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James DG. Monarch Butterflies in Western North America: A Holistic Review of Population Trends, Ecology, Stressors, Resilience and Adaptation. INSECTS 2024; 15:40. [PMID: 38249046 PMCID: PMC10817040 DOI: 10.3390/insects15010040] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/18/2023] [Revised: 01/04/2024] [Accepted: 01/05/2024] [Indexed: 01/23/2024]
Abstract
Monarch butterfly populations in western North America suffered a substantial decline, from millions of butterflies overwintering in California in the 1980s to less than 400,000 at the beginning of the 21st century. The introduction of neonicotinoid insecticides in the mid-1990s and their subsequent widespread use appears to be the most likely major factor behind this sudden decline. Habitat loss and unfavorable climates (high temperatures, aridity, and winter storms) have also played important and ongoing roles. These factors kept overwintering populations stable but below 300,000 during 2001-2017. Late winter storm mortality and consequent poor spring reproduction drove winter populations to less than 30,000 butterflies during 2018-2019. Record high temperatures in California during the fall of 2020 appeared to prematurely terminate monarch migration, resulting in the lowest overwintering population (1899) ever recorded. Many migrants formed winter-breeding populations in urban areas. Normal seasonal temperatures in the autumns of 2021 and 2022 enabled overwintering populations to return to around the 300,000 level, characteristic of the previous two decades. Natural enemies (predators, parasitoids, parasites, and pathogens) may be important regional or local drivers at times but they are a consistent and fundamental part of monarch ecology. Human interference (capture, rearing) likely has the least impact on monarch populations. The rearing of monarch caterpillars, particularly by children, is an important human link to nature that has positive ramifications for insect conservation beyond monarch butterflies and should be encouraged.
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Affiliation(s)
- David G James
- Department of Entomology, Washington State University, Irrigated Agriculture Research and Extension Center, Prosser, WA 99350, USA
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2
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Shirey V, Ries L. Population dynamics and drivers of the eastern monarch (Danaus plexippus) across its full annual cycle: a cross-scale synthesis of a model migratory species. CURRENT OPINION IN INSECT SCIENCE 2023; 60:101132. [PMID: 37871775 DOI: 10.1016/j.cois.2023.101132] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/26/2023] [Revised: 10/11/2023] [Accepted: 10/12/2023] [Indexed: 10/25/2023]
Abstract
The monarch butterfly is arguably the best-known butterfly species throughout its global range. Declines in the size of the overwintering colonies in Mexico have sparked controversy regarding the conservation of the species and this controversy has been heightened since the United States Fish and Wildlife Service and International Union for the Conservation of Nature concluded that the eastern monarch populations were threatened (or in the case of United States Fish and Wildlife Service, warranted listing). Drivers of decline vary through space and time. Here, we present a synthesis of longitudinal monarch abundance studies that aim to disentangle the putative drivers of decline from one another. We find remarkable consistency that suggests monarch populations are indeed declining and that potential drivers of such decline shift over time. We strongly encourage future work on the species paired with mechanistic, experimental designs to address some long-standing knowledge gaps.
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Affiliation(s)
- Vaughn Shirey
- Department of Biology, Georgetown University, 37th and O Streets NW, Washington, DC 20057, USA; Marine and Environmental Biology Section - Department of Biological Sciences, University of Southern California, Allan Hancock Foundation Building, Los Angeles, CA 90089, USA.
| | - Leslie Ries
- Department of Biology, Georgetown University, 37th and O Streets NW, Washington, DC 20057, USA
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3
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Boyle JH, Strickler S, Twyford AD, Ricono A, Powell A, Zhang J, Xu H, Smith R, Dalgleish HJ, Jander G, Agrawal AA, Puzey JR. Temporal matches between monarch butterfly and milkweed population changes over the past 25,000 years. Curr Biol 2023; 33:3702-3710.e5. [PMID: 37607548 DOI: 10.1016/j.cub.2023.07.057] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2022] [Revised: 04/13/2023] [Accepted: 07/26/2023] [Indexed: 08/24/2023]
Abstract
In intimate ecological interactions, the interdependency of species may result in correlated demographic histories. For species of conservation concern, understanding the long-term dynamics of such interactions may shed light on the drivers of population decline. Here, we address the demographic history of the monarch butterfly, Danaus plexippus, and its dominant host plant, the common milkweed Asclepias syriaca (A. syriaca), using broad-scale sampling and genomic inference. Because genetic resources for milkweed have lagged behind those for monarchs, we first release a chromosome-level genome assembly and annotation for common milkweed. Next, we show that despite its enormous geographic range across eastern North America, A. syriaca is best characterized as a single, roughly panmictic population. Using approximate Bayesian computation with random forests (ABC-RF), a machine learning method for reconstructing demographic histories, we show that both monarchs and milkweed experienced population expansion during the most recent recession of North American glaciers 10,000-20,000 years ago. Our data also identify concurrent population expansions in both species during the large-scale clearing of eastern forests (∼200 years ago). Finally, we find no evidence that either species experienced a reduction in effective population size over the past 75 years. Thus, the well-documented decline of monarch abundance over the past 40 years is not visible in our genomic dataset, reflecting a possible mismatch of the overwintering census population to effective population size in this species.
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Affiliation(s)
- John H Boyle
- Biology Department, College of William & Mary, 540 Landrum Dr., Williamsburg, VA 23185, USA; Biology Department, University of Mary, 7500 University Dr., Bismarck, ND 58504, USA
| | - Susan Strickler
- Boyce Thompson Institute, 533 Tower Rd., Ithaca, NY 14853, USA; Chicago Botanic Garden, Plant Science and Conservation, 1000 Lake Cook Rd., Glencoe, IL 60022, USA; Northwestern University, Plant Biology and Conservation Program, 2145 Sheridan Rd., Evanston, IL 60208, USA
| | - Alex D Twyford
- Institute of Ecology and Evolution, University of Edinburgh, Charlotte Auerbach Rd., Edinburgh EH9 3FL, UK; Royal Botanic Garden Edinburgh, Edinburgh EH3 5NZ, UK
| | - Angela Ricono
- Biology Department, College of William & Mary, 540 Landrum Dr., Williamsburg, VA 23185, USA
| | - Adrian Powell
- Boyce Thompson Institute, 533 Tower Rd., Ithaca, NY 14853, USA
| | - Jing Zhang
- Boyce Thompson Institute, 533 Tower Rd., Ithaca, NY 14853, USA
| | - Hongxing Xu
- Boyce Thompson Institute, 533 Tower Rd., Ithaca, NY 14853, USA; College of Life Sciences, Shaanxi Normal University, South Chang'an Rd., Xi'an 710062, China
| | - Ronald Smith
- Data Science Program, College of William & Mary, 540 Landrum Dr., Williamsburg, VA 23185, USA
| | - Harmony J Dalgleish
- Biology Department, College of William & Mary, 540 Landrum Dr., Williamsburg, VA 23185, USA
| | - Georg Jander
- Boyce Thompson Institute, 533 Tower Rd., Ithaca, NY 14853, USA
| | - Anurag A Agrawal
- Department of Ecology and Evolutionary Biology, Cornell University, Corson Hall, Ithaca, NY 14853, USA
| | - Joshua R Puzey
- Biology Department, College of William & Mary, 540 Landrum Dr., Williamsburg, VA 23185, USA.
