| 1. |
- Bijl, Wouter, et al.
(författare)
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Butterfly dichromatism primarily evolved via Darwin's, not Wallace's, model
- 2020
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Ingår i: Evolution letters. - : Oxford University Press (OUP). - 2056-3744. ; 4:6, s. 545-555
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Tidskriftsartikel (refereegranskat)abstract
- Sexual dimorphism is typically thought to result from sexual selection for elaborated male traits, as proposed by Darwin. However, natural selection could reduce expression of elaborated traits in females, as proposed by Wallace. Darwin and Wallace debated the origins of dichromatism in birds and butterflies, and although evidence in birds is roughly equal, if not in favor of Wallace's model, butterflies lack a similar scale of study. Here, we present a large‐scale comparative phylogenetic analysis of the evolution of butterfly coloration, using all European non‐hesperiid butterfly species (n = 369). We modeled evolutionary changes in coloration for each species and sex along their phylogeny, thereby estimating the rate and direction of evolution in three‐dimensional color space using a novel implementation of phylogenetic ridge regression. We show that male coloration evolved faster than female coloration, especially in strongly dichromatic clades, with male contribution to changes in dichromatism roughly twice that of females. These patterns are consistent with a classic Darwinian model of dichromatism via sexual selection on male coloration, suggesting this model was the dominant driver of dichromatism in European butterflies.
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| 2. |
- Buechel, Séverine D., et al.
(författare)
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Brain size affects performance in a reversal-learning test
- 2018
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Ingår i: Proceedings of the Royal Society of London. Biological Sciences. - : The Royal Society. - 0962-8452 .- 1471-2954. ; 285:1871
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Tidskriftsartikel (refereegranskat)abstract
- 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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| 3. |
- Corral-Lopez, Alberto, 1984-, et al.
(författare)
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Evolution of schooling drives changes in neuroanatomy and motion characteristics across predation contexts in guppies
- 2023
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Ingår i: Nature Communications. - : Springer Nature. - 2041-1723. ; 14
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Tidskriftsartikel (refereegranskat)abstract
- One of the most spectacular displays of social behavior is the synchronized movements that many animal groups perform to travel, forage and escape from predators. However, elucidating the neural mechanisms underlying the evolution of collective behaviors, as well as their fitness effects, remains challenging. Here, we study collective motion patterns with and without predation threat and predator inspection behavior in guppies experimentally selected for divergence in polarization, an important ecological driver of coordinated movement in fish. We find that groups from artificially selected lines remain more polarized than control groups in the presence of a threat. Neuroanatomical measurements of polarization-selected individuals indicate changes in brain regions previously suggested to be important regulators of perception, fear and attention, and motor response. Additional visual acuity and temporal resolution tests performed in polarization-selected and control individuals indicate that observed differences in predator inspection and schooling behavior should not be attributable to changes in visual perception, but rather are more likely the result of the more efficient relay of sensory input in the brain of polarization-selected fish. Our findings highlight that brain morphology may play a fundamental role in the evolution of coordinated movement and anti-predator behavior.
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| 4. |
- Corral-López, Alberto, et al.
(författare)
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Female brain size affects the assessment of male attractiveness during mate choice
- 2017
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Ingår i: Science Advances. - : American Association for the Advancement of Science (AAAS). - 2375-2548. ; 3:3
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Tidskriftsartikel (refereegranskat)abstract
- 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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| 5. |
- Corral-López, Alberto, 1984-, et al.
(författare)
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Functional convergence of genomic and transcriptomic architecture underlies schooling behaviour in a live-bearing fish
- 2024
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Ingår i: Nature Ecology and Evolution. - : Springer Nature. - 2397-334X. ; 8:1, s. 98-110
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Tidskriftsartikel (refereegranskat)abstract
- The organization and coordination of fish schools provide a valuable model to investigate the genetic architecture of affiliative behaviours and dissect the mechanisms underlying social behaviours and personalities. Here we used replicate guppy selection lines that vary in schooling propensity and combine quantitative genetics with genomic and transcriptomic analyses to investigate the genetic basis of sociability phenotypes. We show that consistent with findings in collective motion patterns, experimental evolution of schooling propensity increased the sociability of female, but not male, guppies when swimming with unfamiliar conspecifics. This finding highlights a relevant link between coordinated motion and sociability for species forming fission–fusion societies in which both group size and the type of social interactions are dynamic across space and time. We further show that alignment and attraction, the two major traits forming the sociability personality axis in this species, showed heritability estimates at the upper end of the range previously described for social behaviours, with important variation across sexes. The results from both Pool-seq and RNA-seq data indicated that genes involved in neuron migration and synaptic function were instrumental in the evolution of sociability, highlighting a crucial role of glutamatergic synaptic function and calcium-dependent signalling processes in the evolution of schooling.
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| 6. |
- Corral-López, Alberto, et al.
