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Background Snake venoms are trophic adaptations that represent an ideal model to examine the evolutionary factors that shape polymorphic traits under strong natural selection. Venom compositional variation is substantial within and among venomous snake species. However, the forces shaping this phenotypic complexity, as well as the potential integrated roles of biotic and abiotic factors, have received little attention. Here, we investigate geographic variation in venom composition in a wide-ranging rattlesnake ( Crotalus viridis viridis ) and contextualize this variation by investigating dietary, phylogenetic, and environmental variables that covary with venom. Results Using shotgun proteomics, venom biochemical profiling, and lethality assays, we identify 2 distinct divergent phenotypes that characterize major axes of venom variation in this species: a myotoxin-rich phenotype and a snake venom metalloprotease (SVMP)-rich phenotype. We find that dietary availability and temperature-related abiotic factors are correlated with geographic trends in venom composition. Conclusions Our findings highlight the potential for snake venoms to vary extensively within species, for this variation to be driven by biotic and abiotic factors, and for the importance of integrating biotic and abiotic variation for understanding complex trait evolution. Links between venom variation and variation in biotic and abiotic factors indicate that venom variation likely results from substantial geographic variation in selection regimes that determine the efficacy of venom phenotypes across populations and snake species. Our results highlight the cascading influence of abiotic factors on biotic factors that ultimately shape venom phenotype, providing evidence for a central role of local selection as a key driver of venom variation.

Hybrid zones provide valuable opportunities to understand the genomic mechanisms that promote speciation by providing insight into factors involved in intermediate stages of speciation. Here, we investigate introgression in a hybrid zone between two rattlesnake species (Crotalus viridis and Crotalus oreganus concolor) that have undergone historical allopatric divergence and recent range expansion and secondary contact. We use Bayesian genomic cline models to characterize genomic patterns of introgression between these lineages and identify loci potentially subject to selection in hybrids. We find evidence for a large number of genomic regions with biased ancestry that deviate from the genomic background in hybrids (i.e., excess ancestry loci), which tend to be associated with genomic regions with higher recombination rates. We also identify suites of excess ancestry loci that show highly correlated allele frequencies (including conspecific and heterospecific combinations) across physically unlinked genomic regions in hybrids. Our findings provide evidence for multiple multilocus evolutionary processes impacting hybrid fitness in this system.

The global community has adopted ambitious goals to eliminate schistosomiasis as a public health problem, and new tools are needed to achieve them. Mass drug administration programs, for example, have reduced the burden of schistosomiasis, but the identification of hotspots of persistent and reemergent transmission threaten progress toward elimination and underscore the need to couple treatment with interventions that reduce transmission. Recent advances in DNA sequencing technologies make whole-genome sequencing a valuable and increasingly feasible option for population-based studies of complex parasites such as schistosomes. Here, we focus on leveraging genomic data to tailor interventions to distinct social and ecological circumstances. We consider two priority questions that can be addressed by integrating epidemiological, ecological, and genomic information: (1) how often do non-human host species contribute to human schistosome infection? and (2) what is the importance of locally acquired versus imported infections in driving transmission at different stages of elimination? These questions address processes that can undermine control programs, especially those that rely heavily on treatment with praziquantel. Until recently, these questions were difficult to answer with sufficient precision to inform public health decision-making. We review the literature related to these questions and discuss how whole-genome approaches can identify the geographic and taxonomic sources of infection, and how such information can inform context-specific efforts that advance schistosomiasis control efforts and minimize the risk of reemergence.The global community has adopted ambitious goals to eliminate schistosomiasis as a public health problem, and new tools are needed to achieve them. Mass drug administration programs, for example, have reduced the burden of schistosomiasis, but the identification of hotspots of persistent and reemergent transmission threaten progress toward elimination and underscore the need to couple treatment with interventions that reduce transmission. Recent advances in DNA sequencing technologies make whole-genome sequencing a valuable and increasingly feasible option for population-based studies of complex parasites such as schistosomes. Here, we focus on leveraging genomic data to tailor interventions to distinct social and ecological circumstances. We consider two priority questions that can be addressed by integrating epidemiological, ecological, and genomic information: (1) how often do non-human host species contribute to human schistosome infection? and (2) what is the importance of locally acquired versus imported infections in driving transmission at different stages of elimination? These questions address processes that can undermine control programs, especially those that rely heavily on treatment with praziquantel. Until recently, these questions were difficult to answer with sufficient precision to inform public health decision-making. We review the literature related to these questions and discuss how whole-genome approaches can identify the geographic and taxonomic sources of infection, and how such information can inform context-specific efforts that advance schistosomiasis control efforts and minimize the risk of reemergence.