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4
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Rissman AR, Fochesatto A, Lowe EB, Lu Y, Hirsch RM, Jackson RD. Grassland and managed grazing policy review. FRONTIERS IN SUSTAINABLE FOOD SYSTEMS 2023. [DOI: 10.3389/fsufs.2023.1010441] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/06/2023] Open
Abstract
Perennial grasslands, including prairie and pasture, have declined with tremendous environmental and social costs. This decline reflects unequal policy support for grasslands and managed grazing compared to row crops. To create a resource for community partners and decision-makers, we reviewed and analyzed the policy tools and implementation capacity that supports and constrains grasslands and managed grazing in the U.S. Upper Midwest. Risk reduction subsidies for corn and soybeans far outpace the support for pasture. Some states lost their statewide grazing specialist when the federal Grazing Lands Conservation Initiative lapsed. The United States Department of Agriculture, Natural Resources Conservation Service support for lands with prescribed grazing practices declined after 2005 but remained relatively steady 2010–2020. These results reveal the policy disadvantage for grasslands and managed grazing in comparison with row crop agriculture for milk and meat production. Grassland and grazing policies have an important nexus with water quality, biodiversity, carbon and outdoor recreation policy. Socially just transitions to well-managed, grazed grasslands require equity-oriented interventions that support community needs. We synthesized recommendations for national and state policy that farmers and other grazing professionals assert would support perennial grasslands and grazing, including changes in insurance, conservation programs, supply chains, land access, and fair labor. These policies would provide critical support for grass-based agriculture and prairies that we hope will help build soil, retain nutrients, reduce flooding and enhance biodiversity while providing healthy food, jobs, and communities.
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5
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Davis CL, Guralnick RP, Zipkin EF. Challenges and opportunities for using natural history collections to estimate insect population trends. J Anim Ecol 2023; 92:237-249. [PMID: 35716080 DOI: 10.1111/1365-2656.13763] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2021] [Accepted: 06/13/2022] [Indexed: 11/28/2022]
Abstract
Natural history collections (NHC) provide a wealth of information that can be used to understand the impacts of global change on biodiversity. As such, there is growing interest in using NHC data to estimate changes in species' distributions and abundance trends over historic time horizons when contemporary survey data are limited or unavailable. However, museum specimens were not collected with the purpose of estimating population trends and thus can exhibit spatiotemporal and collector-specific biases that can impose severe limitations to using NHC data for evaluating population trajectories. Here we review the challenges associated with using museum records to track long-term insect population trends, including spatiotemporal biases in sampling effort and sparse temporal coverage within and across years. We highlight recent methodological advancements that aim to overcome these challenges and discuss emerging research opportunities. Specifically, we examine the potential of integrating museum records and other contemporary data sources (e.g. collected via structured, designed surveys and opportunistic citizen science programs) in a unified analytical framework that accounts for the sampling biases associated with each data source. The emerging field of integrated modelling provides a promising framework for leveraging the wealth of collections data to accurately estimate long-term trends of insect populations and identify cases where that is not possible using existing data sources.
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Affiliation(s)
- Courtney L Davis
- Department of Integrative Biology; Ecology, Evolution, and Behavior Program, Michigan State University, East Lansing, Michigan, USA.,Cornell Lab of Ornithology, Cornell University, Ithaca, New York, USA
| | - Robert P Guralnick
- Florida Museum of Natural History, University of Florida, Gainesville, Florida, USA.,Biodiversity Institute, University of Florida, Gainesville, Florida, USA
| | - Elise F Zipkin
- Department of Integrative Biology; Ecology, Evolution, and Behavior Program, Michigan State University, East Lansing, Michigan, USA
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6
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Grant TJ, Fisher KE, Krishnan N, Mullins AN, Hellmich RL, Sappington TW, Adelman JS, Coats JR, Hartzler RG, Pleasants JM, Bradbury SP. Monarch Butterfly Ecology, Behavior, and Vulnerabilities in North Central United States Agricultural Landscapes. Bioscience 2022; 72:1176-1203. [PMID: 36451972 PMCID: PMC9699720 DOI: 10.1093/biosci/biac094] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/02/2023] Open
Abstract
The North American monarch butterfly (Danaus plexippus) is a candidate species for listing under the Endangered Species Act. Multiple factors are associated with the decline in the eastern population, including the loss of breeding and foraging habitat and pesticide use. Establishing habitat in agricultural landscapes of the North Central region of the United States is critical to increasing reproduction during the summer. We integrated spatially explicit modeling with empirical movement ecology and pesticide toxicology studies to simulate population outcomes for different habitat establishment scenarios. Because of their mobility, we conclude that breeding monarchs in the North Central states should be resilient to pesticide use and habitat fragmentation. Consequently, we predict that adult monarch recruitment can be enhanced even if new habitat is established near pesticide-treated crop fields. Our research has improved the understanding of monarch population dynamics at the landscape scale by examining the interactions among monarch movement ecology, habitat fragmentation, and pesticide use.
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Affiliation(s)
- Tyler J Grant
- Research scientist, Iowa State University, Ames, Iowa
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7
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Abdul Aziz M, Brini F, Rouached H, Masmoudi K. Genetically engineered crops for sustainably enhanced food production systems. FRONTIERS IN PLANT SCIENCE 2022; 13:1027828. [PMID: 36426158 PMCID: PMC9680014 DOI: 10.3389/fpls.2022.1027828] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/25/2022] [Accepted: 10/18/2022] [Indexed: 06/16/2023]
Abstract
Genetic modification of crops has substantially focused on improving traits for desirable outcomes. It has resulted in the development of crops with enhanced yields, quality, and tolerance to biotic and abiotic stresses. With the advent of introducing favorable traits into crops, biotechnology has created a path for the involvement of genetically modified (GM) crops into sustainable food production systems. Although these plants heralded a new era of crop production, their widespread adoption faces diverse challenges due to concerns about the environment, human health, and moral issues. Mitigating these concerns with scientific investigations is vital. Hence, the purpose of the present review is to discuss the deployment of GM crops and their effects on sustainable food production systems. It provides a comprehensive overview of the cultivation of GM crops and the issues preventing their widespread adoption, with appropriate strategies to overcome them. This review also presents recent tools for genome editing, with a special focus on the CRISPR/Cas9 platform. An outline of the role of crops developed through CRSIPR/Cas9 in achieving sustainable development goals (SDGs) by 2030 is discussed in detail. Some perspectives on the approval of GM crops are also laid out for the new age of sustainability. The advancement in molecular tools through plant genome editing addresses many of the GM crop issues and facilitates their development without incorporating transgenic modifications. It will allow for a higher acceptance rate of GM crops in sustainable agriculture with rapid approval for commercialization. The current genetic modification of crops forecasts to increase productivity and prosperity in sustainable agricultural practices. The right use of GM crops has the potential to offer more benefit than harm, with its ability to alleviate food crises around the world.
