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Van Deynze B, Swinton SM, Hennessy DA, Haddad NM, Ries L. Insecticides, more than herbicides, land use, and climate, are associated with declines in butterfly species richness and abundance in the American Midwest. PLoS One 2024; 19:e0304319. [PMID: 38900768 PMCID: PMC11189219 DOI: 10.1371/journal.pone.0304319] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2023] [Accepted: 05/09/2024] [Indexed: 06/22/2024] Open
Abstract
Mounting evidence shows overall insect abundances are in decline globally. Habitat loss, climate change, and pesticides have all been implicated, but their relative effects have never been evaluated in a comprehensive large-scale study. We harmonized 17 years of land use, climate, multiple classes of pesticides, and butterfly survey data across 81 counties in five states in the US Midwest. We find community-wide declines in total butterfly abundance and species richness to be most strongly associated with insecticides in general, and for butterfly species richness the use of neonicotinoid-treated seeds in particular. This included the abundance of the migratory monarch (Danaus plexippus), whose decline is the focus of intensive debate and public concern. Insect declines cannot be understood without comprehensive data on all putative drivers, and the 2015 cessation of neonicotinoid data releases in the US will impede future research.
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Affiliation(s)
- Braeden Van Deynze
- Washington Department of Fish and Wildlife, Olympia, WA, United States of America
| | - Scott M. Swinton
- Department of Agricultural, Food, and Resource Economics, Michigan State University, East Lansing, MI, United States of America
| | - David A. Hennessy
- Department of Economics, Iowa State University, Ames, IA, United States of America
| | - Nick M. Haddad
- Kellogg Biological Station and Department of Integrative Biology, Michigan State University, Hickory Corners, East Lansing, MI, United States of America
| | - Leslie Ries
- Department of Biology, Georgetown University, Washington, DC, United States of America
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2
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McNeil DJ, Goslee SC, Kammerer M, Lower SE, Tooker JF, Grozinger CM. Illuminating patterns of firefly abundance using citizen science data and machine learning models. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 929:172329. [PMID: 38608892 DOI: 10.1016/j.scitotenv.2024.172329] [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: 09/28/2023] [Revised: 04/06/2024] [Accepted: 04/06/2024] [Indexed: 04/14/2024]
Abstract
As insect populations decline in many regions, conservation biologists are increasingly tasked with identifying factors that threaten insect species and developing effective strategies for their conservation. One insect group of global conservation concern are fireflies (Coleoptera: Lampyridae). Although quantitative data on firefly populations are lacking for most species, anecdotal reports suggest that some firefly populations have declined in recent decades. Researchers have hypothesized that North American firefly populations are most threatened by habitat loss, pesticide use, and light pollution, but the importance of these factors in shaping firefly populations has not been rigorously examined at broad spatial scales. Using data from >24,000 surveys (spanning 2008-16) from the citizen science program Firefly Watch, we trained machine learning models to evaluate the relative importance of a variety of factors on bioluminescent firefly populations: pesticides, artificial lights at night, land cover, soil/topography, short-term weather, and long-term climate. Our analyses revealed that firefly abundance was driven by complex interactions among soil conditions (e.g., percent sand composition), climate/weather (e.g., growing degree days), and land cover characteristics (e.g., percent agriculture and impervious cover). Given the significant impact that climactic and weather conditions have on firefly abundance, there is a strong likelihood that firefly populations will be influenced by climate change, with some regions becoming higher quality and supporting larger firefly populations, and others potentially losing populations altogether. Collectively, our results support hypotheses related to factors threatening firefly populations, especially habitat loss, and suggest that climate change may pose a greater threat than appreciated in previous assessments. Thus, future conservation of North American firefly populations will depend upon 1) consistent and continued monitoring of populations via programs like Firefly Watch, 2) efforts to mitigate the impacts of climate change, and 3) insect-friendly conservation practices.
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Affiliation(s)
- Darin J McNeil
- Department of Forestry and Natural Resources, University of Kentucky, Lexington, KY 40506, USA.
