Ants are social insects that engage in group activities, but every caste in the colony performs a distinct task to ensure the colony’s survival. They exhibit a human-like trait and set a budget for the colony, which allows them to manage uncertainties by employing a few colony members to a specific task.
On 10 July 2023, an article explaining that ants set budgets when facing an uncertain future was published in the Proceedings of the National Academy of Sciences. Daniele Carlesso and a few other researchers from Macquarie University conducted research to see the involvement of weaver ants (Oecophylla smaragdina) in the chain formation at a cost to the colony because the hanging chains are a gamble due to an uncertain future.
Living organisms often face uncertainties in their lifespan when they have to decide to invest their time or money to solve the problem. In the same way, ants also suffer from uncertain challenges when they decide to set budgets and find the best possible solution without knowing about the outcomes, so it is just like gambling.
Adaptation of making budgets in ants for an uncertain future
They are smart creatures that engage in various collective activities, like nest-making, foraging, grooming, etc., as their colonies have a division of labor.
Budgeting in Ants does not mean managing expenses and saving money every month, but it means allocating resources or members to address uncertain circumstances.
They keep themselves prepared for food shortages or weather fluctuations by storing extra food in the nest chambers and building deeper tunnels in the nest.
Similarly, they allocate more workers for food collection when the colony struggles with food scarcity. This way, they set up a budget of foragers even if they have an uncertain payoff.
These foragers approach different food sources, so this flexible allocation of foragers is similar to budgeting resources based on the uncertainty associated with these options.
Furthermore, they allocate more workers to a group of ants working as builders and soldiers when their nests get damaged or need protection from predators.
This allocation or budgeting of workers has an uncertain future because it is not sure that the nests will not get damaged again or that the soldiers will win the fight.
Study of budget setting behavior in weaver ants
Some researchers from the School of Natural Sciences, Macquarie University, named Daniele Carlesso, Chris R. Reid, and Justin M. McNab, and a few others conducted research on weaver ants.
They observed bridge-building behavior in weaver ants (Oecophylla smaragdina) that are known to make long chains after encountering a gap in their path.
This chain formation reflects budget-making behavior when the colonies budget their investment by allowing workers to engage in the task when the outcomes are uncertain.
These workers cannot participate in other activities after becoming a part of the bridge or chain, which is an example of colony budgeting when there is no information about payoffs.
These researchers collected a few ants and conducted an experiment to know their behavior when they reached a gap in their path while moving ahead to explore the other side.
This bridging behavior usually involves linking of the bodies of multiple worker weaver ants, but these hanging chains look like gambling as they are not sure to get food after crossing the gap.
On 10 July 2023, they published research work in the Proceedings of the National Academy of Sciences and shared their observations with the scientific community and people.
Experimental analysis of budget-making behavior in Weaver ants
It is common for ants to make critical decisions by investing the colony’s budget for critical tasks without prior information about the outcomes.
A few colony members perform a specific task, which indicates that these colonies budget their individual investment as the entire colony does not participate in the single task.
Daniele experimented on six colonies of weaver ants to study their chain-forming behavior. Samples were collected from Townsville and maintained in a controlled chamber.
They used 20 sub-colonies with no queens, but each had 200 adult workers. They were starved for 24 hours to motivate them to explore the food source.
A long wooden stick was provided as a hanging platform that was placed directly above the food source. They designed an experiment with three different setups with varying gap lengths.
The food sources were placed at 25mm, 35mm, and 50mm. These researchers started recording videos from the time when ants started making chains until they returned to their containers.
Their behavior was analyzed through experimental, theoretical, and statistical analysis to understand their adaptive decision-making power when facing uncertain futures.
Do ants invest more than their budget when facing problems?
It was observed that ants do not blindly invest all of their workers in chain formation when the future is uncertain and make a budget that depends on several factors, like distance.
These researchers from Macquarie University observed that weaver ants were actively participating in the bridging process until the distance was around 50mm.
Typically, a specific proportion of their colony engages in the bridging process, so the chain began to disintegrate when its length reached 90mm.
Some other experiments demonstrated that they do not build complete chains if the distance increases beyond 11cm, but complete chains were seen for distances less than 11cm (110mm).
Daniele and his research fellows used a theoretical model to know if O. smaragdina keeps building a chain when the distance from the platform increases slightly.
In addition, they moved the platform a few centimeters away from the previous position when the chain of weaver ants was about to end. This way, they tricked them about the total distance.
They found that ants can be visually deceived if the distance from the platform remains constant. These bridging ants thought the gap was not so big to cross and moved ahead, covering long distances.
So, they do not move ahead if the distance is more than 110mm, which indicates that they have a budget to spend when facing an uncertain future.
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