6 replies to this topic

[futurebird]

 

This photo is from a youTube video, not mine. You can see it here.

 

It's late summer and the sidewalk wars are a common sight. Mostly it's pavement ants, often the same species two colonies that have expanded until they overlap. Then a battle begins. If you look closely the ants are mostly in pairs, locking jaws... it goes on for days. 

 

It seems like madness to do this at the time of the year when colonies need to be getting ready to overwinter. I've heard some people say that "not many ants die in these battles" but when I filmed a battle like this I saw plenty of dead ants. Also... the ants are exposed. They could get eaten by predators, or stepped on more easily due to the whole colony being turned out on the sidewalk. 

 

But it got me thinking? Is this ... normal?

 

Every time I've seen this it's been on a sidewalk, often one near a sprinkler or other easy water source, and near human activity and the high calorie food that we drop all over the place. Add to that the shelter and warmth of a sidewalk... the perfect giant flat rock with sand underneath and you have a perfect pavement ant habitat. Almost too perfect. 

 

My theory is that under these conditions these colonies grow to massive size. And the sidewalk means that you have a whole string of colonies in a row one after the other, all with ideal food and water and shelter. So not only do the colonies grow large, but the number of colonies in a region is very dense. 

 

And so when a conflict starts it just grows and grows. Normally two huge colonies would never be so close in the wild. 

 

I guess my question is do battles happen on this scale and density in the wild?

 

If not then maybe the lawns, sidewalks and trash of human environments are the real cause of these "epic battles"

[m99]

I bet it's definitely exacerbated by invasive-friendly environments like a neighborhood sidewalk, for sure. The nature of the ecosystems that let the species get invasive to begin with make it "unnaturally" successful just by living where it does, in that sense.

 

But overall I think it's legitimate to say few ants die. Even if you were to see the battlefield in that picture littered with corpses afterward, it would still only represent some hundreds of casualties in a conflict that appears to easily contain 5-10k+ combatants, which you'd have to guess means the colonies themselves are easily twice as big on top. In which case it really would be a very low-risk activity, relatively speaking. Also, if I'm not mistaken, in a case like pavement ants they're actually dealing with a surplus of population right now after the height of summer activity, and are such omnivorously successful foragers that they're not really scrambling for winter stores, so losing some "dead weight" would be a bonus and relieve some resource requirements for the colony over winter.

 

I know in honeybees pre-winter is often a period of heavy culling, where drones are ejected from the hive and the oldest or least healthy bees often decide to take their suicide/funerary flights even if they're not actually on death's door yet, just to stop the hive from having to feed them anymore of the winter carbohydrate stores, which would make an argument for an evolutionary benefit to seasonal population culling in similar eusocial insects.

[Manitobant]

It is completely normal. Tetramorium immigrans are fiercely territorial, and colonies often engage in huge wars over territory boundaries.

[antgallery]

Somehow I've never seen a war, only the aftermath with huge piles of dead workers. Pretty crazy.

[Kaelwizard]

I saw a couple wars back in Michigan. It probably has to do with their extremely territorial behavior combined with colonies living in close proximity with one another.

[Formiga]

About one month ago, peak summer in the place where I've caught my queens, I've seen a couple of Formica fusca colonies fighting. Their entrance holes were less than a meter apart and even with not so many in numbers, the fight was fierce with a few dead and wounded. Impressive!

 

I'm just wondering if there are any underground fights. I've seen so many entrance holes so next to each other every once in a while while digging and expanding their colonies they should break into their neighbors'.

[KadinB]

I see wars all the time. There not cool at all to me because I see them all the time. Tetras are really common here in nor cal. I have found them in every city around me. If I see one I just look at it for a sec and then leave it and go back inside lol.