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Niclas Kolm - One of the best experts on this subject based on the ideXlab platform.
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Brain Size does not predict learning strategies in a serial reversal learning test.
The Journal of experimental biology, 2020Co-Authors: Annika Boussard, Alexander Kotrschal, Severine D. Buechel, Mirjam Amcoff, Niclas KolmAbstract:Reversal learning assays are commonly used across a wide range of taxa to investigate associative learning and behavioural flexibility. In serial reversal learning, the reward contingency in a binary discrimination is reversed multiple times. Performance during serial reversal learning varies greatly at the interspecific level, as some animals adopt a rule-based strategy that enables them to switch quickly between reward contingencies. A larger relative Brain Size, generating enhanced learning ability and increased behavioural flexibility, has been proposed to be an important factor underlying this variation. Here, we experimentally tested this hypothesis at the intraspecific level. We used guppies (Poecilia reticulata) artificially selected for small and large relative Brain Size, with matching differences in neuron number, in a serial reversal learning assay. We tested 96 individuals over 10 serial reversals and found that learning performance and memory were predicted by Brain Size, whereas differences in efficient learning strategies were not. We conclude that variation in Brain Size and neuron number is important for variation in learning performance and memory, but these differences are not great enough to cause the larger differences in efficient learning strategies observed at higher taxonomic levels.
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variation in sexual Brain Size dimorphism over the breeding cycle in the three spined stickleback
The Journal of Experimental Biology, 2019Co-Authors: Severine D. Buechel, Niclas Kolm, Kristina Noreikiene, Jacquelin Defaveri, Elisavet A Toli, Juha MerilaAbstract:Snapshot analyses have demonstrated dramatic intraspecific variation in the degree of Brain sexual Size dimorphism (SSD). Although Brain SSD is believed to be generated by the sex-specific cognitive demands of reproduction, the relative roles of developmental and population-specific contributions to variation in Brain SSD remain little studied. Using a common garden experiment, we tested for sex-specific changes in Brain anatomy over the breeding cycle in three-spined stickleback (Gasterosteus aculeatus) sampled from four locations in northern Europe. We found that the male Brain increased in Size (ca. 24%) significantly more than the female Brain towards breeding, and that the resulting Brain SSD was similar (ca. 20%) for all populations over the breeding cycle. Our findings support the notion that the stickleback Brain is highly plastic and changes over the breeding cycle, especially in males, likely as an adaptive response to the cognitive demands of reproduction (e.g. nest construction and parental care). The results also provide evidence to suggest that breeding-related changes in Brain Size may be the reason for the widely varying estimates of Brain SSD across studies of this species, cautioning against interpreting Brain Size measurements from a single time point as fixed/static.
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Brain Size affects performance in a reversal learning test
Proceedings of The Royal Society B: Biological Sciences, 2018Co-Authors: Severine D. Buechel, Alexander Kotrschal, Annika Boussard, Wouter Van Der Bijl, Niclas KolmAbstract:It has become increasingly clear that a larger Brain can confer cognitive benefits. Yet not all of the numerous aspects of cognition seem to be affected by Brain Size. Recent evidence suggests that some more basic forms of cognition, for instance colour vision, are not influenced by Brain Size. We therefore hypotheSize that a larger Brain is especially beneficial for distinct and gradually more complex aspects of cognition. To test this hypothesis, we assessed the performance of Brain Size selected female guppies ( Poecilia reticulata ) in two distinct aspects of cognition that differ in cognitive complexity. In a standard reversal-learning test we first investigated basic learning ability with a colour discrimination test, then reversed the reward contingency to specifically test for cognitive flexibility. We found that large-Brained females outperformed small-Brained females in the reversed-learning part of the test but not in the colour discrimination part of the test. Large-Brained individuals are hence cognitively more flexible, which probably yields fitness benefits, as they may adapt more quickly to social and/or ecological cognitive challenges. Our results also suggest that a larger Brain becomes especially advantageous with increasing cognitive complexity. These findings corroborate the significance of Brain Size for cognitive evolution.
