15 replies to this topic

[Amanda]

Interesting seeing this species having 3 different sized majors and 2 different sized queens. I kept this species back in the early 2000's and never noticed different sizes. The largest majors were born first, then later on smaller majors started appearing. 

 

Has anyone else noticed this? 

[Mdrogun]

Pheidole megacephala is not currently known to be present in North Carolina. They need a more tropical climate. The farthest North their range extends on the Eastern seaboard is Northern Florida. The species needs a mild, preferably tropical climate. They also tend to spread relatively slowly as they often have no nuptial flights, or very tiny ones.

 

Regardless of whether or not you have Pheidole megacephala, it is most probable that you are simply witnessing the natural size variation found within a colony as colony size changes, along with food availability. Larger colonies tend to produce larger workers, and even queens. Also, their size is affected by how much food is available. If you look at wild colonies of ants, you will notice that there is some variation in size, even in monomorphic species. This is just the natural result of how plentiful food was at the time of that ants' development.

[ponerinecat]

These are not types of majors/workers, just natural size variation, like in humans.

[Amanda]

Pheidole megacephala is not currently known to be present in North Carolina. They need a more tropical climate. The farthest North their range extends on the Eastern seaboard is Northern Florida. The species needs a mild, preferably tropical climate. They also tend to spread relatively slowly as they often have no nuptial flights, or very tiny ones.

 

Regardless of whether or not you have Pheidole megacephala, it is most probable that you are simply witnessing the natural size variation found within a colony as colony size changes, along with food availability. Larger colonies tend to produce larger workers, and even queens. Also, their size is affected by how much food is available. If you look at wild colonies of ants, you will notice that there is some variation in size, even in monomorphic species. This is just the natural result of how plentiful food was at the time of that ants' development.

Very interesting, I had no idea about size variations in ants as colony size change( besides nanitics).

I was in Florida when I had this species in captivity (south of Tampa).

 

I'm pretty sure this species has made it to the coast of North Carolina, I have witnessed them there along the beach in summer and in some coastal cities maybe surviving the winter indoors?

[Mdrogun]

 

I'm pretty sure this species has made it to the coast of North Carolina, I have witnessed them there along the beach in summer and in some coastal cities maybe surviving the winter indoors?

 

 

There are many areas much farther North than you that Pheidole megacephala are known to be indoor-introduced. Maryland, for example. However, with these findings, it is difficult to tell if the species even survives there year-round, or if they just happened to have made it there in the summer and survive until winter. Even if they are surviving year-round, their range and population will be absolutely tiny and insignificant. 

 

If they are surviving outdoors, you are the first person to find them anywhere near that far north in the western hemisphere. The farthest north their range is known to extend, globally, is in a southern town in Western Turkey. It's strikingly cold there for this species, but even then, the daytime high rarely drops below 50F, and night time temps typically don't go below freezing, only for small amounts of time if they do. Comparing this climate to Charlotte, one of NC's warmest, Charlotte is still significantly colder. The average low for January is 32F, exactly freezing. I don't want to say it's impossible, but if this species is indeed present in NC, they likely wouldn't be thriving and merely surviving.

 

I also urge you to keep in mind, Pheidole is an incredibly diverse genus. Many species of Pheidole are present in NC, some native.

[kalimant]

 

 

I'm pretty sure this species has made it to the coast of North Carolina, I have witnessed them there along the beach in summer and in some coastal cities maybe surviving the winter indoors?

 

 

The farthest north their range is known to extend, globally, is in a southern town in Western Turkey.

 

 

They have been known to occur farther north recently. The current record is at Barcelona, Spain, at 41 degrees latitude

 

https://desinsectado...ler-pradera.pdf

 

Edited by kalimant, March 4 2020 - 5:28 PM.

[Mdrogun]

 

 

 

I'm pretty sure this species has made it to the coast of North Carolina, I have witnessed them there along the beach in summer and in some coastal cities maybe surviving the winter indoors?

