Host Plant Species Mediates Impact of Neonicotinoid Exposure to Monarch Butterflies
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 (imida...
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| Format: | Article |
| Language: | English |
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MDPI AG
2021-11-01
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| Series: | Insects |
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| Online Access: | https://www.mdpi.com/2075-4450/12/11/999 |
| _version_ | 1797509964718145536 |
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| author | Cody Prouty Paola Barriga Andrew K. Davis Vera Krischik Sonia Altizer |
| author_facet | Cody Prouty Paola Barriga Andrew K. Davis Vera Krischik Sonia Altizer |
| author_sort | Cody Prouty |
| collection | DOAJ |
| description | 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 (<i>Asclepias incarnata</i>), 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 (<i>A. incarnata</i>), whereas monarchs reared on the high-cardenolide <i>A. curassavica</i> 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. |
| first_indexed | 2024-03-10T05:25:12Z |
| format | Article |
| id | doaj.art-f69c14e5cbe041e18bc57d490ece9d21 |
| institution | Directory Open Access Journal |
| issn | 2075-4450 |
| language | English |
| last_indexed | 2024-03-10T05:25:12Z |
| publishDate | 2021-11-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Insects |
| spelling | doaj.art-f69c14e5cbe041e18bc57d490ece9d212023-11-22T23:46:58ZengMDPI AGInsects2075-44502021-11-01121199910.3390/insects12110999Host Plant Species Mediates Impact of Neonicotinoid Exposure to Monarch ButterfliesCody Prouty0Paola Barriga1Andrew K. Davis2Vera Krischik3Sonia Altizer4Odum School of Ecology, University of Georgia, Athens, GA 30602, USAOdum School of Ecology, University of Georgia, Athens, GA 30602, USAOdum School of Ecology, University of Georgia, Athens, GA 30602, USADepartment of Entomology, University of Minnesota, St. Paul, MN 55108, USAOdum School of Ecology, University of Georgia, Athens, GA 30602, USANeonicotinoids 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 (<i>Asclepias incarnata</i>), 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 (<i>A. incarnata</i>), whereas monarchs reared on the high-cardenolide <i>A. curassavica</i> 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.https://www.mdpi.com/2075-4450/12/11/999clothianidinimidacloprid<i>Danaus plexippus</i>sub-lethal effectstoxicity<i>Asclepias</i> |
| spellingShingle | Cody Prouty Paola Barriga Andrew K. Davis Vera Krischik Sonia Altizer Host Plant Species Mediates Impact of Neonicotinoid Exposure to Monarch Butterflies Insects clothianidin imidacloprid <i>Danaus plexippus</i> sub-lethal effects toxicity <i>Asclepias</i> |
| title | Host Plant Species Mediates Impact of Neonicotinoid Exposure to Monarch Butterflies |
| title_full | Host Plant Species Mediates Impact of Neonicotinoid Exposure to Monarch Butterflies |
| title_fullStr | Host Plant Species Mediates Impact of Neonicotinoid Exposure to Monarch Butterflies |
| title_full_unstemmed | Host Plant Species Mediates Impact of Neonicotinoid Exposure to Monarch Butterflies |
| title_short | Host Plant Species Mediates Impact of Neonicotinoid Exposure to Monarch Butterflies |
| title_sort | host plant species mediates impact of neonicotinoid exposure to monarch butterflies |
| topic | clothianidin imidacloprid <i>Danaus plexippus</i> sub-lethal effects toxicity <i>Asclepias</i> |
| url | https://www.mdpi.com/2075-4450/12/11/999 |
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