I can't harvest the food of the mobs I kill in my formicarium

[The vegetarian ant]

(I am not really sure if it is a bug because it would be broken but maybe)
I have finished the two formicarium missions and I can make spawn the most of the species of bugs, but when I kill them I can't harvest their food, so I have to farm if I want to make tests...
does someone know if it's a bug or no ? thanks (and sorry for my very bad english I'm french )

 

[Rayalot72]

You cannot get food this way, or it would be far too easy, and clog the formicarium.

 

[MikeSlugDisco]

The spawner is just there for fun - as Rayalot says, way too easy to farm giant quantities of food if we gave food from the end game spawner.