36 replies to this topic

[Foogoo]

Out where I am, it's not unusual to come across Argentine vs. Pogonomyrmex battles. Today, I came across a small group of Pogonomyrmex that appeared to be digging/moving dirt in a frenzy with Argentines dashing about, but no obvious signs of battle. What the heck were they doing? Maybe trying to stack sand grains and bury the combatants??

 

 

[Gregory2455]

I do not specifically know Pogonomyrmex behavior, but if you have ever see a Pogonomyrmex digging (spreads hind legs, and uses front legs to whip particles backward), then the dust kicked up may be an attempt to repel the Argentine ants? That would be my only guess if they were indeed hostile. The other option, is that the two parties were not even aware of each other, and this digging is just normal Pogonomyrmex foraging behavior.

[dspdrew]

I see them do this a lot, even in my containers here. It looks to me like they are looking through the sand for goodies, but that's just my guess.

[Alza]

In my testing I've found pogonomyrmex californicus foraging patterns arent affected by argentine ants, and when argentine ants do raid they don't naturally need to defend themselves as they don't take it as a "serious" threat. Also i say californicus because I've recently done some "Iding" alone on the ant species near me, and they have proven positive to be californicus.

[Gregory2455]

There is a lot of Pogonomyrmex subnitidus in the mountains here, but yes I have seen concolorous Pogonomyrmex californicus and what may be Pogonomyrmex cf. occidentalis.

And yes, Pogonomyrmex usually are unphased by argentine ants, but argentine ants pose a large threat to them in numbers. However, like pretty much everyone so far has said, the digging is just natural Pogonomyrmex "tree-branch" foraging.

[Alza]

Large numbers, I havent found that to be a threat in my experiments. Argentine ants teamwork just isn't enough to kill pogonomyrmex. 

[Gregory2455]

Not going to argue, but how do you suppose they are invasive if they cannot kill native species? 

[Alza]

They are successful due to how fast they populate. Native species have no ice to melt with them, thus they show no aggression towards the argentine ants unless provoked, which gave argentine ants time to grow to a superior size. This time was very valuable and essential for them, and as they grew in numbers they were able to conduct more raids. Also, they can kill native species, but i can't see them killing pogonomyrmex 

[Gregory2455]

Come again?

[Alza]

Its being tugged on, but they can't kill it. Also in my testing when this happens when one of the ones holding it down is killed it has access to make an escape. 

[James C. Trager]

When I lived in California, it seemed Argentine ants were pure death to native formicines, somewhat less so to other subfamilies. Do others agree with this generalization?

[drtrmiller]

Argentines seem to deliberately calculate whether to attack a nest or stay away.  I would speculate that it may be based on the number or condition of "scouts" that successfully return after discovering another ant nest.  

 

They infiltrated all of my ant colonies housed indoors in an uncontrolled office environment, and started first with the youngest, most vulnerable Myrmicines, then moving perfectly linearly to the more mature colonies over a period of about two weeks, only stopping when I intervened with chemicals and relocation of the captive ant formicaria being targeted.

Edited by drtrmiller, October 10 2014 - 7:33 AM.

[Gregory2455]

When I lived in California, it seemed Argentine ants were pure death to native formicines, somewhat less so to other subfamilies. Do others agree with this generalization?

That is actually pretty accurate, but I have not seen Argentine ants here in Simi Valley, I think it is the large population of Nylanderia that keeps them out.

[Foogoo]

So do you get pest ants in the house then?? Because all my life I've lived in Socal, it's always been Argentines roaming the house in hordes.

[dspdrew]

Foogoo, it's always been the same for me too, but strangely, I haven't seen any Argentine ants in my apartment complex, and I live in Costa Mesa where there is an abundance of them. Instead of Argentine ants, we seem to have a lot of Cardiocondyla here.

[Gregory2455]

We still get pest ants, but here is the thing. I have lived in Simi Valley all y life, never have I seen an Argentine ant colony in Simi Valley, or the direct mountains around it. Some pest ants here include Solenopsis molesta. Yes I have seen Argentine ants outside of Simi, there is absolutely, not one colony here.

[Foogoo]

Foogoo, it's always been the same for me too, but strangely, I haven't seen any Argentine ants in my apartment complex, and I live in Costa Mesa where there is an abundance of them. Instead of Argentine ants, we seem to have a lot of Cardiocondyla here.

 

Wandering a bit off topic here, I just looked up Cardiocondyla since I never heard of it and they look a heck lot like Solenopsis xyloni. How would one differentiate the two?

[dspdrew]

A lot of Myrmicines look very much alike. One major difference, is that they have spines, and Solenopsis spp. do not. Also, if I remember right, their queens are extremely tiny--only about 2mm in length.

[James C. Trager]

Gregory2455 - those Nylanderia may be the recently described, and apparently native species N. magnella. You can find out here :http://www.mapress.c...z03508p064f.pdf

(Edit: Just discovered this is only a link to a preview, but if you really want the article you can write author John LaPolla and he'll send a full pdf.)

Edited by James C. Trager, October 11 2014 - 7:03 AM.

[Gregory2455]

Gregory2455 - those Nylanderia may be the recently described, and apparently native species N. magnella. You can find out here :http://www.mapress.c...z03508p064f.pdf

(Edit: Just discovered this is only a link to a preview, but if you really want the article you can write author John LaPolla and he'll send a full pdf.)

That means my journal would be them as well, because it is the same species across the valley.

 

http://forum.formicu...-updated-10314/

I have some good macro images at the bottom of the journal, and if you think that is them, I will set up a formal ID with better pictures.