That is the question researchers posed in a new study of the Florida harvester ant, Pogonomyrmex badius, a resilient creature found in many parts of the southeastern United States. The answer? Both nature (i.e. the ant’s genetic makeup) and nurture (what it eats, for example) play a role in determining its fate.
The research team included scientists from the University of Illinois, the University of Arizona, Linfield College and Arizona State University. The findings were published online on August 14 by American Naturalist.
In the hierarchy of an ant colony, status is everything. If you are a “gyne” and thus destined to become a queen, you can expect the very best accommodations and generous portions at mealtimes. If you are a worker, you must be ready to sacrifice your health, welfare and reproductive capacity for the betterment of the colony.
The researchers were drawn to P. badius because its social structure is more complex than most. Its caste system includes two categories of workers: majors and minors. Major workers are nearly four times heavier than minors, but the minors outnumber them by 20:1. Gynes (pronounced “JINES”) are about eight times heavier than minors.
The researchers wanted to know whether the ant’s genetic endowment dictated its caste and size or whether nutrition also played a role.
“Basically what we found is that things are more complicated than previously thought,” said Christopher R. Smith, a former graduate student in the School of Integrative Biology at Illinois and corresponding author on the study. “Our study shows that there is a large genetic component to caste determination, but that there is also a very strong environmental component.”
The researchers found that the genetic makeup of the colonies they studied was quite diverse. The average P. badius queen had mated with at least 20 males (the norm for ants is one to five). The genetic analysis also suggested that the offspring of most males could develop into any caste, but that some male lineages (patrilines) were more likely to become gynes while others were more likely to become major or minor workers.
A recent study of honey bees found that colonies with a lot of genetic diversity were better at nest building and finding and storing food than their less diverse counterparts.
While historically, it has been assumed that castes are environmentally determined, recent studies on Pogonomyrmex harvester ants have found colonies in which becoming a worker or gyne is determined exclusively by genetic differences. This constrains the colony’s ability to adaptively adjust to environmental realities. For example, colonies that have few workers and yet produce many larvae that are destined to become gynes fail to grow to maturity because they lack the resources to feed the voracious gynes. On the other hand, colonies that can respond to environmental factors and alter the ratio of the castes they produce are often more successful in a changing environment. They can produce more workers when resources are scarce and more gynes when food is plentiful.
“Flexibility in caste determination is essential as it allows the colony to respond to changes in need or environmental fluctuations,” said principal investigator Andrew Suarez, an Illinois professor of animal biology and of entomology and an affiliate of the Institute for Genomic Biology.
In the new study, the researchers analyzed what the P. badius ants were eating. Using stable isotope analysis, which looks for different versions of elements such as nitrogen and carbon in the diet, the researchers could tell whether individual ants were eating higher or lower on the food chain. Those at the top would have a more carnivorous diet, with a higher nitrogen content in their foods. They would also ingest more of a specific isotope of nitrogen in their foods than those eating seeds or plants.
The analysis showed that gynes were at the top of the dietary food chain and had the highest proportion of nitrogen in their diets. The minor workers had the lowest nitrogen content and were eating primarily from plant rather than animal sources. The majors were getting a better diet than the minors, but were not eating as well as the gynes.
“Differences in the nutrition that an individual assimilated during larval growth are strong predictors of caste,” the authors wrote.
The researchers also found that genetic differences predict size in major workers and gynes, but not minor workers. Minor workers increase in size only as the colony grows, probably because larger colonies have more resources available to them.
The exact mechanisms by which genetics or diet influence caste are not yet known, Smith said, but in P. badius both play an important role. There may be a hormonal response, for example, that is driven in part by genetics and in part by nutrition that determines the trajectory of an individual ant’s development, he said. Smith, currently a post-doctoral fellow at Arizona State University's School of Life Sciences, continues to investigate how genetic differences interact with variation in diet to generate so much diversity in the form and function of all ants.
The fact that nutrition can alter the genetic destiny of some individuals in the colony probably allows the colony to adjust the ratio of workers to gynes to survive in tough times, he said.
“But there are still ‘haves’ and ‘have nots’ in the colony: those genetic variants who have a reproductive advantage and those that don’t,” Smith said. “The ant colony and human society have striking parallels.”
Smith quotes Marx and Engels, who theorized in their manifesto: “The history of all past society has consisted in the development of class antagonisms… the exploitation of one part of society by the other.”
WAKE-UP provides new treatment option for stroke patients | International study led by UKE
17.05.2018 | Universitätsklinikum Hamburg-Eppendorf
First form of therapy for childhood dementia CLN2 developed
25.04.2018 | Universitätsklinikum Hamburg-Eppendorf
The more electronics steer, accelerate and brake cars, the more important it is to protect them against cyber-attacks. That is why 15 partners from industry and academia will work together over the next three years on new approaches to IT security in self-driving cars. The joint project goes by the name Security For Connected, Autonomous Cars (SecForCARs) and has funding of €7.2 million from the German Federal Ministry of Education and Research. Infineon is leading the project.
Vehicles already offer diverse communication interfaces and more and more automated functions, such as distance and lane-keeping assist systems. At the same...
A research team led by physicists at the Technical University of Munich (TUM) has developed molecular nanoswitches that can be toggled between two structurally different states using an applied voltage. They can serve as the basis for a pioneering class of devices that could replace silicon-based components with organic molecules.
The development of new electronic technologies drives the incessant reduction of functional component sizes. In the context of an international collaborative...
At the LASYS 2018, from June 5th to 7th, the Laser Zentrum Hannover e.V. (LZH) will be showcasing processes for the laser material processing of tomorrow in hall 4 at stand 4E75. With blown bomb shells the LZH will present first results of a research project on civil security.
At this year's LASYS, the LZH will exhibit light-based processes such as cutting, welding, ablation and structuring as well as additive manufacturing for...
There are videos on the internet that can make one marvel at technology. For example, a smartphone is casually bent around the arm or a thin-film display is rolled in all directions and with almost every diameter. From the user's point of view, this looks fantastic. From a professional point of view, however, the question arises: Is that already possible?
At Display Week 2018, scientists from the Fraunhofer Institute for Applied Polymer Research IAP will be demonstrating today’s technological possibilities and...
So-called quantum many-body scars allow quantum systems to stay out of equilibrium much longer, explaining experiment | Study published in Nature Physics
Recently, researchers from Harvard and MIT succeeded in trapping a record 53 atoms and individually controlling their quantum state, realizing what is called a...
25.05.2018 | Event News
02.05.2018 | Event News
13.04.2018 | Event News
25.05.2018 | Event News
25.05.2018 | Machine Engineering
25.05.2018 | Life Sciences