i feed mine live fly without wings and spiders and somtimes other ants also apple and they had a sugar water test tube in the box to feed from just waiting to pu them into their nest
this happened with my myrmica too, I had over 50 deaths in the first 10 days. But since then no deaths at all and they seem fine.
porbally the younger generation maybe?
how many do you have now?
Didnt wanna start a new thread so i thought id ask this here... Is it normal for my rubra to be producing alates this time of year ??
dunno it might be if you keep them hot i don't know sorry