Lancer wasps are an uncommon or rare spawn, An unruly impaler and An impaler wasp are the common placeholders, A weakened wasp is unrelated. I Know Nothing! Nothing! requires killing 5 lancer wasps, The Blood of the Bear, Part Two (Quest) requires 10 lancer wasps, and you may have to kill half a dozen lancer wasps to get the drop for Drodo's Goodies.
Killing placeholders as a full-time job you can keep just slightly ahead of the spawn rate of all the spawn points in the area. Doing that, expect to spend over an hour repetitively killing placeholders to get the spawns required providing you do all three quests at once, or two hours doing them serially, assuming no twits on saliraptors hop in and steal any of your lancer wasps once you've done all the work to get them to finally spawn.