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female Brain Size affects the assessment of male attractiveness during mate choice
Science Advances, 2017Co-Authors: Alberto Corrallopez, Alexander Kotrschal, Severine D. Buechel, Wouter Van Der Bijl, Natasha I Bloch, Judith E Mank, Niclas KolmAbstract:Mate choice decisions are central in sexual selection theory aimed to understand how sexual traits evolve and their role in evolutionary diversification. We test the hypothesis that Brain Size and cognitive ability are important for accurate assessment of partner quality and that variation in Brain Size and cognitive ability underlies variation in mate choice. We compared sexual preference in guppy female lines selected for divergence in relative Brain Size, which we have previously shown to have substantial differences in cognitive ability. In a dichotomous choice test, large-Brained and wild-type females showed strong preference for males with color traits that predict attractiveness in this species. In contrast, small-Brained females showed no preference for males with these traits. In-depth analysis of optomotor response to color cues and gene expression of key opsins in the eye revealed that the observed differences were not due to differences in visual perception of color, indicating that differences in the ability to process indicators of attractiveness are responsible. We thus provide the first experimental support that individual variation in Brain Size affects mate choice decisions and conclude that differences in cognitive ability may be an important underlying mechanism behind variation in female mate choice.
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Artificial selection on male genitalia length alters female Brain Size
Proceedings of the Royal Society B: Biological Sciences, 2016Co-Authors: Severine D. Buechel, Isobel Booksmythe, Michael D Jennions, Alexander Kotrschal, Niclas KolmAbstract:SDB, 0000-0002-2385-2973 Male harassment is a classic example of how sexual conflict over mating leads to sex-specific behavioural adaptations. Females often suffer significant costs from males attempting forced copulations, and the sexes can be in an arms race over male coercion. Yet, despite recent recognition that divergent sex-specific interests in reproduction can affect Brain evolution, sexual conflict has not been addressed in this context. Here, we investigate whether artificial selection on a correlate of male success at coercion, genital length, affects Brain anatomy in males and females. We analysed the Brains of east-ern mosquitofish (Gambusia holbrooki), which had been artificially selected for long or short gonopodium, thereby mimicking selection arising from differing levels of male harassment. By analogy to how prey species often have relatively larger Brains than their predators, we found that female, but not male, Brain Size was greater following selection for a longer gonopo-dium. Brain subregion volumes remained unchanged. These results suggest that there is a positive genetic correlation between male gonopodium length and female Brain Size, which is possibly linked to increased female cogni-tive ability to avoid male coercion. We propose that sexual conflict is an important factor in the evolution of Brain anatomy and cognitive ability.
Severine D. Buechel - One of the best experts on this subject based on the ideXlab platform.
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Brain Size does not predict learning strategies in a serial reversal learning test.
The Journal of experimental biology, 2020Co-Authors: Annika Boussard, Alexander Kotrschal, Severine D. Buechel, Mirjam Amcoff, Niclas KolmAbstract:Reversal learning assays are commonly used across a wide range of taxa to investigate associative learning and behavioural flexibility. In serial reversal learning, the reward contingency in a binary discrimination is reversed multiple times. Performance during serial reversal learning varies greatly at the interspecific level, as some animals adopt a rule-based strategy that enables them to switch quickly between reward contingencies. A larger relative Brain Size, generating enhanced learning ability and increased behavioural flexibility, has been proposed to be an important factor underlying this variation. Here, we experimentally tested this hypothesis at the intraspecific level. We used guppies (Poecilia reticulata) artificially selected for small and large relative Brain Size, with matching differences in neuron number, in a serial reversal learning assay. We tested 96 individuals over 10 serial reversals and found that learning performance and memory were predicted by Brain Size, whereas differences in efficient learning strategies were not. We conclude that variation in Brain Size and neuron number is important for variation in learning performance and memory, but these differences are not great enough to cause the larger differences in efficient learning strategies observed at higher taxonomic levels.
