Nectar Collecting for Fun and Profit

 is an unmarked and repeatable Fallout 3 quest.

After completing Those!, Doctor Lesko in Marigold Metro Station will ask you to gather Fire Ant Nectar.

Fire Ant Locations
Prior to the quest fire ants can be found in Grayditch and the Marigold Metro tunnels, after the quest they can only be found in the Metro Tunnels. Workers drop nectar 40% of the time, soldiers and warriors 70% of the time. But the actual percentage seems based on the player's Luck.

Rewards
Lesko pays 40 caps per sample.