14 replies to this topic

[RushmoreAnts]

Parasitic Slave-Raiding Formica

Formica sanguina group

Update 1

August 8, 2024

 

Ants_Dakota was camping in Custer State Park in the Black Hills of South Dakota. He came across the tail end of parasitic Formica flights, and caught several queens. He was kind enough to give me the queens he didn't want, so here we are. Shout out to AUD! Anyways, I have two species, both in the sanguinea group, which for now I'm going to call Formica cf. aserva and Formica cf. subintegra. We originally believed they were integra group, so we attempted polygyne, which resulted in the death of a couple queens. I have two of the cf. aserva queens and one of the cf. subintegra queens. AUD only wanted a shinier one that is also presumably in the sanguinea group, as he doesn't want to be completely loaded up with Formica colonies. His was one of the healthier queens. I introduced Formica fusca group host pupae to all of the queens, and they all began to groom them and transport them to the furthest reaches of their test tubes. The cf. subintegra queen seems the healthiest to me, and interestingly her host pupae are naked. Two workers have eclosed so far, with 6 more on the way. She has a total of 25 host brood including a couple larvae they are caring for. The cf. aserva queens have roughly 10 cocooned pupae each. I absolutely love parasitic Formica. While I think pallidefulva group queens are more beautiful per se, I can't get over the robust, aggressive look of sanguinea group Formica. These queens, unlike most others I've kept, seem to have personality. They're quick, nimble, aggressive, and have great eyesight, all of which contribute to their exaggerated-looking movements and behaviors. They seem to be looking at you - watching you - probably because they are. I'm super excited to keep these queens and am hoping they lay eggs before hibernation.

 

Formica cf. aserva Colony A

 

 

 

 

 

 

Formica cf. aserva Colony B

 

Formica cf. aserva Colony B 8/6/2024 (youtube.com)

 

 

 

 

Formica cf. subintegra

 

 

 

Edited by RushmoreAnts, April 28 2025 - 8:34 PM.

[OwlThatLikesAnts]

Are they like rufa where they can live all by themselves after the slaves die out?

[RushmoreAnts]

Are they like rufa where they can live all by themselves after the slaves die out?

They're parasitic, not slave raiders. They need host workers to found their colonies, that's it. Their own workers are self-sufficient.

[Ants_Dakota]

For those experienced with the Formica genus, you can help us ID these queens here.

[RushmoreAnts]

Update 2

December 7, 2024

 

Well, it turns out people actually know what they're talking about after all... These queens, who I discovered are actually sanguinea group slave raiders thanks to Mettcollsus, do not, in fact, lay eggs before hibernation. I have not updated this journal because these colonies have done absolutely nothing noteworthy besides eat and wait. At the end of October, I put them into hibernation along with my Claustral Formica, only taking them out now to film them. I will take them out of hibernation on March 15, as mid-October to mid-March is typically the duration of a South Dakotan winter, or as close to typical as our weather will ever get. I've seen high 60s F in December and snow in May. But for a hibernation schedule, it works.

 

Formica cf. aserva Colony A

These queens ended up eating most of their pupae, as I think I gave them too many originally. This one ended up with 8-9 full-sized, fat host workers, ready for nursing duty come spring.

 

 

Formica cf. aserva Colony B

Well, this queen never ended up opening her pupae and died a few weeks later. At least I still have one...

 

Formica cf. subintegra

Ok, I'm still not sure on the species of this one, just that it's in the sanguinea group. I'm calling it cf. subintegra for now. She only ended up with 4 host workers, and I may give her more host pupae in the spring.

 

Edited by RushmoreAnts, December 7 2024 - 8:47 PM.

[RushmoreAnts]

Update 3

March 22, 2025

 

I'd like to offer an apology for this journal: last year was boring! I've never kept Slave-Raiding Formica before. While I had read they usually wait until spring to lay eggs, I wanted to make the journal anyways just in case, although that just made the journal stagnant for many months.

