrose, or is it the molarity of C646 in the DMSO stock solution? In their prior publication (Libbrecht et al. 2020) the authors say that they added 15 uL of 100 uM C646 in DMSO to the sucrose, and this makes more sense to me.

5) Since in the Introduction the authors speak of “corpulent” and fertile workers (Iines 52/53) I was wondering whether the experimental colonies used here were actually all queenright. Besides being a rather strange term when used with insects, would corpulent (fertile) workers actually be found in queenright colonies, or only when a colony has lost its queen?

6) In line 68 I suggest to change epigenetic stages to epigenetic states.

7) Line 173: better to says “Future research should aim…”

The authors addressed my concerns in a perfectly adequate manner.

I only noted to very minor technical errors:
Minor corrections
- Line 122: the figure mentioned here as Figure 1 is now Figure 2 (Figure 1 is the new workflow representation)
- Line 130: the figure number mentioned here (Figure S2) is correct, but in the supplementary materials file it is labelled as Figure S3.