| 1. |
- Corl, Ammon, et al.
(författare)
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Selective loss of polymorphic mating types is associated with rapid phenotypic evolution during morphic speciation
- 2010
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Ingår i: Proceedings of the National Academy of Sciences of the United States of America. - : Proceedings of the National Academy of Sciences. - 0027-8424 .- 1091-6490. ; 107:9, s. 4254-4259
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Tidskriftsartikel (refereegranskat)abstract
- Polymorphism may play an important role in speciation because new species could originate from the distinctive morphs observed in polymorphic populations. However, much remains to be understood about the process by which morphs found new species. To detail the steps of this mode of speciation, we studied the geographic variation and evolutionary history of a throat color polymorphism that distinguishes the "rock-paper-scissors" mating strategies of the side-blotched lizard, Uta stansburiana. We found that the polymorphism is geographically widespread and has been maintained for millions of years. However, there are many populations with reduced numbers of throat color morphs. Phylogenetic reconstruction showed that the polymorphism is ancestral, but it has been independently lost eight times, often giving rise to morphologically distinct subspecies/species. Changes to the polymorphism likely involved selection because the allele for one particular male strategy, the "sneaker" morph, has been lost in all cases. Polymorphism loss was associated with accelerated evolution of male size, female size, and sexual dimorphism, which suggests that polymorphism loss can promote rapid divergence among populations and aid species formation.
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| 2. |
- Davis, Alison R., et al.
(författare)
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Convergent evolution of kin-based sociality in a lizard
- 2011
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Ingår i: Proceedings of the Royal Society of London. Biological Sciences. - : The Royal Society. - 0962-8452 .- 1471-2954. ; 278:1711, s. 1507-1514
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Tidskriftsartikel (refereegranskat)abstract
- Studies of social birds and mammals have produced extensive theory regarding the formation and dynamics of kin-based social groups in vertebrates. However, comparing kin dynamics in birds and mammals to social reptiles provides the opportunity to identify selective factors that promote independent origins of kin sociality across vertebrates. We combined a 5-year mark-recapture study with a DNA microsatellite analysis of relatedness in a social lizard (Xantusia vigilis) to examine the formation and stability of kin groups. We found that these lizards are highly sedentary and that groups often form through the delayed dispersal of offspring. Groups containing juveniles had higher relatedness than adult-only groups, as juveniles were commonly found in aggregations with at least one parent and/or sibling. Groups containing nuclear family members were more stable than groups of less-related lizards, as predicted by social theory. We conclude that X. vigilis aggregations conform to patterns of kin sociality observed in avian and mammalian systems and represent an example of convergent evolution in social systems. We suggest that kin-based sociality in this and other lizards may be a by-product of viviparity, which can promote delayed juvenile dispersal by allowing prolonged interaction between a neonate and its mother.
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| 3. |
- Garcia-Porta, Joan, et al.
(författare)
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Environmental temperatures shape thermal physiology as well as diversification and genome-wide substitution rates in lizards
- 2019
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Ingår i: Nature Communications. - : Springer Science and Business Media LLC. - 2041-1723. ; 10
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Tidskriftsartikel (refereegranskat)abstract
- Climatic conditions changing over time and space shape the evolution of organisms at multiple levels, including temperate lizards in the family Lacertidae. Here we reconstruct a dated phylogenetic tree of 262 lacertid species based on a supermatrix relying on novel phylogenomic datasets and fossil calibrations. Diversification of lacertids was accompanied by an increasing disparity among occupied bioclimatic niches, especially in the last 10 Ma, during a period of progressive global cooling. Temperate species also underwent a genomewide slowdown in molecular substitution rates compared to tropical and desert-adapted lacertids. Evaporative water loss and preferred temperature are correlated with bioclimatic parameters, indicating physiological adaptations to climate. Tropical, but also some populations of cool-adapted species experience maximum temperatures close to their preferred temperatures. We hypothesize these species-specific physiological preferences may constitute a handicap to prevail under rapid global warming, and contribute to explaining local lizard extinctions in cool and humid climates.
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| 4. |
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| 5. |
- Kuchta, Shawn, et al.
