Ant Colonies Respond Quickly to Distribute Food

two yellow gold ants walk diagonally down a tree branch against a blurry green background

Biological Strategy

Rock ant

Natalie Chen

Image: Sankar Chandrasekaran / Pixabay / Free non-commercial use

Manage Disturbance in a Community

When environmental conditions change, they can disrupt an ecosystem’s equilibrium. Excessive rain can cause flooding and drought can cause forest fires. An ecosystem must be resilient to such disturbances. Disturbances are unpredictable in location, size, and intensity, so ecosystems must be able to regrow and must have a variety of duplicate forms, processes, or systems that are dispersed in location. For example, a forest ecosystem can recover from fire because diverse organisms play different roles in different ways and in different locations. Many organisms can resprout or grow from seeds triggered by fire, and their dispersed distribution ensures that an entire population isn’t decimated. Though the recovered ecosystem may look totally different from the pre-fire one, the ecosystem as a whole remains healthy.

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Cooperate Within the Same Species

A species is a group of organisms capable of breeding to produce fertile offspring. When individuals within a species undertake activities that benefit one another, that cooperation benefits not just the individuals, but also local and wider populations of that species. Collaborating in activities such as finding food, controlling parasites, and protecting from predators enhances overall survival. To cooperate, there must be enough benefit to an individual, and especially to a population, to justify any risk taken by individuals. Through cooperation, risk is distributed among individuals and the benefits to the community are greater than the sum of the benefits to individuals. An example is birds that gather in flocks, a cooperative activity more beneficial than acting alone. While some birds forage, others watch for predators. When one finds food, others also feed on it. Despite potential short-term competition for an individual that finds food, over the long-term, that same individual benefits when others find different food sources.

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Coordinate by Self-Organization

To create and maintain a healthy community of individuals and ecosystems requires that living systems coordinate their activities. Coordination doesn’t necessarily mean that there’s a leader orchestrating what happens. In nature, coordination is usually achieved through self-organization. In a flock of geese flying in a V-formation, for example, there’s no lead goose controlling where all of the others fly. The flock uses this formation because each goose gains energy from air vortices created by the goose in front of it. The lead goose doesn’t gain that benefit, so when it tires, it moves back and another goose takes the front position.

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Distribute Liquids

Liquids include water, as well as body fluids such as blood, gastric juices, nutrient-laden liquids, and more. To survive, many living systems must move such liquids within themselves or between locations. Because of their properties, liquids tend to disperse unless they are confined in some way. To address this, living systems have strategies to confine fluids for transport, and to overcome barriers such as gravity, friction, and other forces. Some of these same barriers also provide opportunities. Trees and giraffes face the same challenge: how to move fluids (water and blood, respectively) upward against gravity. But their strategies are quite different. The tree moves water using capillary action and evaporation, possibly due to water’s properties of polarity and adhesion. The giraffe’s tight skin provides pressure to assist in blood circulation. and keep blood from pooling in the legs.

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Distribute Solids

Solids include resources such as food, seeds, spores, and leaves, which living systems must sometimes move to accomplish various activities such as pollinating, feeding their young, or building shelters. To effectively distribute solids, living systems must use strategies appropriate to the sizes and types of solids and the media in which they exist (air, water, or another medium). This may entail strategies beyond simply holding and carrying solids. For example, some seeds are carried by the wind to new locations for germination. Others–like the burdock plant’s hooked seeds–cling to animal fur to be transported.

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Insects

Class Insecta (“an insect”): Flies, ants, beetles, cockroaches, fleas, dragonflies

Insects are the most abundant arthropods—they make up 90% of the animals in the phylum. They’re found everywhere on earth except the deep ocean, and scientists estimate there are millions of insects not yet described. Most live on land, but many live in freshwater or saltwater marshes for part of their life cycles. Insects have three distinct body sections: a head, which has specialized mouthparts, a thorax, which has jointed legs, and an abdomen. They have well-developed nervous and sensory systems, and are the only invertebrate that can fly, thanks to their lightweight exoskeletons and small size.

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Ant colonies distribute food effectively and safely after famine using a decentralized response to quickly spread food.

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Introduction

A society consists of individuals, each with its own role, in a structured community. A society can be centralized or decentralized. A centralized society consists of a single individual or group of individuals that function as a type of “control center.” This control center has the power to plan and control how the society works. They make decisions first and then they distribute this information to other members of the society. However, in this system it takes time to make group decisions and assign tasks.

On the other hand, a decentralized society does not have a control center. Instead, individuals make decisions independently or in small groups. This allows individuals to act more quickly because information does not have to go through a centralized group first.