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Affiliation(s)
- Mughair Abdul Aziz
- Department of Integrative Agriculture, College of Agriculture and Veterinary Medicine, United Arab Emirates University, Al−Ain, Abu−Dhabi, United Arab Emirates
| | - Faical Brini
- Biotechnology and Plant Improvement Laboratory, Centre of Biotechnology of Sfax, University of Sfax, Sfax, Tunisia
| | - Hatem Rouached
- Michigan State University, Plant and Soil Science Building, East Lansing, MI, United States
| | - Khaled Masmoudi
- Department of Integrative Agriculture, College of Agriculture and Veterinary Medicine, United Arab Emirates University, Al−Ain, Abu−Dhabi, United Arab Emirates
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8
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Krueger AJ, Rault LC, Robinson EA, Weissling TJ, Vélez AM, Anderson TD. Pyrethroid insecticide and milkweed cardenolide interactions on detoxification enzyme activity and expression in monarch caterpillars. PESTICIDE BIOCHEMISTRY AND PHYSIOLOGY 2022; 187:105173. [PMID: 36127039 DOI: 10.1016/j.pestbp.2022.105173] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/23/2022] [Accepted: 07/07/2022] [Indexed: 06/15/2023]
Abstract
Declines of the monarch butterfly population have prompted large-scale plantings of milkweed to restore the population. In North America, there are >73 species of milkweed to choose from for these nationwide plantings. However, it is unclear how different milkweed species affect monarch caterpillar physiology, particularly detoxification enzyme activity and gene expression, given the highly variable cardenolide composition across milkweed species. Here, we investigate the effects of a high cardenolide, tropical milkweed species and a low cardenolide, swamp milkweed species on pyrethroid sensitivity as well as detoxification enzyme activity and expression in monarch caterpillars. Caterpillars fed on each species through the fifth-instar stage and were topically treated with bifenthrin after reaching this final-instar stage. Esterase, glutathione S-transferase, and cytochrome P450 monooxygenase activities were quantified as well as the expression of selected esterase, glutathione S-transferase, ABC transporter, and cytochrome P450 monooxygenase transcripts. There were no significant differences in survival 24 h after treatment with bifenthrin. However, bifenthrin significantly increased glutathione S-transferase activity in caterpillars feeding on tropical milkweed and significantly decreased esterase activity in caterpillars feeding on tropical and swamp milkweed. Significant differential expression of ABC transporter, glutathione S-transferase, and esterase genes was observed for caterpillars feeding on tropical and swamp milkweed and not receiving bifenthrin treatment. Furthermore, significant differential expression of glutathione S-transferase and esterase genes was observed for bifenthrin-treated and -untreated caterpillars feeding on tropical milkweed relative to swamp milkweed. These results suggest that feeding on different milkweed species can affect detoxification and development mechanisms with which monarch caterpillars rely on to cope with their environment.
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Affiliation(s)
- Annie J Krueger
- Department of Entomology, University of Nebraska, Lincoln, NE 68583, USA
| | - Leslie C Rault
- Department of Entomology, University of Nebraska, Lincoln, NE 68583, USA
| | - Emily A Robinson
- Department of Statistics, University of Nebraska, Lincoln, NE 68583, USA
| | - Thomas J Weissling
- Department of Entomology, University of Nebraska, Lincoln, NE 68583, USA
| | - Ana M Vélez
- Department of Entomology, University of Nebraska, Lincoln, NE 68583, USA
| | - Troy D Anderson
- Department of Entomology, University of Nebraska, Lincoln, NE 68583, USA.
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9
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Crossley MS, Meehan TD, Moran MD, Glassberg J, Snyder WE, Davis AK. Opposing global change drivers counterbalance trends in breeding North American monarch butterflies. GLOBAL CHANGE BIOLOGY 2022; 28:4726-4735. [PMID: 35686571 PMCID: PMC9542617 DOI: 10.1111/gcb.16282] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/20/2022] [Accepted: 05/21/2022] [Indexed: 05/26/2023]
Abstract
Many insects are in clear decline, with monarch butterflies (Danaus plexippus) drawing particular attention as a flagship species. It is well documented that, among migratory populations, numbers of overwintering monarchs have been falling across several decades, but trends among breeding monarchs are less clear. Here, we compile >135,000 monarch observations between 1993 and 2018 from the North American Butterfly Association's annual butterfly count to examine spatiotemporal patterns and potential drivers of adult monarch relative abundance trends across the entire breeding range in eastern and western North America. While the data revealed declines at some sites, particularly the US Northeast and parts of the Midwest, numbers in other areas, notably the US Southeast and Northwest, were unchanged or increasing, yielding a slightly positive overall trend across the species range. Negative impacts of agricultural glyphosate use appeared to be counterbalanced by positive effects of annual temperature, particularly in the US Midwest. Overall, our results suggest that population growth in summer is compensating for losses during the winter and that changing environmental variables have offsetting effects on mortality and/or reproduction. We suggest that density-dependent reproductive compensation when lower numbers arrive each spring is currently able to maintain relatively stable breeding monarch numbers. However, we caution against complacency since accelerating climate change may bring growing threats. In addition, increases of summer monarchs in some regions, especially in California and in the south, may reflect replacement of migratory with resident populations. Nonetheless, it is perhaps reassuring that ubiquitous downward trends in summer monarch abundance are not evident.
