Why switching off the torch would cause the worms to die faster than when the torch was switch on?

Some bacteria and worms grow faster and lives more due to the sufficient temperature available for their survival. When a torch is lit up, it generates light energy on conversion of electrical energy and it's a fact that heat energy is also produced by a body if it produces light energy. The Heat which is released increases the temperature of the area which led the bacteria to survive more.

On switching it off, the chances are reduced as the source of heat has been switched off and slowly the temperature will return to normal. Hence on switching off the torch the survival chances of worms and bacteria is get reduced.