| | - Sarah C Goslee
- United States Department of Agriculture - Agricultural Research Service, Pasture Systems and Watershed Management Research Unit, University Park, PA 16802, USA
| | - Melanie Kammerer
- United States Department of Agriculture - Agricultural Research Service, Pasture Systems and Watershed Management Research Unit, University Park, PA 16802, USA
| | - Sarah E Lower
- Department of Biology, Bucknell University, Lewisburg, PA 17837, USA
| | - John F Tooker
- Department of Entomology, Insect Biodiversity Center, Huck Institutes of the Life Sciences, Pennsylvania State University, University Park, PA 16802, USA
| | - Christina M Grozinger
- Department of Entomology, Insect Biodiversity Center, Huck Institutes of the Life Sciences, Pennsylvania State University, University Park, PA 16802, USA
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3
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Merlo-Reyes A, Baduel C, Duwig C, Ramírez MI. Risk assessment of pesticides used in the eastern Avocado Belt of Michoacan, Mexico: A survey and water monitoring approach. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 916:170288. [PMID: 38266736 DOI: 10.1016/j.scitotenv.2024.170288] [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: 10/27/2023] [Revised: 01/06/2024] [Accepted: 01/17/2024] [Indexed: 01/26/2024]
Abstract
Pesticides use raises concerns regarding environmental sustainability, as pesticides are closely linked to the decline of biodiversity and adverse human health outcomes. This study proposed a holistic approach for assessing the potential risks posed by pesticides for human health and the environment in the eastern region of Michoacan, where extensive agricultural lands, especially corn and avocado fields, surround the Monarch Butterfly Biosphere Reserve. We used a combination of qualitative (semi-structured interviews) and quantitative (chemical analysis) data. Fifty-five interviews with smallholder farmers allowed us to identify pesticide types, quantities, frequencies, and application methods. A robust and precise analytical method based on solid-phase extraction and LC-MS/MS was developed and validated to quantify 21 different pesticides in 16 water samples (rivers, wells, runoff areas). We assessed environmental and human health risks based on the pesticides detected in the water samples and reported in the interviews. The interviews revealed the use of 28 active ingredients, including glyphosate (29 % of respondents), imidacloprid (27 %), and benomyl (24 %). The pesticide analysis showed the presence of 13 different pesticides and degradation products in the water samples. The highest concentrations were found for imidacloprid (1195 ngL-1) and carbendazim (a degradation product of benomyl; 932 ngL-1), along with the metabolite of pyrethroid insecticides, 3-PBA (494 ngL-1). The risk assessment indicates that among the most used pesticides, the fungicide benomyl and carbendazim pose the highest risk to human health and aquatic ecosystems, respectively. This study unveils novel insights on agricultural practices for the avocado, a globally consumed crop that is undergoing rapid production expansion. It calls for the harmonisation of crop protection with environmental responsibility, safeguarding the health of the people involved and the surrounding ecosystems.
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Affiliation(s)
- Ana Merlo-Reyes
- Institut des Géosciences et de l'Environnement, Univ. Grenoble Alpes, CNRS, IRD, INRAE, G-INP, 70 rue de la physique, 38400 Saint-Martin-d'Hères, France.
| | - Christine Baduel
- Institut des Géosciences et de l'Environnement, Univ. Grenoble Alpes, CNRS, IRD, INRAE, G-INP, 70 rue de la physique, 38400 Saint-Martin-d'Hères, France
| | - Céline Duwig
- Institut des Géosciences et de l'Environnement, Univ. Grenoble Alpes, CNRS, IRD, INRAE, G-INP, 70 rue de la physique, 38400 Saint-Martin-d'Hères, France.
| | - M Isabel Ramírez
- Centro de Investigaciones en Geografía Ambiental, Universidad Nacional Autónoma de México, UNAM Campus Morelia, Antigua Carretera a Pátzcuaro, 8701, CP 58190 Morelia, Michoacán, Mexico
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4
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Cibotti S, Saum PJ, Myrick AJ, Schilder RJ, Ali JG. Divergent impacts of the neonicotinoid insecticide, clothianidin, on flight performance metrics in two species of migratory butterflies. CONSERVATION PHYSIOLOGY 2024; 12:coae002. [PMID: 38313378 PMCID: PMC10836301 DOI: 10.1093/conphys/coae002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/18/2023] [Revised: 12/05/2023] [Accepted: 01/09/2024] [Indexed: 02/06/2024]
Abstract
Long-distance flight is crucial for the survival of migratory insects, and disruptions to their flight capacity can have significant consequences for conservation. In this study, we examined how a widely used insecticide, clothianidin (class: neonicotinoid), impacted the flight performance of two species of migratory butterflies, monarchs (Danaus plexippus) and painted ladies (Vanessa cardui). To do this, we quantified the free-flight energetics and tethered-flight velocity and distance of the two species using flow-through respirometry and flight mill assays. Our findings show differential effects of the pesticide on the two species. For painted ladies, we found that clothianidin exposure reduced average free-flight metabolic rates, but did not affect either average velocity or total distance during tethered flight. Other studies have linked low flight metabolic rates with reduced dispersal capacity, indicating that clothianidin exposure may hinder painted lady flight performance in the wild. Conversely, for monarchs, we saw no significant effect of clothianidin exposure on average free-flight metabolic rates but did observe increases in the average velocity, and for large individuals, total distance achieved by clothianidin-exposed monarchs in tethered flight. This suggests a potential stimulatory response of monarchs to low-dose exposures to clothianidin. These findings indicate that clothianidin exposure has the potential to influence the flight performance of butterflies, but that not all species are impacted in the same way. This highlights the need to be thoughtful when selecting performance assays, as different assays can evaluate fundamentally distinct aspects of physiology, and as such may yield divergent results.