Artificial nest boxes are critical nesting sites for secondary cavity-nesting birds; however, they are often placed near roadways and in urban areas that experience noise pollution and other human-caused stressors. Recent correlative studies document both negative and positive influences of noise pollution on reproductive success. Additionally, observational studies have not determined which stage of the breeding process is most vulnerable to noise pollution-settlement, incubation, and/or provisioning. Here, we controlled for possible effects from non-random settlement and eliminated potential effects of roadways, such as collisions and chemical and light pollution, by experimentally introducing traffic noise into nest boxes after clutch initiation in two secondary-cavity nesting bird species. We found no evidence for an influence of noise on clutch size, brood size, number of fledglings, or overall nest success in western bluebirds (Sialia mexicana). In contrast, we found that ash-throated flycatcher (Myiarchus cinerascens) nests exposed to noise had lower reproductive success than quiet nests due to higher rates of abandonment at the incubation stage. Our results match recent research demonstrating that ash-throated flycatchers avoid energy-sector noise in their nest placement and, when they do nest in noise, experience stress hormone dysregulation and fitness costs. The lack of a response among western bluebirds differs from reported declines in reproductive success due to exposure to energy-sector noise; however, the absence of a response matches the response seen in other species using an in-box noise playback experiment. These results suggest that in-box noise exposure experiments may be appropriate for assessing noise impacts at the nest, and through some pathways (e.g., direct effects of noise on nestlings), but do not capture other ways in which noise can negatively affect birds during the breeding season that may ultimately cause declines in fitness. Additionally, although manipulative experiments that examine the influence of a single anthropogenic stressor on a single life stage can help reveal causal pathways, urban and other human-dominated environments are characterized by many stressors and future studies should seek to understand how noise interacts with other stressors to impact birds and other wildlife. Finally, in light of mounting evidence demonstrating declines in reproductive success due to noise, our results suggest that nest box placement near roads may be counterproductive to efforts to bolster population densities of some species.

We studied the thermal ecology and microhabitat use of the federally endangered lizard Gambelia sila using temperature-sensitive radio-telemetry and collected data on their preferred body temperature and their upper thermal tolerance. We calculated the number of hours their activity is currently restricted and predicted how climate change may impact activity time.AbstractRecognizing how climate change will impact populations can aid in making decisions about approaches for conservation of endangered species. The blunt-nosed leopard lizard (Gambelia sila) is a federally endangered species that, despite protection, remains in extremely arid, hot areas and may be at risk of extirpation due to climate change. We collected data on the field-active body temperatures, preferred body temperatures and upper thermal tolerance of G. sila. We then described available thermal habitat using biophysical models, which allowed us to (i) describe patterns in lizard body temperatures, microhabitat temperatures and lizard microhabitat use; (ii) quantify the lizards’ thermoregulatory accuracy; (iii) calculate the number of hours they are currently thermally restricted in microhabitat use; (iv) project how the number of restricted hours will change in the future as ambient temperatures rise; and (v) assess the importance of giant kangaroo rat burrows and shade-providing shrubs in the current and projected future thermal ecology of G. sila. Lizards maintained fairly consistent daytime body temperatures over the course of the active season, and use of burrows and shrubs increased as the season progressed and ambient temperatures rose. During the hottest part of the year, lizards shuttled among kangaroo rat burrows, shrubs, and open habitat to maintain body temperatures below their upper thermal tolerance, but, occasionally, higher than their preferred body temperature range. Lizards are restricted from staying in the open habitat for 75% of daylight hours and are forced to seek refuge under shrubs or burrows to avoid surpassing their upper thermal threshold. After applying climatic projections of 1 and 2°C increases to 2018 ambient temperatures, G. sila will lose additional hours of activity time that could compound stressors faced by this population, potentially leading to extirpation.

