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Naujokaitis-Lewis I, Endicott S, Gaudreault E, Maisonneuve F, Robinson SA. Milkweed in agricultural field margins - A neonicotinoid exposure route for pollinators at multiple life stages. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 951:175622. [PMID: 39163943 DOI: 10.1016/j.scitotenv.2024.175622] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/10/2024] [Revised: 08/15/2024] [Accepted: 08/16/2024] [Indexed: 08/22/2024]
Abstract
Neonicotinoid insecticides move from targeted crops to wildflowers located in adjacent field margins, acting as a potential exposure source for wild pollinators and insect species of conservation concern, including monarch butterflies. Monarchs rely on milkweed over multiple life stages, including as a host plant for eggs and a food source for both larvae (leaves) and adults (flowers). Milkweeds, which are closely associated with field margins, can contain neonicotinoid residues, but previous assessments are constrained to a single plant tissue type. In 2017 and 2018, we sampled milkweeds from 95 field margins adjacent to crop fields (corn, soybean, hay, wheat, and barley) in agricultural landscapes of eastern Ontario, Canada. Milkweeds were sampled during the flower blooming period and leaves and flower tissues were analysed. The neonicotinoids acetamiprid, clothianidin, thiamethoxam, and thiacloprid were detected. Maximum concentrations in leaf samples included 10.30 ng/g of clothianidin in 2017, and 24.4 ng/g of thiamethoxam in 2018. Clothianidin and thiamethoxam percent detections in flowers (72 % and 61 %, respectively) were significantly higher than detections in leaves (24 % and 31 %, respectively). Thiamethoxam concentrations were significantly higher in paired flower samples than leaf samples (median 0.33 ng/g vs <0.07 ng/g) while clothianidin concentrations also trended higher in flowers (median 0.18-0.55 ng/g vs <0.18 ng/g). Only thiamethoxam showed significant differences between years, and we found no effect of crop type, with hay, soybean and corn fields all yielding 50-56 % detections in leaves. We found significantly higher concentrations in older milkweed flowers than young flowers or leaves (medians 0.87 ng/g vs <0.18 ng/g and 0.45 ng/g vs <0.07 ng/g for clothianidin and thiamethoxam, respectively). Our results highlight the importance of considering variation in milkweed tissue type and age of flowers in neonicotinoid exposure risk assessments. Efforts to increase milkweed availability in agricultural landscapes should consider how exposure to neonicotinoids can be mitigated.
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Affiliation(s)
- Ilona Naujokaitis-Lewis
- Landscape Science and Technology Division, National Wildlife Research Centre, Environment and Climate Change Canada, Ottawa, ON, Canada.
| | - Sarah Endicott
- Landscape Science and Technology Division, National Wildlife Research Centre, Environment and Climate Change Canada, Ottawa, ON, Canada
| | - Emma Gaudreault
- Production Insurance, Business Risk Management Branch, Ministry of Agriculture and Food, Kelowna, BC, Canada
| | - France Maisonneuve
- Ecotoxicology and Wildlife Health Division, National Wildlife Research Centre, Environment and Climate Change Canada, Ottawa, ON, Canada
| | - Stacey A Robinson
- Ecotoxicology and Wildlife Health Division, National Wildlife Research Centre, Environment and Climate Change Canada, Ottawa, ON, Canada.
