A recent study from the University of Exeter presented an intriguing discovery, suggesting that Trinidadian guppies may challenge the established concept of the “volunteer’s dilemma.” This idea suggests that individuals within larger groups tend to cooperate less, relying on the presumption that others within the group will undertake necessary risks.
However, the study proposes a counter to this belief. In the context of larger shoals, Trinidadian guppies appear more likely to take risks such as venturing close to predators, thereby contributing to the overall benefit of the group. The research team believes that this unexpected cooperation could result from a higher number of cooperative individuals present within larger groups.
The “volunteer’s dilemma” notion postulates a decrease in cooperation within larger groups. Numerous studies have evidenced this trend in humans, yet guppies appear to deviate from this established pattern.
In the conducted experiment, guppies in larger groups showed more willingness to approach predators to gather information for the group’s benefit. “When a potential predator is present, guppies have to weigh risks,” said Rebecca Padget, a researcher at Exeter’s Centre for Research in Animal Behaviour.
“Though a guppy that approaches might get eaten, if no guppy takes this risk, the whole group is at risk. The ‘volunteer’s dilemma’ suggests that individuals in larger groups would be less cooperative, but our observations defy that,” Padget added.
To validate these findings, the researchers conducted a test by placing a clay model of a pike cichlid (a guppy’s natural predator) in a tank with small (5), medium (10), and large (20) groups of guppies. Against all expectations, guppies from the larger groups were more likely to inspect the predator. They were observed doing this an average of 14 times during the seven-minute trials.
In contrast, guppies in the medium-sized groups were less likely to approach, doing so an average of seven times each. These individuals also spent the most time in “refuges,” areas behind plants or near the tank’s edge.
Padget commented on these findings, saying, “We can’t definitively say why guppies in larger groups cooperated more. We know that guppies have distinct personalities, which could mean larger groups are more likely to have more cooperative individuals, possibly influencing others to follow their lead.”
After inspecting a predator, guppies return to their group. Previous studies suggest their behavior upon return communicates the danger to the others. The research defined an “inspection” as a guppy coming within 30 cm (12 inches) of the predator, usually performed by individuals or small sub-groups within the main shoal.
The results of this study, titled “Guppies in large groups cooperate more frequently in an experimental test of the group size paradox,” were published in the Proceedings of the Royal Society B journal.
Reference: “Guppies in large groups cooperate more frequently in an experimental test of the group size paradox” by Rebecca F. B. Padget, Tim W. Fawcett, and Safi K. Darden, 12 July 2023, Proceedings of the Royal Society B. DOI: 10.1098/rspb.2023.0790
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Frequently Asked Questions (FAQs) about Trinidadian guppies cooperation
What species did the University of Exeter study to explore the “volunteer’s dilemma” concept?
The University of Exeter studied Trinidadian guppies to explore and challenge the concept of the “volunteer’s dilemma.”
What is the “volunteer’s dilemma”?
The “volunteer’s dilemma” is a concept suggesting that individuals in larger groups are less likely to cooperate due to the assumption that others in the group will undertake necessary risks.
How did Trinidadian guppies challenge the “volunteer’s dilemma”?
In contradiction to the “volunteer’s dilemma” concept, Trinidadian guppies in larger shoals were observed to be more likely to take risks, such as approaching predators, for the collective benefit of the group.
How was the study conducted?
The researchers conducted the study by placing a clay model of a pike cichlid, a natural predator of guppies, in a tank with small (5), medium (10), and large (20) groups of guppies. They then observed the guppies’ interactions with the model.
What was the unexpected behavior observed in guppies in larger groups?
Guppies in the larger groups were more likely to approach and inspect the predator, contradicting the “volunteer’s dilemma” that suggests individuals in larger groups should be less willing to cooperate.
Where were the results of this study published?
The results of this study were published in the Proceedings of the Royal Society B journal.
More about Trinidadian guppies cooperation
- University of Exeter’s Centre for Research in Animal Behaviour
- The “Volunteer’s Dilemma” concept
- Proceedings of the Royal Society B Journal
- Information on Trinidadian Guppies