 

THAT BEING SAID, stagnation is now with us no more! Any questions about their health and vitality are now resolved. I took both colonies as well as my Claustral Formica colonies out of hibernation on 3/14. I began heating them on 3/16 and feeding them honey-water and mealworms on 3/17. As soon as they awoke, they hit the ground running. They're ready and rearing to make waves this season!

 

As I documented in my Claustral Formica journal, I moved the pallidefulva and incerta colonies into new nests due to test tube drying. However, I only had 1 small heating pad for them and the slave-raiding colonies, so I had to get creative about space:

 

 

 

I thought the setup resembles a Y-Wing fighter from Star Wars, so I'll refer to this group of four colonies as the Y-Wing Complex. The Left Outworld/Bottom Test Tube is the aserva, and the Right Outworld/Top Test Tube is the subintegra.

 

 

Formica cf. aserva

 

HIBERNATION STATS:

   - Ingoing Host Worker Count:   9

   - Outgoing Host Worker Count: 9

   - Total Casualties:                    0

 

This queen wasted absolutely no time. They were the first to become active even before I put them on heat, and practically the moment I did heat them she began pumping out eggs like she was holding them in all winter. She laid well before I even fed them. After I did feed them, the workers gorged themselves, making themselves as close to repletes as Formica can get. I fed them a mealworm head, and they dragged it into their test tube. I believe the egg count only increased from there. I ran a picture of their egg pile through Antcounter by Barristan, a highly effective tool, where you can, as the name suggests, counts ants manually (and in this case, brood). The total which was visible in the photo came out to 40. Considering they have 9 host workers, proportionally this is one of the most impressive egg piles I have ever seen. The bio population will be almost quintuple that of the host population if, as Canadian Anter points out, the hosts don't rebel and start killing the brood. I believe they've spent enough time with the queen to avoid that, yet I won't discount the possibility until an overwhelmingly large generation of bios eclosing essentially seals the hosts into their servitude. But I will continue to remain optimistic, and I am quite excited for this colony in particular.

 

 

 

 

 

 

 

 

Formica cf. subintegra?

 

HIBERNATION STATS:

   - Ingoing Host Worker Count:   4

   - Outgoing Host Worker Count: 4

   - Total Casualties:                    0

 

Despite not having as many host workers as their cousins, this colony is still doing impressive things. They have an egg pile of roughly ~15 eggs, which proportionally is around the same as the aserva. In every other metric, they're doing just as well as the aserva: they're eating well, active, and diligently taking out their trash and organizing debris like the aserva. I also have high hopes for this colony.

 

However, I do hope it's not subintegra as I originally guessed. Nare describes subintegra as the only confirmed obligate slave raider in the sanguina group, i.e. they need a constant supply of host workers to function as a colony. aserva have proven in captivity and in the wild that they can easily be independent from host workers when the need arises, yet subintegra is the opposite. I'm going to treat them like a facultative (doesn't need hosts after founding) species like aserva and hope for the best. Hopefully I can buy a better camera this summer and get a positive ID on both species.

 

Sorry for the poor camera quality, there's quite a bit of condensation in their tube:

 

Edited by RushmoreAnts, March 23 2025 - 11:29 AM.

[RushmoreAnts]

Update 4

April 6, 2025

 

Well, that was fast. Both of these colonies' brood is developing at breakneck speeds, and so far, it appears they're on track to beat my claustral Formica colonies.

 

Formica cf. aserva

We have pupae! The first larvae to hatch took only about a week to fully develop, and two have already pupated, and one is in the process of spinning its cocoon. In total, the colony has around 20 larvae and pupae, as it appears around half of the eggs were trophic (unfertilized & for consumption). As other keepers of slave-raiding Formica have pointed out, the first generation will consist of small, weak minors in order to pacify the host workers, who might otherwise be threatened by the foreign pheromones and normally menacing stature of a full-sized Formica aserva worker or major. Host workers have been known to kill the bio callows as soon as they eclose, and I'm hoping this won't be the case. If this first generation develops properly, we'll be all set!