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Affiliation(s)
- Michael S. Crossley
- Department of Entomology and Wildlife EcologyUniversity of DelawareNewarkDelawareUSA
| | | | - Matthew D. Moran
- Department of Biology and Health SciencesHendrix CollegeConwayArkansasUSA
| | - Jeffrey Glassberg
- North American Butterfly AssociationMorristownNew JerseyUSA
- Rice UniversityHoustonTexasUSA
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10
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Lalonde S, McCune JL, Rivest SA, Kharouba HM. Decline in common milkweed along roadsides around Ottawa, Canada. ECOSCIENCE 2022. [DOI: 10.1080/11956860.2021.1943930] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Affiliation(s)
| | - Jenny L. McCune
- Department of Biological Sciences, University of Lethbridge, Lethbridge, AB, Canada
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11
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Zylstra ER, Ries L, Neupane N, Saunders SP, Ramírez MI, Rendón-Salinas E, Oberhauser KS, Farr MT, Zipkin EF. Changes in climate drive recent monarch butterfly dynamics. Nat Ecol Evol 2021; 5:1441-1452. [PMID: 34282317 DOI: 10.1038/s41559-021-01504-1] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2020] [Accepted: 06/07/2021] [Indexed: 02/06/2023]
Abstract
Declines in the abundance and diversity of insects pose a substantial threat to terrestrial ecosystems worldwide. Yet, identifying the causes of these declines has proved difficult, even for well-studied species like monarch butterflies, whose eastern North American population has decreased markedly over the last three decades. Three hypotheses have been proposed to explain the changes observed in the eastern monarch population: loss of milkweed host plants from increased herbicide use, mortality during autumn migration and/or early-winter resettlement and changes in breeding-season climate. Here, we use a hierarchical modelling approach, combining data from >18,000 systematic surveys to evaluate support for each of these hypotheses over a 25-yr period. Between 2004 and 2018, breeding-season weather was nearly seven times more important than other factors in explaining variation in summer population size, which was positively associated with the size of the subsequent overwintering population. Although data limitations prevent definitive evaluation of the factors governing population size between 1994 and 2003 (the period of the steepest monarch decline coinciding with a widespread increase in herbicide use), breeding-season weather was similarly identified as an important driver of monarch population size. If observed changes in spring and summer climate continue, portions of the current breeding range may become inhospitable for monarchs. Our results highlight the increasingly important contribution of a changing climate to insect declines.
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Affiliation(s)
- Erin R Zylstra
- Department of Integrative Biology, Ecology, Evolution, and Behavior Program, Michigan State University, East Lansing, MI, USA.
| | - Leslie Ries
- Department of Biology, Georgetown University, Washington, DC, USA
| | - Naresh Neupane
- Department of Biology, Georgetown University, Washington, DC, USA
| | - Sarah P Saunders
- Department of Integrative Biology, Ecology, Evolution, and Behavior Program, Michigan State University, East Lansing, MI, USA.,National Audubon Society, New York, NY, USA
| | - M Isabel Ramírez
- Centro de Investigaciones en Geografía Ambiental, Universidad Nacional Autónoma de México, Morelia, Mexico
| | | | - Karen S Oberhauser
- University of Wisconsin Arboretum, University of Wisconsin-Madison, Madison, WI, USA
| | - Matthew T Farr
- Department of Integrative Biology, Ecology, Evolution, and Behavior Program, Michigan State University, East Lansing, MI, USA
| | - Elise F Zipkin
- Department of Integrative Biology, Ecology, Evolution, and Behavior Program, Michigan State University, East Lansing, MI, USA
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12
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Yang LH, Postema EG, Hayes TE, Lippey MK, MacArthur-Waltz DJ. The complexity of global change and its effects on insects. CURRENT OPINION IN INSECT SCIENCE 2021; 47:90-102. [PMID: 34004376 DOI: 10.1016/j.cois.2021.05.001] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/15/2021] [Revised: 05/05/2021] [Accepted: 05/07/2021] [Indexed: 06/12/2023]
Abstract
Global change includes multiple overlapping and interacting drivers: 1) climate change, 2) land use change, 3) novel chemicals, and 4) the increased global transport of organisms. Recent studies have documented the complex and counterintuitive effects of these drivers on the behavior, life histories, distributions, and abundances of insects. This complexity arises from the indeterminacy of indirect, non-additive and combined effects. While there is wide consensus that global change is reorganizing communities, the available data are limited. As the pace of anthropogenic changes outstrips our ability to document its impacts, ongoing change may lead to increasingly unpredictable outcomes. This complexity and uncertainty argue for renewed efforts to address the fundamental drivers of global change.
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Affiliation(s)
- Louie H Yang
- Department of Entomology and Nematology, University of California, Davis, CA 95616 USA.
| | - Elizabeth G Postema
- Department of Entomology and Nematology, University of California, Davis, CA 95616 USA; Animal Behavior Graduate Group, University of California, Davis, CA 95616, USA
| | - Tracie E Hayes
- Department of Entomology and Nematology, University of California, Davis, CA 95616 USA; Population Biology Graduate Group, University of California, Davis, CA 95616, USA
| | - Mia K Lippey
- Department of Entomology and Nematology, University of California, Davis, CA 95616 USA; Entomology Graduate Group, University of California, Davis, CA 95616, USA
| | - Dylan J MacArthur-Waltz
- Department of Entomology and Nematology, University of California, Davis, CA 95616 USA; Population Biology Graduate Group, University of California, Davis, CA 95616, USA
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13
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Meineke EK, Daru BH. Bias assessments to expand research harnessing biological collections. Trends Ecol Evol 2021; 36:1071-1082. [PMID: 34489117 DOI: 10.1016/j.tree.2021.08.003] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2021] [Revised: 08/04/2021] [Accepted: 08/06/2021] [Indexed: 12/22/2022]
Abstract
Biological collections are arguably the most important resources for investigations into the impacts of human activities on biodiversity. However, the apparent opportunities presented by museum-derived datasets have not resulted in consistent or widespread use of specimens in ecology outside phenological research and species distribution modeling. We attribute this gap between opportunity and application to biases introduced by collectors, curators, and preservation practices and an imperfect understanding of these biases and how to mitigate them. To facilitate broader use of specimen-based data, we characterize collection biases across key axes and explore interactions among them. We then present a framework for determining the bias assessments needed when extracting data from biological collections. We show that bias assessments required by particular ecological studies will depend on the response variables being measured and the predictor axes of interest. We argue that quantification of biases in specimen-derived datasets is needed to facilitate the widespread application of these data.
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Affiliation(s)
- Emily K Meineke
- Department of Entomology and Nematology, University of California, Davis 95616, CA, USA.
| | - Barnabas H Daru
- Department of Life Sciences, Texas A&M University-Corpus Christi, Corpus Christi, TX 78412, USA.