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Affiliation(s)
- Staci Cibotti
- Department of Entomology, The Pennsylvania State University, 501 Agricultural Science and Industries Building, University Park, PA 16802, USA
| | - Phineas J Saum
- Department of Entomology, The Pennsylvania State University, 501 Agricultural Science and Industries Building, University Park, PA 16802, USA
| | - Andrew J Myrick
- Department of Entomology, The Pennsylvania State University, 501 Agricultural Science and Industries Building, University Park, PA 16802, USA
| | - Rudolf J Schilder
- Department of Entomology, The Pennsylvania State University, 501 Agricultural Science and Industries Building, University Park, PA 16802, USA
- Department of Biology, Pennsylvania State University, University Park, PA 16802, USA
| | - Jared G Ali
- Department of Entomology, The Pennsylvania State University, 501 Agricultural Science and Industries Building, University Park, PA 16802, USA
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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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6
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Quesada CR, Scharf ME. Whiteflies can excrete insecticide-tainted honeydew on tomatoes. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2023; 337:122527. [PMID: 37699451 DOI: 10.1016/j.envpol.2023.122527] [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: 07/13/2023] [Revised: 09/05/2023] [Accepted: 09/07/2023] [Indexed: 09/14/2023]
Abstract
Whiteflies are important insect pests in a wide variety of agricultural crops that are targeted with large quantities of insecticides on a global scale. Chemical control is the most common strategy to manage whiteflies, however, recent studies had reported that whiteflies and other hemipterans can excrete insecticides through their honeydew, which could have unanticipated, non-target effects. The objective of this study was to determine the concentration of imidacloprid in honeydew excreted by whiteflies feeding on tomato plants. Imidacloprid was applied at its labeled rate to soil at the base of whitefly-infested plants. Densities of whiteflies were assessed before insecticide treatment and 21 days after treatment (DAT). Honeydew was collected in Petri dishes from 1 to 4 DAT and from 5 to 8 DAT. The volume of the honeydew was calculated using stereo microscopy and then rinsed with ethanol. The rinsates were analyzed to determine imidacloprid concentration using liquid chromatography coupled to mass spectrometry. Honeydew production was further quantified by using water sensitive papers. Imidacloprid reduced densities of nymph and adult whiteflies by 81.5% and 76.0% compared to the control at 21DAT. The non-metabolized parent compound imidacloprid was detected from honeydew samples at both collection dates. At 1-4 DAT, imidacloprid concentrations were 180 ng/30 mL in a volume of 39 mm3 of honeydew. At 5-8 DAT, the imidacloprid concentration was 218 ng/30 mL in a volume of 25 mm3 of honeydew. Though the volume of honeydew decreased, the concentration of imidacloprid numerically increased. Last, whiteflies were still producing honeydew 22 DAT in both treatments. These results revealing significant imidacloprid concentrations in honeydew suggest a strong potential for negative secondary impacts on beneficial insects.
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Affiliation(s)
- Carlos R Quesada
- WVU Extension and Division of Plant and Soil Science, West Virginia University, Morgantown, WV, 26506, USA.
| | - Michael E Scharf
- Entomology and Nematology Department, University of Florida, Gainesville, FL, 32611, USA
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Gao YF, Ren YJ, Chen JC, Cao LJ, Qiao GH, Zong SX, Hoffmann AA, Wei SJ, Yang Q. Effects of fungicides on fitness and Buchnera endosymbiont density in Aphis gossypii. PEST MANAGEMENT SCIENCE 2023; 79:4282-4289. [PMID: 37345405 DOI: 10.1002/ps.7625] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/19/2023] [Revised: 06/06/2023] [Accepted: 06/22/2023] [Indexed: 06/23/2023]
Abstract
BACKGROUND Several agricultural fungicides are known to affect insect pests directly and these effects may be transgenerational and mediated through impacts on endosymbionts, providing opportunities for pest control. The cotton aphid Aphis gossypii is a polyphagous pest that can cause large crop yield losses. Here, we tested the effects of three fungicides, pyraclostrobin, trifloxystrobin and chlorothalonil, on the fitness and Buchnera endosymbiont of A. gossypii. RESULTS The formulations of trifloxystrobin and pyraclostrobin, and the active ingredient of pyraclostrobin produced dose-dependent mortality in A. gossypii, whereas there was no dose-dependent mortality for chlorothalonil. The formulations of trifloxystrobin and pyraclostrobin significantly reduced the lifespan and fecundity of A. gossypii, and increased the density of Buchnera in the parental generation but not the (unexposed) F1 . When the active ingredient of pyraclostrobin was tested, the lifespan of the F0 generation was also reduced, but the density of Buchnera was not, indicating that non-insecticidal chemicals in the fungicide formulation may affect the density of the endosymbiont of A. gossypii. There was no transgenerational effect of the active ingredient of pyraclostrobin on the lifespan and Buchnera of (unexposed) F1 . CONCLUSIONS Our results suggest that formulations of two strobilurin fungicides have immediate impacts on the fitness of A. gossypii, and chemicals in the formulation impact the density of the primary Buchnera endosymbiont. Our study highlights the potential effects of non-insecticidal chemicals of fungicides on aphid pests and their primary endosymbionts but direct connections between fitness and Buchnera densities remain unclear. © 2023 Society of Chemical Industry.
