51
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Montgomery GA, Belitz MW, Guralnick RP, Tingley MW. Standards and Best Practices for Monitoring and Benchmarking Insects. Front Ecol Evol 2021. [DOI: 10.3389/fevo.2020.579193] [Citation(s) in RCA: 44] [Impact Index Per Article: 14.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Benchmark studies of insect populations are increasingly relevant and needed amid accelerating concern about insect trends in the Anthropocene. The growing recognition that insect populations may be in decline has given rise to a renewed call for insect population monitoring by scientists, and a desire from the broader public to participate in insect surveys. However, due to the immense diversity of insects and a vast assortment of data collection methods, there is a general lack of standardization in insect monitoring methods, such that a sudden and unplanned expansion of data collection may fail to meet its ecological potential or conservation needs without a coordinated focus on standards and best practices. To begin to address this problem, we provide simple guidelines for maximizing return on proven inventory methods that will provide insect benchmarking data suitable for a variety of ecological responses, including occurrence and distribution, phenology, abundance and biomass, and diversity and species composition. To track these responses, we present seven primary insect sampling methods—malaise trapping, light trapping, pan trapping, pitfall trappings, beating sheets, acoustic monitoring, and active visual surveys—and recommend standards while highlighting examples of model programs. For each method, we discuss key topics such as recommended spatial and temporal scales of sampling, important metadata to track, and degree of replication needed to produce rigorous estimates of ecological responses. We additionally suggest protocols for scalable insect monitoring, from backyards to national parks. Overall, we aim to compile a resource that can be used by diverse individuals and organizations seeking to initiate or improve insect monitoring programs in this era of rapid change.
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52
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Wagner DL, Grames EM, Forister ML, Berenbaum MR, Stopak D. Insect decline in the Anthropocene: Death by a thousand cuts. Proc Natl Acad Sci U S A 2021; 118:e2023989118. [PMID: 33431573 PMCID: PMC7812858 DOI: 10.1073/pnas.2023989118] [Citation(s) in RCA: 373] [Impact Index Per Article: 124.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Affiliation(s)
- David L Wagner
- Ecology and Evolutionary Biology, University of Connecticut, Storrs, CT 06269;
| | - Eliza M Grames
- Ecology and Evolutionary Biology, University of Connecticut, Storrs, CT 06269
| | - Matthew L Forister
- Department of Biology, Program in Ecology, Evolution and Conservation Biology, University of Nevada, Reno, NV 89557
| | - May R Berenbaum
- Department of Entomology, University of Illinois at Urbana-Champaign, Champaign, IL 61801
| | - David Stopak
- National Academy of Sciences, Washington, DC 20002
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Blair J, Weiser MD, Kaspari M, Miller M, Siler C, Marshall KE. Robust and simplified machine learning identification of pitfall trap-collected ground beetles at the continental scale. Ecol Evol 2020; 10:13143-13153. [PMID: 33304524 PMCID: PMC7713910 DOI: 10.1002/ece3.6905] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2020] [Revised: 09/10/2020] [Accepted: 09/18/2020] [Indexed: 11/10/2022] Open
Abstract
Insect populations are changing rapidly, and monitoring these changes is essential for understanding the causes and consequences of such shifts. However, large-scale insect identification projects are time-consuming and expensive when done solely by human identifiers. Machine learning offers a possible solution to help collect insect data quickly and efficiently.Here, we outline a methodology for training classification models to identify pitfall trap-collected insects from image data and then apply the method to identify ground beetles (Carabidae). All beetles were collected by the National Ecological Observatory Network (NEON), a continental scale ecological monitoring project with sites across the United States. We describe the procedures for image collection, image data extraction, data preparation, and model training, and compare the performance of five machine learning algorithms and two classification methods (hierarchical vs. single-level) identifying ground beetles from the species to subfamily level. All models were trained using pre-extracted feature vectors, not raw image data. Our methodology allows for data to be extracted from multiple individuals within the same image thus enhancing time efficiency, utilizes relatively simple models that allow for direct assessment of model performance, and can be performed on relatively small datasets.The best performing algorithm, linear discriminant analysis (LDA), reached an accuracy of 84.6% at the species level when naively identifying species, which was further increased to >95% when classifications were limited by known local species pools. Model performance was negatively correlated with taxonomic specificity, with the LDA model reaching an accuracy of ~99% at the subfamily level. When classifying carabid species not included in the training dataset at higher taxonomic levels species, the models performed significantly better than if classifications were made randomly. We also observed greater performance when classifications were made using the hierarchical classification method compared to the single-level classification method at higher taxonomic levels.The general methodology outlined here serves as a proof-of-concept for classifying pitfall trap-collected organisms using machine learning algorithms, and the image data extraction methodology may be used for nonmachine learning uses. We propose that integration of machine learning in large-scale identification pipelines will increase efficiency and lead to a greater flow of insect macroecological data, with the potential to be expanded for use with other noninsect taxa.
