Good news and bad news. Mostly good news. I'll start with the bad, though.
Turns out trying to boost this queen with brood of a different species was really stupid. Even though I tried to remove it all, a few pieces were stuck in the tube, and after a few days grew some nasty yellow mold. I was forced to move the queen to a new tube, and in the process lost basically all her eggs. No bueno.
So, of course, I tried to offer some P. obtusospinosa brood. No good, the queen hated that too. So I knew what I had to do.
I got in my car and started the 2.5 hour drive (one way) to Mt. Lemmon where I caught this queen. I had to get some P. rhea brood, and this was the spot to do it.
Have you ever driven 5 hours just for a few dozen Pheidole brood? Well, I know I have. Thankfully I was successful in my endeavor, and returned home last night with around 40-50 P. rhea pupae. There were of course quite a few workers that I had to remove, although I left the callows, one minor and one really large major (not a supermajor) with the brood, and then offered it to the queen. Finally, she actually seemed to accept it, and the two callows have even been periodically grooming the queen. The queen is definitely still a little sketched out by the new friends she has, but doesn't seem even slightly aggressive towards them, and after spending all night together I even saw her this morning tending to some of the pupae.
So that's the good news. I don't want to speak too soon, but I'm really hopeful this brood boost will secure this queen's success, and with this number of workers should hopefully kickstart one hell of a colony. I've even got some huge majors right off the bat! Now just to wait for supermajors...