Scientists at McGill University in Montreal made news recently by creating superstrong soldier ants. They created the supersoldier ants by activating the ants' gene with methropene, a juvenile hormone that acts as a growth regulator.
The supersoldier ant has a huge head and jaws. It looks like a monster ant in comparison to the regular ant due to its bigger size. Normal soldier ants are bigger and stronger than the normal worker ants. They usually guard and protect their nests from any other intruders, and they are usually very few in number.
In an exclusive interview with the International Business Times, Dr Ehab Abouheif, biology professor at the McGill University, who led the team which created the super ants, says their achievement is an important milestone in understanding the evolution of species. He says it could also lead to a breakthrough in cancer treatment.
Here are some excerpts:
Can you tell us about what led you to create the supersoldier ants?
There are over 1,100 species of the ant group Pheidole in the western hemisphere. An ant colony typically has a queen that reproduces all of the other individuals in the colony and workers that care for the brood (babies) as well as forage for food.
The defining feature of a Pheidole colony is that it has an additional caste: the soldier. Soldiers defend the nest and process food. Furthermore, of these 1,100 species, there are eight that naturally produce what is called a supersoldier. All of these species live exclusively in the south of Arizona and northern Mexico.
In one of these eight species (Pheidole obtusospinosa), it was observed by one of our collaborators (Ming Huang) that supersoldiers come together and actually use their extra-large heads to block the nest entrance against invading army ants as well as to engage in combat.
One day a few years ago, we had found a colony of Pheidole morrisi (a typical species that does not have supersoldiers) in the field (in Long Island, NY) that seemed normal at first glance but, when examined closer appeared to have huge, abnormal individuals. After some thinking, we realized that these anomalies were, in fact, quite similar to what is found in Arizona with the eight species that naturally produce supersoldiers.
How did this species in Long Island produce these anomalies? What do these anomalies mean?
We went to Arizona and collected some colonies of two species that had natural supersoldiers (Pheidole obtusospinosa and Pheidole rhea). We brought them back into our lab and tried to compare natural supersoldiers with the anomalous supersoldier-like individuals we found in New York. They were strikingly similar!
So we thought perhaps the species in New York has the genetic potential to produce supersoldiers but do not (and thus this potential is hidden in their genome).
To test this, we treated individuals of the New York species with a critical insect developmental hormone: juvenile hormone. This hormone (which is environmentally-sensitive; i.e., produced based on things like optimal nutrition) is known to be involved in caste determination where developing individuals become either queens or soldiers or workers.
Amazingly, the treated Pheidole morrisi individuals of New York developed into supersoldier-like individuals like that found in Arizona! The next step was to test this hidden potential in other
species of Pheidole that don't normally have supersoldiers. We test two others and they also resulted in supersoldiers.
Thus, we hypothesized that all species probably have the ability to produce supersoldiers hidden in their genome and this potential goes way back to the common ancestor of this group (35-60 million year ago) because of the additional fact that one of the oldest known species (Pheidole rhea, which we also worked on) naturally produces supersoldiers. Thus, we discovered that there is an ancestral developmental potential to produce supersoldiers in Pheidole.
How could this feat help future researches?
The discovery of the existence of ancestral developmental potentials could be a very important finding for our understanding of evolution. One would typically think that after 35 million years, if a trait/phenotype is not produced or selected for, then the genetic capacity to produce it would be lost over time. Instead, we demonstrated that the opposite is true. The potential to produce
things that you find in your ancestors can actually be preserved in your genome. This could be a widespread phenomenon in the animal kingdom, from plants to humans.
Will the normal ants accept the supersoldier ants if they are put together in the same environment?
Yes they most probably would. This assertion is based on two key facts:
First, supersoldiers are a natural part of colonies of those eight species that occur in Arizona and Northern Mexico.
Second, ants are social, and as a result of their social interactions, everyone is taken care of in the colony. As long as an ant (no matter how abnormal it may be) is capable of being fed by others, it has the potential to survive. An ant colony is essentially one big family, they take care of their sick.
Why don't all Pheidole have supersoldiers since they might all have the potential to make them in their genomes?
The answer to that question is probably more than what we know thus far but, our group has come up with a nice hypothesis with a natural example to support it. Basically, not all Pheidole species and their respective colonies make supersoldiers because they have evolved alternative strategies to deal with the same problems or selective pressures. Our best example to support this is based on what is known in the species Pheidole hyatti.
Pheidole hyatti is one of the species that does not naturally produce supersoldiers that we were able to treat and succesfully induce supersoldiers in the lab with juvenile hormone. More importantly, this species lives in the same geographical region and similar habitat as the species that naturally produce supersoldiers. Furthermore, as mentioned above, supersoldiers defend their colony against army ants raids using their extra-large heads.
How does Pheidole hyatti deal with these same army ants?
Instead of producing individuals with extra-large heads to block the nest entrance and attack, the whole colony has evolved a multi-phase escape strategy: the queen, workers, soldiers and babies are brought together and then completely evacuate the whole colony and find a new home! Therefore, this species and most likely many others have developed and evolved alternative strategies to deal with the same selective pressures (like army ants).
You said the creation of supersoldier ants will help us understand the evolution of species. Will it have any other application?
This potential fundamental importance of this research does not stop at evolutionary theory. For instance, the understanding of the mechanisms and implications of environmental activation of ancestral developmental potential might be something that we can apply to cancer. A gene can be typically dormant but a change in environment (be it food or a carcinogen) may trigger this dormant gene or pathway and result in cancer.
Another example would be related to biodiversity and conservation: our environment is constantly changing (ex: global warming) what are the consequences on our wildlife in light of our finding that ancestral developmental potential can be unleashed/activated when the environment changes? Maybe if we better understood this influential interplay of the environment with hidden potentials in our genome, we can perhaps address some of these medical and ecological issues as
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