The Strategy

Ant colonies are an example of a decentralized society. An ant can have interactions with nearby individuals, or take cues from the local environment to help make its decisions. For example, ants who have found food can quickly direct other ants to it without needing to check with the ‘control center’ first. They signal to other ants about where food is by emitting chemical signals from their bodies known as pheromones. Other ants will follow this signal, which will lead them to the food source. This decentralized response enables ants to act quickly and allows for resiliency, which is the ability to endure and recover from distress. An ant’s response to food shortages or famine is an example of resiliency.

An ant can have interactions with nearby individuals, or take cues from the local environment to help make its decisions . . . without needing to check with the ‘control center’ first.

Image: Amanda Blom Photography /

When an ant finds food, it can emit pheromone signals that act like olfactory "bread crumbs" so that other ants to find the food source's location.

Image: Wing-Chi Poon / CC BY SA - Creative Commons Attribution + ShareAlike

When was the last time you had to ask management or the government for approval to enact a decision you thought was prudent? Because ants are a form of decentralized society, they don't need to consult with the "hive mind."

Image: MIKHAIL VASILYEV / CC BY - Creative Commons Attribution alone

In human society, bureaucratic processes may add needed controls but sometimes introduce inefficiencies. Because ants are free to act as individuals, they can respond more quickly to stressors such as famine.

Ants can experience food shortages for a variety of reasons. For example, bad weather can disrupt a food source or other ant colonies can compete for the same food source. When ants in a famine find food, they quickly spread it to other ants living in the same nest. Normally, ants each have their own roles in the colony. These roles are completed within the limited areas of the nest. However, when a famine occurs, the ants can move anywhere in the nest to help spread food. In order to feed everyone quickly, foragers (the ants who collect food) move deeper into the nest to pass food to more individuals. Ants that take care of the young usually live deep in the nest. In times of famine, they move to the edges of the nest to receive food from foragers more quickly.

Because ants need to find and spread food quickly during a famine, they often settle for a lower quality of food, which sometimes may contain harmful chemicals. Ants normally wouldn’t eat these foods, but one way to reduce the chances of eating harmful food is to have multiple food sources. Multiple foragers will travel out in different directions from the nest to find different food sources during a famine. Having multiple food sources dilutes harmful chemicals coming from one particular source. Another solution is to use living “silos” where an individual ant stores and tests a food source for harmful chemicals. The ant may die, but the colony would be saved from a food source that was harmful. All of these are quick and coordinated decentralized responses by individual ants. Together, these actions help a colony survive famine.

Last Updated July 2, 2020

References

“Within the first 30 min of famine relief, 95% of the workers received food and the distribution rate was an order of magnitude faster compared to the controls… Good mixing during famine relief was facilitated by the movement of internal workers away from the brood pile and the movement of foragers with food away from the nest entrance. This is intriguing because T. albipennis workers have spatial fidelity zones and in the controls internal and external workers were segregated. We discovered that colony vulnerability to poisons during famine relief might be mitigated by: (1) the dilution of food from the same source through mixing, (2) the concentration of food in workers positioned midway between the colony centre and its periphery and (3) the existence of living ‘silos’. The latter are expendable foragers, who stay inside the nest and store food during famine relief, thus acting as potential disposable testers for food toxicity” (Sendova-Franks et al. 2010: 473)

Journal article

Emergency networking: famine relief in ant colonies

Animal Behaviour | 18/12/2009 | Ana B. Sendova-Franks, Rebecca K. Hayward, Benjamin Wulf, Thomas Klimek, Richard James, Robert Planqué, Nicholas F. Britton, Nigel R. Franks

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Reference

“Some nutrients that are ignored by foragers at low levels of starvation are collected and distributed within colonies after a lengthy period of starvation (Chong et al., 2002). This reveals a lower food quality acceptability threshold of highly starved ants.” (Bles et al. 2018: 1)

Journal article

Food dissemination in ants: robustness of the trophallactic network against resource quality

Journal of Experimental Biology | 10/12/2018 | Olivier Bles, Jean-Louis Deneubourg, Stamatios C. Nicolis

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Reference

“Decentralization is arguably one of the greatest sources of resilience in social insect colonies. In social insect societies, there is no leader and no blueprint; each individual makes decisions based primarily on local information. Even the queen, who is responsible for reproduction, is replaceable. In the event of queen death, honeybees, for example, can rear emergency queens, and do so very quickly [82]. Decentralization contributes to resilience by ensuring that no individual is irreplaceable; it therefore allows colonies to be resistant to the loss of individuals. Moreover, damage to the system can be dealt with as it happens, without need for time-consuming communications with managers..” (Middleton and Latty 2016: 8)

Journal article

Resilience in social insect infrastructure systems.

Journal of the Royal Society Interface | 01/03/2016 | Eliza J. T. Middleton and Tanya Latty

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