Yes, there is no need for honey/sugarwater if you have seeds. My M. barbarus will take sugarwater if it is realy concentrated, and if the sugarwater of another ant dries up then I give it to the messors and they seem to love it. They don't seem to like wet or bloody food (I boil and dry out insects for my messors, and they love it like this )
My M. minor hespirius don't like anything dry, except seeds. they completely declined fishfood flakes, and they drag dry insects to the waste-dump. But fresh insects get dragged into the nest.
I wanna try wetting some of the fishfood flakes and see if they'll try them then.
EDIt: To address Jimmy's question I'll say that I'm pretty sure they don't need sugar-water. All the sugar they need they can get from their seeds.
That is what i'm thinking, but i'm not a 100% sure of that.
Looks like i'm lucky with my Messor barbarus they eat anything i give them, wet, dry. I dont even cut the insects in two, like i do for most of my ants.
Of course they need water! Its really important for them, like for every creature on earth. And it's especially important for this species because they do not eat any honey or sugarwater. Other species additionally get water from those food sources.
So you must give them water with cottonwool? Or just pure water without cottonwool? And wat about a nest in a testtube with water behind cottonsool in the tube, do you still have to give them water outside the nest in this situation?
You HAVE to give them water. If you dont want them go swimming you can use the cotton. I prefer giving them water without. I would give them some honey, too. Perhaps they need it. You cant say that they do not need honey becoause they do not drink any or because anything else.
I don't give mine any honey or sugar mix. They just don't like it. I do give them plenty of fresh water is a bird feeder, with cotton to prefent them from drowning.