17 replies to this topic

[futurebird]

I noticed some people on YouTube talking about videos of "army ants" but I was disappointed when they ants were not a species of dorylus. I (incorrectly) thought that only dorylus were true army ants. But it seems this name is more expansive and interesting than I thought. Being in an army is a way of life... not just a genetic group. But what are the essential characteristics of army ants? My current understanding:

• They need to march, well, like an army. They should not have permanent nests. But they don't need to form a bivouac necessarily. They could be mobile moving from treehollows to rock shelters instead. 
• Unlike most ants army ants reproduce by splitting their colonies when they are large. Virgin queens who have no wings wait for the flying males to find them. The males are brought into the nest to mate.

Is there anything else?
 
This is a fascinating and seemingly effective evolutionary strategy. The most resource expensive colony members are not exposed. But perhaps there is a reason that only highly mobile colonies use this reproductive strategy. I've often wondered why "sausage flies" the male army ant are so large. They are smaller than the queens, but why not have super tiny males? Then they could produce more of them and one or two from a batch might have a better chance of finding a mate... This seems evolutionary extravagant to me look at how fat he is!


Alex Wild conveys the scale of these fatties in this great photo. Source: http://www.myrmecos....sense-of-scale/

I wonder in general why male ants don't take the super small route. They are often smaller than the queen and the advantage is obvious. Colonies with smaller males could produce more males.  They can fly better than queens since they have less body mass. But male ants tend to be about 1/5 up to 1/2 the size of queens... you don't see male ants that are 1/20 the size of the queens even though ant biology can easily produce such extreme size differences within the same family. So why aren't male ants even smaller?

 

Do they need the size to muscle other male ants out of the way? Do they need body fat reserves to last a little longer and search a little further?

 

And why are "army ant" males so big ... relatively speaking?

Edited by futurebird, August 9 2021 - 4:41 AM.

[SYUTEO]

Usually any species of ant in the subfamily Dorylinae are classified as true army ants, and most of the time, their queens are wingless and have huge gasters. The workers are usually very small ranging from just 2mm to 1cm while queens can get up to 2 inches an they also need to produce a LOT of eggs (some species can lay up to 500,000 eggs a day) which may explain why the males are also huge.

[TennesseeAnts]

Like SYUTEO noted, "true" army ants are anything in the Dorylinae subfamily. Technically their queens aren't true queens, either. They're known as a dichthadiigyne, which is basically a modified worker, born wingless with many more ovaries.

[futurebird]

Huh. So in a way I was right... but still it's generally fine to call others that meet the two criteria "army ants" ... also... still thinking about why are the army ant males so big.

[TennesseeAnts]

No, only Dorylines can be true army ants. Others such as Carebara diversa are commonly called army ants, but have no relation to Dorylinae.

[Manitobant]

There are some dorylines that aren’t army ants, such as cerapachys. Army ants are characterized by three things: group predation, dichthaadiform queens and nomadism

[futurebird]

I found some possible reasons for the males being so large (for male ants)

 

"Males that are favoured are superficially similar in size and shape to the queen. The males also produce large quantities of pheromones to pacify the worker ants"

 

In army ants the males are selected by the workers so playing on the worker's positive attitude to a queen may play a role. 

 

https://academic.oup...edFrom=fulltext

[Mettcollsuss]

The way I've understood it is that only dorylines can be army ants, but not all dorylines are army ants. The ones that I would personally refer to as army ants would be Dorylus, Eciton, Aenictus, Labidus, Neivamyrmex, Nomamyrmex, and maybe Cheliomyrmex. They meet the criteria already listed. There also seem to be two different general body shapes for dorylines. One looks sort of myrmicine - longer legs and a constricted 3rd abdominal segment. The other looks sort of ponerine - more elongate and cylindrical body and shorter legs. The "true" army ant dorylines seem to mostly belong to the former group. Looking at this phylogeny tree it looks like all the "true" army ants come from the same side of the tree.