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Affiliation(s)
- Yong-Fu Gao
- Beijing Key Laboratory for Forest Pests Control, Beijing Forestry University, Beijing, China
- Institute of Plant Protection, Beijing Academy of Agriculture and Forestry Sciences, Beijing, China
| | - Ya-Jing Ren
- Institute of Plant Protection, Beijing Academy of Agriculture and Forestry Sciences, Beijing, China
| | - Jin-Cui Chen
- Institute of Plant Protection, Beijing Academy of Agriculture and Forestry Sciences, Beijing, China
| | - Li-Jun Cao
- Institute of Plant Protection, Beijing Academy of Agriculture and Forestry Sciences, Beijing, China
| | - Guang-Hang Qiao
- Institute of Plant Protection, Beijing Academy of Agriculture and Forestry Sciences, Beijing, China
| | - Shi-Xiang Zong
- Beijing Key Laboratory for Forest Pests Control, Beijing Forestry University, Beijing, China
| | - Ary A Hoffmann
- Bio21 Institute, School of BioSciences, University of Melbourne, Parkville, VIC, Australia
| | - Shu-Jun Wei
- Institute of Plant Protection, Beijing Academy of Agriculture and Forestry Sciences, Beijing, China
| | - Qiong Yang
- Bio21 Institute, School of BioSciences, University of Melbourne, Parkville, VIC, Australia
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Halsch CA, Zullo DJ, Forister ML. Additive and interactive effects of anthropogenic stressors on an insect herbivore. Proc Biol Sci 2023; 290:20222431. [PMID: 37015275 PMCID: PMC10072940 DOI: 10.1098/rspb.2022.2431] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2022] [Accepted: 03/13/2023] [Indexed: 04/06/2023] Open
Abstract
The pressures of global change acting on wild plants and animals include exposure to environmental toxins, the introduction of non-native species, and climate change. Relatively few studies have been reported in which these three main classes of stressors have been examined simultaneously, allowing for the possibility of synergistic effects in an experimental context. In this study, we exposed caterpillars of the Melissa blue butterfly (Lycaeides melissa) to three concentrations of chlorantraniliprole, under three experimental climates, on a diet of a native or a non-native host plant throughout larval development in a fully factorial experiment. We find that high pesticide exposure and a non-native diet exhibit strong negative effects on caterpillars, resulting in 62% and 42% reduction in survival, respectively, while interactive effects tend to be weaker, ranging from 15% to 22% reduction in survival. Interactive effects have been shown to be strong in other contexts, but do not appear to be universal; however, our study shows that the cumulative effects of stressors acting in isolation (additively) are sufficiently strong to severely reduce survival and by extension population persistence in the wild.
