Ant Royalty: How Juvenile Hormone Determines Ants Social Hierarchy

Scientists at the University of Copenhagen have been researching the system ants use to determine the types between them in the colony; an example of this could be a worker compared to the queen. The researchers focused on a hormone named juvenile hormone (JH) and its role in developing ants into different types, such as workers or queens. The specimen used for the experiment was pharaoh ants, as in the species, an ant's role in the colony is decided upon birth. The researchers fed 237 baby worker pharaoh ants during the last stage of their development to see whether the juvenile hormone would affect the ants, changing their type from worker ant to queen ant, determining how the juvenile hormone affects the physical features of different ant types.

The study produced intriguing results. When born, worker ants fed the juvenile hormone during the final stages of development started to look similar to young queen ants. These modified workers showed phenotypes of longer bodies, extra eyes on the forehead, and the development of wings with the muscles required for flight. The modified workers also showed the development of a unique organ inside queen ants that stores sperm. However, one significant difference between a natural-born queen and the modified worker ants was that the treated workers did not grow ovaries, which is crucial in making eggs. This data shows that the primary time where the juvenile hormone affects the ant's development does not happen in the egg, as while some changes were observed among the modified workers, the crucial component of ovaries for reproduction was missing. The research also helps explain how new types of ants, like soldiers, might have evolved in other ant species, as natural selection may have favored certain ants with higher levels of juvenile hormones. This hybrid ant between workers and queens may be more favorable for survival in natural selection leading to a new type of ant within the colony.

This study shows that ant colonies act a little like cells work in an animal's body, suggesting that how ants are developed in the colony is more flexible than first believed. The juvenile hormone controls the development of the ant, predetermining the job an ant will have within the colony. This research also allows us to see how much hormones affect a species when being developed as a kid and how it may affect the development.


Article: https://www.sciencedaily.com/releases/2024/11/241122130358.htm

Original Paper: https://journals.biologists.com/jeb/article/220/1/53/33443/Caste-development-and-evolution-in-ants-it-s-all

How Stress Affects Our Response to the Environment

In this study done on rhesus monkeys, female monkeys were slowly introduced to each other to form a group of five female monkeys. The point of introducing them one after another was to play to their concept of seniority. The monkeys earliest in the group were considered socially superior to the ones introduced to the group later. After a year, they mixed up the members and reintroduced them so they would have different rankings. Blood was drawn from the first and second round of groups to compare how they are affected by bacterial and viral disease. The data showed that more than 5,000 genes were expressed differently in the blood collected from the second round fighting off a bacterial infection, and almost 3,000 genes were expressed differently from viral infection. Both of these changes are a result of social ranks the monkeys first had, to the change in behaviour when their rank shifted. It shows conclusively that past experiences do impact how we respond to our world, even as an adult.



original link: https://www.medicalnewstoday.com/articles/326755.php#6
related link: http://primate.uchicago.edu/2011CayoBook02.pdf