[KadinB]

Usually any species of ant in the subfamily Dorylinae are classified as true army ants, and most of the time, their queens are wingless and have huge gasters. The workers are usually very small ranging from just 2mm to 1cm while queens can get up to 2 inches an they also need to produce a LOT of eggs (some species can lay up to 500,000 eggs a day) which may explain why the males are also huge.

sounds like a termite queen


Sent from my iPhone using Tapatalk

[TestSubjectOne]

 

I wonder in general why male ants don't take the super small route. They are often smaller than the queen and the advantage is obvious. Colonies with smaller males could produce more males.  They can fly better than queens since they have less body mass. But male ants tend to be about 1/5 up to 1/2 the size of queens... you don't see male ants that are 1/20 the size of the queens even though ant biology can easily produce such extreme size differences within the same family. So why aren't male ants even smaller?

 

Do they need the size to muscle other male ants out of the way? Do they need body fat reserves to last a little longer and search a little further?

 

And why are "army ant" males so big ... relatively speaking?

 

 

 

 

This is just a shot in the dark, but perhaps the males are so large due to sexual selection? A queen, or the workers that choose her mate, don't care whether or not the male's home colony wasted a  of bunch of resources on making him but by choosing a larger male they have the assurance that his colony is successful enough to have a large amount of spare resources and therefore he will likely have better genes. If males are selected this way then it would make sense for colonies to invest in larger males which are more likely to find a mate despite it being inefficient.

[cosmickalamity]

This thread is why we don’t use common names

[Idontexist]

I noticed some people on YouTube talking about videos of "army ants" but I was disappointed when they ants were not a species of dorylus. I (incorrectly) thought that only dorylus were true army ants. But it seems this name is more expansive and interesting than I thought. Being in an army is a way of life... not just a genetic group. But what are the essential characteristics of army ants? My current understanding:

• They need to march, well, like an army. They should not have permanent nests. But they don't need to form a bivouac necessarily. They could be mobile moving from treehollows to rock shelters instead.
• Unlike most ants army ants reproduce by splitting their colonies when they are large. Virgin queens who have no wings wait for the flying males to find them. The males are brought into the nest to mate.

Is there anything else?

This is a fascinating and seemingly effective evolutionary strategy. The most resource expensive colony members are not exposed. But perhaps there is a reason that only highly mobile colonies use this reproductive strategy. I've often wondered why "sausage flies" the male army ant are so large. They are smaller than the queens, but why not have super tiny males? Then they could produce more of them and one or two from a batch might have a better chance of finding a mate... This seems evolutionary extravagant to me look at how fat he is!


Alex Wild conveys the scale of these fatties in this great photo. Source: http://www.myrmecos....sense-of-scale/

I wonder in general why male ants don't take the super small route. They are often smaller than the queen and the advantage is obvious. Colonies with smaller males could produce more males. They can fly better than queens since they have less body mass. But male ants tend to be about 1/5 up to 1/2 the size of queens... you don't see male ants that are 1/20 the size of the queens even though ant biology can easily produce such extreme size differences within the same family. So why aren't male ants even smaller?

Do they need the size to muscle other male ants out of the way? Do they need body fat reserves to last a little longer and search a little further?

And why are "army ant" males so big ... relatively speaking?

eciton.

[Manitobant]

I noticed some people on YouTube talking about videos of "army ants" but I was disappointed when they ants were not a species of dorylus. I (incorrectly) thought that only dorylus were true army ants. But it seems this name is more expansive and interesting than I thought. Being in an army is a way of life... not just a genetic group. But what are the essential characteristics of army ants? My current understanding:

• They need to march, well, like an army. They should not have permanent nests. But they don't need to form a bivouac necessarily. They could be mobile moving from treehollows to rock shelters instead.
• Unlike most ants army ants reproduce by splitting their colonies when they are large. Virgin queens who have no wings wait for the flying males to find them. The males are brought into the nest to mate.