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14
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Ye Z, Wu F, Hennessy DA. Environmental and economic concerns surrounding restrictions on glyphosate use in corn. Proc Natl Acad Sci U S A 2021; 118:e2017470118. [PMID: 33903235 PMCID: PMC8106354 DOI: 10.1073/pnas.2017470118] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Since the commercialization of transgenic glyphosate-tolerant (GT) crops in the mid-1990s, glyphosate has become the dominant herbicide to control weeds in corn, soybean, and other crops in the United States and elsewhere. However, recent public concerns over its potential carcinogenicity in humans have generated calls for glyphosate-restricting policies. Should a policy to restrict glyphosate use, such as a glyphosate tax, be implemented? The decision involves two types of tradeoffs: human health and environmental (HH-E) impacts versus market economic impacts, and the use of glyphosate versus alternative herbicides, where the alternatives potentially have more serious adverse HH-E effects. Accounting for farmers' weed management choices, we provide empirical evaluation of the HH-E welfare and market economic welfare effects of a glyphosate use restriction policy on US corn production. Under a glyphosate tax, farmers would substitute glyphosate for a combination of other herbicides. Should a 10% glyphosate tax be imposed, then the most conservative welfare estimate is a net HH-E welfare gain with a monetized value of US$6 million per annum but also a net market economic loss of US$98 million per annum in the United States, which translates into a net loss in social welfare. This result of overall welfare loss is robust to a wide range of tax rates considered, from 10 to 50%, and to multiple scenarios of glyphosate's HH-E effects, which are the primary sources of uncertainties about glyphosate's effects.
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Affiliation(s)
- Ziwei Ye
- Department of Agricultural, Food, and Resource Economics, Michigan State University, East Lansing, MI 48824
| | - Felicia Wu
- Department of Agricultural, Food, and Resource Economics, Michigan State University, East Lansing, MI 48824
- Department of Food Science and Human Nutrition, Michigan State University, East Lansing, MI 48824
| | - David A Hennessy
- Department of Agricultural, Food, and Resource Economics, Michigan State University, East Lansing, MI 48824;
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15
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Smith DFQ, Camacho E, Thakur R, Barron AJ, Dong Y, Dimopoulos G, Broderick NA, Casadevall A. Glyphosate inhibits melanization and increases susceptibility to infection in insects. PLoS Biol 2021; 19:e3001182. [PMID: 33979323 PMCID: PMC8115815 DOI: 10.1371/journal.pbio.3001182] [Citation(s) in RCA: 33] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2020] [Accepted: 03/11/2021] [Indexed: 12/23/2022] Open
Abstract
Melanin, a black-brown pigment found throughout all kingdoms of life, has diverse biological functions including UV protection, thermoregulation, oxidant scavenging, arthropod immunity, and microbial virulence. Given melanin's broad roles in the biosphere, particularly in insect immune defenses, it is important to understand how exposure to ubiquitous environmental contaminants affects melanization. Glyphosate-the most widely used herbicide globally-inhibits melanin production, which could have wide-ranging implications in the health of many organisms, including insects. Here, we demonstrate that glyphosate has deleterious effects on insect health in 2 evolutionary distant species, Galleria mellonella (Lepidoptera: Pyralidae) and Anopheles gambiae (Diptera: Culicidae), suggesting a broad effect in insects. Glyphosate reduced survival of G. mellonella caterpillars following infection with the fungus Cryptococcus neoformans and decreased the size of melanized nodules formed in hemolymph, which normally help eliminate infection. Glyphosate also increased the burden of the malaria-causing parasite Plasmodium falciparum in A. gambiae mosquitoes, altered uninfected mosquito survival, and perturbed the microbial composition of adult mosquito midguts. Our results show that glyphosate's mechanism of melanin inhibition involves antioxidant synergy and disruption of the reaction oxidation-reduction balance. Overall, these findings suggest that glyphosate's environmental accumulation could render insects more susceptible to microbial pathogens due to melanin inhibition, immune impairment, and perturbations in microbiota composition, potentially contributing to declines in insect populations.
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Affiliation(s)
- Daniel F. Q. Smith
- W. Harry Feinstone Department of Molecular Microbiology and Immunology, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, United States of America
| | - Emma Camacho
- W. Harry Feinstone Department of Molecular Microbiology and Immunology, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, United States of America
| | - Raviraj Thakur
- Department of Otolaryngology, Head and Neck Surgery, Johns Hopkins Medicine, Baltimore, Maryland, United States of America
| | - Alexander J. Barron
- Department of Biology, Johns Hopkins University, Baltimore Maryland, United States of America
| | - Yuemei Dong
- W. Harry Feinstone Department of Molecular Microbiology and Immunology, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, United States of America
| | - George Dimopoulos
- W. Harry Feinstone Department of Molecular Microbiology and Immunology, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, United States of America
| | - Nichole A. Broderick
- Department of Biology, Johns Hopkins University, Baltimore Maryland, United States of America
| | - Arturo Casadevall
- W. Harry Feinstone Department of Molecular Microbiology and Immunology, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, United States of America
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16
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DeLaMater DS, Couture JJ, Puzey JR, Dalgleish HJ. Range-wide variations in common milkweed traits and their effect on monarch larvae. AMERICAN JOURNAL OF BOTANY 2021; 108:388-401. [PMID: 33792047 DOI: 10.1002/ajb2.1630] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/02/2020] [Accepted: 10/08/2020] [Indexed: 06/12/2023]
Abstract
PREMISE Leaf economic spectrum (LES) theory has historically been employed to inform vegetation models of ecosystem processes, but largely neglects intraspecific variation and biotic interactions. We attempt to integrate across environment-plant trait-herbivore interactions within a species at a range-wide scale. METHODS We measured traits in 53 populations spanning the range of common milkweed (Asclepias syriaca) and used a common garden to determine the role of environment in driving patterns of intraspecific variation. We used a feeding trial to determine the role of plant traits in monarch (Danaus plexippus) larval development. RESULTS Trait-trait relationships largely followed interspecific patterns in LES theory and persisted in a common garden when individual traits change. Common milkweed showed intraspecific variation and biogeographic clines in traits. Clines did not persist in a common garden. Larvae ate more and grew larger when fed plants with more nitrogen. A longitudinal environmental gradient in precipitation corresponded to a resource gradient in plant nitrogen, which produces a gradient in larval performance. CONCLUSIONS Biogeographic patterns in common milkweed traits can sometimes be predicted from LES, are largely driven by environmental conditions, and have consequences for monarch larval performance. Changes to nutrient dynamics of landscapes with common milkweed could potentially influence monarch population dynamics. We show how biogeographic trends in intraspecific variation can influence key ecological interactions, especially in common species with large distributions.
