Here’s some pure conjecture: this summer has been almost three degrees above average in my area. If you read the Wikipedia article about Blochmannia, it says they are heat intolerant. Perhaps queens born and raised in very high temps come out deficient in the bacteria stores they should be passing on to their workers via trophylaxis? Again, pure conjecture...
Edited by ANTdrew, September 7 2019 - 6:17 AM.
"The ants are a people not strong, yet they prepare their meat in the summer." Prov. 30:25
Keep ordinary ants in extraordinary ways.