22 replies to this topic

[Kowal]

Current is enough, a bit too spacious, even. The colony is in full maturity mode - they invest in workers only as much as it is needed to upkeep a healthy population, all excess food ends up being used for alates. 

[Kowal]

Ninth, and unfortunately last season

 

On 2024.11.04 I took the ants out of my fridge. Immediately I noticed unusually high amount of dead ants, but I did not think much of it at first. This is an old colony, deaths of old age are a part of life of a mature, stable sized colony. There were some dead alates too, but still - I just thought that I did not keep the humidity high enough, but each diapause I was adding just few mililiters, so I though that missing a tiny bit couldn't do much harm.
Unfortunately, after connecting the outworld a more grim picture has been painted. No activity in the outworld for first few hours, not a single scout. Only a single male made his way out and looked more like he did it by mistake, and couldn't find the way back. In following days alates started doing their usual thing - males started flying like crazy, females clumsily searched for a suitable starting spot, but I saw just two workers being active in the outworld, and no cleaning being done in the nest. The piles of dead bodies were left to rot where they died. 

 

Alates apparently were hungry and thirsty, and it turns out that when there are no workers to feed them, they are capable of eating on their own. This isn't extremely surprising to me, but considering that a Dolichoderus quadripunctatus winged gyne following a worker trail and drinking honeydew together with workers was sensational enough to write a peer reviewed paper about it, I want to share these materials with you:

Alates of both sexes drank both honey and water. The test tube was emptied far quicker than it would be evaporating on its own, and honey would not disappear completely if it wasn't eaten. I am certain that it wasn't the workers who were sneaking out at night and eating it all, as I observed practically no worker activity at any hour, not even inside the nest. Of course, the nest is full of chambers invisible to me - but I know these ants, I know that if there were any scouts, I would see them next to the honey tray.

 

After a month alate activity has ceased. Outworld was full of dead bodies, mostly of males, and just a handful of females had been wandering around. Some of them were wingless - but I have absolutely zero doubt about their fertility status, by now I am certain that they simply cannot mate with their brothers in an outworld this small.
Today I decided to clean the outworld and tear down the nest, bit by bit I opened every unseen chamber. I did count bodies of alates, both in outworld and in the nest. Unfortunately I did not count the worker bodies - I was so used to counting only the alates that the thought about actually learning the number of workers, after years of guesstimating it, simply did not occur to me before a first batch of trash containing worker bodies landed in the trash bin. 

What I have learned:

I found 642 dead males, more than half of which were in the outworld. I think it is safe to assume that due to no signs of cleaning the nest of dead bodies, if something was found dead in the outworld, it can be considered to be still alive after the winter and dying out there later.

I found 71 dead gynes. This is far less than males, possibly not heating them has affected the sex ratio, or due to less consistend protein feeding last season, or just due to poor condition of the colony - it's possible the current problem has already existed before winter but I missed the cues. 

Some of the gynes were wingless. I did not do exact count, but I did not feel that there's a correlation between still having wings and surviving. 

I found just a few dead workers in the outworld. I can't tell whether they walked out and died, or whether their bodies were removed from the nest. I found a whole lot of dead workers inside the nest, and I estimate that there were less than 500 of them, definitely under a thousand. This is less than I expected based on what I saw in the nest in previous season. 

I found two chambers which contained dried up larvae. In one of them, to my surprise, I found few live workers! I thought there were 3, but later I could only see 2. Few queens, including wingless, were present in this chamber. If (and that's a big IF) the original, fertile queen is still alive, I think it is very likely it was one of those.

 

This is an example of a chamber which was impossible to peek inside before tearing the front off. I could see some holes leading to such chambers, but I did not even know the extent of them. If you ever find yourself keeping these ants, I think cork is still best nesting material, but keep in mind that they will hide from your view even in thin pieces of material.

 

So, after tearing down the nest I was left with less than 20 wingless gynes, two workers, and a bunch of dried larvae. I saw some of the queens gathering them up, so perhaps they are not fully dried? Or they just can't cope with the collapse of the colony and refuse to leave the long dead larvae, as they still smell like family.

Yes, this bunch of ants is really what's left of the colony. It's a shameful, terrible sight. I have no hopes of them ever recovering, even though I spotted something resembling a fresh egg or a healthy larva among the dried larvae. I will, of course, provide them shelter and food. I still am not sure what role do the wingless queens perform in the colony - I haven't ever seen them doing any work, in the past they mostly hanged around close to nest entrance like guards (I have seen wild colonies do that too) and store food, so a bit like majors, but majors will sometimes perform other tasks too. If they are not capable of foraging and bringing back protein, then this whole colony would rely on two workers - I don't think this has any chance of success.

 

So, to summarize - the most likely cause of this situation is me failing to moisten the nest during diapause. But the bizarre pattern of who died is puzzling, I can't wrap my head around it. If too low humidity was the cause of the collapse, then I would expect the winged individuals to be at disadvantage, since wings are a big piece of surface area to evaporate your moisture from. But the alates were the one which mostly survived, only the wingless caste was wiped out almost completely. Perhaps workers shared last bits of their water reserves selflessly to alates, which are their chance of spreading genes? 
 

Edited by Kowal, December 7 2024 - 2:48 PM.

[Kowal]

Interesting. The small bunch of wingless queens and two workers are not giving up completely. They gathered up the dried, withered larvae and are not willing to throw that out, but apart from that, they're laying a lot of fresh eggs. One of them has hatched, seen on the right, under a queen. 

 

I am still not having hopes for them, but all queens I separated in previous seasons, even if laid any eggs, never cared for them, letting them dry out. Only once I had any of them reach larval stage of her offspring - when I boosted her with worker pupae. She was still behaving very aggressive, being the first one to exit nest part of her test tube and attack fresh food (not eat it, attack it). This bunch is... calm. I think there is a high chance the OG queen is among these worker-queens. Time will tell whether they will forage for food and raise a new workforce, or at least share enough of their own resources without sneaking in own sons.