Relationship between cleaning rates and ectoparasite loads in coral reef fishes

Wickler²,

Fricke³

2001

Anim.Cogn.

240

166

We provide selected examples from the fish literature of phenomena found in fish that are currently being examined in discussions of cognitive abilities and evolution of neocortex size in primates. In the context of social intelligence, we looked at living in individualised groups and corresponding social strategies, social learning and tradition, and co-operative hunting. Regarding environmental intelligence, we searched for examples concerning special foraging skills, tool use, cognitive maps, memory, anti-predator behaviour, and the manipulation of the environment. Most phenomena of interest for primatologists are found in fish as well. We therefore conclude that more detailed studies on decision rules and mechanisms are necessary to test for differences between the cognitive abilities of primates and other taxa. Cognitive research can benefit from future fish studies in three ways: first, as fish are highly variable in their ecology, they can be used to determine the specific ecological factors that select for the evolution of specific cognitive abilities. Second, for the same reason they can be used to investigate the link between cognitive abilities and the enlargement of specific brain areas. Third, decision rules used by fish could be used as 'null-hypotheses' for primatologists looking at how monkeys might make their decisions. Finally, we propose a variety of fish species that we think are most promising as study objects.

Section: Social Learning and Traditionmentioning

confidence: 99%

Fish cognition: a primate's eye view

Wickler²,

Fricke³

2001

Anim.Cogn.

240

166

“…Rather than avoiding cleaners on the basis of personal negative experience, clients could use information from observed interactions and attribute an image to the cleaner. As cleaners have more than 2000 interactions per day (Grutter 1995), interactions indeed often take place in the presence of other clients. Note that image scoring is one sided as non-predatory clients have no means to cheat cleaners and cleaners therefore do not need to attribute an image to their clients (attributing an image score to predatory clients would be useful if the predator interacted in sight with another cleaner, which is an unlikely scenario).…”

Section: Introductionmentioning

confidence: 99%

Biting cleaner fish use altruism to deceive image–scoring client reef fish

2002

Proc. R. Soc. Lond. B

131

110

Humans are more likely to help those who they have observed helping others previously. Individuals may thus benefit from being altruistic without direct reciprocity of recipients but due to gains in 'image' and associated indirect reciprocity. I suggest, however, that image-scoring individuals may be exploitable by cheaters if pay-offs vary between interactions. I illustrate this point with data on cleaner-client reef fish interactions. I show the following: (i) there is strong variation between cleaners with respect to cheating of clients (i.e. feeding on client tissue instead of parasites); (ii) clients approach cleaners, that they observe cooperating with their current client and avoid cleaners that they observe cheating; (iii) cleaners that cheat frequently are avoided more frequently than more cooperative cleaners; (iv) cleaners that cheat frequently behave altruistically towards their smallest client species; (v) altruistic acts are followed by exploitative interactions. Thus, it appears that cleaners indeed have an image score, which selects for cooperative cleaners. However, cheating cleaners use altruism in potentially low-pay-off interactions to deceive and attract image-scoring clients that will be exploited.

“…We have used the last example as our model system. Cleaners prefer the mucus of some client species more than gnathiid isopods 7 , the most commonly found ectoparasites of reef fishes 14 . Clients use various actions to make cleaners forage against their preference 15,16 , the simplest form of control being to terminate the interaction by swimming off in response to a cheating bite 17 .…”

mentioning

confidence: 99%

Pairs of cooperating cleaner fish provide better service quality than singletons

Grutter

Willener

et al. 2008

Nature

110

Service providers may vary service quality depending on whether they work alone or provide the service simultaneously with a partner. The latter case resembles a prisoner's dilemma [1][2][3][4] , in which one provider may try to reap the benefits of the interaction without providing the service. Here we present a game-theory model based on the marginal value theorem 5 , which predicts that as long as the client determines the duration, and the providers cooperate towards mutual gain, service quality will increase in the pair situation. This prediction is consistent with field observations and with an experiment on cleaning mutualism, in which stable male-female pairs of the cleaner wrasse Labroides dimidiatus repeatedly inspect client fish jointly. Cleaners cooperate by eating ectoparasites 6 off clients but actually prefer to cheat and eat client mucus 7 . Because clients often leave in response to such cheating, the benefits of cheating can be gained by only one cleaner during a pair inspection. In both data sets, the increased service quality during pair inspection was mainly due to the smaller females behaving significantly more cooperatively than their larger male partners. In contrast, during solitary inspections, cleaning behaviour was very similar between the sexes. Our study highlights the importance of incorporating interactions between service providers to make more quantitative predictions about cooperation between species.Many cooperative interactions can be seen as an exchange of goods, services or commodities between two classes of traders [8][9][10] . Here we investigated traders that provide a service to a second class of traders, such as an ant partner species-for example, lycaenid butterfly larvae-providing a sugary solution to ants 11 , rhizobial bacteria fixing nitrogen for leguminous plants 12 or cleaner fish removing ectoparasites from client reef fish 13 . We have used the last example as our model system. Cleaners prefer the mucus of some client species more than gnathiid isopods 7 , the most commonly found ectoparasites of reef fishes 14 . Clients use various actions to make cleaners forage against their preference 15,16 , the simplest form of control being to terminate the interaction by swimming off in response to a cheating bite 17 . Adult cleaners often live in pairs of a male and the largest female in his harem 18 and they commonly inspect larger clients simultaneously. Pair inspections result in cleaners facing a problem: a visiting client may leave after a cheat, even though only one cleaner was responsible for the cheating whereas the second cleaner cooperated. Hence, the cooperative cleaner loses a foraging opportunity owing to its partner's action, whereas the cheating cleaner gains a bite of mucus. We explored both mathematically and empirically how these pay-off asymmetries influence the service quality provided in paired compared with solitary inspections.We explored a game in which one class of individuals provides a service (cleaners remove ectoparasites) to a second clas...