The foragers save energy for the next working day.
I did read once that young house bees work 24/7 and take a tea break a few times a day for upto 20 minutes when they are still.
Go to any hive after dark when there is a honey flow on,and they are flat out fanning off the moisture from the nectar collected during the day,and they still have brood to feed. In the winter or cold weather they are clustering to generate heat,consuming stores to do so.
Heard a noise from my hive last night whilst re-filling the Miller, at 11pm they we merrily feeding so there is one answer. More importantly they had only nicked my old vhs and were watching 'B' movie, shouldn't have given them brood and a half space for winter