Recognizing how climate change will impact populations can aid in making decisions about approaches for conservation of endangered species. The Blunt-nosed Leopard Lizard (Gambelia sila) is a federally endangered species that, despite protection, remains in extremely arid, hot areas and may be at risk of extirpation due to climate change. We collected data on the field-active body temperatures, preferred body temperatures, and upper thermal tolerance of G. sila. We then described available thermal habitat using biophysical models, which allowed us to (1) describe patterns in lizard body temperatures, microhabitat temperatures, and lizard microhabitat use, (2) quantify the lizards’ thermoregulatory accuracy, (3) calculate the number of hours they are currently thermally restricted in microhabitat use, (4) project how the number of restricted hours will change in the future as ambient temperatures rise, and (5) assess the importance of Giant Kangaroo Rat burrows and shade-providing shrubs in the current and projected future thermal ecology of G. sila. Lizards maintained fairly consistent daytime body temperatures over the course of the active season, and use of burrows and shrubs increased as the season progressed and ambient temperatures rose. During the hottest part of the year, lizards shuttled among kangaroo rat burrows, shrubs, and open habitat to maintain body temperatures below their upper thermal tolerance, but occasionally, higher than their preferred body temperature range. Lizards are restricted from staying in the open habitat for 75% of daylight hours and are forced to seek refuge under shrubs or burrows to avoid surpassing their upper thermal threshold. After applying climatic projections of 1 and 2˚C increases to 2018 ambient temperatures, G. silawill lose additional hours of activity time that could compound stressors faced by this population, potentially leading to extirpation.Finally, temperature-based activity estimation (TBAE) is an automated method for predicting surface activity and microhabitat use based on the temperature of an organism and its habitat. We assessed continuously logged field active body temperatures as a tool to predict the surface activity and microhabitat use of Gambelia sila.We found that TBAE accurately predicts whether a lizard is above or below ground 75.7% of the time when calculated using air temperature, and 60.5% of the time when calculated using biophysical models. While surface activity was correctly predicted about 93% of the time using either method, accuracy in predicting below ground (burrow) occupancy was 62% for air temperature and 51% for biophysical models. Using biophysical model data, TBAE accurately predicts microhabitat use in 79% of observations in which lizards are in the sun, 47% in the shade, and 51% in burrows. Heliotherms bask in the sun, and thus body temperatures can shift rapidly when the animal moves to a new microhabitat. This sensitivity, makes TBAE a promising means of remotely monitoring animal activity, particularly for specific variables like emergence time and surface activity.

Beginning in March 2020, the COVID-19 pandemic and response, which included physical distancing and stay-at-home orders, disrupted daily life in the United States. Compared with the rate in 2019, a 31% increase in the proportion of mental health-related emergency department (ED) visits occurred among adolescents aged 12-17 years in 2020 (1). In June 2020, 25% of surveyed adults aged 18-24 years reported experiencing suicidal ideation related to the pandemic in the past 30 days (2). More recent patterns of ED visits for suspected suicide attempts among these age groups are unclear. Using data from the National Syndromic Surveillance Program (NSSP),* CDC examined trends in ED visits for suspected suicide attempts† during January 1, 2019-May 15, 2021, among persons aged 12-25 years, by sex, and at three distinct phases of the COVID-19 pandemic. Compared with the corresponding period in 2019, persons aged 12-25 years made fewer ED visits for suspected suicide attempts during March 29-April 25, 2020. However, by early May 2020, ED visit counts for suspected suicide attempts began increasing among adolescents aged 12-17 years, especially among girls. During July 26-August 22, 2020, the mean weekly number of ED visits for suspected suicide attempts among girls aged 12-17 years was 26.2% higher than during the same period a year earlier; during February 21-March 20, 2021, mean weekly ED visit counts for suspected suicide attempts were 50.6% higher among girls aged 12-17 years compared with the same period in 2019. Suicide prevention measures focused on young persons call for a comprehensive approach, that is adapted during times of infrastructure disruption, involving multisectoral partnerships (e.g., public health, mental health, schools, and families) and implementation of evidence-based strategies (3) that address the range of factors influencing suicide risk.Beginning in March 2020, the COVID-19 pandemic and response, which included physical distancing and stay-at-home orders, disrupted daily life in the United States. Compared with the rate in 2019, a 31% increase in the proportion of mental health-related emergency department (ED) visits occurred among adolescents aged 12-17 years in 2020 (1). In June 2020, 25% of surveyed adults aged 18-24 years reported experiencing suicidal ideation related to the pandemic in the past 30 days (2). More recent patterns of ED visits for suspected suicide attempts among these age groups are unclear. Using data from the National Syndromic Surveillance Program (NSSP),* CDC examined trends in ED visits for suspected suicide attempts† during January 1, 2019-May 15, 2021, among persons aged 12-25 years, by sex, and at three distinct phases of the COVID-19 pandemic. Compared with the corresponding period in 2019, persons aged 12-25 years made fewer ED visits for suspected suicide attempts during March 29-April 25, 2020. However, by early May 2020, ED visit counts for suspected suicide attempts began increasing among adolescents aged 12-17 years, especially among girls. During July 26-August 22, 2020, the mean weekly number of ED visits for suspected suicide attempts among girls aged 12-17 years was 26.2% higher than during the same period a year earlier; during February 21-March 20, 2021, mean weekly ED visit counts for suspected suicide attempts were 50.6% higher among girls aged 12-17 years compared with the same period in 2019. Suicide prevention measures focused on young persons call for a comprehensive approach, that is adapted during times of infrastructure disruption, involving multisectoral partnerships (e.g., public health, mental health, schools, and families) and implementation of evidence-based strategies (3) that address the range of factors influencing suicide risk.