 

 

The farthest north their range is known to extend, globally, is in a southern town in Western Turkey.

 

 

They have been known to occur farther north recently. The current record is at Barcelona, Spain, at 41 degrees latitude

 

https://desinsectado...ler-pradera.pdf

 

 

The specimen was fairly far south if I'm reading this correctly, and Europe also has a climate that is much warmer than NA at comparable latitudes. There is some kind of trans-Atlantic current that brings up warm tropical waters from the Caribbean, making Europe significantly warmer than it would otherwise be. I don't think it's impossible for them to survive in North Carolina, I just don't think it's likely. We have seen a lot of tropical species that were more cold tolerant than expected.

 

Either way, no concrete evidence has been found of them surviving outside in NC long-term, or in similar climates.

Edited by Mdrogun, March 4 2020 - 8:24 PM.

[Vendayn]

Well in a post above she kept Pheidole megacephala when she lived in Florida. Pretty common there.

 

As for soldier sizes. They actually adapt their sizes of soldiers based on how tough an enemy they are encountering. For example, in areas of no competitor (Argentine ants), soldiers are pretty small. On borders where they encounter Argentine ants, soldiers can actually get really big (almost compared to the size of an Argentine ant worker). So their size varies pretty greatly actually. And same with Solenopsis invicta or whatever tough competitor they end up going up against.

[Mdrogun]

Well in a post above she kept Pheidole megacephala when she lived in Florida. Pretty common there.

 

 

Either way, no concrete evidence has been found of them surviving outside in NC long-term, or in similar climates.

 

I have found Pheidole megacephala myself in Florida. I meant "outside" as in THE outside, haha. 

[kalimant]

The specimen was fairly far south if I'm reading this correctly, and Europe also has a climate that is much warmer than NA at comparable latitudes. There is some kind of trans-Atlantic current that brings up warm tropical waters from the Caribbean, making Europe significantly warmer than it would otherwise be. I don't think it's impossible for them to survive in North Carolina, I just don't think it's likely. We have seen a lot of tropical species that were more cold tolerant than expected.

 

 

Either way, no concrete evidence has been found of them surviving outside in NC long-term, or in similar climates.

 

 

Yes, the latitudes might be higher up, but the climate is somewhat different. I only noted Barcelona because you mentioned that Turkey at 40 degrees latitude is the highest reported sighting for the species.

 

[kalimant]

Well in a post above she kept Pheidole megacephala when she lived in Florida. Pretty common there.

 

As for soldier sizes. They actually adapt their sizes of soldiers based on how tough an enemy they are encountering. For example, in areas of no competitor (Argentine ants), soldiers are pretty small. On borders where they encounter Argentine ants, soldiers can actually get really big (almost compared to the size of an Argentine ant worker). So their size varies pretty greatly actually. And same with Solenopsis invicta or whatever tough competitor they end up going up against.

 

Do you have a paper reference for this? The only one I know was comparing multi continent populations. Bigger in Australia (supposedly due to stronger native ant competition), smaller in Hawaii, for example, and I have my doubts about that study.

https://academic.oup...3/2/423/2416021

[Vendayn]

 

Well in a post above she kept Pheidole megacephala when she lived in Florida. Pretty common there.

 

As for soldier sizes. They actually adapt their sizes of soldiers based on how tough an enemy they are encountering. For example, in areas of no competitor (Argentine ants), soldiers are pretty small. On borders where they encounter Argentine ants, soldiers can actually get really big (almost compared to the size of an Argentine ant worker). So their size varies pretty greatly actually. And same with Solenopsis invicta or whatever tough competitor they end up going up against.

 

Do you have a paper reference for this? The only one I know was comparing multi continent populations. Bigger in Australia (supposedly due to stronger native ant competition), smaller in Hawaii, for example, and I have my doubts about that study.

https://academic.oup...3/2/423/2416021

 

There is this that talks about that article

 

https://phys.org/new...ompetitors.html

 

Don't think it has anything to do with the continent, but what competitors they face up against.

