Biology subjects

Streby, H. M.

Publications and source records attributed to Streby, H. M..

3 recordsLinked to original sources

bioRxiv2025

Parallel elevational replacement of hosts and parasites in a highly susceptible songbird genus

Elevational replacement distribution patterns underpin montane diversity and reflect the interaction of both biotic and abiotic pressures, but the degree to which parasites exhibit elevational zonation remains unclear. Investigating infection patterns in related host species across elevational gradients can reveal whether parasites and hosts show concordant patterns of elevational turnover, potentially due to shared historical and ecological factors. Here, we assessed patterns of elevational replacement in haemosporidian parasite assemblages that infect three congeneric songbird species: Bells vireo (Vireo bellii), gray vireo (V. vicinior), and plumbeous vireo (V. plumbeus), each of which breeds across distinct elevations and habitats in the southwestern United States. We screened a total of 248 individuals using cytochrome b PCR and microscopy. We identified 19 haemosporidian haplotypes, including eight novel lineages. We found that each of the three vireo species exhibited high haemosporidian prevalence (55.0-86.2%), with nearly all infections from the genus Haemoproteus (subgenus Parahaemoproteus). Haemosporidian assemblages varied across elevations; each sampled range of elevations harbored abundant, yet host-specific lineages with different environmental associations. Bells and plumbeous vireos, but not gray vireos, hosted several phylogenetically distinct, putative generalist lineages, likely reflecting spillover from more diverse local breeding bird communities. Repeated infections in individuals across breeding seasons, together with moderate parasitemia (x{square} {approx} 1%) suggest that these focal vireo species harbor chronic infections during their respective breeding seasons. These results demonstrate that elevational replacement patterns in avian hosts may be mirrored by their haemosporidian parasites, particularly among host-specialized lineages.

ecology↗

bioRxiv2023

Drab and distant birds are studied less than their fancy-feathered friends

Human decisions are influenced by implicit biases, and scientists do not exist in an objectivity vacuum. Subconscious biases in scientists choices about which species to study may beget distorted knowledge bases and stagnant paradigms. Disparities in biological knowledge can result from bias in study species selection within a cycle of policymaking, funding, and publication, all subject to implicit biases. Here, we show that ornithological research in the USA and Canada is biased toward birds with greater aesthetic salience and those with larger breeding ranges and ranges that encompass more universities. We quantified components of aesthetic salience (e.g., color, pattern/contrast, body size) of 293 passerines and near-passerines based on empirically documented human visual preferences and investigated whether these components were associated with research effort. We also quantified each species breeding range size and the number of universities within that range. Accounting for phylogenetic relatedness, we found that these metrics of aesthetics, familiarity, and accessibility combined to explain 45% of the variation in the number of published papers about each species from 1965-2020. On average, birds in the top 10% of aesthetic salience were studied 3.0X more than birds in the bottom 10%, and publication numbers were predicted most strongly by color and pattern components of aesthetic salience. Birds in the top 10% of breeding range size and university abundance were studied 3.8X and 3.5X more often than species in the bottom 10% of those categories, respectively. Species listed as Endangered and those featured on journal covers have greater aesthetic salience scores than other species. We discuss how these biases may influence perceived relative value of species with respect to culture and conservation. The disparities in empirical knowledge we describe here perpetuate a positive feedback loop, thus widening the gap between the avian "haves" and "have-nots", with some questions answered repeatedly while potentially critical discoveries are left undiscovered. O_QD"All animals are equal, but some animals are more equal than others." --George Orwell, Animal Farm (1945) C_QD

ecology↗

bioRxiv2019

Selection on VPS13A linked to long-distance migratory behavior in a songbird

Animal migration demands an interconnected suite of physiological, behavioral, and neurological adaptations for individuals to successfully navigate and travel over long distances1-3. This trait complex is especially crucial for small songbirds whose migratory behaviors--like directionality and orientation--are innate4,5, rather than being learned as in many large, longer-lived birds. Identifying causal genes involved in these traits has been a central goal of migration ecology, and this endeavor has been furthered by genome-scale comparisons6. However, even the most successful studies of migration genetics have only achieved low resolution associations, identifying large chromosomal regions, across multiple haplotype blocks, that encompass hundreds of putatively causal genes7,8. Here we leverage the extreme genomic similarity among golden-winged (Vermivora chrysoptera) and blue-winged warblers (Vermivora cyanoptera)9 to identify a single gene--Vacuolar Protein Sorting 13 Homolog A (VPS13A)--that is associated with distinct differences in migration directionality to Central American (CA) versus South American (SA) wintering areas10. Moreover, we find significantly reduced sequence variation in this gene-region for SA wintering birds, and show this is the result of strong natural selection on this gene. In humans, VPS13A codes for chorein, and variants of this gene are associated with the neurodegenerative disorder chorea-acanthocytosis11. This new association provides the strongest gene-level linkage for avian migration directionality, and further interrogation of this gene will allow for a better understanding of its role in neuro-muscular processes across vertebrates.

evolutionary biology↗