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Affiliation(s)
- Jarrett Blair
- Department of ZoologyUniversity of British ColumbiaVancouverBCCanada
| | | | | | | | - Cameron Siler
- Department of BiologyUniversity of OklahomaNormanOKUSA
- Sam Noble Oklahoma Museum of Natural HistoryUniversity of OklahomaNormanOKUSA
| | - Katie E. Marshall
- Department of ZoologyUniversity of British ColumbiaVancouverBCCanada
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54
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Michielini JP, Dopman EB, Crone EE. Changes in flight period predict trends in abundance of Massachusetts butterflies. Ecol Lett 2020; 24:249-257. [PMID: 33166071 DOI: 10.1111/ele.13637] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2020] [Revised: 07/02/2020] [Accepted: 10/02/2020] [Indexed: 01/09/2023]
Abstract
Phenological shifts are well-documented in the ecological literature. However, their significance for changes in demography and abundance is less clear. We used 27 years of citizen science monitoring to quantify trends in phenology and relative abundance across 89 butterfly species. We calculated shifts in phenology using quantile regression and shifts in relative abundance using list length analysis and counts from field trips. Elongated activity periods within a year were the strongest predictor of increases in relative abundance. These changes may be driven in part by changes in voltinism, as this association was stronger in multivoltine species. Some species appear to be adding a late-season generation, whereas other species appear to be adding a spring generation, revealing a possible shift from vagrant to resident. Our results emphasise the importance of evaluating phenological changes throughout species' flight period and understanding the consequences for such climate-related changes on viability or population dynamics.
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55
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Prescott SL. A butterfly flaps its wings: Extinction of biological experience and the origins of allergy. Ann Allergy Asthma Immunol 2020; 125:528-534. [PMID: 32474160 PMCID: PMC7256009 DOI: 10.1016/j.anai.2020.05.025] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2020] [Revised: 05/17/2020] [Accepted: 05/21/2020] [Indexed: 12/13/2022]
Abstract
OBJECTIVE To explore links between biodiversity on all scales and allergic disease as a measure of immune dysregulation. DATA SOURCES PubMed and Web of Science were searched using the keywords biodiversity, nature relatedness, allergic disease, microbiome, noncommunicable diseases, coronavirus disease 2019, and associated terms. STUDY SELECTIONS Studies were selected based on relevance to human health and biodiversity. RESULTS Contact with natural environments enriches the human microbiome, promotes regulated immune responses, and protects against allergy and both acute and chronic inflammatory disorders. These important links to ecopsychological constructs of the extinction of experience, which indicates that loss of direct, personal contact with biodiversity (wildlife and the more visible elements of the natural world), might lead to emotional apathy and irresponsible behaviors toward the environment. CONCLUSION The immune system is a useful early barometer of environmental effects and, by means of the microbiome, is a measure of the way in which our current experiences differ from our ancestral past. Although we would benefit from further research, efforts to increase direct, personal contact with biodiversity have clear benefits for multiple aspects of physical and mental health, the skin and gut microbiome, immune function, food choices, sleep, and physical activity and promote environmental responsibility.
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Affiliation(s)
- Susan L Prescott
- The ORIGINS Project, Telethon Kids Institute, University of Western Australia, Perth Children's Hospital, Nedlands, Australia; inVIVO Planetary Health of the Worldwide Universities Network, West New York, New Jersey.
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56
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Nocturnal pollination: an overlooked ecosystem service vulnerable to environmental change. Emerg Top Life Sci 2020; 4:19-32. [PMID: 32478390 PMCID: PMC7326339 DOI: 10.1042/etls20190134] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2020] [Revised: 05/11/2020] [Accepted: 05/12/2020] [Indexed: 12/14/2022]
Abstract
Existing assessments of the ecosystem service of pollination have been largely restricted to diurnal insects, with a particular focus on generalist foragers such as wild and honey bees. As knowledge of how these plant-pollinator systems function, their relevance to food security and biodiversity, and the fragility of these mutually beneficial interactions increases, attention is diverting to other, less well-studied pollinator groups. One such group are those that forage at night. In this review, we document evidence that nocturnal species are providers of pollination services (including pollination of economically valuable and culturally important crops, as well as wild plants of conservation concern), but highlight how little is known about the scale of such services. We discuss the primary mechanisms involved in night-time communication between plants and insect pollen-vectors, including floral scent, visual cues (and associated specialized visual systems), and thermogenic sensitivity (associated with thermogenic flowers). We highlight that these mechanisms are vulnerable to direct and indirect disruption by a range of anthropogenic drivers of environmental change, including air and soil pollution, artificial light at night, and climate change. Lastly, we highlight a number of directions for future research that will be important if nocturnal pollination services are to be fully understood and ultimately conserved.
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57
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Lee NSM, Clements GR, Ting ASY, Wong ZH, Yek SH. Persistent mosquito fogging can be detrimental to non-target invertebrates in an urban tropical forest. PeerJ 2020; 8:e10033. [PMID: 33062440 PMCID: PMC7533057 DOI: 10.7717/peerj.10033] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2020] [Accepted: 09/03/2020] [Indexed: 11/21/2022] Open
Abstract
Background Human population growth has led to biodiversity declines in tropical cities. While habitat loss and fragmentation have been the main drivers of urban biodiversity loss, man-made interventions to reduce health risks have also emerged as an unintentional threat. For instance, insecticide fogging to control mosquito populations has become the most common method of preventing the expansion of mosquito-borne diseases such as Dengue. However, the effectiveness of fogging in killing mosquitoes has been called into question. One concern is the unintended effect of insecticide fogging on non-target invertebrates that are crucial for the maintenance of urban ecosystems. Here, we investigate the impacts of fogging on: (1) target invertebrate taxon (Diptera, including mosquitoes); (2) non-target invertebrate taxa; and (3) the foraging behavior of an invertebrate pollinator taxon (Lepidoptera) within an urban tropical forest. Methods We carried out fogging with Pyrethroid insecticide (Detral 2.5 EC) at 10 different sites in a forest situated in the state of Selangor, Peninsular Malaysia. Across the sites, we counted the numbers of knocked-down invertebrates and identified them based on morphology to different taxa. We constructed Bayesian hierarchical Poisson regression models to investigate the effects of fogging on: (1) a target invertebrate taxon (Diptera) 3-h post-fogging; (2) selected non-target invertebrate taxa 3-h post-fogging; and (3) an invertebrate pollinator taxon (Lepidoptera) 24-h post-fogging. Results A total of 1,874 invertebrates from 19 invertebrate orders were knocked down by the fogging treatment across the 10 sites. Furthermore, 72.7% of the invertebrates counted 3-h post-fogging was considered dead. Our regression models showed that given the data and prior information, the probability that fogging had a negative effect on invertebrate taxa 3-h post-fogging was 100%, with reductions to 11% of the pre-fogging count of live individuals for the target invertebrate taxon (Diptera), and between 5% and 58% of the pre-fogging count of live individuals for non-target invertebrate taxa. For the invertebrate pollinator, the probability that fogging had a negative effect 24-h post-fogging was also 100%, with reductions to 53% of the pre-fogging count of live individuals. Discussion Our Bayesian models unequivocally demonstrate that fogging has detrimental effects on one pollinator order and non-target invertebrate orders, especially taxa that have comparatively lower levels of chitinisation. While fogging is effective in killing the target order (Diptera), no mosquitos were found dead in our experiment. In order to maintain urban biodiversity, we recommend that health authorities and the private sector move away from persistent insecticide fogging and to explore alternative measures to control adult mosquito populations.