Population segregation catalyses genetic differentiation and can lead to speciation. Population genetic structure is also critically important for population management, especially in species characterised by small, isolated populations. Sandhill Crane (Antigone canadensis) populations of the Pacific Flyway are made up of breeding populations nesting west of the Rocky Mountains, and isolated by intermediate mountain ranges. Current management policy in British Columbia treats all Sandhill Cranes as a single population, whereas in the western United States, subpopulations are subject to population‐specific management. Here, we analyse microsatellite markers, mitochondrial DNA sequences, and mitochondrial haplogroups derived from 203 individual Sandhill Cranes to elucidate the population genetic structure of cranes migrating along the Pacific Flyway to summer breeding habitat on the North and Central Coast of British Columbia and Southeast Alaska. STRUCTURE, AMOVA, FST, DAPC, and phylogenetic analyses reveal that geographically separated crane populations along the west coast of North America show substantial genetic differentiation in the Pacific Flyway. These findings are consistent with behavioural and ecological evidence—divergent diets, flyways, and breeding habitats. We conclude that the relatively small coastal Sandhill Crane populations deserve special management consideration to safeguard their genetic diversity and adaptations, and to mitigate deleterious impacts of current and future climate change scenarios. Sandhill Crane populations of the Pacific Flyway are made up of breeding populations nesting west of the Rocky Mountains, and isolated by intermediate mountain ranges. Here, we analyze microsatellite markers, mitochondrial DNA sequences, and mitochondrial haplogroups to elucidate population genetic structure and found substantial genetic differentiation. The conservation of Sandhill Cranes west of the Rocky Mountains depends on safeguarding the genetic diversity and adaptations within and between populations to protect them from current and future climate scenarios.

Persons who are infected with human immunodeficiency virus (HIV) are at high risk of human papillomavirus (HPV)-associated cancers. The objectives are to compare antibody titers to HPV 6, 11, 16, and 18 and rate of abnormal cytology between perinatally HIV-infected (PHIV) and perinatally HIV-exposed, uninfected (PHEU) youth. This is a prospective observational cohort study of HPV4 vaccinated youth performed as part of the multicenter Pediatric HIV/AIDS Cohort Study Adolescent Master Protocol. Seroconversion and geometric mean titer (GMT) against HPV types 6, 11, 16, and 18 were calculated. Vaccine effectiveness included rates of abnormal cervical cytology and genital warts. Seroconversion to HPV 6, 11, 16, and 18 occurred in 83%, 84%, 90%, and 62% of 310 vaccinated PHIV youth compared to 94%, 96%, 99%, and 87% of 148 vaccinated PHEU youth, respectively (P < .05 for all comparisons). GMTs were lower in the PHIV vs PHEU within each category of HPV4 doses received. Higher GMTs were associated with younger age, lower HIV type 1 RNA viral load, and higher CD4% at first HPV4 vaccination, as well as shorter duration between last vaccine dose and antibody specimen. Abnormal cytology occurred in 33 of 56 PHIV and 1 of 7 PHEU sexually active vaccinated females, yielding incidence rates per 100 person-years of 15.0 (10.9 to 20.6) and 2.9 (0.4 to 22.3), respectively. Antibody titers to HPV4 were lower for all serotypes in PHIV compared to PHEU youth. Protection against abnormal cytology was also diminished in sexually active PHIV females.