 

 

 

 

 

 

That's not a Tetra escapee, you're a Tetra escapee.

 

 

I love how the colony appears to revolve around that cricket skull.   

 

 

Formica cf. subintegra?

This colony chose to devote all of their resources to three larvae, all of which look almost ready to pupate, while the rest of the larvae look like they hatched yesterday. This colony looks like it will raise 10-15 bio workers in its first generation, which makes sense considering they have half the host worker population.

 

 

The queen is noticeably more skittish than the aserva queen, immediately evacuating the nest and going for a stroll around the outworld. I've even seen her foraging on a couple occasions. Perhaps it's the difference in species? Or perhaps it's the difference in host worker population? I hope it's not a difference in fertility (it doesn't seem to be, she's plenty fertile from the looks of it). Either way, it's entertaining and amusing to observe the queen being the boldest, most adventurous ant in that colony.

 

Edited by RushmoreAnts, April 6 2025 - 12:55 PM.

[RushmoreAnts]

Update 5

April 19, 2025

 

Things just got interesting. The aserva may be in jeopardy and the 'subintegra' may not be what any of us thought!

 

Formica cf. aserva

I am both excited and apprehensive about this colony. Shortly after last update, the colony had 20 pupae. Since then, the host workers have destroyed half of them, leaving only 10. I'm not rounding these numbers either; it was exactly 20 and exactly 10. Formica must have a base 10 counting system.   Of the 10 remaining pupae, however, several are starting to darken and appear like they may eclose soon. So, I am apprehensive that the hosts may kill off the rest of the pupae, yet excited that several of these pupae are so close to eclosing and may have a shot. Even if only a few bio workers eclose, they will force some of the hosts into outworld duty, which will allow even more of the next generation which the queen just laid a few days ago to survive. 

 

 

 

 

 

 

Remains of dead pupae.

 

Formica cf. talbotae???

This colony took a HUGE turn from their sister colony. While the aserva invested into many small workers, this colony put all their eggs into one basket (no pun intended). That basket just so happens to be an alate??? That's right. They ate all other brood (she laid more since) and produced one single massive alate pupa. Not sure if it's a queen or a male, as Formica alates are actually similar in size to one another. Either way, this (likely) means that 1. the queen is unmated or 2. she is a workerless inquiline. A permanent inquiline is a parasitic species that doesn't kill the host queen, instead tolerating the host queen(s) in a multi-species polygyne and producing her own offspring alongside the hosts. A workerless inquiline is the same except they only produce queen and male alates, which the host colony will raise and release in their next nuptial flight. According to AntWiki, the only known workerless inquiline in the genus Formica is Formica talbotae, which I am assuming this queen is for now. The only normal inquiline (ones that produce workers) is Formica exsectoides, although even if she was a normal inquiline she would still, as the definition suggests, produce workers instead of jumping right to alates. If she is a workerless inquiline and not simply unmated, I am still going to keep them anyways. Unmated queen alates often drop their wings and act like workers, and I would be interested to see if raising a colony of only queen-workers would be possible. I will document that progress further in future updates.

 

 

 

Edited by RushmoreAnts, April 19 2025 - 7:09 PM.

[Nare]

As far as I remember, F. talbotae is associated with F. obscuripes, so I expect it to be in the integra-group. I can't really tell much about your queen though. In post #6 the thing you labelled as subintegra gives me sanguinea-group vibes, but then from post #7 in the queen's morning jog video I'm getting integra-group vibes, based on the slimmer proportions and the way she holds herself a bit higher. This is by no means a formal ID just a vibe check. If you can get a nice shot of her face so that I can check for a clypeal notch I'll be able to confirm if she's integra-group or sanguinea-group.