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Affiliation(s)
- David S DeLaMater
- Department of Biology, William & Mary, 540 Landrum Drive, Williamsburg, VA, 23185, USA
| | - John J Couture
- Departments of Entomology and Forestry and Natural Resources, Purdue University, 170 S. University Street, West Lafayette, IN, 47907, USA
| | - Joshua R Puzey
- Department of Biology, William & Mary, 540 Landrum Drive, Williamsburg, VA, 23185, USA
| | - Harmony J Dalgleish
- Department of Biology, William & Mary, 540 Landrum Drive, Williamsburg, VA, 23185, USA
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17
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Duke SO. Glyphosate: Uses Other Than in Glyphosate-Resistant Crops, Mode of Action, Degradation in Plants, and Effects on Non-target Plants and Agricultural Microbes. REVIEWS OF ENVIRONMENTAL CONTAMINATION AND TOXICOLOGY 2021; 255:1-65. [PMID: 33895876 DOI: 10.1007/398_2020_53] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Glyphosate is the most used herbicide globally. It is a unique non-selective herbicide with a mode of action that is ideal for vegetation management in both agricultural and non-agricultural settings. Its use was more than doubled by the introduction of transgenic, glyphosate-resistant (GR) crops. All of its phytotoxic effects are the result of inhibition of only 5-enolpyruvylshikimate-3-phosphate synthase (EPSPS), but inhibition of this single enzyme of the shikimate pathway results in multiple phytotoxicity effects, both upstream and downstream from EPSPS, including loss of plant defenses against pathogens. Degradation of glyphosate in plants and microbes is predominantly by a glyphosate oxidoreductase to produce aminomethylphosphonic acid and glyoxylate and to a lesser extent by a C-P lyase to produce sarcosine and phosphate. Its effects on non-target plant species are generally less than that of many other herbicides, as it is not volatile and is generally sprayed in larger droplet sizes with a relatively low propensity to drift and is inactivated by tight binding to most soils. Some microbes, including fungal plant pathogens, have glyphosate-sensitive EPSPS. Thus, glyphosate can benefit GR crops by its activity on some plant pathogens. On the other hand, glyphosate can adversely affect some microbes that are beneficial to agriculture, such as Bradyrhizobium species, although GR crop yield data indicate that such an effect has been minor. Effects of glyphosate on microbes of agricultural soils are generally minor and transient, with other agricultural practices having much stronger effects.
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Affiliation(s)
- Stephen O Duke
- National Center for Natural Products Research, School of Pharmacy, University of Mississippi, University, MS, USA.
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18
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Talla V, Pierce AA, Adams KL, de Man TJB, Nallu S, Villablanca FX, Kronforst MR, de Roode JC. Genomic evidence for gene flow between monarchs with divergent migratory phenotypes and flight performance. Mol Ecol 2020; 29:2567-2582. [PMID: 32542770 DOI: 10.1111/mec.15508] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2019] [Accepted: 06/05/2020] [Indexed: 12/24/2022]
Abstract
Monarch butterflies are known for their spectacular annual migration in eastern North America, with millions of monarchs flying up to 4,500 km to overwintering sites in central Mexico. Monarchs also live west of the Rocky Mountains, where they travel shorter distances to overwinter along the Pacific Coast. It is often assumed that eastern and western monarchs form distinct evolutionary units, but genomic studies to support this notion are lacking. We used a tethered flight mill to show that migratory eastern monarchs have greater flight performance than western monarchs, consistent with their greater migratory distances. However, analysing more than 20 million SNPs in 43 monarch genomes, we found no evidence for genomic differentiation between eastern and western monarchs. Genomic analysis also showed identical and low levels of genetic diversity, and demographic analyses indicated similar effective population sizes and ongoing gene flow between eastern and western monarchs. Gene expression analysis of a subset of candidate genes during active flight revealed differential gene expression related to nonmuscular motor activity. Our results demonstrate that eastern and western monarchs maintain migratory differences despite ongoing gene flow, and suggest that migratory differences between eastern and western monarchs are not driven by select major-effects alleles. Instead, variation in migratory distance and destination may be driven by environmentally induced differential gene expression or by many alleles of small effect.
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Affiliation(s)
- Venkat Talla
- Department of Biology, Emory University, Atlanta, GA, USA
| | | | - Kandis L Adams
- Department of Biology, Emory University, Atlanta, GA, USA
| | - Tom J B de Man
- Department of Biology, Emory University, Atlanta, GA, USA
| | - Sumitha Nallu
- Department of Ecology and Evolution, University of Chicago, Chicago, IL, USA
| | - Francis X Villablanca
- Biological Sciences Department, California Polytechnic State University, San Luis Obispo, CA, USA
| | - Marcus R Kronforst
- Department of Ecology and Evolution, University of Chicago, Chicago, IL, USA
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19
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Meineke EK, Tomasi C, Yuan S, Pryer KM. Applying machine learning to investigate long-term insect-plant interactions preserved on digitized herbarium specimens. APPLICATIONS IN PLANT SCIENCES 2020; 8:e11369. [PMID: 32626611 PMCID: PMC7328658 DOI: 10.1002/aps3.11369] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/01/2019] [Accepted: 03/04/2020] [Indexed: 05/28/2023]
Abstract
PREMISE Despite the economic significance of insect damage to plants (i.e., herbivory), long-term data documenting changes in herbivory are limited. Millions of pressed plant specimens are now available online and can be used to collect big data on plant-insect interactions during the Anthropocene. METHODS We initiated development of machine learning methods to automate extraction of herbivory data from herbarium specimens by training an insect damage detector and a damage type classifier on two distantly related plant species (Quercus bicolor and Onoclea sensibilis). We experimented with (1) classifying six types of herbivory and two control categories of undamaged leaf, and (2) detecting two of the damage categories for which several hundred annotations were available. RESULTS Damage detection results were mixed, with a mean average precision of 45% in the simultaneous detection and classification of two types of damage. However, damage classification on hand-drawn boxes identified the correct type of herbivory 81.5% of the time in eight categories. The damage classifier was accurate for categories with 100 or more test samples. DISCUSSION These tools are a promising first step for the automation of herbivory data collection. We describe ongoing efforts to increase the accuracy of these models, allowing researchers to extract similar data and apply them to biological hypotheses.
