Hey!
I have a few colonies in wooden formicaria at the moment - a Tapinoma sessile colony with 7 workers, a Crematogaster colony with 4 workers, 2 C. pennsylvanicus colonies, each with ~3 workers, and a C. subbarbatus colony with 4 workers.
Two of them have had water issues due to design flaws - the T. sessile, Crematogaster sp., and one of the C. pennsylvanicus' formicariums are having water issues, and are starting to show mold. I decided to introduce springtails into the formicaria. The results:
Crematogaster sp.: I didn't see what happened, but when I came back, the workers were unhappy, and there were some dead springtails. Later, the springtail bodies had been moved to the watering block... which the ants unfortunately also treat as their garbage dump. I am guessing that Crematogaster are not friendly towards springtails which are comparable in size to them. I'd have to investigate closer to see if juvenile springtails are still alive.
C. pennsylvanicus: They ignore the springtails.
T. sessile: The workers... appear to hunt the larger springtails. They don't dispose of the bodies, but rather carry the springtails back to their main nesting area alive. I couldn't tell if they are killing them at that point, but they are certainly alive and wriggling while being carried. They ignore the smaller springtails. It almost looks like framing/ranching, as the workers will occasionally 'forage' for them in the damp chambers, only grabbing the largest springtails if they're there.
I may be, and likely am, reading too much into the Tapinoma behavior - most likely the largest ones are the only ones they notice or are the only ones worth hunting, but their hunting behavior seems somewhat sustainable in the short term.
Thoughts?