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Affiliation(s)
- Nicole S M Lee
- School of Science, Monash University Malaysia, Bandar Sunway, Selangor, Malaysia
| | - Gopalasamy R Clements
- Department of Biological Sciences and Jeffrey Sachs on Sustainable Development, Sunway University, Bandar Sunway, Selangor, Malaysia
| | - Adeline S Y Ting
- School of Science, Monash University Malaysia, Bandar Sunway, Selangor, Malaysia
| | - Zhi H Wong
- Malaysia Immersion Hub, Monash University Malaysia, Bandar Sunway, Selangor, Malaysia
| | - Sze H Yek
- School of Science, Monash University Malaysia, Bandar Sunway, Selangor, Malaysia
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58
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Bried J, Ries L, Smith B, Patten M, Abbott J, Ball-Damerow J, Cannings R, Cordero-Rivera A, Córdoba-Aguilar A, De Marco P, Dijkstra KD, Dolný A, van Grunsven R, Halstead D, Harabiš F, Hassall C, Jeanmougin M, Jones C, Juen L, Kalkman V, Kietzka G, Mazzacano CS, Orr A, Perron MA, Rocha-Ortega M, Sahlén G, Samways M, Siepielski A, Simaika J, Suhling F, Underhill L, White E. Towards Global Volunteer Monitoring of Odonate Abundance. Bioscience 2020. [DOI: 10.1093/biosci/biaa092] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
AbstractInsects are reportedly experiencing widespread declines, but we generally have sparse data on their abundance. Correcting this shortfall will take more effort than professional entomologists alone can manage. Volunteer nature enthusiasts can greatly help to monitor the abundance of dragonflies and damselflies (Odonata), iconic freshwater sentinels and one of the few nonpollinator insect groups appreciated by the public and amenable to citizen science. Although counting individual odonates is common in some locations, current data will not enable a global perspective on odonate abundance patterns and trends. Borrowing insight from butterfly monitoring efforts, we outline basic plans for a global volunteer network to count odonates, including organizational structure, advertising and recruiting, and data collection, submission, and synthesis. We hope our proposal serves as a catalyst for richer coordinated efforts to understand population trends of odonates and other insects in the Anthropocene.
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Affiliation(s)
- Jason Bried
- Illinois Natural History Survey, University of Illinois, Urbana–Champaign
| | - Leslie Ries
- Department of Biology at Georgetown University, Washington, DC
| | - Brenda Smith
- Oklahoma Biological Survey, University of Oklahoma, Norman
| | - Michael Patten
- Oklahoma Biological Survey, University of Oklahoma, Norman
| | - John Abbott
- Alabama Museum of Natural History, University of Alabama, Tuscaloosa
| | | | | | | | - Alex Córdoba-Aguilar
- Departamento de Ecología Evolutiva, Universidad Nacional Autónoma de México, Coyoacán, México
| | - Paulo De Marco
- Departamento de Ecología, Universidade Federal de Goiás, Goiânia, Brazil
| | | | - Aleš Dolný
- Department of Biology and Ecology, University of Ostrava, Ostrava, Czech Republic
| | - Roy van Grunsven
- De Vlinderstichting, Dutch Butterfly Conservation, Wageningen, Netherlands
| | - David Halstead
- School of Natural Resources and the Built Environment at Saskatchewan Polytechnic, Prince Albert, Canada
| | - Filip Harabiš
- Department of Ecology, Czech University of Life Sciences, Prague, Czech Republic
| | - Christopher Hassall
- Institute of Integrative and Comparative Biology, University of Leeds, Leeds, United Kingdom
| | - Martin Jeanmougin
- Laboratoire d'Ecologie Alpine, Université Grenoble Alpes—CNRS, Grenoble, France
| | - Colin Jones
- Ontario Ministry of Natural Resources and Forestry, Peterborough, Canada
| | - Leandro Juen
- Instituto de Ciências Biológicas, Universidade Federal do Pará, Pará, Brazil
| | | | - Gabriella Kietzka
- Department of Conservation Ecology and Entomology at Stellenbosch University, Stellenbosch, South Africa
| | | | - Albert Orr
- Environmental Futures Research Institute at Griffith University, Brisbane, Australia
| | - Mary Ann Perron
- Department of Biology, University of Ottawa, Ontario, Canada
| | - Maya Rocha-Ortega
- Departamento de Ecología Evolutiva, Universidad Nacional Autónoma de México, Coyoacán, México
| | - Göran Sahlén
- Ecology and Environmental Science, RLAS at Halmstad University, Halmstad, Sweden
| | - Michael Samways
- Department of Conservation Ecology and Entomology at Stellenbosch University, Stellenbosch, South Africa
| | - Adam Siepielski
- Department of Biological Sciences, University of Arkansas, Fayetteville
| | - John Simaika
- Department of Water Science and Engineering at IHE Delft Institute for Water Education, Delft, Netherlands
| | - Frank Suhling
- Institute of Geoecology at Technische Universität Braunschweig, Braunschweig, Germany
| | - Les Underhill
- Department of Biological Sciences, University of Cape Town, Rondebosch, South Africa
| | - Erin White
- New York Natural Heritage Program, Albany, New York
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Larval pesticide exposure impacts monarch butterfly performance. Sci Rep 2020; 10:14490. [PMID: 32879347 PMCID: PMC7468139 DOI: 10.1038/s41598-020-71211-7] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2020] [Accepted: 08/05/2020] [Indexed: 12/18/2022] Open
Abstract
