scholarly journals Speciation in the face of long-range dispersal: population genomic structure within a species complex of biting midges

2021 ◽  
Author(s):  
Phillip Shults ◽  
Matthew Hopken ◽  
Pierre-André Eyer ◽  
Alexander Blumenfeld ◽  
Mariana Mateos ◽  
...  
Keyword(s):  
Reproductive Isolation ◽  
Long Range ◽  
Species Complex ◽  
Genomic Structure ◽  
The United States ◽  
Pathogen Transmission ◽  
Secondary Contact ◽  
Biting Midges ◽  
Behavioral Isolation ◽  
Snp Data

The level of gene flow between diverging lineages ultimately determines the outcome of a speciation event. If secondary contact occurs before this process is complete, reproductive isolation barriers must exist or evolve to prevent hybridization. The selective pressures facilitating and maintaining genetic divergence do not always involve an observable phenotypic response, thus cryptic species form. The inability to distinguish between sibling species can be a particularly serious problem in groups responsible for pathogen transmission. Culicoides biting midges occur almost world-wide and vector many disease-causing pathogens that affect wildlife and livestock. In North America, the C. variipennis species complex contains three currently recognized species, only one of which is a vector, and limited molecular and morphological differences have hindered vector surveillance. Here, genomic methods were used to investigate speciation and genetic structure within this complex. Single nucleotide polymorphism (SNP) data were generated using ddRAD sequencing for 206 individuals originating from 17 locations throughout the United States and Canada. Clustering analyses consistently suggest the occurrence of five putative species with significant differentiation occurring in both sympatric and allopatric populations. Evidence of hybridization was detected in three different species pairings, indicating a lack of pre-zygotic reproductive isolation within the complex. Mitochondrial genes were used to trace the hybrid parentage of these individuals, which illuminated discordance with the SNP data. In this study, we highlight the potential role of geographic, ecological, and behavioral isolation in speciation and in maintaining species boundaries, despite hybridization and long range dispersal.

THE LESSONIA NIGRESCENS SPECIES COMPLEX (LAMINARIALES, PHAEOPHYCEAE) SHOWS STRICT PARAPATRY AND COMPLETE REPRODUCTIVE ISOLATION IN A SECONDARY CONTACT ZONE1

2011 ◽  
Vol 47 (4) ◽  
pp. 894-903 ◽  
Author(s):  
Florence Tellier ◽  
Javier Tapia ◽  
Sylvain Faugeron ◽  
Christophe Destombe ◽  
Myriam Valero
Keyword(s):  
Reproductive Isolation ◽  
Species Complex ◽  
Secondary Contact ◽  
Lessonia Nigrescens

scholarly journals Revealing the spatial shifting pattern of COVID-19 pandemic in the United States

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Di Zhu ◽  
Xinyue Ye ◽  
Steven Manson
Keyword(s):  
United States ◽  
Long Range ◽  
Network Optimization ◽  
Network Modeling ◽  
The United States ◽  
Standard Series ◽  
Time And Space ◽  
Long Range Interactions ◽  
Dynamic Relationships ◽  
Over Time

AbstractWe describe the use of network modeling to capture the shifting spatiotemporal nature of the COVID-19 pandemic. The most common approach to tracking COVID-19 cases over time and space is to examine a series of maps that provide snapshots of the pandemic. A series of snapshots can convey the spatial nature of cases but often rely on subjective interpretation to assess how the pandemic is shifting in severity through time and space. We present a novel application of network optimization to a standard series of snapshots to better reveal how the spatial centres of the pandemic shifted spatially over time in the mainland United States under a mix of interventions. We find a global spatial shifting pattern with stable pandemic centres and both local and long-range interactions. Metrics derived from the daily nature of spatial shifts are introduced to help evaluate the pandemic situation at regional scales. We also highlight the value of reviewing pandemics through local spatial shifts to uncover dynamic relationships among and within regions, such as spillover and concentration among states. This new way of examining the COVID-19 pandemic in terms of network-based spatial shifts offers new story lines in understanding how the pandemic spread in geography.

scholarly journals Widespread detection of antibodies to Leptospira in feral swine in the United States

2014 ◽  
Vol 143 (10) ◽  
pp. 2131-2136 ◽  
Author(s):  
K. PEDERSEN ◽  
K. L. PABILONIA ◽  
T. D. ANDERSON ◽  
S. N. BEVINS ◽  
C. R. HICKS ◽  
...  
Keyword(s):  
United States ◽  
The United States ◽  
Domestic Animals ◽  
Pathogen Transmission ◽  
Geographical Range ◽  
Crop Damage ◽  
Feral Swine ◽  
Livestock Predation

SUMMARYAs feral swine continue to expand their geographical range and distribution across the United States, their involvement in crop damage, livestock predation, and pathogen transmission is likely to increase. Despite the relatively recent discovery of feral swine involvement in the aetiology of a variety of pathogens, their propensity to transmit and carry a wide variety of pathogens is disconcerting. We examined sera from 2055 feral swine for antibody presence to six serovars of Leptospira that can also infect humans, livestock or domestic animals. About 13% of all samples tested positive for at least one serovar, suggesting that Leptospira infection is common in feral swine. Further studies to identify the proportion of actively infected animals are needed to more fully understand the risk they pose.

