Nectar Collecting for Fun and Profit

 is an unmarked and repeatable Fallout 3 quest.

After completing Those!, Doctor Lesko in Grayditch (initially located in his underground lab in Marigold Metro Station he will eventually move back to his shack after the quest) 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. The base percentage chance of the nectar being dropped by workers is 40%, and for soldiers and warriors, 70%. However, these percentage are changed by the player's Luck.

Rewards
Lesko pays 40 caps per sample.