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variation in sexual Brain Size dimorphism over the breeding cycle in the three spined stickleback
The Journal of Experimental Biology, 2019Co-Authors: Severine D. Buechel, Niclas Kolm, Kristina Noreikiene, Jacquelin Defaveri, Elisavet A Toli, Juha MerilaAbstract:Snapshot analyses have demonstrated dramatic intraspecific variation in the degree of Brain sexual Size dimorphism (SSD). Although Brain SSD is believed to be generated by the sex-specific cognitive demands of reproduction, the relative roles of developmental and population-specific contributions to variation in Brain SSD remain little studied. Using a common garden experiment, we tested for sex-specific changes in Brain anatomy over the breeding cycle in three-spined stickleback (Gasterosteus aculeatus) sampled from four locations in northern Europe. We found that the male Brain increased in Size (ca. 24%) significantly more than the female Brain towards breeding, and that the resulting Brain SSD was similar (ca. 20%) for all populations over the breeding cycle. Our findings support the notion that the stickleback Brain is highly plastic and changes over the breeding cycle, especially in males, likely as an adaptive response to the cognitive demands of reproduction (e.g. nest construction and parental care). The results also provide evidence to suggest that breeding-related changes in Brain Size may be the reason for the widely varying estimates of Brain SSD across studies of this species, cautioning against interpreting Brain Size measurements from a single time point as fixed/static.
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Brain Size affects performance in a reversal learning test
Proceedings of The Royal Society B: Biological Sciences, 2018Co-Authors: Severine D. Buechel, Alexander Kotrschal, Annika Boussard, Wouter Van Der Bijl, Niclas KolmAbstract:It has become increasingly clear that a larger Brain can confer cognitive benefits. Yet not all of the numerous aspects of cognition seem to be affected by Brain Size. Recent evidence suggests that some more basic forms of cognition, for instance colour vision, are not influenced by Brain Size. We therefore hypotheSize that a larger Brain is especially beneficial for distinct and gradually more complex aspects of cognition. To test this hypothesis, we assessed the performance of Brain Size selected female guppies ( Poecilia reticulata ) in two distinct aspects of cognition that differ in cognitive complexity. In a standard reversal-learning test we first investigated basic learning ability with a colour discrimination test, then reversed the reward contingency to specifically test for cognitive flexibility. We found that large-Brained females outperformed small-Brained females in the reversed-learning part of the test but not in the colour discrimination part of the test. Large-Brained individuals are hence cognitively more flexible, which probably yields fitness benefits, as they may adapt more quickly to social and/or ecological cognitive challenges. Our results also suggest that a larger Brain becomes especially advantageous with increasing cognitive complexity. These findings corroborate the significance of Brain Size for cognitive evolution.
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female Brain Size affects the assessment of male attractiveness during mate choice
Science Advances, 2017Co-Authors: Alberto Corrallopez, Alexander Kotrschal, Severine D. Buechel, Wouter Van Der Bijl, Natasha I Bloch, Judith E Mank, Niclas KolmAbstract:Mate choice decisions are central in sexual selection theory aimed to understand how sexual traits evolve and their role in evolutionary diversification. We test the hypothesis that Brain Size and cognitive ability are important for accurate assessment of partner quality and that variation in Brain Size and cognitive ability underlies variation in mate choice. We compared sexual preference in guppy female lines selected for divergence in relative Brain Size, which we have previously shown to have substantial differences in cognitive ability. In a dichotomous choice test, large-Brained and wild-type females showed strong preference for males with color traits that predict attractiveness in this species. In contrast, small-Brained females showed no preference for males with these traits. In-depth analysis of optomotor response to color cues and gene expression of key opsins in the eye revealed that the observed differences were not due to differences in visual perception of color, indicating that differences in the ability to process indicators of attractiveness are responsible. We thus provide the first experimental support that individual variation in Brain Size affects mate choice decisions and conclude that differences in cognitive ability may be an important underlying mechanism behind variation in female mate choice.