1—by Captain A. Wepster

1963 ◽  
Vol 16 (4) ◽  
pp. 389-398
Keyword(s):  
United States ◽  
Travel Time ◽  
Long Range ◽  
The United States ◽  
Point Of View ◽  
Ship Routing ◽  
Waves And Currents ◽  
Meteorological Institute

In 1960 Hanssen and James described to the Institute a system developed and used by the United States Hydrographic Office for selecting the optimum track for transoceanic crossings by applying long-range predictions of winds, waves and currents to a knowledge of how the routed vessel reacts to these variables. The paper (Journal, 13, 253) described how, over a period of two years, an average reduction in travel time of 14 hours was achieved over 1000 optimum routes.In the present papers, presented at an Institute meeting held in London on 19 April, Captain Wepster of the Holland-America Line first of all goes into the benefits which effective ship routing offers the ship operator and then describes the results of the experimental routing programme undertaken by his Company in association with the Royal Netherlands Meteorological Institute. Mr. Verploegh of that Institute then discusses the programme from the forecaster's point of view.

Optimum Ship Routing

1960 ◽  
Vol 13 (3) ◽  
pp. 253-272 ◽  
Author(s):  
George L. Hanssen ◽  
Richard W. James
Keyword(s):  
United States ◽  
Travel Time ◽  
Long Range ◽  
Wind Waves ◽  
The United States ◽  
Ship Routing ◽  
Waves And Currents

The paper describes the system developed and used by the United States Hydrographic Office for selecting the optimum track for transoceanic crossings by applying long-range predictions of wind, waves and currents to a knowledge of how the routed vessel reacts to these variables. Over a period of two years, over 1000 optimum ship routes were provided to one authority, with an average reduction in travel time of 14 hours.

scholarly journals Host Associations Of Biting Midges (Diptera: Ceratopogonidae: Culicoides) Near Sentinel Chicken Surveillance Locations In Florida, USA

2019 ◽  
Vol 35 (3) ◽  
pp. 200-206 ◽  
Author(s):  
Kristin E. Sloyer ◽  
Carolina Acevedo ◽  
Alfred E. Runkel ◽  
Nathan D. Burkett-Cadena
Keyword(s):  
Mosquito Control ◽  
Pathogen Transmission ◽  
Host Use ◽  
Culicoides Species ◽  
Biting Midges ◽  
Total Blood ◽  
Avian Blood ◽  
Vector Borne ◽  
Arbovirus Surveillance ◽  
Blood Meals

ABSTRACT Quantifying host use is important for understanding transmission of vector-borne pathogens. Despite the importance of biting midges (Diptera: Ceratopogonidae) in pathogen transmission, the vector–host relationships of most Culicoides species are poorly documented, even in locations where active arbovirus surveillance is conducted. Polymerase chain reaction–based blood-meal analysis was performed on 663 blood-engorged Culicoides females collected by 7 Florida mosquito control districts at 24 sentinel chicken arbovirus surveillance sites in 2017. A total of 638 blood meals were successfully analyzed to determine host species source, representing 11 Culicoides species. The most commonly bitten host was domestic chicken (Gallus gallus) (presumably sentinel chickens), constituting 565 of 638 (88.6%) the total blood meals. Other common hosts included humans (5.8%), white-tailed deer (Odoocoileus virginianus) (2.5%), and brown basilisk (Basiliscus vittatus) (1.6%). Significant differences in distribution of mammal and avian blood meals were found for a number of Culicoides species, and these patterns did not vary across locations. These results indicate that sentinel chickens are exposed to bites by Culicoides, potentially exposing them to Culicoides-borne pathogens. The findings that vertebrate host use was consistent across locations suggests that each Culicoides species has affinity for one or more specific animal groups, and does not feed randomly upon available animals.

scholarly journals 1342. TOSCANA: The Observational Seroepidemiologic Study of COVID-19 at the United States Naval Academy