(författare)
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Why does the Yellow-eyed ensatina have yellow eyes? Batesian mimicry of Pacific newts (genus Taricha) by the salamander Ensatina eschscholtzii xanthoptica
- 2008
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Ingår i: Evolution. - : Wiley. - 1558-5646 .- 0014-3820. ; 62:4, s. 984-990
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Tidskriftsartikel (refereegranskat)abstract
- Color patterns commonly vary geographically within species, but it is rare that such variation corresponds with divergent antipredator strategies. The polymorphic salamander Ensatina eschscholtzii, however, may represent such a case. In this species, most subspecies are cryptically colored, whereas E. e. xanthoptica, the Yellow eyed ensatina, is hypothesized to be an aposematic mimic of highly toxic Pacific newts (genus Taricha). To test the mimicry hypothesis, we conducted feeding trials using Western Scrub-Jays, Aphelocoma californica. In every feeding trial, we found that jays, following presentation with the presumed model (T. torosa), were more hesitant to contact the presumed mimic (E. e. xanthoptica) than a control subspecies lacking the postulated aposematic colors (E. e. oregonensis). The median time to contact was 315 sec for the mimic and 52 sec for the control. These results support the mimicry hypothesis, and we suggest that E. e. xanthoptica is likely a Batesian mimic, rather a Mullerian or quasi-Batesian mimic, of Pacific newts.
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| 6. |
- Rabosky, Alison R. Davis, et al.
(författare)
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Direct Fitness Correlates and Thermal Consequences of Facultative Aggregation in a Desert Lizard
- 2012
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Ingår i: PLOS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 7:7, s. e40866-
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Tidskriftsartikel (refereegranskat)abstract
- Social aggregation is a common behavioral phenomenon thought to evolve through adaptive benefits to group living. Comparing fitness differences between aggregated and solitary individuals in nature - necessary to infer an evolutionary benefit to living in groups - has proven difficult because communally-living species tend to be obligately social and behaviorally complex. However, these differences and the mechanisms driving them are critical to understanding how solitary individuals transition to group living, as well as how and why nascent social systems change over time. Here we demonstrate that facultative aggregation in a reptile (the Desert Night Lizard, Xantusia vigilis) confers direct reproductive success and survival advantages and that thermal benefits of winter huddling disproportionately benefit small juveniles, which can favor delayed dispersal of offspring and the formation of kin groups. Using climate projection models, however, we estimate that future aggregation in night lizards could decline more than 50% due to warmer temperatures. Our results support the theory that transitions to group living arise from direct benefits to social individuals and offer a clear mechanism for the origin of kin groups through juvenile philopatry. The temperature dependence of aggregation in this and other taxa suggests that environmental variation may be a powerful but underappreciated force in the rapid transition between social and solitary behavior.
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| 7. |
- Svensson, Erik, et al.
(författare)
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Intralocus Sexual Conflict over Immune Defense, Gender Load and Sex-Specific Signaling in a Natural Lizard Population.
- 2009
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Ingår i: Evolution. - : Wiley. - 1558-5646 .- 0014-3820. ; 63:12, s. 3124-3135
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Tidskriftsartikel (refereegranskat)abstract
- ABSTRACT In species with separate sexes, antagonistic selection on males and females (intralocus sexual conflict) can result in a gender load that can be resolved through the evolution of sexual dimorphism. We present data on intralocus sexual conflict over immune defense in a natural population of free-ranging lizards (Uta stansburiana) and discuss the resolution of this conflict. Intralocus sexual conflict arises from correlational selection between immune defense and orange throat coloration in these lizards. Males with orange throats and high antibody responses had enhanced survival, but the same trait combination reduced female fitness. This sexual antagonism persisted across the life-cycle and was concordant between the juvenile and adult life stages. The opposing selective pressure on males and females is ameliorated by a negative intersexual genetic correlation (rm,f =-0.86) for immune defense. Throat coloration was also genetically correlated with immune defense, but the sign of this genetic correlation differed between the sexes. This resulted in sex-specific signaling of immunological condition. We also found evidence for a sex-specific maternal effect on sons with potential to additionally reduce the gender load. These results have implications for signaling evolution, genetic integration between adaptive traits, sex allocation and mutual mate choice for indirect fitness benefits.
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