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Artificial selection on male genitalia length alters female Brain Size
Proceedings of the Royal Society B: Biological Sciences, 2016Co-Authors: Severine D. Buechel, Isobel Booksmythe, Michael D Jennions, Alexander Kotrschal, Niclas KolmAbstract:SDB, 0000-0002-2385-2973 Male harassment is a classic example of how sexual conflict over mating leads to sex-specific behavioural adaptations. Females often suffer significant costs from males attempting forced copulations, and the sexes can be in an arms race over male coercion. Yet, despite recent recognition that divergent sex-specific interests in reproduction can affect Brain evolution, sexual conflict has not been addressed in this context. Here, we investigate whether artificial selection on a correlate of male success at coercion, genital length, affects Brain anatomy in males and females. We analysed the Brains of east-ern mosquitofish (Gambusia holbrooki), which had been artificially selected for long or short gonopodium, thereby mimicking selection arising from differing levels of male harassment. By analogy to how prey species often have relatively larger Brains than their predators, we found that female, but not male, Brain Size was greater following selection for a longer gonopo-dium. Brain subregion volumes remained unchanged. These results suggest that there is a positive genetic correlation between male gonopodium length and female Brain Size, which is possibly linked to increased female cogni-tive ability to avoid male coercion. We propose that sexual conflict is an important factor in the evolution of Brain anatomy and cognitive ability.
Alexander Kotrschal - One of the best experts on this subject based on the ideXlab platform.
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Brain Size does not predict learning strategies in a serial reversal learning test.
The Journal of experimental biology, 2020Co-Authors: Annika Boussard, Alexander Kotrschal, Severine D. Buechel, Mirjam Amcoff, Niclas KolmAbstract:Reversal learning assays are commonly used across a wide range of taxa to investigate associative learning and behavioural flexibility. In serial reversal learning, the reward contingency in a binary discrimination is reversed multiple times. Performance during serial reversal learning varies greatly at the interspecific level, as some animals adopt a rule-based strategy that enables them to switch quickly between reward contingencies. A larger relative Brain Size, generating enhanced learning ability and increased behavioural flexibility, has been proposed to be an important factor underlying this variation. Here, we experimentally tested this hypothesis at the intraspecific level. We used guppies (Poecilia reticulata) artificially selected for small and large relative Brain Size, with matching differences in neuron number, in a serial reversal learning assay. We tested 96 individuals over 10 serial reversals and found that learning performance and memory were predicted by Brain Size, whereas differences in efficient learning strategies were not. We conclude that variation in Brain Size and neuron number is important for variation in learning performance and memory, but these differences are not great enough to cause the larger differences in efficient learning strategies observed at higher taxonomic levels.
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Brain Size affects performance in a reversal learning test
Proceedings of The Royal Society B: Biological Sciences, 2018Co-Authors: Severine D. Buechel, Alexander Kotrschal, Annika Boussard, Wouter Van Der Bijl, Niclas KolmAbstract:It has become increasingly clear that a larger Brain can confer cognitive benefits. Yet not all of the numerous aspects of cognition seem to be affected by Brain Size. Recent evidence suggests that some more basic forms of cognition, for instance colour vision, are not influenced by Brain Size. We therefore hypotheSize that a larger Brain is especially beneficial for distinct and gradually more complex aspects of cognition. To test this hypothesis, we assessed the performance of Brain Size selected female guppies ( Poecilia reticulata ) in two distinct aspects of cognition that differ in cognitive complexity. In a standard reversal-learning test we first investigated basic learning ability with a colour discrimination test, then reversed the reward contingency to specifically test for cognitive flexibility. We found that large-Brained females outperformed small-Brained females in the reversed-learning part of the test but not in the colour discrimination part of the test. Large-Brained individuals are hence cognitively more flexible, which probably yields fitness benefits, as they may adapt more quickly to social and/or ecological cognitive challenges. Our results also suggest that a larger Brain becomes especially advantageous with increasing cognitive complexity. These findings corroborate the significance of Brain Size for cognitive evolution.
