I came across this dead honey bee last year during a heatwave. There had been lots of warnings on tv and in the newspapers at the time reminding people to drink plenty of water and stay cool.
The hardworking bee had obviously keeled over and died while collecting pollen and the hairs on its underside were still sprinkled with the yellow pollen dust. The bee may have been a victim of the heatwave since its not normal to see dead bees inside flowers [it didn't appear to have been injured by a predator.]
It is relatively common to see exhausted bumble bees in the summer time , who seem to be at great risk of being stood on or eaten by birds . If I am able to, I give them a drop of honey and water which quickly revives them.