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Here is an interesting paper I found about Tapinoma sessile in urban areas. I remember when I posted about their huge colonies a few years back, a few of you saying it was strange how big their colonies were and they only had small colonies by their house. Not sure if there was more to the journal entry or not, but here is the link

http://www3.interscience.wiley.com/journal/121426476/abstract?CRETRY=1&SRETRY=0

No sign of them having any kind of alate activity going on...maybe a month early for Southern Cali. Hopefully they do fly...I think they did last year and thats where the second colony came from.

The second nest area has a large colony of Cardiocondyla species nesting somewhere.

In the main nest area, a native ground nesting bee has made its nest. I think its a solitary species, I've seen them around. It has a little dome shaped mound where its nesting, and I sometimes see it sitting right at the entrance. They are pretty cool. That be cool if more of them make their nest there.

Well I was going to bring bad news. but it turned into good news.

Both colonies of Tapinoma sessile were massively attacked. The Argentine ants have been having their mating thing and colonizing a lot of new areas.

The main nest of T.sessile was attacked by Argentine ants numbering in the high thousands if not the low 10s of thousands. Thick lines of Argentine ants were everywhere attacking the T.sessile nests. The T.sessile kept falling back until they were pushed to the wall of the garages. They ended up climbing up and nesting on the roof somewhere…the Argentine ants didn't follow them.

The second, smaller nest was also attacked. Not as much as the main nest was, but still thousands of Argentine ants attacking the T.sessile. This one as I've described is a much smaller area, not many places to nest or forage. The T.sessile actually did a lot better here, but were pushed out a lot of their main nesting areas. They ended up nesting in the power/electric box that is there.

Well, today I went to look at them. The second nest had defeated most of the Argentine ants and regained a lot of their area…still some Argentine ants, but not nearly as much as before. I would say less than a couple hundred at the most. And the T.sessile had thick lines going back to their old nesting spots.

At the main nest there are still a good number of Argentine ants, but again, not nearly as many. I would say somewhere around a few hundred. A lot less T.sessile too though, but they have sort of retaken some of the area back…they have some lines going back to their old nests. But they are doing a lot better too, and it seems they drove off or killed a lot of the Argentine ants.

Also, found a third nest. A much smaller nest that must have been from last year, or maybe even earlier this year. Seems to be only a few hundred in this one, so its pretty new. Probably over the Summer or when it stays consistently warm (when T.sessile do the best) they'll number in the thousands. This one must have been from a queen that flew, because its in no way connected to the other colonies. Too far away from them.

So, some big news today.

nest B has really grown a lot, and seem to be having some kind of mating thing going on. Queens, workers and brood moving to different parts of the area. Guess they are budding out. There was an Argentine ant nest here, where most of the attacks came from...now there isn't one Argentine ant left in this area. The T.sessile beat them.

Nest A is doing okay, they actually did the worst...but still a lot of ants, and over the Summer they'll be back to where they are. Seeing that T.sessile seem to do the best in late spring/summer/early fall. Not much to report on here.

The newest colony, nest C has grown A LOT. There are a lot more ants crawling around than there were when I made my last post. And they defeated a large Argentine ant nest too, where the Argentine ants were, now there are T.sessile. The Argentine ants did try to attack, but guess they lost. Still one Argentine ant nest left, by where the dumpsters are...but its a lot smaller than the one the T.sessile took over. The Argentine ants don't seem to have any luck against the T.sessile, at least when they are cut off from the "main land". That is one of the advantages to these plant areas, road is on all sides of them, so the Argentine ants can't really recruit from other nests. Still, nest C took over a pretty large Argentine ant nest...I was pretty surprised.

I wonder if the T.sessile have evolved or learned how to fight against the Argentine ants? Because when I first brought the T.sessile to the two plant areas, the Argentine ants did a lot better against them. Nest C was one of the first areas I put a colony of T.sessile. But after a few months, the Argentine ants killed all of them, there was barely any left...and after a few weeks, none at all. This was...about 3 years ago. Now skip to today, and the T.sessile are the ones beating the Argentine ants. Even with the Argentine ants being cut off from their main nests, when I first introduced the T.sessile here, they still were losing against the Argies...so not sure what changed, except maybe they learned or something.

Now...the nest I got them from, a few years back...they would have lost for sure. Because the pest control had just killed the Solenopsis invicta, and the Argentine ants took advantage of it...they killed all the S.xyloni nests, the remaining part of the S.invicta nest...and a few other native ants. The Solenopsis invicta, if pest control didn't kill them...the native ants would have had a much better chance. The last species remaining was T.sessile...but they were surrounded on all sides, and were losing a lot of ants in battles. So I took as much as I could and spread them around, outside my apartment building.