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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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Mamy L, Pesce S, Sanchez W, Aviron S, Bedos C, Berny P, Bertrand C, Betoulle S, Charles S, Chaumot A, Coeurdassier M, Coutellec MA, Crouzet O, Faburé J, Fritsch C, Gonzalez P, Hedde M, Leboulanger C, Margoum C, Mougin C, Munaron D, Nélieu S, Pelosi C, Rault M, Sucré E, Thomas M, Tournebize J, Leenhardt S. Impacts of neonicotinoids on biodiversity: a critical review. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2023:10.1007/s11356-023-31032-3. [PMID: 38036909 DOI: 10.1007/s11356-023-31032-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/16/2023] [Accepted: 11/08/2023] [Indexed: 12/02/2023]
Abstract
Neonicotinoids are the most widely used class of insecticides in the world, but they have raised numerous concerns regarding their effects on biodiversity. Thus, the objective of this work was to do a critical review of the contamination of the environment (soil, water, air, biota) by neonicotinoids (acetamiprid, clothianidin, imidacloprid, thiacloprid, thiamethoxam) and of their impacts on terrestrial and aquatic biodiversity. Neonicotinoids are very frequently detected in soils and in freshwater, and they are also found in the air. They have only been recently monitored in coastal and marine environments, but some studies already reported the presence of imidacloprid and thiamethoxam in transitional or semi-enclosed ecosystems (lagoons, bays, and estuaries). The contamination of the environment leads to the exposure and to the contamination of non-target organisms and to negative effects on biodiversity. Direct impacts of neonicotinoids are mainly reported on terrestrial invertebrates (e.g., pollinators, natural enemies, earthworms) and vertebrates (e.g., birds) and on aquatic invertebrates (e.g., arthropods). Impacts on aquatic vertebrate populations and communities, as well as on microorganisms, are less documented. In addition to their toxicity to directly exposed organisms, neonicotinoid induce indirect effects via trophic cascades as demonstrated in several species (terrestrial and aquatic invertebrates). However, more data are needed to reach firmer conclusions and to get a clearer picture of such indirect effects. Finally, we identified specific knowledge gaps that need to be filled to better understand the effects of neonicotinoids on terrestrial, freshwater, and marine organisms, as well as on ecosystem services associated with these biotas.
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Affiliation(s)
- Laure Mamy
- Université Paris-Saclay, INRAE, AgroParisTech, UMR ECOSYS, 91120, Palaiseau, France.
| | | | | | | | - Carole Bedos
- Université Paris-Saclay, INRAE, AgroParisTech, UMR ECOSYS, 91120, Palaiseau, France
| | - Philippe Berny
- UR ICE Vetagro Sup, Campus Vétérinaire, 69280, Marcy‑L'Etoile, France
| | - Colette Bertrand
- Université Paris-Saclay, INRAE, AgroParisTech, UMR ECOSYS, 91120, Palaiseau, France
| | - Stéphane Betoulle
- Université de Reims Champagne-Ardenne, Normandie Université, ULH, INERIS, SEBIO, 51100, Reims, France
| | | | | | - Michael Coeurdassier
- Laboratoire Chrono-Environnement, UMR 6249 CNRS-Université de Franche-Comté, 25000, Besançon, France
| | - Marie-Agnès Coutellec
- DECOD (Ecosystem Dynamics and Sustainability), INRAE, L'Institut Agro, Ifremer, 35042, Rennes, France
| | - Olivier Crouzet
- OFB, Direction de la Recherche et Appui Scientifique (DRAS), 78610, Auffargis, France
| | - Juliette Faburé
- Université Paris-Saclay, INRAE, AgroParisTech, UMR ECOSYS, 91120, Palaiseau, France
| | - Clémentine Fritsch
- Laboratoire Chrono-Environnement, UMR 6249 CNRS-Université de Franche-Comté, 25000, Besançon, France
| | - Patrice Gonzalez
- CNRS, Bordeaux INP, EPOC, UMR 5805, Univ. Bordeaux, 33600, Pessac, France
| | - Mickael Hedde
- Eco&Sols, Univ. Montpellier, INRAE, IRD, CIRAD, Institut Agro Montpellier, 34060, Montpellier, France
| | | | | | - Christian Mougin
- Université Paris-Saclay, INRAE, AgroParisTech, UMR ECOSYS, 91120, Palaiseau, France
| | | | - Sylvie Nélieu
- Université Paris-Saclay, INRAE, AgroParisTech, UMR ECOSYS, 91120, Palaiseau, France
| | - Céline Pelosi
- INRAE, Avignon Université, UMR EMMAH, 84000, Avignon, France
| | - Magali Rault
- Université d'Avignon, Université Aix-Marseille, CNRS, IRD, IMBE, Pôle Agrosciences, 84916, Avignon, France
