Life Sciences Commons^™

Leaf Optical And Indirect Lai Measurements In Wheat And Alfalfa At Maciv: Agmet Progress Report 89-4, E. A. Walter-Shea, B. L. Blad

School of Natural Resources: Documents and Reviews

No abstract provided.

Concepts In Animal Parasitology: Master Bibliography, Sue Ann Gardner

Concepts in Animal Parasitology Textbook

Master bibliography for the open educational resource/open access textbook Concepts in Animal Parasitology, Scott L. Gardner and Sue Ann Gardner, editors, published by Zea Books, Lincoln, Nebraska, United States, 2024. This includes the references from literature cited and suggested supplemental reading.

Analyzing Phototaxis And Related Visual Behaviors Among Diverse Species Of Drosophila, Madeline M. Hill

Honors Theses

Phototaxis and related visual behaviors can vary between species, and thus members of the genus Drosophila make an excellent study system to examine the evolution of vision. While some existing research points to these phototactic behaviors arising due to mating requirements or due to their species-specific ecology or environmental factors, there exists a lack of understanding as to why striking behavioral differences can exist between closely related species, or between members belonging to the same genus. The present research seeks to uncover the specifics regarding these discrepancies in visual evolution and aims to provide a foundation of knowledge about visual …

Consequences Of The Megafauna Extinction: Changes In Food Web Networks On The Edwards Plateau Across The Pleistocene-Holocene Transition, Quentin A. Smith Jr.

School of Biological Sciences: Dissertations, Theses, and Student Research

We are experiencing biodiversity loss due to climate change and human impacts, which is not only harmful to the environment but can also alter the composition of communities and interactions among species. The late Pleistocene experienced a loss of large-bodied mammals which resulted in significant changes in community structure due to changes in body size, diet, and species associations. The impact of these changes on species interactions and community structure across the Pleistocene-Holocene transition remains poorly understood. Using a robust data set of species composition, stable isotopes, body size, and climate variables, we constructed and compared ecological networks of mammal …

An Examination Of The Eastern Nebraska And Western Iowa Flash Flood Event Of 6-7 August 1999, Catherine M. Zapotocny

NOAA Technical Reports and Related Materials

Flash flooding occurs each summer in eastern Nebraska and western Iowa. While 10-inch rains are extraordinary, it is not uncommon to have at least one excessive rain event during the annual convective season. A significant flash flood occurred in east central Nebraska and western Iowa the night of August 6, 1999 into the morning of August 7, 1999. Antecedent hydrologic conditions limited the loss of life, however considerable property damage resulted as the heavy rain fell over the urbanized areas in eastern Nebraska and western Iowa.

Several flash flood ingredients came together over the area. These meteorological factors are typical …

Demographic Consequences Of Off-River Nesting For Piping Plover (Charadrius Melodus) And Interior Least Tern (Sternula Antillarum Athalassos) In The Lower Platte River System, Nebraska, Elsa M. Forsberg

School of Natural Resources: Dissertations, Theses, and Student Research

Piping plovers (Charadrius melodus; hereafter, plovers) and interior least terns (Sternula antillarum athalassos; hereafter, terns) are two avian species that nest along the Lower Platte River system (LPRS) in Nebraska. In the LPRS, river sandbars provide natural nesting habitat, but off-river sites provide substantial nesting habitat especially when sandbar habitat is scarce. Although presumed to be important for the persistence of plovers and terns, off-river habitat is not self-sustaining and predicted to decline. Understanding the vital rates of plovers and terns in the LPRS will inform the role of off- river sites in the future conservation …

Pollinator Communities And Their Ecosystem Services At Conservation Grasslands And Adjacent Croplands, Araceli Gomez Villegas

Department of Entomology: Dissertations, Theses, and Student Research

Pollinators are intrinsically linked to the success of unmanaged and managed ecosystems by providing pollination services that aid in the reproduction of wildflowers and many crops. Land use change, habitat loss, fragmentation, and related landscape-level phenomena (for example, increased pesticide exposure) threaten pollinators and have been associated with population declines. In the Midwestern region of the United States, land conversion of native prairies and grasslands to row-crop agriculture has been one of the largest contributors to pollinator habitat loss. Conservation programs, such as the Conservation Reserve Program, have worked towards removing environmentally sensitive lands from agriculture production and enrolling them …

