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The guppy Poecilia reticulata has proven a model species for behavioural ecology; in this thesis, its patterns of group-living were examined in a variety of contexts. These fish engage in inspection, the risky approaching of a predator to gain information on the threat posed. To lessen this risk, guppies may cooperate by approaching together, taking it in turns to advance. The temptation is for fish to defect by holding back and observing the inspection of others, gaining information at their partner's expense. Theory predicts that individuals should associate with those that have been previously cooperative in order to avoid being defected against. To test this, I quantified the social networks of wild-caught female shoals of guppies and then exposed them to a pike cichlid predator Crenicichla frenata. Guppies that inspected together frequently were both more cooperative and more associated in the network than infrequently inspecting partners. Simulating defection by preventing some fish inspecting. in similar female shoals, I found, contrary to predictions, that there was no change in the preference of others. to partner with them afterwards. Guppies appear to assort with respect to cooperation but not reassort in response to defection. Additional experiments found that the number of fish, and thus the number of partners to choose from, did not change how cooperative fish were during inspection, perhaps because of consistent partner choice. I then examined if these stable partnerships observed in the laboratory occurred in the much larger social networks seen in the wild. I found that female guppies of similar inspection tendencies interacted more often than predicted by random models. If guppies prefer shoaling with particular individuals over others, they may learn preferentially from others also. Testing shoals of domestic female guppies in a novel foraging task, naIve guppies performed the task fas~er when a trained fish was highly connected to them in their social network. However, if there were two trained fish with conflicting tasks, then they performed the task of the less connected fish faster. The network position of trained fish appears to impact upon the potential for social learning of naIve fish but other factors, e.g. the competitive ability of the trained fish, may influence how naIve fish act on that information. Thus we see that the benefits to a fish of shoaling with others depend upon the shoaling partners chosen and that guppies exercise this choice with care in a number of contexts.

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Here I search for the potential relationship between behavioural flexibility and brains in cephalopods, within and between species, foIIowing the behavioural drive (Wyles et al., 1983). At the intra-specific level (Octopus vulgaris), I evaluated whether differences in performance between individuals reflected differences in body and brain size and the effect of other intervening factors (e.g. sex, site of capture). In order to do so, a battery of eight consecutive experiments (spamling over 12 days) was presented to a total of 55 naIve octopuses (other 46 animals figured as controls). I utilized Octopus' predatory behaviour to measure its: ability to adapt to the captive condition (Acclimatization); response towards novel stimuli (Neophobia); capability of social learning; capacity to apply previous experience to a novel context (Innovation), and response to artificial baIls (Preferences and Individual learning). The results show that octopuses were able to adjust their predatory behaviour to the multitude of tasks they were faced with. Performances were distributed along a continuum characterized by a progressively: quicker recovery in predatory performance, higher success rate in problem-solving tasks and higher exploration rate. Age appeared to be correlated with the exploratory behaviour of the animals. Moreover, I found that environment and life rustory traits could affect Octopus' behaviour and learning capabilities. I discuss these findings foIIowing the current literature on cephalopods and other animal models, including vertebrates. At the inter-specific level, I attempted to relate the brain size and the behaviour of cephalopods with their life history~ ecology and distribution. I found a good relationship between cerebrotypes and life styles in this taxon. My results support the working hypothesis that the taxon evolved different sensorial and computational strategies to cope with the various environments (niches) occupied in the oceans. This study is novel for invertebrates, to the best of my knoHere I search for the potential relationship between behavioural flexibility and brains in cephalopods, within and between species, foIIowing the behavioural drive (Wyles et al., 1983). At the intra-specific level (Octopus vulgaris), I evaluated whether differences in performance between individuals reflected differences in body and brain size and the effect of other intervening factors (e.g. sex, site of capture). In order to do so, a battery of eight consecutive experiments (spamling over 12 days) was presented to a total of 55 naIve octopuses (other 46 animals figured as controls). I utilized Octopus' predatory behaviour to measure its: ability to adapt to the captive condition (Acclimatization); response towards novel stimuli (Neophobia); capability of social learning; capacity to apply previous experience to a novel context (Innovation), and response to artificial baIls (Preferences and Individual learning). The results show that octopuses were able to adjust their predatory behaviour to the multitude of tasks they were faced with. Performances were distributed along a continuum characterized by a progressively: quicker recovery in predatory performance, higher success rate in problem-solving tasks and higher exploration rate. Age appeared to be correlated with the exploratory behaviour of the animals. Moreover, I found that environment and life rustory traits could affect Octopus' behaviour and learning capabilities. I discuss these findings foIIowing the current literature on cephalopods and other animal models, including vertebrates. At the inter-specific level, I attempted to relate the brain size and the behaviour of cephalopods with their life history~ ecology and distribution. I found a good relationship between cerebrotypes and life styles in this taxon. My results support the working hypothesis that the taxon evolved different sensorial and computational strategies to cope with the various environments (niches) occupied in the oceans. This study is novel for invertebrates, to the best of my knowledge. Here I search for the potential relationship between behavioural flexibility and brains in cephalopods, within and between species, foIIowing the behavioural drive (Wyles et al., 1983). At the intra-specific level (Octopus vulgaris), I evaluated whether differences in performance between individuals reflected differences in body and brain size and the effect of other intervening factors (e.g. sex, site of capture). In order to do so, a battery of eight consecutive experiments (spamling over 12 days) was presented to a total of 55 naIve octopuses (other 46 animals figured as controls). I utilized Octopus' predatory behaviour to measure its: ability to adapt to the captive condition (Acclimatization); response towards novel stimuli (Neophobia); capability of social learning; capacity to apply previous experience to a novel context (Innovation), and response to artificial baIls (Preferences and Individual learning). The results show that octopuses were able to adjust their predatory behaviour to the multitude of tasks they were faced with. Performances were distributed along a continuum characterized by a progressively: quicker recovery in predatory performance, higher success rate in problem-solving tasks and higher exploration rate. Age appeared to be correlated with the exploratory behaviour of the animals. Moreover, I found that environment and life rustory traits could affect Octopus' behaviour and learning capabilities. I discuss these findings foIIowing the current literature on cephalopods and other animal models, including vertebrates. At the inter-specific level, I attempted to relate the brain size and the behaviour of cephalopods with their life history~ ecology and distribution. I found a good relationship between cerebrotypes and life styles in this taxon. My results support the working hypothesis that the taxon evolved different sensorial and computational strategies to cope with the various environments (niches) occupied in the oceans. This study is novel for invertebrates, to the best of my knowledge.

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