| | - Elliott Sucré
- MARBEC, Univ Montpellier, CNRS, Ifremer, IRD, 34200, Sète, France
- Centre Universitaire de Formation Et de Recherche de Mayotte (CUFR), 97660, Dembeni, Mayotte, France
| | - Marielle Thomas
- Université de Lorraine, INRAE, UR AFPA, 54000, Nancy, France
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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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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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James DG, Kappen L. Further Insights on the Migration Biology of Monarch Butterflies, Danaus plexippus (Lepidoptera: Nymphalidae) from the Pacific Northwest. INSECTS 2021; 12:161. [PMID: 33672834 PMCID: PMC7917764 DOI: 10.3390/insects12020161] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/30/2020] [Revised: 02/05/2021] [Accepted: 02/10/2021] [Indexed: 02/06/2023]
Abstract
The fall migration of monarch butterflies, Danaus plexippus (L.), in the Pacific Northwest was studied during 2017-2019 by tagging 14,040 captive-reared and 450 wild monarchs. One hundred and twenty-two captive-reared monarchs (0.87%) were recovered at distances averaging 899.9 ± 98.6 km for Washington-released and 630.5 ± 19.9 km for Oregon-released monarchs. The greatest straight-line release to recovery distance was 1392.1 km. A mean travel rate of 20.7 ± 2.2 km/day and maximum travel of 46.1 km/day were recorded. Recovery rates were greater for Oregon-released monarchs (0.92%) than Washington-released (0.34%) or Idaho-released monarchs (0.30%). Most monarchs (106/122) were recovered SSW-S-SSE in California, with 82 at 18 coastal overwintering sites. Two migrants from Oregon were recovered just weeks after release ovipositing in Santa Barbara and Palo Alto, CA. Two migrants released in central Washington recovered up to 360.0 km to the SE, and recoveries from Idaho releases to the S and SE suggests that some Pacific Northwest migrants fly to an alternative overwintering destination. Monarchs released in southern Oregon into smoky, poor quality air appeared to be as successful at reaching overwintering sites and apparently lived just as long as monarchs released into non-smoky, good quality air. Migration and lifespan for monarchs infected with the protozoan parasite, Ophryocystis elektroscirrha (McLaughlin and Myers), appeared to be similar to the migration and survival of uninfected monarchs, although data are limited. Our data improve our understanding of western monarch migration, serving as a basis for further studies and providing information for conservation planning.
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Affiliation(s)
- David G. James
- Irrigated Agriculture Research and Extension Center, Department of Entomology, Washington State University, Prosser, WA 99350, USA;
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Saha S, Das S, Sarkar O, Chattopadhyay A, Rissanen K, Sahoo P. Introduction of a luminescent sensor for tracking trace levels of hydrazine in insect pollinated cropland flowers. NEW J CHEM 2021. [DOI: 10.1039/d1nj02661e] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Introduction of an efficient chemodosimeter (NCD) to estimate the mutagenic hydrazine within several affected cropland flowers promptly showing ‘turn-on’ fluorescence.
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Affiliation(s)
- Shrabani Saha
- Department of Chemistry, Visva-Bharati University, Santiniketan, 731235, India
| | - Sujoy Das
- Department of Chemistry, Visva-Bharati University, Santiniketan, 731235, India
| | - Olivia Sarkar
- Department of Zoology, Visva-Bharati University, Santiniketan, 731235, India
| | | | - Kari Rissanen
- Department of Chemistry, University of Jyväskylä, P.O. Box 35, 40014 Jyväskylä, Finland
| | - Prithidipa Sahoo
- Department of Chemistry, Visva-Bharati University, Santiniketan, 731235, India
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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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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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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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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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