My newly caught queen died before laying any eggs. What might have gone wrong?
There are a few usual causes. The one that catches people out most is a species that needs a winter before it starts a colony.
She needed a diapause. Some species, Crematogaster cerasi among them, have evolved so that a newly mated queen rests through winter before founding. Kept warm, she waits for a winter that never comes, and eventually dies without laying. If you catch these queens in late summer or fall, keep them cool through the winter and expect eggs after that rest. How To Diapause Your Ants covers which species need it and how to run it.
She was too cold. Room temperature is below ideal for most species. A queen kept at 68°F when her species thrives at 90°F is trying to lay, but everything happens slowly. Look her species up in our care guides before adding heat: heat helps, but done carelessly it kills.
She was disturbed. Founding queens want somewhere dark, calm and still. Checking on her often can be enough to put her off laying.
She needed food. Most queens raise their first workers on stored reserves, but semi-claustral species, such as Pogonomyrmex occidentalis and Odontomachus brunneus, have to be fed during founding.
The tube failed. A flooded or dried-out tube is an emergency for a founding queen.
Why Isn't My Queen Laying Eggs? walks through each of these. If it happens again, ask us here with the species and your setup, and we'll help narrow it down.