(författare)
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No association between brain size and male sexual behavior in the guppy
- 2015
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Ingår i: Current Zoology. - : Oxford University Press (OUP). - 1674-5507 .- 2396-9814. ; 61:2, s. 265-273
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Tidskriftsartikel (refereegranskat)abstract
- Animal behavior is remarkably variable at all taxonomic levels. Over the last decades, research on animal behavior has focused on understanding ultimate processes. Yet, it has progressively become more evident that to fully understand behavioral variation, ultimate explanations need to be complemented with proximate ones. In particular, the mechanisms generating variation in sexual behavior remain an open question. Variation in aspects of brain morphology has been suggested as a plausible mechanism underlying this variation. However, our knowledge of this potential association is based almost exclusively on comparative analyses. Experimental studies are needed to establish causality and bridge the gap between micro-and macroevolutionary mechanisms concerning the link between brain and sexual behavior. We used male guppies that had been artificially selected for large or small relative brain size to study this association. We paired males with females and scored the full known set of male and female sexual behaviors described in guppies. We found several previously demonstrated associations between male traits, male behavior and female behavior. Females responded more strongly towards males that courted more and males with more orange coloration. Also, larger males and males with less conspicuous coloration attempted more coerced copulations. However, courting, frequency of coerced copulation attempts, total intensity of sexual behavior, and female response did not differ between large-and small-brained males. Our data suggest that relative brain size is an unlikely mechanism underlying variation in sexual behavior of the male guppy. We discuss these findings in the context of the conditions under which relative brain size might affect male sexual behavior
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| 7. |
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| 8. |
- Eckerström-Liedholm, Simon, et al.
(författare)
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Macroevolutionary evidence suggests trait-dependent coevolution between behavior and life-history
- 2019
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Ingår i: Evolution. - : Wiley. - 0014-3820 .- 1558-5646. ; 73:11, s. 2312-2323
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Tidskriftsartikel (refereegranskat)abstract
- Species with fast life-histories typically prioritize current over future reproductive events, compared to species with slow life-histories. These species therefore require greater energetic input into reproduction, and also likely have less time to realize their reproductive potential. Hence, behaviors that increase access to both resources and mating opportunities, at a cost of increased mortality risk, could coevolve with the pace of life-history. However, whether this prediction holds across species, remains untested under standardized conditions. Here, we test how risky behaviors, which facilitate access to resources and mating opportunities (i.e., activity, boldness, and aggression), along with metabolic rate, coevolve with the pace of life-history across 20 species of killifish that present remarkable divergences in the pace of life-history. We found a positive association between the pace of life-history and aggression, but interestingly not with other behavioral traits or metabolic rate. Aggression is linked to interference competition, and in killifishes is often employed to secure mates, while activity and boldness are more relevant for exploiting energetic resources. Our results suggest that the trade-off between current and future reproduction plays a more prominent role in shaping mating behavior, while behaviors related to energy acquisition may be influenced by ecological factors.
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| 9. |
- Eckerström-Liedholm, Simon, 1988-, et al.
(författare)
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Macroevolutionary evidence suggests trait-dependent coevolution between behaviour and life-history
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- Species with fast life-histories prioritize current over future reproduction, which ought to require greater energetic resources, but also results in a shorter time-period to realize their reproductive potential, compared to slow life-histories, which prioritize future reproduction. Hence, behaviours that increase access to both resources and mating opportunities, at a cost of increased mortality risk, are thought to coevolve with the pace of life-history. However, whether this prediction holds across species, is yet to be tested under standardized conditions. Here, we test how potentially risky behaviours, which facilitate access to resources and mating opportunities (i.e. activity, boldness and aggression), along with metabolic rate, correlates with the pace of life-history across 20 species of killifish, which present a remarkable divergence in the pace of their life-histories. We found a positive correlation between the pace of life-history and aggression, but not with any other behavioural traits or metabolic rate. Aggression is often expressed in the context of mating, while the other behaviours we measured might be more relevant for access to energetic resources. Our results therefore suggest that the trade-off between current and future reproduction plays a more prominent role in shaping mating behaviour, while behaviours related to acquisition of energetic resources may be more affected by ecological factors.
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| 10. |
- Fong, Stephanie, 1990-, et al.
(författare)
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Rapid mosaic brain evolution under artificial selection for relative telencephalon size in the guppy (Poecilia reticulata)
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- The vertebrate brain displays enormous morphological variation and the quest to understand the evolutionary causes and consequences of this variation has spurred over a century of research. The mosaic brain evolution hypothesis, stating that brain regions can evolve relatively independently, is a highly influential idea in this research field. Here we provide the first experimental support for this hypothesis through an artificial selection experiment in the guppy (Poecilia reticulata). After three generations of selection on relative telencephalon volume in replicated up-selected, down-selected and control selection lines, we found substantial overall changes in relative telencephalon size (i.e. relative to brain size), but no changes in other brain regions. The differences were not evident at birth but present at the time of sexual maturation. There was a non-significant trend towards asymmetry in the response to selection in both sexes, with larger changes occurring during upwards selection as opposed to downwards selection. Our results demonstrate that independent evolutionary changes in specific brain regions can be an important mechanism during cognitive evolution.
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