Later On

A blog written for those whose interests more or less match mine.

Shy v. bold at the colony level

with 2 comments

In the Guide I discuss two mindsets: explorers and settlers. Explorers are risk-tolerant and novelty seeking, looking for any excuse to try something new; settlers are risk-averse and prefer the familiar, looking for any excuse to stick with the status quo. I mention that the same differences are seen in the animal kingdom, where they are generally called “bold” and “shy” respectively.

Now it’s found that these different mindsets (if one can call it that) can even be observed in ant colonies at the colony level. (This is not so surprising if you think the difference is genetic, since the ants in a colony are offspring of the same mother.) In Science Claire Asher reports:

. . . Some [ant] colonies are full of adventurous risk-takers, whereas others are less aggressive about foraging for food and exploring the great outdoors. Researchers say that these group “personality types” are linked to food-collecting strategies, and they could alter our understanding of how social insects behave.

Personality—consistent patterns of individual behavior—was once considered a uniquely human trait. But studies since the 1990s have shown that animals from great tits to octopuses exhibit “personality.” Even insects have personalities. Groups of cockroaches have consistently shy and bold members, whereas damselflies have shown differences in risk tolerance that stay the same from grubhood to adulthood.

To determine how group behavior might vary between ant colonies, a team of researchers led by Raphaël Boulay, an entomologist at the University of Tours in France, tested the insects in a controlled laboratory environment. They collected 27 colonies of the funnel ant (Aphaenogaster senilis) and had queens rear new workers in the lab. This meant that all ants in the experiment were young and inexperienced—a clean slate to test for personality.

The researchers then observed how each colony foraged for food and explored new environments. They counted the number of ants foraging, exploring, or hiding during set periods of time, and then compared the numbers to measure the boldness, adventurousness, and foraging efforts of each group. They also measured risk tolerance by gradually increasing the temperature of the ants’ foraging area from 26°C to 60°C. Ants that stayed out at temperatures higher than 46°C, widely considered to be the upper limit of their tolerance, were considered risk-takers.

When they reviewed their data, the scientists found strong personality differences between colonies, they reported online this month in Behavioral Ecology. Some were bold, adventurous risk-takers with highly active foragers. Others were shy, risk-averse, and fearful of new environments. Their foragers were less active, and they were less inclined to search for food at very high temperatures. When the team performed the same tests 11 weeks later, they saw that these differences persisted over time. More than half of all variation between colonies fell into distinct categories known as “behavioral syndromes.” These syndromes—similar to personality types among humans—are present across the animal kingdom and include categories like “proactive” (animals are bold, aggressive, and risk-prone) and “reactive” (animals are shy, calm, and risk-averse).

So how do these personality types affect how ants interact with each other? To find out, the researchers gave two colonies access to a shared foraging area. They observed how the laboratory colonies interacted with intruders and how well they competed with other colonies for food. They found that—not surprisingly—bold, risk-taking colonies were more aggressive toward other ants and were more efficient at collecting food. But the authors speculate that those colonies would experience higher mortality in the wild because of their risk-taking tendencies. As a result, they concluded that such behavioral strategies represent a tradeoff.

This idea is supported by a 2014 study that investigated colony-level personality in the rock ant, Temnothorax rugatulus, which ranges from northern Mexico to southern Canada. . .

Continue reading.

There’s quite a bit more, and it’s interesting.

Written by Leisureguy

31 August 2015 at 8:45 am

Posted in Daily life, Science, Shaving

2 Responses

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  1. Interesting post. I’ll have to read the whole article. Temperament certainly has a genetic component. My frateral twin boys have had very different personalities since birth.


    Brian Trepka

    31 August 2015 at 10:13 am

  2. One interesting thing in the article is how ant colonies at the northern (harsh) extreme of the range have a much bolder “personality” than the colonies of the same species farther south because of different selection pressures from the environment.



    31 August 2015 at 11:12 am

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