The long-term decline of monarch butterflies has been attributed to loss of their milkweed (Asclepias sp.) host-plants after the introduction of herbicide-tolerant crops. However, recent studies report pesticide residues on milkweed leaves that could act as a contributing factor when ingested as part of their larval diet. In this study, we exposed monarch larvae to six pesticides (insecticide: clothianidin; herbicides: atrazine, S-metolachlor; fungicides: azoxystrobin, pyraclostrobin, trifloxystrobin) on their primary host-plant, A. syriaca. Each was tested at mean and maximum levels reported from published analyses of milkweeds bordering cropland and thus represent field-relevant concentrations. Monarch lethal and sub-lethal responses were tracked over their complete development, from early instar larvae to adult death. Overall, we found no impact of any pesticide on immature development time and relatively weak effects on larval herbivory or survival to adulthood. Comparatively stronger effects were detected for adult performance; namely, a 12.5% reduction in wing length in response to the fungicides azoxystrobin and trifloxystrobin. These data collectively suggest that monarch responses to host-plant pesticides are largely sublethal and more pronounced in the adult stage, despite exposure only as larvae. This outcome has important implications for risk assessment and the migratory success of monarchs in North America.
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60
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Campbell DL, Thessen AE, Ries L. A novel curation system to facilitate data integration across regional citizen science survey programs. PeerJ 2020; 8:e9219. [PMID: 32821528 PMCID: PMC7395600 DOI: 10.7717/peerj.9219] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2019] [Accepted: 04/28/2020] [Indexed: 11/20/2022] Open
Abstract
Integrative modeling methods can now enable macrosystem-level understandings of biodiversity patterns, such as range changes resulting from shifts in climate or land use, by aggregating species-level data across multiple monitoring sources. This requires ensuring that taxon interpretations match up across different sources. While encouraging checklist standardization is certainly an option, coercing programs to change species lists they have used consistently for decades is rarely successful. Here we demonstrate a novel approach for tracking equivalent names and concepts, applied to a network of 10 regional programs that use the same protocols (so-called “Pollard walks”) to monitor butterflies across America north of Mexico. Our system involves, for each monitoring program, associating the taxonomic authority (in this case one of three North American butterfly fauna treatments: Pelham, 2014; North American Butterfly Association, Inc., 2016; Opler & Warren, 2003) that shares the most similar overall taxonomic interpretation to the program’s working species list. This allows us to define each term on each program’s list in the context of the appropriate authority’s species concept and curate the term alongside its authoritative concept. We then aligned the names representing equivalent taxonomic concepts among the three authorities. These stepping stones allow us to bridge a species concept from one program’s species list to the name of the equivalent in any other program, through the intermediary scaffolding of aligned authoritative taxon concepts. Using a software tool we developed to access our curation system, a user can link equivalent species concepts between data collecting agencies with no specialized knowledge of taxonomic complexities.
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Affiliation(s)
- Dana L Campbell
- Division of Biological Sciences, School of STEM, University of Washington, Bothell, WA, USA
| | - Anne E Thessen
- The Ronin Institute for Independent Scholarship, Montclair, NJ, USA.,Center for Genome Research and Biocomputing, Oregon State University, Corvallis, OR, USA
| | - Leslie Ries
- Department of Biology, Georgetown University, Washington, DC, USA
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Crossley MS, Meier AR, Baldwin EM, Berry LL, Crenshaw LC, Hartman GL, Lagos-Kutz D, Nichols DH, Patel K, Varriano S, Snyder WE, Moran MD. No net insect abundance and diversity declines across US Long Term Ecological Research sites. Nat Ecol Evol 2020; 4:1368-1376. [PMID: 32778751 DOI: 10.1038/s41559-020-1269-4] [Citation(s) in RCA: 70] [Impact Index Per Article: 17.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2020] [Accepted: 06/26/2020] [Indexed: 11/09/2022]
Abstract
Recent reports of dramatic declines in insect abundance suggest grave consequences for global ecosystems and human society. Most evidence comes from Europe, however, leaving uncertainty about insect population trends worldwide. We used >5,300 time series for insects and other arthropods, collected over 4-36 years at monitoring sites representing 68 different natural and managed areas, to search for evidence of declines across the United States. Some taxa and sites showed decreases in abundance and diversity while others increased or were unchanged, yielding net abundance and biodiversity trends generally indistinguishable from zero. This lack of overall increase or decline was consistent across arthropod feeding groups and was similar for heavily disturbed versus relatively natural sites. The apparent robustness of US arthropod populations is reassuring. Yet, this result does not diminish the need for continued monitoring and could mask subtler changes in species composition that nonetheless endanger insect-provided ecosystem services.
