FORUM Behavioral syndromes: carryover effects, false discovery rates, and a priori hypotheses Ned... more FORUM Behavioral syndromes: carryover effects, false discovery rates, and a priori hypotheses Ned A. Dochtermann 437 Flush early and avoid the rush: a general rule of antipredator behavior? Daniel T. Blumstein 440 ORIGINAL ARTICLES Dominance in relation to age, sex, and competitive contexts in a group of free-ranging domestic dogs Simona Cafazzo, Paola Valsecchi, Roberto Bonanni, and Eugenia Natoli 443 Feeding decisions of eastern bluebirds are situationally influenced by fledgling plumage color Russell A.
FORUM: INVITED REVIEW Indicators of development as sexually selected traits: the developmental st... more FORUM: INVITED REVIEW Indicators of development as sexually selected traits: the developmental stress hypothesis in context Karen A. Spencer and Scott A. MacDougall-Shackleton 1 FORUM: COMMENTARIES ON INVITED REVIEW Stressing out about singing Michael M. Kasumovic 10 Are better singers smarter? Stephen Nowicki and William A. Searcy 10 Stressed singers and symmetric lovers Charlotta Kvarnemo 11 The developmental stress hypothesis: a special case of the evolution of condition-dependent sexual traits Katherine L.
Abstract How different levels of biological organization interact to shape each other's function ... more Abstract How different levels of biological organization interact to shape each other's function is a central question in biology. One particularly important topic in this context is how individuals' variation in behaviour shapes group-level characteristics.
The comparative approach has become a powerful tool for understanding how predation has shaped pr... more The comparative approach has become a powerful tool for understanding how predation has shaped prey behavior. In this study we recorded the occurrence of common aquatic predator species and their densities in seven natural populations of Trinidadian guppies, Poecilia reticulata. We then exposed shoals of guppies from each of these populations to a series of predator treatments.
Aggregations of different-looking animals are frequently seen in nature, despite well-documented ... more Aggregations of different-looking animals are frequently seen in nature, despite well-documented selection pressures on individuals to maintain phenotypically homogenous groups. Two well-known theories, the 'confusion effect' (reduced ability of a predator to accurately target an individual in a group) and the 'oddity effect' (preferential targeting of phenotypically distinct, 'odd', individuals) act together to predict the evolution of behaviours in prey that lead to groups of animals that are homogeneous in appearance. In contrast, a recently proposed mechanism suggests that mixed groups could be maintained if one species in a mixed group is more conspicuous against the habitat than the other, as confusion effects generated by the conspicuous species impede predator targeting of the cryptic species; thus, cryptic species benefit from association with conspicuous ones. We test these contrasting predictions from the perspective of both predators and prey, and show that cryptic individual Daphnia are at reduced risk of predation from three-spine sticklebacks Gasterosteus aculeatus when in mixed-phenotype groups, a risk that is reduced further as the number of conspicuous individuals increases, supporting the hypothesis for the evolution of mixed groups. In contrast, while the preference for associating with colour-matched conspecifics by mollies (Poecilia sphenops) was reduced when they were cryptic, we found no evidence for active association with conspicuous conspecifics. We conclude that prey animals must balance the relative risks of oddity and conspicuousness in their social decisions, and that this could potentially lead to the evolution of mixed-phenotype grouping as a response to predation risk alone.
Grouping behaviour is widespread across the animal kingdom, and is known to reduce an individual'... more Grouping behaviour is widespread across the animal kingdom, and is known to reduce an individual's risk of predation, for example through predator confusion. Theory predicts that individuals that are different in appearance to the rest of the group are at a greater risk of predation because they are more conspicuous to predators (the ‘oddity’ effect). Thus, animals should choose group mates that are the most similar in appearance to themselves. Another common antipredator tactic is crypsis (camouflage). Fishes are capable of changing colour to match their visual background, but few studies have examined how this might influence shoaling decisions, particularly in the context of the oddity effect. We induced colour pattern changes in a colourful species of freshwater fish, the western rainbowfish, Melanotaenia australis, by maintaining fish in dark and pale aquaria for 2 weeks. Analysis of the proportion of black body pigmentation confirmed that rainbowfish in dark environments developed darker colour patterns than those held in pale environments. We then conducted behavioural observations to determine whether fish subsequently based their shoaling decisions on body coloration. We found that rainbowfish preferred to shoal with similar individuals; fish that had been held in dark aquaria preferred to shoal with other dark fish and fish from pale aquaria preferred other pale fish. Our findings are consistent with the predictions of the oddity effect and demonstrate how morphological colour pattern changes and behavioural decisions interact to mediate antipredator tactics in fish.