Taxonomic Advances Driven By The Genomic Analysis Of Butterflies, Jing Zhang, Qian Cong, Jinhui Shen, Leina Song, Nick V. Grishin

The Taxonomic Report of the International Lepidoptera Survey

This study presents new findings based on a large-scale analysis of butterfly genomic sequences. Focusing on species identification through comparative genomics, we define subspecies as populations differentiated to a lesser extent than distinct species ("species in the making"). Additionally, we propose further adjustments to the current butterfly classification. As a result, 3 subgenera, 12 species, and 4 subspecies are described as new. New subgenera are (type species in parenthesis): Hyalaus Grishin, subgen. n. (Papilio epidaus E. Doubleday, 1846) of Eurytides Hübner, [1821] (Papilionidae Latreille, [1802]) and Astria Grishin, subgen. n. (Lycaena astraea Freyer, 1851) of Glaucopsyche Scudder, 1872 …

Site-Specific Space Use And Resource Selection By Black Vultures (Coragyps Atratus) In The Southeastern Usa, Betsy Evans, John S. Humphrey, Eric A. Tillman, Michael L. Avery, Bryan M. Kluever

USDA Wildlife Services: Staff Publications

North American populations of Black Vultures Coragyps atratus have increased and expanded their distribution in the southern and eastern USA. In conjunction with these patterns has been a rise in human–vulture conflicts. To improve our understanding of space use patterns and better inform management, we evaluated the movements of Black Vultures (n = 23) in the southeastern USA using a long-term GPS tracking database. Our specific objectives were to: (1) quantify home-range sizes in relation to season and geographical study location and (2) examine within-home-range resource selection to identify landscape and anthropogenic factors influencing roost and diurnal space use. …

Treatment With The Immunocontraceptive Vaccine, Gonacon, Induces Temporary Fertility Control In Free-Ranging Prairie Dog Populations In Colorado, Usa, Aaron B. Shiels, Jackson Runte, Emily W. Ruell, Douglas C. Eckery, Gary W. Witmer, Daniel J. Salkeld

USDA Wildlife Services: Staff Publications

Context

Prairie dogs (Cynomys spp.) are rodents enjoyed by some humans; yet, they cause crop and property damage, and carry zoonotic disease. Non-lethal control of prairie dogs is of interest in urban/suburban settings. The injectable immunocontraceptive vaccine GonaCon (active ingredient is gonadotropin-releasing hormone [GnRH]) has been shown to be effective at reducing fertility in equine and deer, and is a US EPA-registered vaccine for use in these ungulate species.

Aims

To conduct a replicated field study to test efficacy of GonaCon in black-tailed prairie dogs (C. ludovicianus), and if found to be efficacious, to help facilitate …

Comparison Of Ketamine-Xylazine, Butorphanol-Azaperone-Medetomidine, And Nalbuphine-Medetomidine-Azaperone For Raccoon (Procyon Lotor) Immobilization, Shylo R. Johnson, Christine K. Ellis, Chad Wickham, Molly R. Selleck, Amy T. Gilbert

USDA Wildlife Services: Staff Publications

Raccoons (Procyon lotor) are frequently handled using chemical immobilization in North America for management and research. In a controlled environment, we compared three drug combinations: ketamine-xylazine (KX), butorphanol-azaperone-medetomidine (BAM), and nalbuphinemedetomidine- azaperone (NalMed-A) for raccoon immobilization. In crossover comparisons, raccoons received a mean of the following: 8.66 mg/kg ketamine and 1.74 mg/kg xylazine (0.104 mL/kg KX); 0.464 mg/kg butorphanol, 0.155 mg/kg azaperone, and 0.185 mg/kg medetomidine (0.017 mL/kg BAM); and 0.800 mg/kg nalbuphine, 0.200 mg/kg azaperone, and 0.200 mg/kg medetomidine (0.020 mL/kg NalMed-A). Induction time was shortest with KX (mean6SE, 10.060.7 min) and longest with NalMed-A (13.061.3 min). …

Oral Rabies Vaccination Of Raccoons (Procyon Lotor) Across A Development Intensity Gradient In Burlington, Vermont, Usa, 2015–2017, Emily M. Beasley, Kathleen M. Nelson, Dennis Slate, Amy T. Gilbert, Frederick E. Pogmore, Richard B. Chipman, Amy J. Davis