 

I guess the other thing to check is if the pupa is as large as the queen or not. If it's smaller, we're probably talking a male.

 

Also curious about where you got F. exsectoides being an inquiline from? I know it's fighting over semantics but I guess the implication is that they've been found in nests with the host queen still alive? I'm curious to see where that was reported because as far as I know the exsecta-group in North America are fairly integra-like in their behaviour, in that they spread through parasitism but also (and maybe primarily depending on locale?) by colonial budding. Them leaving the host queen alive would be news to me assuming it isn't just a fluke - especially given the offensive equipment those queens come with.

[RushmoreAnts]

As far as I remember, F. talbotae is associated with F. obscuripes, so I expect it to be in the integra-group. I can't really tell much about your queen though. In post #6 the thing you labelled as subintegra gives me sanguinea-group vibes, but then from post #7 in the queen's morning jog video I'm getting integra-group vibes, based on the slimmer proportions and the way she holds herself a bit higher. This is by no means a formal ID just a vibe check. If you can get a nice shot of her face so that I can check for a clypeal notch I'll be able to confirm if she's integra-group or sanguinea-group.

I will try to get a better shot of her later today.

 

I guess the other thing to check is if the pupa is as large as the queen or not. If it's smaller, we're probably talking a male.

 

Well, the pupa is roughly the same size as the queen. It may be 1 mm smaller or so, I figured that may be due to the fact that pupae are curled up.

 

Also curious about where you got F. exsectoides being an inquiline from? I know it's fighting over semantics but I guess the implication is that they've been found in nests with the host queen still alive? I'm curious to see where that was reported because as far as I know the exsecta-group in North America are fairly integra-like in their behaviour, in that they spread through parasitism but also (and maybe primarily depending on locale?) by colonial budding. Them leaving the host queen alive would be news to me assuming it isn't just a fluke - especially given the offensive equipment those queens come with.

It was listed as a permanent inquiline in this AntWiki page.

[RushmoreAnts]

If you can get a nice shot of her face so that I can check for a clypeal notch I'll be able to confirm if she's integra-group or sanguinea-group.

These are the best I could get:

 

 

 

 

 

 

[Nare]

 

If you can get a nice shot of her face so that I can check for a clypeal notch I'll be able to confirm if she's integra-group or sanguinea-group.

These are the best I could get:

 

 

 

 

 

 

 

Nice pictures - there's definitely a clypeal notch so she's sanguinea-group. We'll have to wait and see what the pupa is then but my money's on a male. Doesn't mean all the rest of the brood is infertile though, again just have to wait and see - fingers crossed. You can probably ID her from the clypeal notch and the margin of the petiole node (looking at it down her back from over her head) to species level.

[RushmoreAnts]

Update 6

April 28, 2025

 

Both colonies have stabilized since the past update. The future is looking bright for my slave-raider collection!

 

Formica cf. aserva

We have BIOS!!   This is currently the first time I have ever raised a parasitic or slave-raiding species to biological workers. After the dust settled, 9 bio workers emerged. They only killed one worker right after it eclosed, which is great for securing the future generations. I knew the bio workers were supposed to be small, but I was not prepared for how tiny these ants are! They are barely bigger than large Tetra workers and seem to be smaller than all other Formica nanitics. Now with only 6 host workers left, the colony is suddenly majority bio workers, meaning less host workers are caring for the brood, meaning less new bios will be killed.

 

Speaking of brood, the colony wasted no time in pushing forward the next generation. There are currently around 30 brood, about 15 eggs & small larvae, and 15 medium/large larvae. I hope they all develop into workers, although if some are trophic/still killed, I hope this time this generation stabilizes at at least 20. They dragged a cornucopia of insects into the nest to support the new generation of larvae. 

