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Individuals that are consistent in risk-taking benefit during collective foraging

View Article: PubMed Central - PubMed

ABSTRACT

It is well established that living in groups helps animals avoid predation and locate resources, but maintaining a group requires collective coordination, which can be difficult when individuals differ from one another. Personality variation (consistent behavioural differences within a population) is already known to be important in group interactions. Growing evidence suggests that individuals also differ in their consistency, i.e. differing in how variable they are over time, and theoretical models predict that this consistency can be beneficial in social contexts. We used three-spined sticklebacks (Gasterosteus aculeatus) to test whether the consistency in, as well as average levels of, risk taking behaviour (i.e. boldness) when individuals were tested alone affects social interactions when fish were retested in groups of 2 and 4. Behavioural consistency, independently of average levels of risk-taking, can be advantageous: more consistent individuals showed higher rates of initiating group movements as leaders, more behavioural coordination by joining others as followers, and greater food consumption. Our results have implications for both group decision making, as groups composed of consistent individuals are more cohesive, and personality traits, as social interactions can have functional consequences for consistency in behaviour and hence the evolution of personality variation.

No MeSH data available.


Related in: MedlinePlus

The experimental tank (to scale).Fish were habituated in a mesh-covered refuge (shaded grey) before the door (thick dotted black line) was raised remotely. The fish had to swim past a visual barrier before being able to see a food stimulus in one of two arms at the other end of the arena; the dotted lines represent lines of sight when the food stimulus was placed in the right side arm (bottom right of the figure, indicated by the arrow). The dashed lines connected to the food stimulus represent lines of sight when the fish first leave the refuge, and the other line is the point at which the fish were deemed to have made a decision as at this point the stimulus in the other arm (if present) would not be visible. Once this decision had been made, 2 bloodworms per fish being tested were released.
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f1: The experimental tank (to scale).Fish were habituated in a mesh-covered refuge (shaded grey) before the door (thick dotted black line) was raised remotely. The fish had to swim past a visual barrier before being able to see a food stimulus in one of two arms at the other end of the arena; the dotted lines represent lines of sight when the food stimulus was placed in the right side arm (bottom right of the figure, indicated by the arrow). The dashed lines connected to the food stimulus represent lines of sight when the fish first leave the refuge, and the other line is the point at which the fish were deemed to have made a decision as at this point the stimulus in the other arm (if present) would not be visible. Once this decision had been made, 2 bloodworms per fish being tested were released.

Mentions: Fish were tested in a V-shaped arena (Fig. 1), with fish starting at the base of the V in a darkened refuge. The latency to leave the refuge was used as a measure of risk-taking tendency as it is widely used to assess boldness, and has been shown to be repeatable in sticklebacks3032, correlated to other behavioural measures of risk-taking3334 and negatively related to anti-predatory morphological adaptations35. This is also ecologically important as refuge use affects predator-prey dynamics36, for example by affecting growth rates and fecundity in prey37 and having different effects on predators depending on their hunting strategy38. The fish had to swim past a visual barrier before being able to see a conspicuous food stimulus in one of two arms at the other end of the arena. When a fish had crossed the arena and entered the arm with the stimulus, two bloodworms per fish were released. Due to the greater analytical tractability in two-fish trials, we focus our analysis of social interactions on these trials, but also explore the consequences of boldness and its consistency on initiating leaving the refuge and food competition in the four-fish trials. Bolder individuals are more likely to accept risk (e.g. from predation3940) in return for greater rewards (e.g. during foraging32), and have been previously shown to be more likely to lead30 and outcompete others for food2. After controlling for average levels of boldness, we predicted that more consistent individuals would be less sensitive to being in a social context and thus be more likely to lead and less likely to follow their group mates.


Individuals that are consistent in risk-taking benefit during collective foraging
The experimental tank (to scale).Fish were habituated in a mesh-covered refuge (shaded grey) before the door (thick dotted black line) was raised remotely. The fish had to swim past a visual barrier before being able to see a food stimulus in one of two arms at the other end of the arena; the dotted lines represent lines of sight when the food stimulus was placed in the right side arm (bottom right of the figure, indicated by the arrow). The dashed lines connected to the food stimulus represent lines of sight when the fish first leave the refuge, and the other line is the point at which the fish were deemed to have made a decision as at this point the stimulus in the other arm (if present) would not be visible. Once this decision had been made, 2 bloodworms per fish being tested were released.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC5037426&req=5

f1: The experimental tank (to scale).Fish were habituated in a mesh-covered refuge (shaded grey) before the door (thick dotted black line) was raised remotely. The fish had to swim past a visual barrier before being able to see a food stimulus in one of two arms at the other end of the arena; the dotted lines represent lines of sight when the food stimulus was placed in the right side arm (bottom right of the figure, indicated by the arrow). The dashed lines connected to the food stimulus represent lines of sight when the fish first leave the refuge, and the other line is the point at which the fish were deemed to have made a decision as at this point the stimulus in the other arm (if present) would not be visible. Once this decision had been made, 2 bloodworms per fish being tested were released.
Mentions: Fish were tested in a V-shaped arena (Fig. 1), with fish starting at the base of the V in a darkened refuge. The latency to leave the refuge was used as a measure of risk-taking tendency as it is widely used to assess boldness, and has been shown to be repeatable in sticklebacks3032, correlated to other behavioural measures of risk-taking3334 and negatively related to anti-predatory morphological adaptations35. This is also ecologically important as refuge use affects predator-prey dynamics36, for example by affecting growth rates and fecundity in prey37 and having different effects on predators depending on their hunting strategy38. The fish had to swim past a visual barrier before being able to see a conspicuous food stimulus in one of two arms at the other end of the arena. When a fish had crossed the arena and entered the arm with the stimulus, two bloodworms per fish were released. Due to the greater analytical tractability in two-fish trials, we focus our analysis of social interactions on these trials, but also explore the consequences of boldness and its consistency on initiating leaving the refuge and food competition in the four-fish trials. Bolder individuals are more likely to accept risk (e.g. from predation3940) in return for greater rewards (e.g. during foraging32), and have been previously shown to be more likely to lead30 and outcompete others for food2. After controlling for average levels of boldness, we predicted that more consistent individuals would be less sensitive to being in a social context and thus be more likely to lead and less likely to follow their group mates.

View Article: PubMed Central - PubMed

ABSTRACT

It is well established that living in groups helps animals avoid predation and locate resources, but maintaining a group requires collective coordination, which can be difficult when individuals differ from one another. Personality variation (consistent behavioural differences within a population) is already known to be important in group interactions. Growing evidence suggests that individuals also differ in their consistency, i.e. differing in how variable they are over time, and theoretical models predict that this consistency can be beneficial in social contexts. We used three-spined sticklebacks (Gasterosteus aculeatus) to test whether the consistency in, as well as average levels of, risk taking behaviour (i.e. boldness) when individuals were tested alone affects social interactions when fish were retested in groups of 2 and 4. Behavioural consistency, independently of average levels of risk-taking, can be advantageous: more consistent individuals showed higher rates of initiating group movements as leaders, more behavioural coordination by joining others as followers, and greater food consumption. Our results have implications for both group decision making, as groups composed of consistent individuals are more cohesive, and personality traits, as social interactions can have functional consequences for consistency in behaviour and hence the evolution of personality variation.

No MeSH data available.


Related in: MedlinePlus