USDA Wildlife Services: Staff Publications

Management of the raccoon rabies virus variant in North America is conducted primarily using oral rabies vaccination (ORV). When a sufficient proportion of the population is vaccinated (60%), rabies transmission can be eliminated. To date, ORV programs have successfully controlled and eliminated raccoon rabies in rural areas, but there has been less success in urban areas. We studied the proportions of rabies virus neutralizing antibodies (RVNA) in a raccoon (Procyon lotor) population during a 3-year ORV trial in developed areas of Burlington, Vermont, United States. We used a modified N-mixture model to estimate raccoon abundance, RVNA seroprevalence, and …

Recent Beak Evolution In North American Starlings After Invasion, Julia M. Zichello, Shelagh T. Deliberto, Paul Shrewsbury, Agnieszka A. Pierwola, Scott J. Werner

USDA Wildlife Services: Staff Publications

European starlings are one of the most abundant and problematic avian invaders in the world. From their native range across Eurasia and North Africa, they have been introduced to every continent except Antarctica. In 160 years, starlings have expanded into different environments throughout the world, making them a powerful model for understanding rapid evolutionary change and adaptive plasticity. Here, we investigate their spatiotemporal morphological variation in North America and the native range. Our dataset includes 1,217 specimens; a combination of historical museum skins and modern birds. Beak length in the native range has remained unchanged during the past 206 years, …

Characterization Of Recent Wild Pig‑Vehicle Collisions In Georgia, Usa, Jeremiah L. Psiropoulos, Emily Howe, John J. Mayer, Sophie C. Mckee

USDA Wildlife Services: Staff Publications

Vehicle collisions with wild pigs (Sus scrofa) are reported almost everywhere this species is found. However, this is one of the least studied and characterized forms of damage that these invasive animals cause in the United States (US). We analyzed 518 wild pig-vehicle collisions (WPVCs) that took place statewide in Georgia between 2015 and 2021. From that dataset, we analyzed several parameters in order to better understand and characterize these accidents on a scale that had previously not been done in the US. Wild pig-vehicle collisions were reported from 105 out of the 159 counties in Georgia, increasing …

Assessing The Efficiency Of Local Rabies Vaccination Strategies For Raccoons (Procyon Lotor) In An Urban Setting, Guillaume Bastille-Rousseau, Nicole T. Gorman, Katherine M. Mcclure, Larissa Nituch, Tore Buchanan, Richard B. Chipman, Amy T. Gilbert, Kim M. Pepin

USDA Wildlife Services: Staff Publications

Raccoon rabies virus (RRV) has been managed using multiple vaccination strategies, including oral rabies vaccination and trap-vaccinate-release (TVR). Identifying a rabies vaccination strategy for an area is a nontrivial task. Vaccination strategies differ in the amount of effort and monetary costs required to achieve a particular level of vaccine seroprevalence (efficiency). Simulating host movement relative to different vaccination strategies in silico can provide a useful tool for exploring the efficiency of different vaccination strategies. We refined a previously developed individual-based model of raccoon movement to evaluate vaccination strategies for urban Hamilton, Ontario, Canada. We combined different oral rabies vaccination baiting …

Distribution And Prevalence Of Antibodies To Trichinella Spp. And Toxoplasma Gondii In Wild Pigs (Sus Scrofa) In The United States, Christopher A. Cleveland, Ellen Haynes, Katherine C. Callaghan, Alinde Fojtik, Sarah Coker, Emily Doub, Vienna R. Brown, Ania A. Majewska, Michael J. Yabsley

USDA Wildlife Services: Staff Publications

Invasive wild pigs (Sus scrofa) are a reservoir for over 100 viral, bacterial, and parasitic pathogens that are transmissible to humans, livestock, domestic animals, and wildlife in North America. Numerous historical local surveys and results from a nation-wide survey (2006–2010) indicated that wild pigs in the United States act as reservoirs for Trichinella spp. and Toxoplasma gondii, two zoonotic pathogens of importance for human and animal health. Since that time, wild pig populations have expanded and increased in density in many areas. Population expansion of wild pigs creates opportunities for the introduction of pathogens to new areas …

Two New Species Of False Click Beetles (Coleoptera: Eucnemidae) From The Americas, Robert L. Otto

Insecta Mundi

Abstract

Identifications of recently collected Eucnemidae (Coleoptera: Elateroidea) borrowed from two collections have resulted in the discovery of two new species: Entomophthalmus abbreviatus Otto (Cuba) and Trigonopleurus cordobaalfaroi Otto (Guatemala and Louisiana, United States). Images of the two newly described species along with two New World Entomophthalmus Bonvouloir species for comparative purposes are included.

