Biology subjects

Myers, C. E.

Publications and source records attributed to Myers, C. E..

3 recordsLinked to original sources

bioRxiv2026

Drift drives phenotypic evolution in a rapid island radiation

Understanding the processes that generate phenotypic diversity is central to explaining how new species form1,2. Evolutionary theory predicts that rapid evolution of signaling traits, such as feather coloration, can promote speciation3,4 but empirical support is inconsistent5,6. Phenotypic divergence of such traits is expected during speciation4, but these microevolutionary dynamics are rarely examined at macroevolutionary scales or linked to underlying population demography. Here, we leverage complete taxon sampling across an iconic insular bird radiation that helped shape early theories of allopatric speciation. We integrate whole-genome data with a comprehensive, fine-scale dataset of whole-body plumage coloration to directly test whether signaling trait evolution covaries with lineage diversification and to disentangle the roles of selection and drift. We find that lineages with faster rates of color evolution diversify more rapidly. Strikingly, rates of color evolution accelerate as genomic diversity declines, providing direct evidence that genetic drift--rather than strong sexual or ecological selection--can drive rapid phenotypic change in small, isolated insular populations. Together, these results provide compelling evidence that neutral demographic processes can accelerate the evolution of sexual signals and play a central role in generating phenotypic diversity during island radiations.

zoology↗

bioRxiv2024

Phylogenomics of a genus of "Great Speciators" reveals rampant incomplete lineage sorting, gene flow, and mitochondrial capture in island systems

The flora and fauna of island systems, especially those in the Indo-Pacific, are renowned for their high diversification rates and outsized contribution to the development of evolutionary theories. The total diversity of geographic radiations of many Indo-Pacific fauna is often incompletely sampled in phylogenetic studies due to the difficulty in obtaining single island endemic forms across the Pacific and the relatively poor performance of degraded DNA when using museum specimens for inference of evolutionary relationships. New methods for production and analysis of genome-wide datasets sourced from degraded DNA are facilitating insights into the complex evolutionary histories of these influential island faunas. Here, we leverage whole genome resequencing (20X average coverage) and extensive sampling of all taxonomic diversity within Todiramphus kingfishers, a rapid radiation of largely island endemic Great Speciators. We find that whole genome datasets do not outright resolve the evolutionary relationships of this clade: four types of molecular markers (UCEs, BUSCOs, SNPs, and mtDNA) and tree building methods did not find a single well-supported and concordant species-level topology. We then uncover evidence of widespread incomplete lineage sorting and both ancient and contemporary gene flow and demonstrate how these factors contribute to conflicting evolutionary histories. Our complete taxonomic sampling allowed us to further identify a novel case of mitochondrial capture between two allopatric species, suggesting a potential historical (but since lost) hybrid zone as islands were successively colonized. Taken together, these results highlight how increased genomic and taxon sampling can reveal complex evolutionary patterns in rapid island radiations.

zoology↗

bioRxiv2019

Demonstrating and disrupting well-learned habits

Researchers have exerted tremendous efforts to empirically study how habits form and dominate at the expense of deliberation, yet we know very little about breaking these rigid habits to restore goal-directed control. In a three-experiment study, we first illustrate a novel approach of studying well-learned habits, in order to effectively demonstrate habit disruption. In Experiment 1, we use a Go/NoGo task with familiar color-response associations to demonstrate outcome-insensitivity when compared to novel, more flexible associations. Specifically, subjects perform more accurately when the required mapping is the familiar association of green-Go/red-NoGo than when it is red-Go/green-NoGo, confirming outcome-insensitive, habitual control. As a control condition, subjects show equivalent performance with unfamiliar color-response mappings (using the colors blue and purple mapped to Go and NoGo responses). Next, in Experiments 2 and 3, we test a motivation-based feedback manipulation in varying magnitudes (i.e., performance feedback with and without monetary incentives) to break the well-established habits elicited by our familiar stimuli. We find that although performance feedback prior to the contingency reversal test is insufficient to disrupt outcome-insensitivity in Experiment 2, a combination of performance feedback and monetary incentive is able to restore goal-directed control in Experiment 3, effectively breaking the habits. As the first successful demonstration of well-learned habit disruption in the laboratory, these findings provide new insights into how we execute and modify habits, while fostering new and translational research avenues that may be applicable to treating habit-based pathologies.

neuroscience↗