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Affiliation(s)
- Emily K. Meineke
- Department of Entomology and NematologyUniversity of CaliforniaDavisCalifornia95616USA
| | - Carlo Tomasi
- Department of Computer ScienceDuke UniversityDurhamNorth Carolina27708USA
| | - Song Yuan
- Department of Mechanical Engineering and Materials ScienceDuke UniversityDurhamNorth Carolina27708USA
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20
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Tracking trends in monarch abundance over the 20th century is currently impossible using museum records. Proc Natl Acad Sci U S A 2020; 116:13745-13748. [PMID: 31291704 DOI: 10.1073/pnas.1904807116] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
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21
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Monarch butterfly trends are sensitive to unexamined changes in museum collections over time. Proc Natl Acad Sci U S A 2020; 116:13742-13744. [PMID: 31291703 DOI: 10.1073/pnas.1903511116] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
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22
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Reply to Wepprich and Ries et al.: Alternative methods do not provide support for the contribution of GM crops to monarch declines. Proc Natl Acad Sci U S A 2020; 116:13749-13750. [PMID: 31291705 DOI: 10.1073/pnas.1908593116] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
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23
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Bakker FT, Antonelli A, Clarke JA, Cook JA, Edwards SV, Ericson PGP, Faurby S, Ferrand N, Gelang M, Gillespie RG, Irestedt M, Lundin K, Larsson E, Matos-Maraví P, Müller J, von Proschwitz T, Roderick GK, Schliep A, Wahlberg N, Wiedenhoeft J, Källersjö M. The Global Museum: natural history collections and the future of evolutionary science and public education. PeerJ 2020; 8:e8225. [PMID: 32025365 PMCID: PMC6993751 DOI: 10.7717/peerj.8225] [Citation(s) in RCA: 47] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2019] [Accepted: 11/15/2019] [Indexed: 12/27/2022] Open
Abstract
Natural history museums are unique spaces for interdisciplinary research and educational innovation. Through extensive exhibits and public programming and by hosting rich communities of amateurs, students, and researchers at all stages of their careers, they can provide a place-based window to focus on integration of science and discovery, as well as a locus for community engagement. At the same time, like a synthesis radio telescope, when joined together through emerging digital resources, the global community of museums (the ‘Global Museum’) is more than the sum of its parts, allowing insights and answers to diverse biological, environmental, and societal questions at the global scale, across eons of time, and spanning vast diversity across the Tree of Life. We argue that, whereas natural history collections and museums began with a focus on describing the diversity and peculiarities of species on Earth, they are now increasingly leveraged in new ways that significantly expand their impact and relevance. These new directions include the possibility to ask new, often interdisciplinary questions in basic and applied science, such as in biomimetic design, and by contributing to solutions to climate change, global health and food security challenges. As institutions, they have long been incubators for cutting-edge research in biology while simultaneously providing core infrastructure for research on present and future societal needs. Here we explore how the intersection between pressing issues in environmental and human health and rapid technological innovation have reinforced the relevance of museum collections. We do this by providing examples as food for thought for both the broader academic community and museum scientists on the evolving role of museums. We also identify challenges to the realization of the full potential of natural history collections and the Global Museum to science and society and discuss the critical need to grow these collections. We then focus on mapping and modelling of museum data (including place-based approaches and discovery), and explore the main projects, platforms and databases enabling this growth. Finally, we aim to improve relevant protocols for the long-term storage of specimens and tissues, ensuring proper connection with tomorrow’s technologies and hence further increasing the relevance of natural history museums.
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Affiliation(s)
- Freek T Bakker
- Biosystematics Group, Wageningen University & Research, Wageningen, The Netherlands
| | | | - Julia A Clarke
- Jackson School of Geosciences, University of Texas at Austin, Austin, TX, United States of America
| | - Joseph A Cook
- Museum of Southwestern Biology, Department of Biology, University of New Mexico, Albuquerque, NM, United States of America
| | - Scott V Edwards
- Department of Organismic and Evolutionary Biology, Museum of Comparative Zoology, Harvard University, Cambridge, MA, United States of America.,Gothenburg Centre for Advanced Studies in Science and Technology, Chalmers University of Technology and University of Gothenburg, Göteborg, Sweden
| | - Per G P Ericson
- Department of Bioinformatics and Genetics, Swedish Museum of Natural History, Stockholm, Sweden
| | - Søren Faurby
- Department of Biological and Environmental Sciences, Gothenburg Global Biodiversity Centre, University of Gothenburg, Göteborg, Sweden
| | - Nuno Ferrand
- Museu de História Natural e da Ciência, Universidade do Porto, Porto, Portugal
| | - Magnus Gelang
- Department of Zoology, Gothenburg Natural History Museum, Göteborg, Sweden.,Gothenburg Global Biodiversity Centre, University of Gothenburg, Göteborg, Sweden
| | - Rosemary G Gillespie
- Essig Museum of Entomology, Department of Environmental Science, Policy and Management, University of California, Berkeley, Berkeley, CA, United States of America
| | - Martin Irestedt
- Department of Bioinformatics and Genetics, Swedish Museum of Natural History, Stockholm, Sweden
| | - Kennet Lundin
- Department of Zoology, Gothenburg Natural History Museum, Göteborg, Sweden.,Gothenburg Global Biodiversity Centre, University of Gothenburg, Göteborg, Sweden
| | - Ellen Larsson
- Department of Biological and Environmental Sciences, Gothenburg Global Biodiversity Centre, University of Gothenburg, Göteborg, Sweden.,Gothenburg Global Biodiversity Centre, University of Gothenburg, Göteborg, Sweden
| | - Pável Matos-Maraví
- Biology Centre of the Czech Academy of Sciences, Institute of Entomology, České Budějovice, Czechia
| | - Johannes Müller
- Leibniz-Institut für Evolutions- und Biodiversitätsforschung, Museum für Naturkunde, Berlin, Germany
| | - Ted von Proschwitz
- Department of Zoology, Gothenburg Natural History Museum, Göteborg, Sweden.,Gothenburg Global Biodiversity Centre, University of Gothenburg, Göteborg, Sweden
| | - George K Roderick
- Essig Museum of Entomology, Department of Environmental Science, Policy and Management, University of California, Berkeley, Berkeley, CA, United States of America
| | - Alexander Schliep
- Department of Computer Science and Engineering, University of Gothenburg, Göteborg, Sweden
| | | | - John Wiedenhoeft
- Department of Computer Science and Engineering, University of Gothenburg, Göteborg, Sweden
| | - Mari Källersjö
- Gothenburg Global Biodiversity Centre, University of Gothenburg, Göteborg, Sweden.,Gothenburg Botanical Garden, Göteborg, Sweden
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24
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Abstract
Insect declines are being reported worldwide for flying, ground, and aquatic lineages. Most reports come from western and northern Europe, where the insect fauna is well-studied and there are considerable demographic data for many taxonomically disparate lineages. Additional cases of faunal losses have been noted from Asia, North America, the Arctic, the Neotropics, and elsewhere. While this review addresses both species loss and population declines, its emphasis is on the latter. Declines of abundant species can be especially worrisome, given that they anchor trophic interactions and shoulder many of the essential ecosystem services of their respective communities. A review of the factors believed to be responsible for observed collapses and those perceived to be especially threatening to insects form the core of this treatment. In addition to widely recognized threats to insect biodiversity, e.g., habitat destruction, agricultural intensification (including pesticide use), climate change, and invasive species, this assessment highlights a few less commonly considered factors such as atmospheric nitrification from the burning of fossil fuels and the effects of droughts and changing precipitation patterns. Because the geographic extent and magnitude of insect declines are largely unknown, there is an urgent need for monitoring efforts, especially across ecological gradients, which will help to identify important causal factors in declines. This review also considers the status of vertebrate insectivores, reporting bias, challenges inherent in collecting and interpreting insect demographic data, and cases of increasing insect abundance.