Reciprocal altruism has been proposed as a possible mechanism for the evolution of cooperative be... more Reciprocal altruism has been proposed as a possible mechanism for the evolution of cooperative behaviour. However, very few investigations have tested predictions of reciprocity in wild animal populations. In the current investigation we simulated defection during predator inspection in a wild population of guppies, Poecilia reticulata. Two experiments were run: the first simulating defection during a single exposure to a predator and the second during multiple exposures to a predator. We then compared subsequent social and cooperative interactions with those observed prior to the treatments. From theory and previous experiments on cooperation and reciprocity, we predicted that defection would result in a reduction in social and cooperative interactions during subsequent predator inspections. However, our experiments did not find any effect of simulated defection(s) on the subsequent social structure, or on patterns of predator inspection behaviour. We discuss the potential reasons for the observed results and suggest future directions for research to address mechanisms underpinning the nature of cooperative interactions during predator inspection.
Group living is the result of a dynamic trade-off between associated costs and benefits. However,... more Group living is the result of a dynamic trade-off between associated costs and benefits. However, these costs and benefits are not necessarily distributed equally across different spatial positions of groups which may result in different fitness returns for individuals occupying different positions in groups. Here we consider whether leadership of a group during a navigation task in humans may have a specific cost associated with it. Pairs of students performed a counting task whilst walking through two obstacle courses, once as leader and once as follower. We found that leaders made significantly more errors in the counting task than followers suggesting that there is an attention cost associated with leadership/navigation behaviour.
FORUM Behavioral syndromes: carryover effects, false discovery rates, and a priori hypotheses Ned... more FORUM Behavioral syndromes: carryover effects, false discovery rates, and a priori hypotheses Ned A. Dochtermann 437 Flush early and avoid the rush: a general rule of antipredator behavior? Daniel T. Blumstein 440 ORIGINAL ARTICLES Dominance in relation to age, sex, and competitive contexts in a group of free-ranging domestic dogs Simona Cafazzo, Paola Valsecchi, Roberto Bonanni, and Eugenia Natoli 443 Feeding decisions of eastern bluebirds are situationally influenced by fledgling plumage color Russell A.
FORUM: INVITED REVIEW Indicators of development as sexually selected traits: the developmental st... more FORUM: INVITED REVIEW Indicators of development as sexually selected traits: the developmental stress hypothesis in context Karen A. Spencer and Scott A. MacDougall-Shackleton 1 FORUM: COMMENTARIES ON INVITED REVIEW Stressing out about singing Michael M. Kasumovic 10 Are better singers smarter? Stephen Nowicki and William A. Searcy 10 Stressed singers and symmetric lovers Charlotta Kvarnemo 11 The developmental stress hypothesis: a special case of the evolution of condition-dependent sexual traits Katherine L.
Abstract How different levels of biological organization interact to shape each other's function ... more Abstract How different levels of biological organization interact to shape each other's function is a central question in biology. One particularly important topic in this context is how individuals' variation in behaviour shapes group-level characteristics.
The comparative approach has become a powerful tool for understanding how predation has shaped pr... more The comparative approach has become a powerful tool for understanding how predation has shaped prey behavior. In this study we recorded the occurrence of common aquatic predator species and their densities in seven natural populations of Trinidadian guppies, Poecilia reticulata. We then exposed shoals of guppies from each of these populations to a series of predator treatments.
