How do Female Damaraland Mole Rats Become Queen?

Damaraland mole rats are eusocial and are one of two mammals that exhibit eusociality.

Eusociality is a caste system. There is one pair that is able to reproduce. The breeding pair

consists of one female and one male Damaraland mole rat. The rest of the mole rats are

anovulatory and they have jobs. Some roles the subordinate mole rats fulfill are taking care of

their siblings and digging tunnels. To further understand how this system works, a study was

conducted on female Damaraland mole rats. The study compared nonreproductive mole rats to

reproductive mole rats.

The blood from their brains was assayed for hormones and plasma. In the plasma assays,

testosterone and progesterone were the main hormones examined. In situ hybridization was used

on the brain to locate three receptor mRNA (androgen, estrogen, and aromatase). There were low

levels of testosterone which led to the results of testosterone being disregarded. Progesterone

indicates reproductive activity which is directly proportional to follicular development as well as

ovulation. The reproductive female mole rats had high levels of progesterone. The

nonreproductive mole rats had high expression of the androgen receptor mRNA. The androgen

receptor mRNA was correlated to the physiological suppression that led the rest of the mole rats

(excluding the queen) to become anovulatory.

In addition to the genetic component, there are certain behaviors that mole rats display regarding

the position of queen. Sometimes other female mole rats will try to fight for the position of

queen. The winner of the fight becomes queen. This is why the queen is usually a strong,

aggressive, and dominant mole rat. There are both genetic and behavioral characteristics to the

role of the queen. Both factors allow the mole rats to continue as eusocial mammals. Their caste

system remains organized and structured.

Posted by Lorena Soldevilla (3)

Source:

Voigt, C., Gahr, M., Leitner, S. Lutermann, H., Bennett, N. (May 08, 2014) Breeding status and

social environment differentially affect the expression of sex steroid receptor and aromatase

mRNA in the brain of female Damaraland mole-rats. Front Zool 11, 38 [accessed Oct. 09, 2023]

https://doi.org/10.1186/1742-9994-11-38

Comments

  1. AnonymousOctober 10, 2023 at 2:47 PM

    Hi Lorena, I had no idea that eusocial mammals existed. I find it incredible that such social structures exist. It's interesting how a social structure that seems very immoral to most humans became normal in these mole rats. These animals could not follow a system of equality if they tried because they are literally genetically programmed to have one female that can ovulate at a time. Eusociality is a rather interesting feat of evolution. I read that mole rats are often inbred; I wonder how this factors into things and affects their survival.

    ReplyDelete
    Replies
    1. AnonymousOctober 10, 2023 at 2:47 PM

      - Calvin Keating

      Delete
    2. AnonymousOctober 14, 2023 at 6:48 PM

      Hi Calvin. Eusociality is such an interesting topic. Its true what you said about how this hierarchy would not have been viable for humans, but its the way of living for the Damaraland mole rats. I find it interesting how this hierarchy could be applied to humans. It is definitely not a great way to continue the human species. Since the mole rats are inbred, they recognize each other as siblings which increases their need to help out the colony. They feel a responsibility towards the other members of the colony. I hope this helps.
      - Lorena Soldevilla

      Delete
  2. AnonymousOctober 10, 2023 at 6:44 PM

    Hi Lorena! This topic is really interesting! Animal behavior can be so complex. It is amazing to think that animals establish a sort of human-like hierarchy. I also find it interesting how there are genetic and behavioral components to being a queen. You have to be "born" a queen, but you also have to fight for your spot. I hope to learn more about this topic. Thanks for sharing!
    -Anya Quaglietta

    ReplyDelete
    Replies
    1. AnonymousOctober 14, 2023 at 6:27 PM

      Hi Anya. I’m glad this topic interested you as it did to me. The genetic and behavioral components are both necessary for the queen mole rat. I’m not sure born is a good word to describe this phenomenon, but some mole rats could be born queen. The study supported the existence of a sole reproductive queen. I will definitely try to research more about them.
      - Lorena Soldevilla

      Delete
  3. AnonymousOctober 11, 2023 at 9:20 AM

    Hi Lorena, it's really interesting to think that there are animal species that only have one reproductive pair and are able to survive with just this mode of reproduction. Most species you think of are in a system where most of the species reproduce, I have only heard of something similar in insects. Did the moles fighting for the queen spot also have higher levels of progesterone or just demonstrate a more dominant behavior?
    Alexis Carson

    ReplyDelete
    Replies
    1. AnonymousOctober 14, 2023 at 3:06 PM

      Hi Alexis. I have also only heard of eusociality concerning insects. I was intrigued when I found out only 2 mammals reproduce similarly to insects and they're both types of mole rats. To answer your question, it's both the levels of progesterone and the dominant behavior. The dominant behavior was used to secure the position of the queen and the high levels of progesterone allow the queen to reproduce.
      -Lorena Soldevilla

      Delete
  4. AnonymousOctober 11, 2023 at 9:27 AM

    Hi Lorena! What an interesting topic. Like Calvin stated above, I had no idea that eusocial mammals existed; seeing things like social structure expand beyond humans and into other species is fascinating. I think it's also cool that the queen is born, not raised, which can be tied to human social hierarchies, such as royal families that pass the throne down to their generations. Thanks for sharing, this was a great read!

    ReplyDelete

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