Anthony, very good idea and journal.
I have a little story of my own too, about how my native Formica pacifica rose up against the invasive Tetramorium immigrans and successfully drove them off.
In the past few years, I have been finding more and more Tetramorium immigrans workers in my yard. For a little while, I began quite frightened that they would displace the native Leptothorax canadensis, Formica pacifica, Camponotus modoc, Camponotus herculeanus, and Myrmica incompleta; as the Tetramorium were becoming more and more prominent by the day.
Over time though, I witnessed less and less T. immigrans present, and more and more F. pacifica; as it was before the Tetramorium came. I was happy but also confused by this. I wondered to myself, how did the Formica drive the Tetramorium off, as the Tetramorium should be able to outcompete the Formica, as they had begun to do before?
My answer came to me a few months later, when I was heading home from a walk. I noticed a large number of the native Formica pacifica, gathering around a small little rock. Then, I noticed a lot of the workers disappearing underneath the rock. I became quite intrigued by this, and lifted up the rock. Then came the most striking thing of all; there was a small Tetramorium colony living underneath the rock.
The native Formica were attacking and killing all of them in sight.
This was quite interesting behavior from a species in the Formica fusca group. They had behaved a lot like how the Formica slave raiders do, although they didn't bring any brood or workers back to their nest. This must be their way of suppressing other ant populations, which might be a contributing factor to why they are so dominate in many parts of British Columbia.
I have also witnessed Formica pacifica engage in large street wars between each other, and raid another small Formica pacifica colony I was in the process of releasing. So, it does point to the fact that as a species, they are quite aggressive. I didn't actually witness what the raiding colony did with the small colony, I just found a large trail of the raiding colony leading into their test tube, with no sign of the small colonies' brood, queen, or workers in sight. Presumably, they carried them back into their nest to eat them.
Anyways, I'm not really sure what to make of all this behavior, I just thought I'd share it with you guys. If anything, it is quite interesting.
Edited by AntsBC, June 29 2019 - 4:10 PM.