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Estresaditos cooperate

cooperation is undoubtedly one of the favorite topics of theoretical ecologists. A lot of mathematical models have been developed to try to understand under what conditions is cooperation more likely and what the benefits are short and long term of such conduct. Both model has not been in vain because they have helped us to understand and a pleasure to philosophize about the evolution of this behavior. However, it is still necessary to know more about what the proximate causes of cooperation, ie, what are the immediate triggers of the behavior and how these triggers vary from one individual to another according to their experience, internal state, physiology, etc. Some human studies have found that the inclination of individuals to punish those who cheated, in a situation where they could have cooperated, and correlates with the activity that these individuals have in the reward system; that which is right in the neocortex . Then, the action is exciting to punish cheaters more likely is the occurrence of punishment. Another study found that the highest levels were oxytocin (the hormone of happiness) in the blood more confident were the subjects of study, even in situations where the risk of being deceived was high. But how is the thing in those animals where there is also cooperation?

In an attempt to expand the doubts about this, the international team of Redouan Bshary , Rui F. and Alexandra Oliveira S. Grutter was given the task of making an experimental proof-of-a few questions about the factors that trigger or inhibit cooperation on cleaner fish. The results of their study were published this month in the journal Ethology .

No, cleaner fish do just that. Image taken from here .

The interactions of these small fish cleaners ( Dimidiatus Labroides ) with their clients are fascinating. Has been well documented that these fish offer a removal service to other fish parasites and for this they have to their individual cleaning stations. However, what is taste like mucus from the customers, ie, the living tissue of the same. When these fish endure the urge to eat mucus and parasites feed on are, say, eating against their preference. In doing so we might as well say they are "cooperating" because they would be exchanging the cleaning service for the opportunity to eat something. But it's not just cooperate with charming rather because they seem to know what kind of customers interact: when customers are predatory fish, which potentially could respond to abuse with a cleaner fish bite-abuse least compared with customers who are not predators. That is, eat more of the parasites of a predator that their client mucus. Biologists know that interactions are observed when a client has received a bribe in the mucus and the client in question jumps, in a manner similar to that of any human on the beach that has been chewed by a fish. Since fish cleaners can be more than 2000 daily interactions with customers Redouan and his team suggest that cleaner fish should be able to adjust their levels of exploitation in ways that maximize their caloric intake by taking into account the risk of predation. If so, the fish cleaners should be able to adjust their abuse of interaction to another, so that a particular interaction may determine the subsequent. For example, a customer interaction with a predator could affect their stress levels and satiety and thus the subsequent cooperation with customers. For their study, Redouan, Rui and Alexandra, gathered data taken in the tropical waters of Egypt and data collected in the laboratory of Alexandra, in Australia. So not only was international team of researchers also observed the fish belonged to different latitudes. With data from field observations analyzed the effect of the client in subsequent interactions and found that a given customer is less likely to be chewed when the client was a client before predator. cleaning station. Image Nick Hobgood taken Wikimedia Commons . In the laboratory, tested the effect of a stressor-in this case a red-before offering a favorite food (shrimp chips) and some less so ( fish food) at the same time. Previous studies have shown that fish prefer to always eat shrimp flakes compared to the boring business. However, during the experiment, leaflets were removed immediately after the fish taste the shrimp. So if the fish wanted to eat something it was imperative to eat against their preference, eating chips sink his teeth before the shrimp. Interestingly, laboratory fish ate more often against their preference when they had been exposed to stressful network. The study authors considered that the cleaners were stressed because they proved to flee and to present certain characteristic movements in these situations and are similar to a "dance." With this, the authors wanted to show whether the quality of service of a cleaner fish depend solely on the customer's identity or if the service is modified by other stress in the aquatic life of fish. The field observations allowed the authors do not distinguish whether the change in attitude of the cleaner after a customer interacted with predator to the next was due to an "internal state" of fish satiation level wiper or due to a physiological change resulting from the interaction with the predator. However, the fact that after being subjected to stressor (red) cleaners were more inclined to feed against their preference (as when they cooperate) suggests that 1) the fish can actively select food on the other (in other words, stress does not confuse the issue) and 2) that have been exposed to a stressful situation makes them more prone to cooperation. latter, however, needs to be checked with other experiments in which the handling of the cleaner fish physiology, eg varying the level of hormones related to stress rather than using a network. So Redouan and computer, using field and laboratory information on these fishes showed the existence of short-term variation in the feeding behavior of fish cleaners. Their results suggest that short-term stress-whether in the form of a predator or a network-promotes cooperation in these fish with a tendency to abuse. Reference article:

Bshary, R., Oliveira, R., & Grutter, A. (2011). Short-Term Variation in the Level of Cooperation in the Cleaner Wrasse Labroides dimidiatus: Implications for the Role of Potential Stressors Ethology, 117 (3), 246-253 DOI: 10.1111/j.1439-0310.2010.01872.x