Only one colony lived (nest A), since the second colony, as I was saying, was killed off by Argentine ants. Nest A as you can tell, as spread a lot since then, to make a lot more colonies.

Funny how an invasive ant like S.invicta can in a way, help native ants stay alive...at least when Argentine ants are involved. Because as soon as pest control killed them, that was it...the native ants were taken over in less than one week. Still a lot of native ants left...just none on my apartment side (minus the T.sessile that have been spreading). Mostly just native ants around and in the valley, down the road from here.

Now...according to this article I read (and linked to in one of the posts)...in spring/summer/early fall, the T.sessile make huge super colonies (only in urban areas, in their native habitat they have really small colonies, of a few hundred at most)...but late fall/winter and early spring, the T.sessile retreat back to their main nest, and slow down a lot. But there should still remain three large nests, since the nests are all cut off from each other from the parking places and the street...but they'll go into a sort of "hibernation". They won't be hatching a lot of ants, and will have mostly stopped laying eggs. Last year they were sort of active in the Winter (mostly on warmer days), but no where near as much as they are now. The Argentine ants will sort of have an advantage during this time...but last Winter, even they slowed down a lot.

Can't really take pictures or video of ants. I need to buy a good magnifying glass for my camera to get pictures of them. Can barely, if at all, take pictures of my queen I have, and she is half an inch long (so, she is pretty big). One of these days I'll get a magnifying glass to be able to take pictures of my ants and the colonies outside. It would be nice to be able to take pictures/videos of all these ants though.

Aug-16-09, 10:59 AM

Well, bad news. Guess the Argentine ant colony was a lot bigger than I thought, as hundreds were attacking the Tapinoma sessile this morning. I spent a good part of the morning killing a bunch of them, but there are still a lot. I'll have to go back out later this evening and see if I can do anything.

Still, Plant Area C has a good amount of other ants besides Argentine ants. There are Cardiocondyla mauriticana (not native, but their colonies are small and don't do any harm) and there is a new colony of Crematogaster! I noticed some workers crawling around the Argentine ants that looked different. Well I took a closer look at a few of them, and they have that heart shaped abdomen that Crematogaster have. Not sure how they will do against the Argentine ants...but they are being left alone. I noticed Argentine ants leave small colonies alone, but once they prove a threat, they attack on mass. It will be interesting to see what happens to the Crematogaster over the next few months and next year. I think they may prove tougher for the Argentine ants than the Tapinoma sessile.

Wouldn't be so sure, not yet anyway

Aug-16-09, 5:56 PM

With my help of repeatedly drowning the attacking Argentine ants with soapy water, the Tapinoma sessile have re-conquered their main nest.

Bad news...though they aren't Argentine ants, I see Solenopsis invicta workers crawling around. I guess they hatched from their last flight. They aren't Solenopsis xyloni, they are darker and larger than the S.xyloni. Didn't find their nest, but it must be a new one. I didn't see any mound or anything, but there are a lot of cracks and stuff in the road/dumpster area that they could be in. Too many to look through, even if it is a small area.

Its cool to see the Tapinoma have taken back their nest, though If I wasn't killing the Argentine ants, the Argentine ants would have won.

I noticed the T.sessile do have a smart strategy. They let the ants attack them, and they evacuate the area. I noticed they did this in Nest A and B too.What they do is, leave the dirt area and go up to the roof of the car garages in middle of the road, or go inside the garages themselves, or/and go further back (there are 3 car garages, then a two car parking spaces, and garages again, parking spaces, more garages than the plant areas with the dumpsters nearby)...for you to get an idea of the length. Well the T.sessile went 2 cars down where the Argentine ants don't really go, even when attacking. I noticed Argentine ants tend to stay around dirt, never see them going too far away from it). Well, once the Argentine ants take over their nest, at first it seems like the T.sessile have lost. But all three colonies of T.sessile did this...they would suddenly invade their old nests that were conquered and start killing the Argentine ants by the hundreds. Then the Argentine ants are pushed back or wiped out. And after that, the T.sessile regain their territory.

Like I said, Nest A, B have done this. And with my help, Nest C is doing this too. But maybe even without my help, they would still do that.

6:30 PM

Finally found another Argentine ant nest! It was the biggest one so far, along the curb by the dumpsters. They were all in the dirt and under the bark/leaves. I flooded the nests out with soapy water, so that should take care of that. Got rid of hopefully the source of the problem. Even if not, thats a lot less Argentine ants (must have got a few hundred of them). Which helps the Tapinoma sessile, which in 30 minutes have already regained a lot of their territory.