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Affiliation(s)
| | - Amanda R Meier
- Department of Entomology, University of Georgia, Athens, GA, USA
| | - Emily M Baldwin
- Department of Biology and Health Sciences, Hendrix College, Conway, AR, USA
| | - Lauren L Berry
- Department of Biology and Health Sciences, Hendrix College, Conway, AR, USA
| | - Leah C Crenshaw
- Department of Biology and Health Sciences, Hendrix College, Conway, AR, USA
| | - Glen L Hartman
- Agricultural Research Service, United States Department of Agriculture, Urbana, IL, USA
| | - Doris Lagos-Kutz
- Agricultural Research Service, United States Department of Agriculture, Urbana, IL, USA
| | - David H Nichols
- Department of Biology and Health Sciences, Hendrix College, Conway, AR, USA
| | - Krishna Patel
- Department of Biology and Health Sciences, Hendrix College, Conway, AR, USA
| | - Sofia Varriano
- Department of Biology and Health Sciences, Hendrix College, Conway, AR, USA
| | - William E Snyder
- Department of Entomology, University of Georgia, Athens, GA, USA
| | - Matthew D Moran
- Department of Biology and Health Sciences, Hendrix College, Conway, AR, USA
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Kinsella RS, Thomas CD, Crawford TJ, Hill JK, Mayhew PJ, Macgregor CJ. Unlocking the potential of historical abundance datasets to study biomass change in flying insects. Ecol Evol 2020; 10:8394-8404. [PMID: 32788988 PMCID: PMC7417223 DOI: 10.1002/ece3.6546] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2020] [Revised: 05/11/2020] [Accepted: 05/14/2020] [Indexed: 11/08/2022] Open
Abstract
Trends in insect abundance are well established in some datasets, but far less is known about how abundance measures translate into biomass trends. Moths (Lepidoptera) provide particularly good opportunities to study trends and drivers of biomass change at large spatial and temporal scales, given the existence of long-term abundance datasets. However, data on the body masses of moths are required for these analyses, but such data do not currently exist.To address this data gap, we collected empirical data in 2018 on the forewing length and dry mass of field-sampled moths, and used these to train and test a statistical model that predicts the body mass of moth species from their forewing lengths (with refined parameters for Crambidae, Erebidae, Geometridae and Noctuidae).Modeled biomass was positively correlated, with high explanatory power, with measured biomass of moth species (R 2 = 0.886 ± 0.0006, across 10,000 bootstrapped replicates) and of mixed-species samples of moths (R 2 = 0.873 ± 0.0003), showing that it is possible to predict biomass to an informative level of accuracy, and prediction error was smaller with larger sample sizes.Our model allows biomass to be estimated for historical moth abundance datasets, and so our approach will create opportunities to investigate trends and drivers of insect biomass change over long timescales and broad geographic regions.
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Affiliation(s)
| | - Chris D. Thomas
- Department of BiologyUniversity of YorkYorkUK
- Leverhulme Centre for Anthropocene BiodiversityUniversity of YorkYorkUK
| | | | - Jane K. Hill
- Department of BiologyUniversity of YorkYorkUK
- Leverhulme Centre for Anthropocene BiodiversityUniversity of YorkYorkUK
| | | | - Callum J. Macgregor
- Department of BiologyUniversity of YorkYorkUK
- Leverhulme Centre for Anthropocene BiodiversityUniversity of YorkYorkUK
- Energy and Environment InstituteUniversity of HullHullUK
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Olaya‐Arenas P, Scharf ME, Kaplan I. Do pollinators prefer pesticide‐free plants? An experimental test with monarchs and milkweeds. J Appl Ecol 2020. [DOI: 10.1111/1365-2664.13711] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
| | | | - Ian Kaplan
- Department of Entomology Purdue University West Lafayette IN USA
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64
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Halsch CA, Code A, Hoyle SM, Fordyce JA, Baert N, Forister ML. Pesticide Contamination of Milkweeds Across the Agricultural, Urban, and Open Spaces of Low-Elevation Northern California. Front Ecol Evol 2020. [DOI: 10.3389/fevo.2020.00162] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
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65
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Vertebrates on the brink as indicators of biological annihilation and the sixth mass extinction. Proc Natl Acad Sci U S A 2020; 117:13596-13602. [PMID: 32482862 PMCID: PMC7306750 DOI: 10.1073/pnas.1922686117] [Citation(s) in RCA: 199] [Impact Index Per Article: 49.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
The ongoing sixth mass extinction may be the most serious environmental threat to the persistence of civilization, because it is irreversible. Thousands of populations of critically endangered vertebrate animal species have been lost in a century, indicating that the sixth mass extinction is human caused and accelerating. The acceleration of the extinction crisis is certain because of the still fast growth in human numbers and consumption rates. In addition, species are links in ecosystems, and, as they fall out, the species they interact with are likely to go also. In the regions where disappearing species are concentrated, regional biodiversity collapses are likely occurring. Our results reemphasize the extreme urgency of taking massive global actions to save humanity’s crucial life-support systems. The ongoing sixth mass species extinction is the result of the destruction of component populations leading to eventual extirpation of entire species. Populations and species extinctions have severe implications for society through the degradation of ecosystem services. Here we assess the extinction crisis from a different perspective. We examine 29,400 species of terrestrial vertebrates, and determine which are on the brink of extinction because they have fewer than 1,000 individuals. There are 515 species on the brink (1.7% of the evaluated vertebrates). Around 94% of the populations of 77 mammal and bird species on the brink have been lost in the last century. Assuming all species on the brink have similar trends, more than 237,000 populations of those species have vanished since 1900. We conclude the human-caused sixth mass extinction is likely accelerating for several reasons. First, many of the species that have been driven to the brink will likely become extinct soon. Second, the distribution of those species highly coincides with hundreds of other endangered species, surviving in regions with high human impacts, suggesting ongoing regional biodiversity collapses. Third, close ecological interactions of species on the brink tend to move other species toward annihilation when they disappear—extinction breeds extinctions. Finally, human pressures on the biosphere are growing rapidly, and a recent example is the current coronavirus disease 2019 (Covid-19) pandemic, linked to wildlife trade. Our results reemphasize the extreme urgency of taking much-expanded worldwide actions to save wild species and humanity’s crucial life-support systems from this existential threat.