Resumen

Las identificaciones de Eucnemidae (Coleoptera: Elateroidea) recolectados recientemente tomados de dos colecciones han resultado en el descubrimiento de dos nuevas especies: Entomophthalmus abbreviatus Otto (Cuba) y Trigonopleurus cordobaalfaroi Otto (Guatemala y Louisiana, United States). Se incluyen imágenes de las dos especies recientemente descritas junto con …

New State Records Of Buprestidae (Coleoptera) For Idaho, Usa, Richard L. Westcott

Insecta Mundi

Five new state records for Idaho in the genera Agrilus Curtis, Anthaxia Eschscholtz, and Buprestis Linnaeus (Coleoptera: Buprestidae) are included herein, with brief comments thereon. Two of the species are believed to be introduced. Agrilus liragus Barter and Brown is elevated to a full species, resurrected status.

The Unbelievable Fauna Of American Lamiinae (Coleoptera: Cerambycidae): Description Of Two New Species, Transference, And Notes In Acanthocinini, And A New Record In Calliini, Antonio Santos-Silva, Juan Pablo Botero

Insecta Mundi

Two new species and one new genus of Lamiinae (Coleoptera: Cerambycidae) are described in Acanthocinini: Embera flava new species, new genus, from Panama; and Nealcidion lingafelteri new species from Costa Rica. The species-group name of Nealcidion napoensis Nascimento and McClarin, 2018 is corrected and morphological variations in Leptostylus cristulatus Bates, 1872 are reported. Trypanidius mimicavus Carelli, Monné, and Souza, 2013 is redescribed and transferred to Carphina Bates, 1872, forming the new combination Carphina mimicavus. Colombicallia curta Galileo and Martins, 1992 (Calliini) is recorded from Panama for the first time.

Platygastroidea In The Oxford University Museum Of Natural History: Taxonomic Updates And A Photographic Catalog Of Type Specimens, Elijah J. Talamas, Jessica Awad, Francesco Tortorici, Norman F. Johnson

Insecta Mundi

High resolution images are provided for type specimens of Platygastroidea (Hymenoptera: Apocrita) in the Hope Entomological Collections, Oxford University. We formally resurrect Trissoscelio Kieffer revised status to accommodate T. bifasciata (Dodd) new combination, T. indica (Mani) new combination, T. nigriceps Kieffer revised combination, T. ruficeps Kieffer revised combination, and T. punctaticeps Kieffer revised combination. Paridris subplana (Dodd) new combination is transferred from Sceliacantha Dodd to Paridris Kieffer and treated as a senior synonym of P. coorgensis Sharma.

Analysis Of Pepsis Basifusca Lucas (Hymenoptera: Pompilidae: Pepsinae) Taxonomy, Morphology, Biogeography, And Potential Host Spider, Frank E. Kurczewski

Insecta Mundi

A first-time analysis of taxonomically relevant characters, functional morphology, geographic distribution, ecoregion preference, and hypothetical host spiders of Pepsis basifusca Lucas (Hymenoptera: Pompilidae: Pepsinae) is presented. This analysis is compared with other Nearctic species in Vardy’s (2005) Pepsis menechma species-group, particularly P. cerberus Lucas and P. elegans Lepeletier which are suspected parasitoids of trapdoor spiders. Pepsis basifusca females differ from females of these species in possessing a rounded gena-postgena in dorsal view; straight mid and hind tibial spurs; short hind tibial inner spur; and short, very stout, and backward slanted hind tibial bristles. Pepsis basifusca Level III Ecoregions …

Two New Species Of Bumblebee Scarabs (Coleoptera: Glaphyridae: Lichnanthe Burmeister) From The Central United States: A New Discovery In Wyoming Resolves A Century-Old Puzzle From The Nebraska Sand Hills, Matthew J. Paulsen

Insecta Mundi

The genus Lichnanthe Burmeister (Coleoptera: Scarabaeoidea: Glaphyridae) has comprised eight Nearctic species and contains the only New World members of their family. Here, two new species of arenicolous bumblebee scarabs are described from the central United States. The recent discovery of an undescribed Wyoming species led to the reevaluation of a dubious 134-year-old Nebraska Lichnanthe specimen, indicating that it also was an undescribed species. These two species, Lichnanthe brusti new species from central Wyoming and L. bruneri new species from central Nebraska are immediately distinguishable from all existing species of the genus by their square mandibles.