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Affiliation(s)
- Christopher A. Halsch
- Department of Biology, Program in Ecology, Evolution and Conservation Biology, University of Nevada, Reno, NV, USA
| | - Dominic J. Zullo
- Department of Biology, Program in Ecology, Evolution and Conservation Biology, University of Nevada, Reno, NV, USA
| | - Matthew L. Forister
- Department of Biology, Program in Ecology, Evolution and Conservation Biology, University of Nevada, Reno, NV, USA
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Li Z, Li M, Niu S. A Modeling Approach for Assessing Ecological Risks of Neonicotinoid Insecticides from Emission to Nontarget Organisms: A Case Study of Cotton Plant. ENVIRONMENTAL TOXICOLOGY AND CHEMISTRY 2023; 42:928-938. [PMID: 36779656 DOI: 10.1002/etc.5583] [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: 06/25/2022] [Revised: 10/07/2022] [Accepted: 02/06/2023] [Indexed: 06/18/2023]
Abstract
The use of neonicotinoid insecticides in agriculture has posed threats to ecological systems, and there is a need to assess the ecological risks of neonicotinoids from emission to nontarget organisms. We introduced a modeling approach to assess the ecological risks of neonicotinoids using honeybee and earthworm as model organisms, and the simulation was flexible under different environmental conditions. Using the cotton plant as an example, the simulation results demonstrated that under current recommended application rates, the use of common neonicotinoid insecticides posed no threat to earthworms, with the simulated risk quotients (RQs) much lower than 1. However, the simulation for some neonicotinoid insecticides (e.g., acetamiprid) indicated that using these insecticides on cotton plants could threaten honeybees, with simulated RQs higher than 1. The variability analysis showed that in high-latitude regions, the unacceptable risk to honeybees posed by insecticide application can be further elevated due to cold, wet weather that results in relatively high insecticide levels in pollen and nectar. The model evaluation showed large overlaps of simulated risk intervals between the proposed and existing (BeeREX) models. Because the proposed and existing models have different simulation mechanisms, we recommend that these two models be used together to complement each other in future studies. Environ Toxicol Chem 2023;42:928-938. © 2023 SETAC.
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Affiliation(s)
- Zijian Li
- School of Public Health (Shenzhen), Sun Yat-sen University, Shenzhen, Guangdong, PR China
| | - Minmin Li
- Key Laboratory of Agroproducts Quality and Safety Control in the Storage and Transport Process, Ministry of Agriculture and Rural Affairs/Institute of Food Science and Technology, Chinese Academy of Agricultural Sciences, Beijing, PR China
| | - Shan Niu
- Department of Civil & Environmental Engineering, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
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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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11
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Chirgwin E, Yang Q, Umina PA, Gill A, Soleimannejad S, Gu X, Ross P, Hoffmann AA. Fungicides have transgenerational effects on Rhopalosiphum padi but not their endosymbionts. PEST MANAGEMENT SCIENCE 2022; 78:4709-4718. [PMID: 35866313 DOI: 10.1002/ps.7091] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/21/2021] [Revised: 07/12/2022] [Accepted: 07/22/2022] [Indexed: 06/15/2023]
Abstract
BACKGROUND While several agricultural fungicides are known to directly affect invertebrate pests, including aphids, the mechanisms involved are often unknown. One hypothesis is that fungicides with antibacterial activity suppress bacterial endosymbionts present in aphids which are important for aphid survival. Endosymbiont-related effects are expected to be transgenerational, given that these bacteria are maternally inherited. Here, we test for these associations using three fungicides (chlorothalonil, pyraclostrobin and trifloxystrobin) against the bird cherry-oat aphid, Rhopalosiphum padi, using a microinjected strain that carried both the primary endosymbiont Buchnera and the secondary endosymbiont Rickettsiella. RESULTS We show that the fungicide chlorothalonil did not cause an immediate effect on aphid survival, whereas both strobilurin fungicides (pyraclostrobin and trifloxystrobin) decreased survival after 48 h exposure. However, chlorothalonil substantially reduced the lifespan and fecundity of the F1 generation. Trifloxystrobin also reduced the lifespan and fecundity of F1 offspring, however, pyraclostrobin did not affect these traits. None of the fungicides consistently altered the density of Buchnera or Rickettsiella in whole aphids. CONCLUSIONS Our results suggest fungicides have sublethal impacts on R. padi that are not fully realized until the generation after exposure, and these sublethal impacts are not associated with the density of endosymbionts harbored by R. padi. However, we cannot rule out other effects of fungicides on endosymbionts that might influence fitness, like changes in their tissue distribution. We discuss these results within the context of fungicidal effects on aphid suppression across generations and point to potential field applications. © 2022 Society of Chemical Industry.