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66
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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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67
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van Klink R, Bowler DE, Gongalsky KB, Swengel AB, Gentile A, Chase JM. Meta-analysis reveals declines in terrestrial but increases in freshwater insect abundances. Science 2020; 368:417-420. [PMID: 32327596 DOI: 10.1126/science.aax9931] [Citation(s) in RCA: 372] [Impact Index Per Article: 93.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2019] [Accepted: 03/03/2020] [Indexed: 01/16/2023]
Abstract
Recent case studies showing substantial declines of insect abundances have raised alarm, but how widespread such patterns are remains unclear. We compiled data from 166 long-term surveys of insect assemblages across 1676 sites to investigate trends in insect abundances over time. Overall, we found considerable variation in trends even among adjacent sites but an average decline of terrestrial insect abundance by ~9% per decade and an increase of freshwater insect abundance by ~11% per decade. Both patterns were largely driven by strong trends in North America and some European regions. We found some associations with potential drivers (e.g., land-use drivers), and trends in protected areas tended to be weaker. Our findings provide a more nuanced view of spatiotemporal patterns of insect abundance trends than previously suggested.
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Affiliation(s)
- Roel van Klink
- German Centre for Integrative Biodiversity Research (iDiv) Halle-Jena-Leipzig, 04103 Leipzig, Germany. .,Leipzig University, 04109 Leipzig, Germany.,WBBS Foundation, 9409 TV, Loon, Netherlands
| | - Diana E Bowler
- German Centre for Integrative Biodiversity Research (iDiv) Halle-Jena-Leipzig, 04103 Leipzig, Germany.,Institute of Biodiversity, Friedrich Schiller University Jena, 07743 Jena, Germany.,Helmholtz Centre for Environmental Research (UFZ), 04318 Leipzig, Germany
| | - Konstantin B Gongalsky
- A.N. Severtsov Institute of Ecology and Evolution, Russian Academy of Sciences, Moscow 119071, Russia.,M.V. Lomonosov Moscow State University, Moscow 119991, Russia
| | | | - Alessandro Gentile
- German Centre for Integrative Biodiversity Research (iDiv) Halle-Jena-Leipzig, 04103 Leipzig, Germany
| | - Jonathan M Chase
- German Centre for Integrative Biodiversity Research (iDiv) Halle-Jena-Leipzig, 04103 Leipzig, Germany.,Department of Computer Science, Martin Luther University-Halle Wittenberg, 06099 Halle (Saale), Germany
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68
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Nyffeler M, Bonte D. Where Have All the Spiders Gone? Observations of a Dramatic Population Density Decline in the Once Very Abundant Garden Spider, Araneus diadematus (Araneae: Araneidae), in the Swiss Midland. INSECTS 2020; 11:insects11040248. [PMID: 32326490 PMCID: PMC7240396 DOI: 10.3390/insects11040248] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/06/2020] [Revised: 04/09/2020] [Accepted: 04/10/2020] [Indexed: 12/02/2022]
Abstract
Aerial web-spinning spiders (including large orb-weavers), as a group, depend almost entirely on flying insects as a food source. The recent widespread loss of flying insects across large parts of western Europe, in terms of both diversity and biomass, can therefore be anticipated to have a drastic negative impact on the survival and abundance of this type of spider. To test the putative importance of such a hitherto neglected trophic cascade, a survey of population densities of the European garden spider Araneus diadematus—a large orb-weaving species—was conducted in the late summer of 2019 at twenty sites in the Swiss midland. The data from this survey were compared with published population densities for this species from the previous century. The study verified the above-mentioned hypothesis that this spider’s present-day overall mean population density has declined alarmingly to densities much lower than can be expected from normal population fluctuations (0.7% of the historical values). Review of other available records suggested that this pattern is widespread and not restricted to this region. In conclusion, the decline of this once so abundant spider in the Swiss midland is evidently revealing a bottom-up trophic cascade in response to the widespread loss of flying insect prey in recent decades.
