Excavating an army ant nest (and finding the queen)

Matthew called my attention to this tweet about the excavation of a driver-ant (army ant) colony, and I’ve put the video at the bottom.

Dorylus molestus is an African army ant, some of whose drones are the largest ants in the world, not to mention the huge queen, who appears at 2:52 in the video below.  Some Wikipedia notes:

Some Dorylus molestus queen are the largest known extant ants. Queens typically grow to 5.2 centimetres (2.0 in) but can reach 8 centimetres (3.1 in).

Its size of Molestus queens allows it to hold the world record in egg laying. Workers (sterile females in the presence of the only living queen) range from .3–1.1 centimetres (0.12–0.43 in). Huge and specialised soldier morphs (permanent sterile females) provide protection during migration raids.

Here are the YouTube notes on the excavation, and they’re biologically quite informative.

Join us on a hunt for the elusive army ant queen (Dorylus molestus) at Mount Kenya. Army ant queens are the biggest ants on the planet and highly unusual looking. First, their gasters [JAC: abdomens] are massively enlarged to accommodate the huge ovaries. Second, unlike the queens of most other ants, they are permanently wingless, reflecting the fact that army ant queens never leave the colony, and colonies reproduce by fission. This video provides background footage for my upcoming book “Army Ants: Nature’s Ultimate Social Hunters“, which will be released by Harvard University Press later this year [JAC: in October]

I’m a bit pissed off that they dug up such an extensive colony and removed the colony’s heartbeat and sole source of propagation: the queen. Perhaps there was a research objective to this, but it would have to justify destroying a colony.

Or perhaps they put the queen back.

11 Comments

  1. GBJames
    Posted April 15, 2020 at 2:51 pm | Permalink

    sub (terrainian)

    • JezGrove
      Posted April 15, 2020 at 2:58 pm | Permalink

      Let’s hope the queen did get put back and avoided the homesick blues…

  2. Mark R.
    Posted April 15, 2020 at 3:44 pm | Permalink

    Colonizing insects are some of the most interesting evolved critters on earth.

    Like you, I hope they put the queen back…but if they did, wouldn’t they have mentioned it? 🐜🐜🐜

  3. Posted April 15, 2020 at 3:44 pm | Permalink

    I am bothered also by the seemingly wanton destruction of this colony. Perhaps there was a good reason for it. I doubt E. O. Wilson would be happy.

  4. Posted April 15, 2020 at 4:07 pm | Permalink

    Would the colony survive if they put the queen back in that chamber? If so, what would they do to repair their nest? Can they save all those eggs falling out of the chamber? I’m not an ant but it seems that a better strategy would be to look for a new home or get started on their “nest fission” process a bit early.

  5. rickflick
    Posted April 15, 2020 at 4:34 pm | Permalink

    Fascinating. I read E. O. Wilson’s, “The Ants”, years ago. I think I have a copy in some box somewhere. It’s a very good read. Not too technical.

  6. ThyroidPlanet
    Posted April 15, 2020 at 4:48 pm | Permalink

    Sub

  7. Posted April 15, 2020 at 4:59 pm | Permalink

    First of all, thanks for posting Jerry!
    I’m the author of the video and, given some of the concerns raised, I thought I should provide some additional context.
    With about 50 colonies per 100 ha, the species is extremely abundant at Mt. Kenya (for comparison, population densities of the Neotropical army ant Eciton burchellii are about an order of magnitude lower; Schöning et al. 2010), and this colony was located on a private farmland property outside the national park. So purely from a conservation point of view there should be little concern. Still, destroying something as marvelous as an army ant colony of course has to be considered very carefully in each case, and it is never an easy decision. I have conducted scientific research on army ants for almost two decades, and for the vast majority of studies, collecting a few workers as reference specimens without disturbing the colony is absolutely sufficient (if you think of the ant colony as a superorganism, this is equivalent to drawing a tiny bit of blood). For a few questions, however, queens need to be collected (see e.g. our study on how worker behavior changes after queen loss – it turns out that they join neighboring colonies in what might be an unusual case of altruism; Kronauer et al. 2010). My intention with this video and the upcoming book in particular is to help raise awareness for how amazing army ants are, and thereby promote their study and conservation. So just to reiterate what Jerry already said, nobody should dig up an army ant colony without a solid justification, which will be the case for most people who don’t study army ants professionally. And even if you are an experimental biologist, these kinds of ethical questions have to be weighed very carefully, no matter whether you work with fruit flies, ants, primates, or viruses.

    Kronauer DJC, Schöning C, d’Ettorre P, Boomsma JJ. 2010. Colony fusion and worker reproduction after queen loss in army ants. Proceedings of the Royal Society of London, Series B: Biological Sciences 277: 755–763.
    Schöning C, Csuzdi C, Kinuthia W. 2010. Influence of driver ant swarm raids on earthworm prey densities in the Mount Kenya forest: implications for prey population dynamics and colony migrations. Insectes Sociaux 57: 73–82.

    • Posted April 15, 2020 at 5:01 pm | Permalink

      Thanks for the explanation. I can rest a bit easier now. Cheers!

    • rickflick
      Posted April 15, 2020 at 6:43 pm | Permalink

      Yes, thanks for the feedback. I was unaware of the amount of thought and concern, but it makes sense. People who study a species are going to be their best protectors.

    • Posted April 16, 2020 at 10:03 am | Permalink

      Very interesting work! Glad to hear the army ants have a backup plan.


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