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Affiliation(s)
| | - Qiong Yang
- School of BioSciences, The University of Melbourne, Victoria, Australia
| | - Paul A Umina
- Cesar Australia, Victoria, Australia
- School of BioSciences, The University of Melbourne, Victoria, Australia
| | - Alex Gill
- School of BioSciences, The University of Melbourne, Victoria, Australia
| | | | - Xinyue Gu
- School of BioSciences, The University of Melbourne, Victoria, Australia
| | - Perran Ross
- School of BioSciences, The University of Melbourne, Victoria, Australia
| | - Ary A Hoffmann
- School of BioSciences, The University of Melbourne, Victoria, Australia
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Pollinator biological traits and ecological interactions mediate the impacts of mosquito-targeting malathion application. Sci Rep 2022; 12:17039. [PMID: 36220841 PMCID: PMC9554017 DOI: 10.1038/s41598-022-20823-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2022] [Accepted: 09/19/2022] [Indexed: 12/29/2022] Open
Abstract
Mosquito adulticides are perceived by the public as detrimental to nontarget arthropods, contributing to declines of native and beneficial insects. However, the actual impact of adulticides on nontarget arthropods in nature needs to incorporate biological and ecological elements. Here, we investigated the effect of biological/behavioral traits (butterfly roosting at different heights, roosting in sites underneath foliage, bumblebee hive usage) and interactions (parasitism, predation) of pollinators (butterflies and bumblebees) that could mediate the impacts of malathion application in manipulative semi-field experiments in Florida, USA. Roosting height from the spray route had a significant negative relationship with mortality of butterflies treated with ULV malathion, with high survival at the highest roosting height (7 m), but butterflies roosting among vegetation did not have higher survival. Bumblebees with hive access had significantly higher survival than bumblebees without hive access. Host plants treated with ULV malathion significantly reduced parasitism of monarch eggs by Trichogramma platneri, but increased predation of monarch caterpillars by Polistes paper wasps. These data provide insight into the realistic impacts of adulticide applications on pollinators in nature which will enable mosquito control districts to better limit nontarget effects of adulticide treatments and may help to address concerns related to potential nontarget effects.
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Past insecticide exposure reduces bee reproduction and population growth rate. Proc Natl Acad Sci U S A 2021; 118:2109909118. [PMID: 34810261 DOI: 10.1073/pnas.2109909118] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/09/2021] [Indexed: 11/18/2022] Open
Abstract
Pesticides are linked to global insect declines, with impacts on biodiversity and essential ecosystem services. In addition to well-documented direct impacts of pesticides at the current stage or time, potential delayed "carryover" effects from past exposure at a different life stage may augment impacts on individuals and populations. We investigated the effects of current exposure and the carryover effects of past insecticide exposure on the individual vital rates and population growth of the solitary bee, Osmia lignaria Bees in flight cages freely foraged on wildflowers, some treated with the common insecticide, imidacloprid, in a fully crossed design over 2 y, with insecticide exposure or no exposure in each year. Insecticide exposure directly to foraging adults and via carryover effects from past exposure reduced reproduction. Repeated exposure across 2 y additively impaired individual performance, leading to a nearly fourfold reduction in bee population growth. Exposure to even a single insecticide application can have persistent effects on vital rates and can reduce population growth for multiple generations. Carryover effects had profound implications for population persistence and must be considered in risk assessment, conservation, and management decisions for pollinators to mitigate the effects of insecticide exposure.
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Prouty C, Barriga P, Davis AK, Krischik V, Altizer S. Host Plant Species Mediates Impact of Neonicotinoid Exposure to Monarch Butterflies. INSECTS 2021; 12:insects12110999. [PMID: 34821799 PMCID: PMC8623494 DOI: 10.3390/insects12110999] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/12/2021] [Revised: 10/27/2021] [Accepted: 11/02/2021] [Indexed: 11/16/2022]
Abstract
Simple Summary Neonicotinoids are the most widely used insecticides in North America and many studies document the negative effects of neonicotinoids on bees. Monarch butterflies are famous for their long-distance migrations, and for their ability to sequester toxins from their milkweed host plants. The neonicotinoids imidacloprid and clothianidin were suggested to correlate with declines in North American monarchs. We examined how monarch development, survival, and flight were affected by exposure to neonicotinoids, and how these effects depend on milkweed host plant species that differ in their cardenolide toxins. Monarch survival and flight were unaffected by low and intermediate neonicotinoid doses. At the highest dose, neonicotinoids negatively affected monarch pupation and survival, for caterpillars that fed on the least toxic milkweed. Monarchs fed milkweed of intermediate toxicity experienced moderate negative effects of high insecticide doses. Monarchs fed the most toxic milkweed species had no negative consequences associated with neonicotinoid treatment. Our work shows that monarchs tolerate low neonicotinoid doses, but experience detrimental effects at higher doses, depending on milkweed species. To our knowledge, this is the first study to show that host plant species potentially reduce the residue of neonicotinoid insecticides on the leaf surface, and this phenomenon warrants further investigation. Abstract Neonicotinoids are the most widely used insecticides in North America. Numerous studies document the negative effects of neonicotinoids on bees, and it remains crucial to demonstrate if neonicotinoids affect other non-target insects, such as butterflies. Here we examine how two neonicotinoids (imidacloprid and clothianidin) affect the development, survival, and flight of monarch butterflies, and how these chemicals interact with the monarch’s milkweed host plant. We first fed caterpillars field-relevant low doses (0.075 and 0.225 ng/g) of neonicotinoids applied to milkweed leaves (Asclepias incarnata), and found no significant reductions in larval development rate, pre-adult survival, or adult flight performance. We next fed larvae higher neonicotinoid doses (4–70 ng/g) and reared them on milkweed species known to produce low, moderate, or high levels of secondary toxins (cardenolides). Monarchs exposed to the highest dose of clothianidin (51–70 ng/g) experienced pupal deformity, low survival to eclosion, smaller body size, and weaker adult grip strength. This effect was most evident for monarchs reared on the lowest cardenolide milkweed (A. incarnata), whereas monarchs reared on the high-cardenolide A. curassavica showed no significant reductions in any variable measured. Our results indicate that monarchs are tolerant to low doses of neonicotinoid, and that negative impacts of neonicotinoids depend on host plant type. Plant toxins may confer protective effects or leaf physical properties may affect chemical retention. Although neonicotinoid residues are ubiquitous on milkweeds in agricultural and ornamental settings, commonly encountered doses below 50 ng/g are unlikely to cause substantial declines in monarch survival or migratory performance.