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Affiliation(s)
- Martin Nyffeler
- Department of Environmental Sciences, Section of Conservation Biology, University of Basel, CH–4056 Basel, Switzerland
- Correspondence:
| | - Dries Bonte
- Department of Biology, Terrestrial Ecology Unit, Ghent University, 9000 Ghent, Belgium;
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69
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Riva F, Gentile G, Bonelli S, Acorn JH, Denes FV, Crosby AD, Nielsen SE. Of detectability and camouflage: evaluating Pollard Walk rules using a common, cryptic butterfly. Ecosphere 2020. [DOI: 10.1002/ecs2.3101] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Affiliation(s)
- Federico Riva
- Department of Renewable Resources University of Alberta General Services Building Edmonton Alberta T6G 2H1 Canada
| | - Giorgio Gentile
- Dipartimento di Scienze della Vita e Biologia dei Sistemi University of Turin Turin Via Verdi 8‐10124 Italy
| | - Simona Bonelli
- Dipartimento di Scienze della Vita e Biologia dei Sistemi University of Turin Turin Via Verdi 8‐10124 Italy
| | - John H. Acorn
- Department of Renewable Resources University of Alberta General Services Building Edmonton Alberta T6G 2H1 Canada
| | - Francisco V. Denes
- Department of Renewable Resources University of Alberta General Services Building Edmonton Alberta T6G 2H1 Canada
| | - Andrew D. Crosby
- Department of Biological Sciences University of Alberta Biological Sciences Building Edmonton Alberta T6G 2H1 Canada
| | - Scott E. Nielsen
- Department of Renewable Resources University of Alberta General Services Building Edmonton Alberta T6G 2H1 Canada
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70
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Welti EAR, Prather RM, Sanders NJ, de Beurs KM, Kaspari M. Bottom-up when it is not top-down: Predators and plants control biomass of grassland arthropods. J Anim Ecol 2020; 89:1286-1294. [PMID: 32115723 DOI: 10.1111/1365-2656.13191] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2019] [Accepted: 12/20/2019] [Indexed: 11/30/2022]
Abstract
We investigate where bottom-up and top-down control regulates ecological communities as a mechanism linking ecological gradients to the geography of consumer abundance and biomass. We use standardized surveys of 54 North American grasslands to test alternate hypotheses predicting 100-fold shifts in the biomass of four common grassland arthropod taxa-Auchenorrhyncha, sucking herbivores, Acrididae, chewing herbivores, Tettigoniidae, omnivores, and Araneae, predators. Bottom-up models predict that consumer biomass tracks plant quantity (e.g. productivity and standing biomass) and quality (nutrient content) and that ectotherm access to food increases with temperature. Each of the focal trophic groups responded differently to these drivers: the biomass of sucking herbivores and omnivores increased with plant biomass; that of chewing herbivores tracked plant quality; and predator biomass did not depend on plant quality, plant quantity or temperature. The Exploitation Ecosystem Hypothesis is a top-down hypothesis that predicts a shift from resource limitation of herbivores when plant production is low, to predator limitation when plant production is high. In grasslands where spider biomass was low, herbivore biomass increased with plant biomass, whereas bottom-up structuring was not evident when spiders were abundant. Furthermore, neither predator biomass nor trophic position (via stable isotope analysis) increased with plant biomass, suggesting predators themselves are top-down limited. Stable isotope analysis revealed that trophic position of the chewing herbivore and omnivore increased significantly with plant biomass, suggesting these groups increased scavenging and meat consumption in grasslands with higher carbohydrate availability. Taken together, our snapshot sampling documents gradients of food web structure across 54 grasslands, consistent with multiple hypotheses of bottom-up and top-down regulation.
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Affiliation(s)
- Ellen A R Welti
- Geographical Ecology Group, Department of Biology, University of Oklahoma, Norman, OK, USA
| | - Rebecca M Prather
- Geographical Ecology Group, Department of Biology, University of Oklahoma, Norman, OK, USA
| | - Nathan J Sanders
- The Environmental Program, Rubenstein School of Environment and Natural Resources, University of Vermont, Burlington, VT, USA
| | - Kirsten M de Beurs
- Department of Geography and Environmental Sustainability, University of Oklahoma, Norman, OK, USA
| | - Michael Kaspari
- Geographical Ecology Group, Department of Biology, University of Oklahoma, Norman, OK, USA
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71
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Nutrient dilution and climate cycles underlie declines in a dominant insect herbivore. Proc Natl Acad Sci U S A 2020; 117:7271-7275. [PMID: 32152101 DOI: 10.1073/pnas.1920012117] [Citation(s) in RCA: 54] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Evidence for global insect declines mounts, increasing our need to understand underlying mechanisms. We test the nutrient dilution (ND) hypothesis-the decreasing concentration of essential dietary minerals with increasing plant productivity-that particularly targets insect herbivores. Nutrient dilution can result from increased plant biomass due to climate or CO2 enrichment. Additionally, when considering long-term trends driven by climate, one must account for large-scale oscillations including El Niño Southern Oscillation (ENSO), North Atlantic Oscillation (NAO), and Pacific Decadal Oscillation (PDO). We combine long-term datasets of grasshopper abundance, climate, plant biomass, and end-of-season foliar elemental content to examine potential drivers of abundance cycles and trends of this dominant herbivore. Annual grasshopper abundances in 16- and 22-y time series from a Kansas prairie revealed both 5-y cycles and declines of 2.1-2.7%/y. Climate cycle indices of spring ENSO, summer NAO, and winter or spring PDO accounted for 40-54% of the variation in grasshopper abundance, mediated by effects of weather and host plants. Consistent with ND, grass biomass doubled and foliar concentrations of N, P, K, and Na-nutrients which limit grasshopper abundance-declined over the same period. The decline in plant nutrients accounted for 25% of the variation in grasshopper abundance over two decades. Thus a warming, wetter, more CO2-enriched world will likely contribute to declines in insect herbivores by depleting nutrients from their already nutrient-poor diet. Unlike other potential drivers of insect declines-habitat loss, light and chemical pollution-ND may be widespread in remaining natural areas.