Limitations Of Invasive Snake Control Tools In The Context Of A New Invasion On An Island With Abundant Prey, Shane R. Siers, Melia G. Nafus, Jereid E. Calaor, Rachel M. Volsteadt, Matthew S. Grassi, Megan Volsteadt, Aaron F. Collins, Patrick D. Barnhart, Logan T. Huse, Amy A. Yackel Adams, Diane L. Vice

USDA Wildlife Services: Staff Publications

In October 2020, a new population of invasive brown treesnakes (Boiga irregularis) was discovered on the 33-ha Cocos Island, 2.5 km off the south coast of Guam, United States. Cocos Island is a unique conservation resource, providing refuge for many lizards and birds, including endangered species, which were extirpated from mainland Guam by invasive predators including brown treesnakes. We sought to evaluate the usefulness of toxic baiting with acetaminophen-treated carrion baits and cage trapping, common tools for the control of brown treesnakes on mainland Guam, as potential eradication tools on Cocos Island. We evaluated multiple bait types and …

A Revision Of Dyscolotaxia Horn, 1890 (Coleoptera: Eucnemidae: Macraulacinae: Macraulacini), With The Description Of Amazotaxia New Genus From South America, Robert L. Otto

Insecta Mundi

Abstract

The Neotropical eucnemid genus, Dyscolotaxia Horn, is revised following the examination of specimens from five collections, examination of the published original description of Plesiofornax tetratoma Chassain, and from images provided by Fernanda Salazar-Buenaño (QCAZI). Dyscolotaxia championi Horn is redescribed with included descriptions of the male genitalia and a female specimen. Three new species of false click beetles (Coleoptera: Eucnemidae) are described from the Neotropical region. These new species are: Dyscolotaxia chiriquiensis (Panama), Dyscolotaxia hispaniolensis (Dominican Republic), and Dyscolotaxia picea (Ecuador). Amazotaxia new genus is described from South America for Plesiofornax tetratoma Chassain, creating Amazotaxia tetratoma (Chassain) new combination. Morphology …

Melittological Notes From Guatemala (Hymenoptera: Anthophila), 1. New Country Records For Centris Fabricius (Apidae) And Zikanapis Moure (Colletidae), Silas Bossert, José Monzón-Sierra, Richard S. Zack, Ana Cristina García, Elizabeth A. Murray

Insecta Mundi

Abstract

Three species of bees (Hymenoptera: Apidae, Colletidae) are newly recorded for Guatemala: Centris obscurior Michener, Centris vidua Mocsáry, and Zikanapis inbio (Michener, Engel and Ayala). We discuss aspects of their biology and circumstances of the collecting events and provide information on their presently known distribution.

Resumen

Se registran por primera vez tres especies de abejas (HymenopteraN: Apidae, Colletidae) para Guatemala: Centris obscurior Michener, Centris vidua Mocsáry, y Zikanapis inbio (Michener, Engel y Ayala). Discutimos aspectos de su biología, circunstancias bajo las cuáles fueron colectadas y se provee información en la distribución conocida actualmente.

Genomic Analysis Reveals New Species And Subspecies Of Butterflies, Jing Zhang, Qian Cong, Jinhui Shen, Leina Song, Nick V. Grishin

The Taxonomic Report of the International Lepidoptera Survey

Large-scale genomic sequencing of butterfly taxa reveals new findings that are presented here. While we focus on detecting species by comparative genomics and define subspecies as groups of populations genetically differentiated from each other but not as strongly as species (that is, subspecies as species in the making), we report other adjustments to butterfly classification. As a result, 4 subgenera, 11 species, and 6 subspecies are proposed as new. New subgenera are: Rapis Grishin, subgen. n. (type species Papilio rapae Linnaeus, 1758, genus Pieris Schrank, 1801) in Pieridae Swainson, 1820 and Callitera Grishin, subgen. n. (type species Eurygona? pulcherrima …

Reassessment Of Amblyscirtes Hegon (Hesperiidae) As A Complex Of Four Distinct Species Revealed By Genomic Analysis, Harry Pavulaan, Ricky Patterson, Nick V. Grishin

The Taxonomic Report of the International Lepidoptera Survey

After the discovery of a unique phenotype in the southern United States with a different ventral ground color than nominotypical Amblyscirtes hegon (Scudder, 1863), which occurs in the northeastern United States, genomic analysis revealed that A. hegon is a species complex. Phenotypic, genitalic, and genomic differences of the complex are presented here. Four species are identified: A. hegon; A. nemoris (W. H. Edwards, 1864), stat. rest.; A. matheri Patterson, Pavulaan & Grishin, sp. n. (TL: USA, Mississippi, Warren County); and A. gelidus Grishin, Patterson & Pavulaan, sp. n. (TL: USA, Michigan, Van Buren County).