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female Brain Size affects the assessment of male attractiveness during mate choice
Science Advances, 2017Co-Authors: Alberto Corrallopez, Alexander Kotrschal, Severine D. Buechel, Wouter Van Der Bijl, Natasha I Bloch, Judith E Mank, Niclas KolmAbstract:Mate choice decisions are central in sexual selection theory aimed to understand how sexual traits evolve and their role in evolutionary diversification. We test the hypothesis that Brain Size and cognitive ability are important for accurate assessment of partner quality and that variation in Brain Size and cognitive ability underlies variation in mate choice. We compared sexual preference in guppy female lines selected for divergence in relative Brain Size, which we have previously shown to have substantial differences in cognitive ability. In a dichotomous choice test, large-Brained and wild-type females showed strong preference for males with color traits that predict attractiveness in this species. In contrast, small-Brained females showed no preference for males with these traits. In-depth analysis of optomotor response to color cues and gene expression of key opsins in the eye revealed that the observed differences were not due to differences in visual perception of color, indicating that differences in the ability to process indicators of attractiveness are responsible. We thus provide the first experimental support that individual variation in Brain Size affects mate choice decisions and conclude that differences in cognitive ability may be an important underlying mechanism behind variation in female mate choice.
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Artificial selection on male genitalia length alters female Brain Size
Proceedings of the Royal Society B: Biological Sciences, 2016Co-Authors: Severine D. Buechel, Isobel Booksmythe, Michael D Jennions, Alexander Kotrschal, Niclas KolmAbstract:SDB, 0000-0002-2385-2973 Male harassment is a classic example of how sexual conflict over mating leads to sex-specific behavioural adaptations. Females often suffer significant costs from males attempting forced copulations, and the sexes can be in an arms race over male coercion. Yet, despite recent recognition that divergent sex-specific interests in reproduction can affect Brain evolution, sexual conflict has not been addressed in this context. Here, we investigate whether artificial selection on a correlate of male success at coercion, genital length, affects Brain anatomy in males and females. We analysed the Brains of east-ern mosquitofish (Gambusia holbrooki), which had been artificially selected for long or short gonopodium, thereby mimicking selection arising from differing levels of male harassment. By analogy to how prey species often have relatively larger Brains than their predators, we found that female, but not male, Brain Size was greater following selection for a longer gonopo-dium. Brain subregion volumes remained unchanged. These results suggest that there is a positive genetic correlation between male gonopodium length and female Brain Size, which is possibly linked to increased female cogni-tive ability to avoid male coercion. We propose that sexual conflict is an important factor in the evolution of Brain anatomy and cognitive ability.
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Brain Size affects the behavioural response to predators in female guppies (Poecilia reticulata)
Proceedings. Biological sciences, 2015Co-Authors: Wouter Van Der Bijl, Alexander Kotrschal, Malin Thyselius, Niclas KolmAbstract:Large Brains are thought to result from selection for cognitive benefits, but how enhanced cognition leads to increased fitness remains poorly understood. One explanation is that increased cognitive ability results in improved monitoring and assessment of predator threats. Here, we use male and female guppies (Poecilia reticulata), artificially selected for large and small Brain Size, to provide an experimental evaluation of this hypothesis. We examined their behavioural response as singletons, pairs or shoals of four towards a model predator. Large-Brained females, but not males, spent less time performing predator inspections, an inherently risky behaviour. Video analysis revealed that large-Brained females were further away from the model predator when in pairs but that they habituated quickly towards the model when in shoals of four. Males stayed further away from the predator model than females but again we found no Brain Size effect in males. We conclude that differences in Brain Size affect the female predator response. Large-Brained females might be able to assess risk better or need less sensory information to reach an accurate conclusion. Our results provide experimental support for the general idea that predation pressure is likely to be important for the evolution of Brain Size in prey species.
Juha Merila - One of the best experts on this subject based on the ideXlab platform.
