The Naked Mole-Rat |
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MechanismOne of the best ways to understand what traits H. glaber utilize is to examine the changes that occur in subordinate helper females once the dominant female dies and similarly what shifts in subordinate males once breeders are made impotent. Because only one female mates in a colony that is 30-60 individuals, the death of a queen is a big event in a den, and the other females respond accordingly (9). BehaviorThe queen maintains her dominance by behavioral cues, mainly through shoving and walking all over the subordinate mole-rats (5). Instances where a mole-rat shoved another or walked over one indicated a higher social ranking of the mole-rat. Social rank was also based off of incidences of genital nuzzling, lordosis, or copulation (16). There are three basic ranks: the highest is the queen, the second are non working, non breeding females and the third are the working males and females.
To learn more, see the Ontogeny page. MorphologyThe queen is larger and fatter than all the other females, and if she is removed, the metabolic changes in females are drastic. The second level begins to eat much more and gain 18.7% more body mass. They begin to show typical female rodent dimorphism, although only the new queen will develop a perforated vagina. Males also begin to gain mass, but their gain is not as drastic, although it is significant (5, 7). One of the most amazing shifts that occurs is the lengthening of the new queen’s vertebrae during pregnancies (9). Body size is directly correlated to social standing in the hierarchy, and the largest workers are more likely to become the new queens because they can shove more (17).
However, even smaller female mole-rats can achieve reproductive with huge lumber growth that can allow for her to function in her society. As the researchers that discovered this phenomena explain, the queen provides is responsible for all reproduction, and so litter sizes are more favorable if they are large. However, the naked mole-rat queen depends on her behavioral cues to remain dominant and so she cannot be limited to her nest during pregnancy. Increasing lumbar length allows for all elements to be accounted for (9). To learn more, see the Ontogeny page. HoromonalAlthough there is not much controlled experimentation of gonadal hormones on reproductive bonding or suppression of reproduction, observations and baseline measurements give an idea of how gondatropins and pheromones function in H. glaber society.
To learn more, see the Ontogeny page. |