 

 

Formica cf. subintegra

Turns out I was wrong last update, though I'm not too disappointed. This colony is not a workerless inquiline, as the new brood is pupating, and they are clearly worker pupae. There are around 25 larvae and pupae as well as the alate (presumably male) pupa. This is excellent news, as this was the number of brood the aserva colony originally developed. So basically, they're doing just as well as the aserva while they have half the host workers (and are a little behind timewise). They should have bios within a couple weeks. Stay tuned!

 

Edited by RushmoreAnts, April 28 2025 - 8:35 PM.

[OwlThatLikesAnts]

The size difference between the nanitics and mature workers in the Formica genus is wild. Also I’d like to point out that you may have like 15 eggs but then sooner or later  you find yourself with 40 small larva. (This is exaggeration)

Edited by OwlThatLikesAnts, April 29 2025 - 5:26 AM.

[Ants_Dakota]

 

 

If you can get a nice shot of her face so that I can check for a clypeal notch I'll be able to confirm if she's integra-group or sanguinea-group.

These are the best I could get:

Nice pictures - there's definitely a clypeal notch so she's sanguinea-group. We'll have to wait and see what the pupa is then but my money's on a male. Doesn't mean all the rest of the brood is infertile though, again just have to wait and see - fingers crossed. You can probably ID her from the clypeal notch and the margin of the petiole node (looking at it down her back from over her head) to species level.

 

Alright here is my attempt at an ID, please correct me with any issues that you see. This uses the Key to New England Formica as a reference.
Firstly, according to Antmaps, the species of Formica native to South Dakota:
Formica altipetens

Formica argentea

Formica aserva

Formica bradleyi

Formica canadensis

Formica ciliata

Formica comata

Formica criniventris

Formica dakotensis

Formica hewitti

Formica incerta

Formica integra

Formica laeviceps

Formica lasioides

Formica lepida

Formica limata

Formica montana

Formica neoclara

Formica neogagates

Formica neorufibarbis

Formica obscuripes

Formica obscuriventris

Formica obtusopilosa

Formica oreas

Formica pallidefulva

Formica pergandei

Formica podzolica

Formica puberula

Formica ravida

Formica rubicunda

Formica spatulata

Formica subaenescens

Formica subintegra

Formica subnitens

Formica subsericea

Formica ulkei

Formica wheeleri

Next lets narrow that down to the parasitic species. 

Formica aserva

Formica dakotensis

Formica integra

Formica pergandei

Formica puberula

Formica ravida

Formica rubicunda
Formica subintegra
Formica wheeleri

Now lets examine the key for any of these that exist. Firstly, as ReignofRage noted, we can narrow this list down further when we reach Step #4 on the key: Clypeus notched; ant bi-colored (head and mesosoma reddish-orange, gaster dark); slave-makers (sanguinea group). That leaves:

Formica aserva

Formica pergandei

Formica rubicunda

Formica subintegra

Formica wheeleri
Formica puberula

Moving down the key, we next will evaluate if the queen could be Formica aserva. Few (normally < 6) very short (< 0.06mm) hairs or no erect hairs on dorsum or gaster; petiole large (broad), fan-shaped, and lacking erect hairs on its crest; a northern species found at high elevations in Massachusetts as well as throughout northern New England . . . . . Formica aserva

The issue here is that the petiole is difficult to see and is only visible in the second image. However, we do have a lot to go off of from the first line. In the image there appear to be a lot more than 6 hairs on the gaster, protruding from between the exoskeleton plates. To the best of my knowledge this counts as hairs on the gaster, so my conclusion is this this is likely not F. aserva, although I would need to compare to RushmoreAnt's other colony to be sure.

 

More than 6 longer hairs on the gaster

Mesosoma saddle-backed in profile; erect hairs absent on the propodeum; crest of petiole blunt in profile . . . . . Formica subintegra

The mesosoma is saddle-backed in profile with all parasitic Formica so this is little help in this circumstance. In all of the images it does look like hair is absent from the propodeum as well.