Aksakidion Odontokeras (Coleoptera: Chrysomelidae: Eumolpinae: Eumolpini), A New Genus And Species In An Old Collection From Paraguay, Wills Flowers

Insecta Mundi

Aksakidion odontokeras, new genus and new species (Coleoptera: Chrysomelidae: Eumolpinae: Eumolpini), is described from four specimens in the Bowditch Collection at Harvard University. It is dis­tinguished from all other genera in the Eumolpinae by an elongate, seta-bearing, tusk-like projection on the dorsal side of each mandible. Although locality data only mention Paraguay as the country of origin, information about the collector indicates it was collected in the late 19th century in the vicinity of Asunción.

During a recent visit to the Museum of Comparative Zoology at Harvard University (MCZ) to study type mate­rial of Neotropical Chrysomelidae, a short series …

Accelerated Evolution Of Sars-Cov-2 In Free-Ranging White-Tailed Deer, Dillon S. Mcbride, Sofya K. Garushyants, John Franks, Andrew F. Magee, Steven H. Overend, Devra Huey, Amanda M. Williams, Seth A. Faith, Ahmed Kandeil, Sanja Trifkovic, Lance Miller, Trushar Jeevan, Anami Patel, Jacqueline M. Nolting, Michael J. Tonkovich, J. Tyler Genders, Andrew J. Montoney, Kevin Kasnyik, Timothy J. Linder, Sarah N. Bevins, Julianna B. Lenoch, Jeffrey C. Chandler, Thomas J. Deliberto, Eugene V. Koonin, Marc A. Suchard, Philippe Lemey, Richard J. Webby, Martha I. Nelson, Andrew S. Bowman

USDA Wildlife Services: Staff Publications

The zoonotic origin of the COVID-19 pandemic virus highlights the need to fill the vast gaps in our knowledge of SARS-CoV-2 ecology and evolution in non-human hosts. Here, we detected that SARS-CoV-2 was introduced from humans into white-tailed deer more than 30 times in Ohio, USA during November 2021-March 2022. Subsequently, deer-to-deer transmission persisted for 2–8 months, disseminating across hundreds of kilometers. Newly developed Bayesian phylogenetic methods quantified how SARS-CoV-2 evolution is not only three-times faster in white-tailed deer compared to the rate observed in humans but also driven by different mutational biases and selection pressures. The long-term effect of …

Rapid Evolution Of A(H5n1) Influenza Viruses After Intercontinental Spread To North America, Ahmed Kandeil, Christopher Patton, Jeremy C. Jones, Trushar Jeevan, Walter N. Harrington, Sanja Trifkovic, Jon P. Seiler, Thomas Fabrizio, Karlie Woodard, Jasmine C. Turner, Jeri Carol Crumpton, Lance Miller, Adam Rubrum, Jennifer Debeauchamp, Charles J. Russell, Elena A. Govorkova, Peter Vogel, Mia Kim-Torchetti, Yohannes Berhane, David Stallknecht, Rebecca Poulson, Lisa Kercher, Richard J. Webby

USDA Wildlife Services: Staff Publications

Highly pathogenic avian influenza A(H5N1) viruses of clade 2.3.4.4b underwent an explosive geographic expansion in 2021 among wild birds and domestic poultry across Asia, Europe, and Africa. By the end of 2021, 2.3.4.4b viruses were detected in North America, signifying further intercontinental spread. Here we show that the western movement of clade 2.3.4.4b was quickly followed by reassortment with viruses circulating in wild birds in North America, resulting in the acquisition of different combinations of ribonucleoprotein genes. These reassortant A(H5N1) viruses are genotypically and phenotypically diverse, with many causing severe disease with dramatic neurologic involvement in mammals. The proclivity of …