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Affiliation(s)
- Cody Prouty
- Odum School of Ecology, University of Georgia, Athens, GA 30602, USA; (P.B.); (A.K.D.); (S.A.)
- Correspondence:
| | - Paola Barriga
- Odum School of Ecology, University of Georgia, Athens, GA 30602, USA; (P.B.); (A.K.D.); (S.A.)
| | - Andrew K. Davis
- Odum School of Ecology, University of Georgia, Athens, GA 30602, USA; (P.B.); (A.K.D.); (S.A.)
| | - Vera Krischik
- Department of Entomology, University of Minnesota, St. Paul, MN 55108, USA;
| | - Sonia Altizer
- Odum School of Ecology, University of Georgia, Athens, GA 30602, USA; (P.B.); (A.K.D.); (S.A.)
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Grant TJ, Krishnan N, Bradbury SP. Conservation risks and benefits of establishing monarch butterfly (Danaus plexippus) breeding habitats close to maize and soybean fields in the north central United States: A landscape-scale analysis of the impact of foliar insecticide on nonmigratory monarch butterfly populations. INTEGRATED ENVIRONMENTAL ASSESSMENT AND MANAGEMENT 2021; 17:989-1002. [PMID: 33629511 DOI: 10.1002/ieam.4402] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/13/2020] [Revised: 12/30/2020] [Accepted: 02/22/2021] [Indexed: 06/12/2023]
Abstract
Establishing habitat in agricultural landscapes of the north central United States is critical to reversing the decline of North America's eastern monarch butterfly (Danaus plexippus) population. Insecticide use could create population sinks and threaten recovery. Discouraging habitat establishment within a 38-m zone around crop fields is a suggested risk mitigation measure. In Story County, Iowa, United States, this mitigation would discourage habitat establishment in 84% of roadsides and 38% of noncrop land. It is unclear if the conservation benefits from establishing habitat close to crop fields outweigh suppression of population growth owing to insecticide exposure. Consequently, monarch conservation plans require spatially and temporally explicit landscape-scale assessments. Using an agent-based model that incorporates female monarch movement and egg laying, the number and location of eggs laid in Story County were simulated for four habitat scenarios: current condition, maximum new establishment, moderate establishment, and moderate establishment only outside a 38-m no-plant zone around crop fields. A demographic model incorporated mortality from natural causes and insecticide exposure to simulate adult monarch production over 10 years. Assuming no insecticide exposure, simulated adult production increased 24.7% and 9.3%, respectively, with maximum and moderate habitat establishment and no planting restrictions. A 3.5% increase was simulated assuming moderate habitat establishment with a 38-m planting restriction. Impacts on adult production were simulated for six representative insecticides registered for soybean aphid (Aphis glycines) management. Depending on the frequency of insecticide applications over a 10-year period, simulated production increased 8.2%-9.3%, assuming moderate habitat establishment with no planting restrictions. Results suggest that the benefits of establishing habitat close to crop fields outweigh the adverse effects of insecticide spray drift; that is, metapopulation extirpation is not a concern for monarchs. These findings are only applicable to species that move at spatial scales greater than the scale of potential spray-drift impacts. Integr Environ Assess Manag 2021;17:989-1002. © 2021 The Authors. Integrated Environmental Assessment and Management published by Wiley Periodicals LLC on behalf of Society of Environmental Toxicology & Chemistry (SETAC).