 

No visible hair on propodeum, although the camera may not have captured them

 

Finally, and most importantly in my opinion: crest of petiole blunt in profile. The difference is very obvious when comparing Formica subintegra with another parasidic Formica species such as Formica aserva.

 

Sharp petiole (F. aserva)

 

Blunt petiole (F. subintegra)

 

Here is another example with a queen.

 

Notice again the stubby petiole

 

This does check out. In image 4 and 5, you can see the unusually short petiole that is quite flat and stubby at the top. So far, my best guess would be Formica subintegra, but there is more keying to do.
Mesosoma more curvaceous in profile; erect hairs present on the propodeum; crest of petiole sharp . . . . . Formica rubicunda

This is really easily dismissed because of the last clause: crest of petiole sharp. As previously mentioned, RushmoreAnt's queen's petiole is anything but sharp. For further clarification, you can see the image below.

 

Sharp and thin petiole

 

Head at least as broad as it is long, and usually broader; scape shorter than length of the head; erect hairs on the gaster > 0.13 mm long and usually longer; hairs on the second gastral tergites dense and closely packed (separated by a distance less than their own length); enslaves neogagates, pallidefulva, and fusca group ants; widespread throughout New England . . . . . Formica pergandei
While it is not immediately obvious if the head is broader than it is long in image 3, what is certain is that there are few or no hairs on the second gastral tergite. I am not completely sure what to count as a tergite here, perhaps someone could help? Do you count from the first exoskeleton plate on the abdomen or is that distinctly the post petiole, a different thing all together. At any rate, densely packed hair is not something this queen has. 

 

Little to no hair

 

Neither Formica wheeleri nor Formica puberula are on the Antwiki Formica key, so I cannot be too certain about them. However, here are my thoughts.
Formica wheeleri appears to be super rare. As far as I know, no queen has ever been caught and only workers have been photographed, so there is little to go off of. Instead, I will use the description given on Antwiki.
The petiole of this species has a blunt apex and is wide as seen from the front. The head is often darker than the mesosoma. The underside of the head usually has a pair of erect hairs. The hairs on the gaster are about 0.1 mm long, and are moderately fine, mostly sharp-tipped. Those on the pronotum are shorter, thicker and at least a few are blunt-tipped. The eyes are large, extending past the sides of the head in most workers. (Mackay and Mackay 2002)

The blunt apex we have already seen and the petiole looks quite wide when seen from the front, see image 4 in the original post. The head is indeed darker than the mesosoma.


Darker head

While I cannot measure the hair on the abdomen, they do appear to be sharp. Let me know if you agree.

 

Sharp hair

 

However, I am uncertain about the hair on the pronotum. If you look at the 2nd to latest image, you can see at least one hair on the pronotum, and it kind of looks shorter and blunter? I think a better camera is necessary though to fully make sure. Looking at images 3 and 4 in the original post as well, it does appear the eyes of the queen are well to the side of the head. This queen could possibly be F. wheeleri, but it still seems that subintegra is the best fit. If you are a myrmecologist or expert though, I would really love to know how you would distinguish between these species.
 

For Formica puberula, I am using the same method to ID as the F. wheeleri.

The scape of this species has appressed to suberect, relatively coarse hairs, giving it a slight bristly appearance. The underside of the head has at least a pair of hairs. The erect hairs on the gaster are about 0.1 mm long, and are of about the same form and density as those on the pronotum. Most hairs have sharp tips. (Mackay and Mackay 2002)

The antenna are not visible enough in the images to judge the hairs on them, and neither is the underside of the head. However, the gaster hairs do not appear to have the same density as the hairs on the pronotum, although a better image is necessary to be positive.

In the end, I think F. subintegra has the most positive evidence for it being the species, although F. wheeleri seems quite close. Please let me know what you think though and any constructive criticism of my methods is needed!
Ants_Dakota

Edited by Ants_Dakota, Yesterday, 7:51 PM.