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72
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Douglas MR, Sponsler DB, Lonsdorf EV, Grozinger CM. County-level analysis reveals a rapidly shifting landscape of insecticide hazard to honey bees (Apis mellifera) on US farmland. Sci Rep 2020; 10:797. [PMID: 31964921 PMCID: PMC6972851 DOI: 10.1038/s41598-019-57225-w] [Citation(s) in RCA: 55] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2019] [Accepted: 12/10/2019] [Indexed: 01/04/2023] Open
Abstract
Each year, millions of kilograms of insecticides are applied to crops in the US. While insecticide use supports food, fuel, and fiber production, it can also threaten non-target organisms, a concern underscored by mounting evidence of widespread decline of pollinator populations. Here, we integrate several public datasets to generate county-level annual estimates of total 'bee toxic load' (honey bee lethal doses) for insecticides applied in the US between 1997-2012, calculated separately for oral and contact toxicity. To explore the underlying components of the observed changes, we divide bee toxic load into extent (area treated) and intensity (application rate x potency). We show that while contact-based bee toxic load remained relatively steady, oral-based bee toxic load increased roughly 9-fold, with reductions in application rate outweighed by disproportionate increases in potency (toxicity/kg) and extent. This pattern varied markedly by region, with the greatest increase seen in Heartland (121-fold increase), likely driven by use of neonicotinoid seed treatments in corn and soybean. In this "potency paradox", farmland in the central US has become more hazardous to bees despite lower volumes of insecticides applied, raising concerns about insect conservation and highlighting the importance of integrative approaches to pesticide use monitoring.
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Affiliation(s)
- Margaret R Douglas
- Department of Environmental Studies & Environmental Science, Dickinson College, Carlisle, PA, 17013, USA.
| | - Douglas B Sponsler
- Department of Entomology, Center for Pollinator Research, Huck Institutes of the Life Sciences, Pennsylvania State University, University Park, 16802, PA, USA
| | - Eric V Lonsdorf
- Institute on the Environment, University of Minnesota, St Paul, MN, 55108, USA
| | - Christina M Grozinger
- Department of Entomology, Center for Pollinator Research, Huck Institutes of the Life Sciences, Pennsylvania State University, University Park, 16802, PA, USA
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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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74
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Moth biomass has fluctuated over 50 years in
Britain but lacks a clear trend. Nat Ecol Evol 2019; 3:1645-1649. [DOI: 10.1038/s41559-019-1028-6] [Citation(s) in RCA: 92] [Impact Index Per Article: 18.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2019] [Accepted: 10/04/2019] [Indexed: 01/30/2023]
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75
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Faltýnek Fric Z, Rindoš M, Konvička M. Phenology responses of temperate butterflies to latitude depend on ecological traits. Ecol Lett 2019; 23:172-180. [DOI: 10.1111/ele.13419] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2019] [Revised: 10/02/2019] [Accepted: 10/14/2019] [Indexed: 12/31/2022]
Affiliation(s)
- Zdeněk Faltýnek Fric
- The Czech Academy of Sciences, Biology Centre Institute of Entomology Branišovská 31 37005 České Budějovice Czech Republic
- Faculty of Science University of South Bohemia Branišovská1760, 37005 České Budějovice Czech Republic
| | - Michal Rindoš
- The Czech Academy of Sciences, Biology Centre Institute of Entomology Branišovská 31 37005 České Budějovice Czech Republic
- Faculty of Science University of South Bohemia Branišovská1760, 37005 České Budějovice Czech Republic
| | - Martin Konvička
- The Czech Academy of Sciences, Biology Centre Institute of Entomology Branišovská 31 37005 České Budějovice Czech Republic
- Faculty of Science University of South Bohemia Branišovská1760, 37005 České Budějovice Czech Republic
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76
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Hermann SL, Blackledge C, Haan NL, Myers AT, Landis DA. Predators of monarch butterfly eggs and neonate larvae are more diverse than previously recognised. Sci Rep 2019; 9:14304. [PMID: 31586127 PMCID: PMC6778129 DOI: 10.1038/s41598-019-50737-5] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2019] [Accepted: 09/12/2019] [Indexed: 11/14/2022] Open
Abstract
Conserving threatened organisms requires knowledge of the factors impacting their populations. The Eastern monarch butterfly (Danaus plexippus L.) has declined by as much as 80% in the past two decades and conservation biologists are actively seeking to understand and reverse this decline. While it is well known that most monarchs die as eggs and young larvae, few studies have focused on identifying what arthropod taxa contribute to these losses. The aim of our study was to identify previously undocumented predators of immature monarchs in their summer breeding range in the United States. Using no-choice feeding assays augmented with field observations, we evaluated 75 arthropod taxa commonly found on the primary host plant for their propensity to consume immature monarchs. Here we report 36 previously unreported monarch predators, including representatives from 4 new orders (Orthoptera, Dermaptera, Lepidoptera and Opiliones) and 11 taxa (Acrididae, Gryllidae, Tettigoniidae, Forficulidae, Anthocoridae, Geocoridae, Lygaeidae, Miridae, Nabidae, Erebidae and Opilliones). Surprisingly, several putative herbivores were found to readily consume immature monarchs, both in a targeted fashion or incidentally as a result of herbivory. This work expands our understanding of the monarch predator community and highlights the importance of unrecognized predation on insects of conservation concern.
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Affiliation(s)
- Sara L Hermann
- Department of Entomology, The Pennsylvania State University, University Park, USA.
| | | | - Nathan L Haan
- Department of Entomology, Michigan State University, East Lansing, USA
| | - Andrew T Myers
- Department of Entomology, Michigan State University, East Lansing, USA.,Program in Ecology, Evolutionary Biology and Behavior, Michigan State University, East Lansing, USA
| | - Douglas A Landis
- Department of Entomology, Michigan State University, East Lansing, USA.,Program in Ecology, Evolutionary Biology and Behavior, Michigan State University, East Lansing, USA
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77
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Kozak GM, Wadsworth CB, Kahne SC, Bogdanowicz SM, Harrison RG, Coates BS, Dopman EB. Genomic Basis of Circannual Rhythm in the European Corn Borer Moth. Curr Biol 2019; 29:3501-3509.e5. [DOI: 10.1016/j.cub.2019.08.053] [Citation(s) in RCA: 44] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2019] [Revised: 08/15/2019] [Accepted: 08/20/2019] [Indexed: 12/15/2022]
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