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Affiliation(s)
- Tyler J Grant
- Department of Natural Resource Ecology and Management, Iowa State University, Ames, Iowa, USA
| | - Niranjana Krishnan
- Toxicology Program and Department of Entomology, Iowa State University, Ames, Iowa, USA
| | - Steven P Bradbury
- Department of Natural Resource Ecology and Management, Iowa State University, Ames, Iowa, USA
- Toxicology Program and Department of Entomology, Iowa State University, Ames, Iowa, USA
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Krishnan N, Zhang Y, Aust ME, Hellmich RL, Coats JR, Bradbury SP. Monarch Butterfly (Danaus plexippus) Life-Stage Risks from Foliar and Seed-Treatment Insecticides. ENVIRONMENTAL TOXICOLOGY AND CHEMISTRY 2021; 40:1761-1777. [PMID: 33590905 DOI: 10.1002/etc.5016] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/12/2020] [Revised: 01/05/2021] [Accepted: 02/11/2021] [Indexed: 06/12/2023]
Abstract
Conservation of North America's eastern monarch butterfly (Danaus plexippus) population would require establishment of milkweed (Asclepias spp.) and nectar plants in the agricultural landscapes of the north central United States. A variety of seed-treatment and foliar insecticides are used to manage early- and late-season pests in these landscapes. Thus, there is a need to assess risks of these insecticides to monarch butterfly life stages to inform habitat conservation practices. Chronic and acute dietary toxicity studies were undertaken with larvae and adults, and acute topical bioassays were conducted with eggs, pupae, and adults using 6 representative insecticides: beta-cyfluthrin (pyrethroid), chlorantraniliprole (anthranilic diamide), chlorpyrifos (organophosphate), imidacloprid, clothianidin, and thiamethoxam (neonicotinoids). Chronic dietary median lethal concentration values for monarch larvae ranged from 1.6 × 10-3 (chlorantraniliprole) to 5.3 (chlorpyrifos) μg/g milkweed leaf, with the neonicotinoids producing high rates of arrested pupal ecdysis. Chlorantraniliprole and beta-cyfluthrin were generally the most toxic insecticides to all life stages, and thiamethoxam and chlorpyrifos were generally the least toxic. The toxicity results were compared to insecticide exposure estimates derived from a spray drift model and/or milkweed residue data reported in the literature. Aerial applications of foliar insecticides are expected to cause high downwind mortality in larvae and eggs, with lower mortality predicted for adults and pupae. Neonicotinoid seed treatments are expected to cause little to no downslope mortality and/or sublethal effects in larvae and adults. Given the vagile behavior of nonmigratory monarchs, considering these results within a landscape-scale context suggests that adult recruitment will not be negatively impacted if new habitat is established in close proximity of maize and soybean fields in the agricultural landscapes of the north central United States. Environ Toxicol Chem 2021;40:1761-1777. © 2021 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC.
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Affiliation(s)
- Niranjana Krishnan
- Toxicology Program and Department of Entomology, Iowa State University, Ames, Iowa, USA
| | - Yang Zhang
- Beijing Great-Agri Institute of Pesticide Technology, Beijing, China
| | - Melanie E Aust
- Conservation Corp Minnesota and Iowa, Granger, Iowa, USA
| | - Richard L Hellmich
- US Department of Agriculture, Agricultural Research Service, Corn Insects and Crop Genetics Research Unit, Ames, Iowa, USA
| | - Joel R Coats
- Toxicology Program and Department of Entomology, Iowa State University, Ames, Iowa, USA
| | - Steven P Bradbury
- Toxicology Program and Department of Entomology, Iowa State University, Ames, Iowa, USA
- Department of Natural Resource Ecology and Management, Iowa State University, Ames, Iowa, USA
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Butterfly Conservation in China: From Science to Action. INSECTS 2020; 11:insects11100661. [PMID: 32992975 PMCID: PMC7600441 DOI: 10.3390/insects11100661] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/23/2020] [Revised: 09/20/2020] [Accepted: 09/22/2020] [Indexed: 12/26/2022]
Abstract
About 10% of the Earth's butterfly species inhabit the highly diverse ecosystems of China. Important for the ecological, economic, and cultural services they provide, many butterfly species experience threats from land use shifts and climate change. China has recently adopted policies to protect the nation's biodiversity resources. This essay examines the current management of butterflies in China and suggests various easily implementable actions that could improve these conservation efforts. Our recommendations are based on the observations of a transdisciplinary group of entomologists and environmental policy specialists. Our analysis draws on other successful examples around the world that China may wish to consider. China needs to modify its scientific methodologies behind butterfly conservation management: revising the criteria for listing protected species, focusing on umbrella species for broader protection, identifying high priority areas and refugia for conservation, among others. Rural and urban land uses that provide heterogeneous habitats, as well as butterfly host and nectar plants, must be promoted. Butterfly ranching and farming may also provide opportunities for sustainable community development. Many possibilities exist for incorporating observations of citizen scientists into butterfly data collection at broad spatial and temporal scales. Our recommendations further the ten Priority Areas of China's National Biodiversity Conservation Strategy and Action Plan (2011-2030).
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