Aggregations of different-looking animals are frequently seen in nature, despite well-documented ... more Aggregations of different-looking animals are frequently seen in nature, despite well-documented selection pressures on individuals to maintain phenotypically homogenous groups. Two well-known theories, the 'confusion effect' (reduced ability of a predator to accurately target an individual in a group) and the 'oddity effect' (preferential targeting of phenotypically distinct, 'odd', individuals) act together to predict the evolution of behaviours in prey that lead to groups of animals that are homogeneous in appearance. In contrast, a recently proposed mechanism suggests that mixed groups could be maintained if one species in a mixed group is more conspicuous against the habitat than the other, as confusion effects generated by the conspicuous species impede predator targeting of the cryptic species; thus, cryptic species benefit from association with conspicuous ones. We test these contrasting predictions from the perspective of both predators and prey, and show that cryptic individual Daphnia are at reduced risk of predation from three-spine sticklebacks Gasterosteus aculeatus when in mixed-phenotype groups, a risk that is reduced further as the number of conspicuous individuals increases, supporting the hypothesis for the evolution of mixed groups. In contrast, while the preference for associating with colour-matched conspecifics by mollies (Poecilia sphenops) was reduced when they were cryptic, we found no evidence for active association with conspicuous conspecifics. We conclude that prey animals must balance the relative risks of oddity and conspicuousness in their social decisions, and that this could potentially lead to the evolution of mixed-phenotype grouping as a response to predation risk alone.
Grouping behaviour is widespread across the animal kingdom, and is known to reduce an individual'... more Grouping behaviour is widespread across the animal kingdom, and is known to reduce an individual's risk of predation, for example through predator confusion. Theory predicts that individuals that are different in appearance to the rest of the group are at a greater risk of predation because they are more conspicuous to predators (the ‘oddity’ effect). Thus, animals should choose group mates that are the most similar in appearance to themselves. Another common antipredator tactic is crypsis (camouflage). Fishes are capable of changing colour to match their visual background, but few studies have examined how this might influence shoaling decisions, particularly in the context of the oddity effect. We induced colour pattern changes in a colourful species of freshwater fish, the western rainbowfish, Melanotaenia australis, by maintaining fish in dark and pale aquaria for 2 weeks. Analysis of the proportion of black body pigmentation confirmed that rainbowfish in dark environments developed darker colour patterns than those held in pale environments. We then conducted behavioural observations to determine whether fish subsequently based their shoaling decisions on body coloration. We found that rainbowfish preferred to shoal with similar individuals; fish that had been held in dark aquaria preferred to shoal with other dark fish and fish from pale aquaria preferred other pale fish. Our findings are consistent with the predictions of the oddity effect and demonstrate how morphological colour pattern changes and behavioural decisions interact to mediate antipredator tactics in fish.
Reciprocal altruism has been proposed as a possible mechanism for the evolution of cooperative be... more Reciprocal altruism has been proposed as a possible mechanism for the evolution of cooperative behaviour. However, very few investigations have tested predictions of reciprocity in wild animal populations. In the current investigation we simulated defection during predator inspection in a wild population of guppies, Poecilia reticulata. Two experiments were run: the first simulating defection during a single exposure to a predator and the second during multiple exposures to a predator. We then compared subsequent social and cooperative interactions with those observed prior to the treatments. From theory and previous experiments on cooperation and reciprocity, we predicted that defection would result in a reduction in social and cooperative interactions during subsequent predator inspections. However, our experiments did not find any effect of simulated defection(s) on the subsequent social structure, or on patterns of predator inspection behaviour. We discuss the potential reasons for the observed results and suggest future directions for research to address mechanisms underpinning the nature of cooperative interactions during predator inspection.
Group living is the result of a dynamic trade-off between associated costs and benefits. However,... more Group living is the result of a dynamic trade-off between associated costs and benefits. However, these costs and benefits are not necessarily distributed equally across different spatial positions of groups which may result in different fitness returns for individuals occupying different positions in groups. Here we consider whether leadership of a group during a navigation task in humans may have a specific cost associated with it. Pairs of students performed a counting task whilst walking through two obstacle courses, once as leader and once as follower. We found that leaders made significantly more errors in the counting task than followers suggesting that there is an attention cost associated with leadership/navigation behaviour.
Game theory has been used to investigate a wide range of evolutionary questions, and has been imp... more Game theory has been used to investigate a wide range of evolutionary questions, and has been important in explaining apparently selfish patterns in animal behaviour, and behaviours that do not appear to benefit the individual. The modelling chapters in this thesis develop new game theory approaches to modelling animal conflict, investigating the acquisition of territories and the trade-offs that occur between behaviours. Many game theory models of conflicts between individuals make predictions regarding the duration of ...
Uploads