Is there anything else?
This is a fascinating and seemingly effective evolutionary strategy. The most resource expensive colony members are not exposed. But perhaps there is a reason that only highly mobile colonies use this reproductive strategy. I've often wondered why "sausage flies" the male army ant are so large. They are smaller than the queens, but why not have super tiny males? Then they could produce more of them and one or two from a batch might have a better chance of finding a mate... This seems evolutionary extravagant to me look at how fat he is!
Alex Wild conveys the scale of these fatties in this great photo. Source: http://www.myrmecos....sense-of-scale/
I wonder in general why male ants don't take the super small route. They are often smaller than the queen and the advantage is obvious. Colonies with smaller males could produce more males. They can fly better than queens since they have less body mass. But male ants tend to be about 1/5 up to 1/2 the size of queens... you don't see male ants that are 1/20 the size of the queens even though ant biology can easily produce such extreme size differences within the same family. So why aren't male ants even smaller?
Do they need the size to muscle other male ants out of the way? Do they need body fat reserves to last a little longer and search a little further?
And why are "army ant" males so big ... relatively speaking?

eciton.

thanks captain obvious.

[Idontexist]

True army ants include: bts stans
True army ants include: bts stans
True army ants include: bts stans

[FloridaAnts]

I noticed some people on YouTube talking about videos of "army ants" but I was disappointed when they ants were not a species of dorylus. I (incorrectly) thought that only dorylus were true army ants. But it seems this name is more expansive and interesting than I thought. Being in an army is a way of life... not just a genetic group. But what are the essential characteristics of army ants? My current understanding:

• They need to march, well, like an army. They should not have permanent nests. But they don't need to form a bivouac necessarily. They could be mobile moving from treehollows to rock shelters instead.
• Unlike most ants army ants reproduce by splitting their colonies when they are large. Virgin queens who have no wings wait for the flying males to find them. The males are brought into the nest to mate.

Is there anything else?
This is a fascinating and seemingly effective evolutionary strategy. The most resource expensive colony members are not exposed. But perhaps there is a reason that only highly mobile colonies use this reproductive strategy. I've often wondered why "sausage flies" the male army ant are so large. They are smaller than the queens, but why not have super tiny males? Then they could produce more of them and one or two from a batch might have a better chance of finding a mate... This seems evolutionary extravagant to me look at how fat he is!
Alex Wild conveys the scale of these fatties in this great photo. Source: http://www.myrmecos....sense-of-scale/
I wonder in general why male ants don't take the super small route. They are often smaller than the queen and the advantage is obvious. Colonies with smaller males could produce more males. They can fly better than queens since they have less body mass. But male ants tend to be about 1/5 up to 1/2 the size of queens... you don't see male ants that are 1/20 the size of the queens even though ant biology can easily produce such extreme size differences within the same family. So why aren't male ants even smaller?
Do they need the size to muscle other male ants out of the way? Do they need body fat reserves to last a little longer and search a little further?
And why are "army ant" males so big ... relatively speaking?

eciton.

thanks captain obvious.

Doesn’t really answer the question, but here is a neat documentary(short) on the mating. Sorry if you don’t find it interesting

Edited by FloridaAnts, May 28 2022 - 2:35 PM.

[FloridaAnts]

 

I wonder in general why male ants don't take the super small route. They are often smaller than the queen and the advantage is obvious. Colonies with smaller males could produce more males.  They can fly better than queens since they have less body mass. But male ants tend to be about 1/5 up to 1/2 the size of queens... you don't see male ants that are 1/20 the size of the queens even though ant biology can easily produce such extreme size differences within the same family. So why aren't male ants even smaller?
 
Do they need the size to muscle other male ants out of the way? Do they need body fat reserves to last a little longer and search a little further?
 
And why are "army ant" males so big ... relatively speaking?

 
This is just a shot in the dark, but perhaps the males are so large due to sexual selection? A queen, or the workers that choose her mate, don't care whether or not the male's home colony wasted a  of bunch of resources on making him but by choosing a larger male they have the assurance that his colony is successful enough to have a large amount of spare resources and therefore he will likely have better genes. If males are selected this way then it would make sense for colonies to invest in larger males which are more likely to find a mate despite it being inefficient.

If I remember correctly, in ants that have nuptial flights, larger males mate with larger females, and to guarantee this, larger queens apparently fly further to guarantee a stronger male.

[mmcguffi]

https://twitter.com/...517776748519424

[Tyr_Ants]

They're not real they don't exist, wake up