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Affiliation(s)
- David L Wagner
- Department of Ecology and Evolutionary Biology, University of Connecticut, Storrs, Connecticut 06269, USA;
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25
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Yang LH, Cenzer ML. Seasonal windows of opportunity in milkweed–monarch interactions. Ecology 2019; 101:e02880. [DOI: 10.1002/ecy.2880] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/09/2019] [Revised: 07/25/2019] [Accepted: 08/02/2019] [Indexed: 01/11/2023]
Affiliation(s)
- Louie H. Yang
- Department of Entomology and Nematology University of California Davis California 95616 USA
| | - Meredith L. Cenzer
- Department of Entomology and Nematology University of California Davis California 95616 USA
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26
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Crone EE, Pelton EM, Brown LM, Thomas CC, Schultz CB. Why are monarch butterflies declining in the West? Understanding the importance of multiple correlated drivers. ECOLOGICAL APPLICATIONS : A PUBLICATION OF THE ECOLOGICAL SOCIETY OF AMERICA 2019; 29:e01975. [PMID: 31310685 DOI: 10.1002/eap.1975] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/05/2018] [Revised: 05/15/2019] [Accepted: 06/14/2019] [Indexed: 06/10/2023]
Abstract
Understanding the factors associated with declines of at-risk species is an important first step in setting management and recovery targets. This step can be challenging when multiple aspects of climate and land use are changing simultaneously, and any or all could be contributing to population declines. We analyzed population trends of monarch butterflies in western North America in relation to likely environmental drivers. Unlike the larger eastern monarch population, past analyses of western monarchs have only evaluated the importance of climate (i.e., not land use) factors as drivers of abundance. We used partial least squares regression (PLSR) to evaluate the potential importance of changes in land use and climate variables. Trends in western monarch abundance were more strongly associated with land use variables than climate variables. Conclusions about importance of climate and land use variables were robust to changes in PLSR model structure. However, individual variables were too collinear to unambiguously separate their effects. We compared these conclusions to the more widely used technique of multiple regression, followed by multi-model inference (MRMI). Naïve interpretation of MRMI results could be misleading, if collinearity were not taken into account. MRMI was also highly sensitive to variation in model construction. Our results suggest a two-pronged approach to monarch conservation, specifically, starting efforts now to restore habitat, while also using experiments to more clearly delineate separate effects of climate and land use factors. They also demonstrate the utility of PLSR, a technique that is growing in use but is still relatively under-appreciated in conservation biology.
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Affiliation(s)
- Elizabeth E Crone
- Department of Biology, Tufts University, 200 College Avenue, Medford, Massachusetts, 02155, USA
| | - Emma M Pelton
- Xerces Society, 628 Northeast Broadway Suite 200, Portland, Oregon, 97232, USA
| | - Leone M Brown
- Department of Biology, Tufts University, 200 College Avenue, Medford, Massachusetts, 02155, USA
| | - Cameron C Thomas
- School of Biological Sciences, Washington State University, 14204 Northeast Salmon Creek Avenue, Vancouver, Washington, 98686, USA
| | - Cheryl B Schultz
- School of Biological Sciences, Washington State University, 14204 Northeast Salmon Creek Avenue, Vancouver, Washington, 98686, USA
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27
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Abstract
The annual migration of the monarch butterfly Danaus plexippus is in peril. In an effort to aid population recovery, monarch enthusiasts across North America participate in a variety of conservation efforts, including captive rearing and release of monarch butterflies throughout the summer and autumn. However, the impact of captive breeding on monarchs remains an open question. Here, we show that captive breeding, both commercially and by summertime hobbyists, causes migratory behavior to be lost. Monarchs acquired commercially failed to orient south when reared outdoors in the autumn, unlike wild-caught North American monarchs, yet they did enter reproductive diapause. The commercial population was genetically highly divergent from wild-caught North American monarchs and had rounder forewings, similar to monarchs from nonmigratory populations. Furthermore, rearing wild-caught monarchs in an indoor environment mimicking natural migration-inducing conditions failed to elicit southward flight orientation. In fact, merely eclosing indoors after an otherwise complete lifecycle outdoors was enough to disrupt southern orientation. Our results provide a window into the complexity-and remarkable fragility-of migration.
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28
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Struckman S, Couture JJ, LaMar MD, Dalgleish HJ. The demographic effects of functional traits: an integral projection model approach reveals population-level consequences of reproduction-defence trade-offs. Ecol Lett 2019; 22:1396-1406. [PMID: 31209991 DOI: 10.1111/ele.13325] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2019] [Revised: 03/14/2019] [Accepted: 05/11/2019] [Indexed: 11/29/2022]
Abstract
Quantitatively linking individual variation in functional traits to demography is a necessary step to advance our understanding of trait-based ecological processes. We constructed a population model for Asclepias syriaca to identify how functional traits affect vital rates and population growth and whether trade-offs in chemical defence and demography alter population growth. Plants with higher foliar cardenolides had lower fibre, cellulose and lignin levels, as well as decreased sexual and clonal reproduction. Average cardenolide concentrations had the strongest effect on population growth. In both the sexual and clonal pathway, the trade-off between reproduction and defence affected population growth. We found that both increasing the mean of the distribution of individual plant values for cardenolides and herbivory decreased population growth. However, increasing the variance in both defence and herbivory increased population growth. Functional traits can impact population growth and quantifying individual-level variation in traits should be included in assessments of population-level processes.
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Affiliation(s)
- Soren Struckman
- Department of Biology, College of William and Mary, Williamsburg, VA, 23185, USA
| | - John J Couture
- Department of Entomology and Department of Forestry and Natural Resources, Purdue University, West Lafayette, IN, 47907, USA
| | - M Drew LaMar
- Department of Biology, College of William and Mary, Williamsburg, VA, 23185, USA
| | - Harmony J Dalgleish
- Department of Biology, College of William and Mary, Williamsburg, VA, 23185, USA
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29
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Grant TJ, Bradbury SP. The Role of Modeling in Monarch Butterfly Research and Conservation. Front Ecol Evol 2019. [DOI: 10.3389/fevo.2019.00197] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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30
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Haan NL, Landis DA. The Importance of Shifting Disturbance Regimes in Monarch Butterfly Decline and Recovery. Front Ecol Evol 2019. [DOI: 10.3389/fevo.2019.00191] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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31
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Advances in understanding the long-term population decline of monarch butterflies. Proc Natl Acad Sci U S A 2019; 116:8093-8095. [PMID: 30926661 DOI: 10.1073/pnas.1903409116] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
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