2021 ◽  
Vol 8 (Supplement_1) ◽  
pp. S758-S759
Author(s):  
Eugene Millar ◽  
Eric Laing ◽  
Adam Saperstein ◽  
Jitu Modi ◽  
Christopher Heaney ◽  
...  
Keyword(s):  
United States ◽  
Risk Factors ◽  
Blood Sample ◽  
Saliva Sample ◽  
The United States ◽  
Pathogen Transmission ◽  
Naval Academy ◽  
United States Naval Academy ◽  
Increased Risk ◽  
Seroepidemiologic Study

Abstract Background University students, including those at military service academies, are at increased risk of acute respiratory infection (ARI), including SAR-CoV-2, due to crowded living conditions, frequent social interaction and other factors that facilitate pathogen transmission. Unlike many universities, the United States Naval Academy (USNA) continued in-person instruction in Fall 2020 in the midst of the COVID-19 pandemic. The Observational Seroepidemiologic Study of COVID-19 at the United States Naval Academy (TOSCANA,) a longitudinal cohort characterizes the burden and risk factors of SARS-CoV-2 in USNA midshipmen. Methods Midshipmen were enrolled August- October 2020. Participants were queried about their ARI risk factors, COVID-19 history, and recent receipt of medical care for any ARI at enrollment, in December 2020 and again in May 2021. Subjects were also asked to provide blood and saliva samples to assess their SARS-CoV-2 serostatus at the same three timepoints. A saliva sample was collected by a subset of subjects in February 2021. Presence of anti-SARS-CoV-2 serum IgG in dried blood spots and saliva was measured by multiplex magnetic microparticle-based immunoassays. Results 181 midshipmen consented to the study and completed the baseline survey (Table 1). 17 (17.5%) of the 97 subjects who submitted baseline blood sample were SARS-CoV-2 seropositive. Only 4 (24%) positive individuals reported having been tested for or diagnosed with COVID-19 prior to arrival at USNA. 121 participants completed the midyear survey, of whom 61 (50%) submitted a blood sample. 16 (26%) of the midyear specimens were SARS-CoV-2 positive. Of these, 3 were new infections. 73 subjects completed the May survey, and 63 (100%) of the submitted blood samples were positive. 83 subjects provided baseline saliva samples, and ~55 submitted saliva at each successive time point. 1 (5%) was positive at enrollment, 9 (17%) were positive at midyear and 47 (96%) were positive in May. Table 1. Key characteristics of TOSCANA participants Conclusion SAR-CoV-2 prevalence in a sample of USNA midshipmen was < 20% at enrollment. A small proportion of subjects seroconverted between the September and December visits. SARS-CoV-2 positivity rose in May, following a COVID-19 outbreak in February and COVID-19 vaccination efforts in March at USNA. Disclosures Jitu Modi, MD, GSK (Speaker’s Bureau)

Bitter Rot of Apple in the Mid-Atlantic US: Causal Species and Evaluation of the Impacts of Regional Weather Patterns and Cultivar Susceptibility

2021 ◽  
Author(s):  
Phillip L. Martin ◽  
Teresa Krawczyk ◽  
Fatemeh Khodadadi ◽  
Srđan G. Aćimović ◽  
Kari Peter
Keyword(s):  
Growth Rates ◽  
Species Complex ◽  
Warming Trend ◽  
The United States ◽  
Weather Data ◽  
Apple Cultivar ◽  
Colletotrichum Species ◽  
Bitter Rot ◽  
Cultivar Susceptibility

Apple growers in the Mid-Atlantic region of the United States have been reporting an increase in losses to bitter rot of apple and are requesting up-to-date management recommendations. Management is complicated by variations in apple cultivar susceptibility, temperature and rainfall, and biology of the Colletotrichum species that cause bitter rot. Over 500 apples with bitter rot were obtained from 38 orchards across the Mid-Atlantic and the causal species identified as C. fioriniae and C. nymphaeae of the C. acutatum species complex and C. chrysophilum, C. noveboracense, C. siamense, C. fructicola, C. henanense, and C. gloeosporioides sensu stricto of the C. gloeosporioides species complex, the latter two being first reports. Species with faster in vitro growth rates at higher temperatures were more abundant in warmer regions of the Mid-Atlantic, while those with slower growth rates at higher temperatures were more abundant in cooler regions. Regional bloom dates are earlier and weather data shows a gradual warming trend that likely influenced, but was not necessarily the main cause of the recent increase in bitter rot in the region. A grower survey of apple cultivar susceptibility showed high variation, with the increase in acres planted to the highly susceptible cultivar ‘Honeycrisp’ broadly corresponding to the increase in reports of bitter rot. These results form a basis for future studies on the biology and ecology of the Colletotrichum species responsible, and suggest that integrated bitter rot management must begin with selection of less-susceptible apple cultivars.

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