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variation in sexual Brain Size dimorphism over the breeding cycle in the three spined stickleback
The Journal of Experimental Biology, 2019Co-Authors: Severine D. Buechel, Niclas Kolm, Kristina Noreikiene, Jacquelin Defaveri, Elisavet A Toli, Juha MerilaAbstract:Snapshot analyses have demonstrated dramatic intraspecific variation in the degree of Brain sexual Size dimorphism (SSD). Although Brain SSD is believed to be generated by the sex-specific cognitive demands of reproduction, the relative roles of developmental and population-specific contributions to variation in Brain SSD remain little studied. Using a common garden experiment, we tested for sex-specific changes in Brain anatomy over the breeding cycle in three-spined stickleback (Gasterosteus aculeatus) sampled from four locations in northern Europe. We found that the male Brain increased in Size (ca. 24%) significantly more than the female Brain towards breeding, and that the resulting Brain SSD was similar (ca. 20%) for all populations over the breeding cycle. Our findings support the notion that the stickleback Brain is highly plastic and changes over the breeding cycle, especially in males, likely as an adaptive response to the cognitive demands of reproduction (e.g. nest construction and parental care). The results also provide evidence to suggest that breeding-related changes in Brain Size may be the reason for the widely varying estimates of Brain SSD across studies of this species, cautioning against interpreting Brain Size measurements from a single time point as fixed/static.
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evolutionary ecology of intraspecific Brain Size variation a review
Ecology and Evolution, 2013Co-Authors: Abigel Gonda, Gabor Herczeg, Juha MerilaAbstract:The Brain is a trait of central importance for organismal performance and fitness. To date, evolutionary studies of Brain Size variation have mainly utilized comparative methods applied at the level of species or higher taxa. However, these studies suffer from the difficulty of separating causality from correlation. In the other extreme, studies of Brain plasticity have focused mainly on within-population patterns. Between these extremes lie interpopulational studies, focusing on Brain Size variation among populations of the same species that occupy different habitats or selective regimes. These studies form a rapidly growing field of investigations which can help us to understand Brain evolution by providing a test bed for ideas born out of interspecific studies, as well as aid in uncovering the relative importance of genetic and environmental factors shaping variation in Brain Size and architecture. Aside from providing the first in depth review of published intraspecific studies of Brain Size variation, we discuss the prospects embedded with interpopulational studies of Brain Size variation. In particular, the following topics are identified as deserving further attention: (i) studies focusing on disentangling the contributions of genes, environment, and their interactions on Brain variation within and among populations, (ii) studies applying quantitative genetic tools to evaluate the relative importance of genetic and environmental factors on Brain features at different ontogenetic stages, (iii) apart from utilizing simple gross estimates of Brain Size, future studies could benefit from use of neuroanatomical, neurohistological, and/or molecular methods in characterizing variation in Brain Size and architecture.
Beren W. Robinson - One of the best experts on this subject based on the ideXlab platform.
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intraspecific Brain Size variation between coexisting sunfish ecotypes
Proceedings of The Royal Society B: Biological Sciences, 2018Co-Authors: Caleb J Axelrod, Frederic Laberge, Beren W. RobinsonAbstract:Variation in spatial complexity and foraging requirements between habitats can impose different cognitive demands on animals that may influence Brain Size. However, the relationship between ecologically related cognitive performance and Brain Size is not well established. We test whether variation in relative Brain Size and Brain region Size is associated with habitat use within a population of pumpkinseed sunfish composed of different ecotypes that inhabit either the structurally complex shoreline littoral habitat or simpler open-water pelagic habitat. Sunfish using the littoral habitat have on average 8.3% larger Brains than those using the pelagic habitat. We found little difference in the proportional Sizes of five Brain regions between ecotypes. The results suggest that cognitive demands on sunfish may be reduced in the pelagic habitat given no habitat-specific differences in body condition. They also suggest that either a short divergence time or physiological processes may constrain changes to concerted, global modifications of Brain Size between sunfish ecotypes.
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intraspecific Brain Size variation between coexisting sunfish ecotypes
Proceedings of The Royal Society B: Biological Sciences, 2018Co-Authors: Caleb J Axelrod, Frederic Laberge, Beren W. RobinsonAbstract:Variation in spatial complexity and foraging requirements between habitats can impose different cognitive demands on animals that may influence Brain Size. However, the relationship between ecologi...