 

And my own observations with the Pheidole megacephala here that I've watched past few years. The soldiers in conquered areas are pretty small, not a single soldier that is bigger. Where as when they border Argentine ant areas, the soldiers are quite bigger. I've seen the occasional soldier almost but not quite match the size of an Argentine ant worker. Seen them get pretty big. If the size isn't a response to the fierce competition of Argentine ants, then not sure what else would make sense. 

[gcsnelling]

One thing comes to mind as far as  major size goes, it is known that under conditions of heavy resource availability you get more and larger majors, fewer resources=fewer/smaller.

[kalimant]

There is this that talks about that article

 

 

https://phys.org/new...ompetitors.html

 

Don't think it has anything to do with the continent, but what competitors they face up against.

 

And my own observations with the Pheidole megacephala here that I've watched past few years. The soldiers in conquered areas are pretty small, not a single soldier that is bigger. Where as when they border Argentine ant areas, the soldiers are quite bigger. I've seen the occasional soldier almost but not quite match the size of an Argentine ant worker. Seen them get pretty big. If the size isn't a response to the fierce competition of Argentine ants, then not sure what else would make sense. 

 

 

 

Yes, that link references the same article. It was a global comparison of P. megacephala populations.

I think problems with that paper were:

(1)  They kinda assumed there was stronger biotic competition from australian native ants based on simply the notion that some of the native ants are  dominant ecologically and aggressive. Even though other studies showed P. megacephala had no problems decimating these ants when abiotic conditions were good for the species.

 

(2) They only sampled 5 countries

 

(3) They only sampled 6 or less "colonies" per country!

I am thinking those are really low sample sizes to make such sweeping statements.

 

[kalimant]

 

There is this that talks about that article

 

 

https://phys.org/new...ompetitors.html

 

Don't think it has anything to do with the continent, but what competitors they face up against.

 

And my own observations with the Pheidole megacephala here that I've watched past few years. The soldiers in conquered areas are pretty small, not a single soldier that is bigger. Where as when they border Argentine ant areas, the soldiers are quite bigger. I've seen the occasional soldier almost but not quite match the size of an Argentine ant worker. Seen them get pretty big. If the size isn't a response to the fierce competition of Argentine ants, then not sure what else would make sense. 

 

 

 

Yes, that link references the same article. It was a global comparison of P. megacephala populations.

I think problems with that paper were:

(1)  They kinda assumed there was stronger biotic competition from australian native ants based on simply the notion that some of the native ants are  dominant ecologically and aggressive. Even though other studies showed P. megacephala had no problems decimating these ants when abiotic conditions were good for the species.

 

(2) They only sampled 5 countries

 

(3) They only sampled 6 or less "colonies" per country!

I am thinking those are really low sample sizes to make such sweeping statements.

 

 

 

 

The study found no significant increase in number of majors in  areas with stronger competition, which I'll be honest seems the better thing to do than making the majors sightly bigger.

If you look at the graphs for increased body size in majors, the only one that showed real increase was in Australia. Even though Florida is supposedly very competitive, the increase in major mass there is almost same as in Hawaii. That seems to me more like an outlier effect, where either the genetic bottleneck that occurred in australia or some environmental condition in Australia has caused increases in both major and minor sizes.

https://academic.oup...86-fig-0002.png

[Vendayn]

I think its more like GCsnelling said actually and has more to do with diet. The colonies here started fighting again, and despite being on the border of Argentine ant territory the soldiers are kinda small. Last year they were a lot bigger. And since Winter just passed, it would make sense they'd have small soldiers with less food. Maybe temperature could play a part too?

 

Tbh, it would make more sense to produce more soldiers than just bigger soldiers. In any case, doesn't sound like the study was very thorough.