Exposure to Non-Native Tropical Milkweed Promotes Reproductive Development in Migratory Monarch Butterflies
Background: North American monarchs (<i>Danaus plexippus</i>) are well-known for their long-distance migrations; however, some monarchs within the migratory range have adopted a resident lifestyle and breed year-round at sites where tropical milkweed (<i>Asclepias curassavica</i...
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| Format: | Article |
| Language: | English |
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MDPI AG
2019-08-01
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| Series: | Insects |
| Subjects: | |
| Online Access: | https://www.mdpi.com/2075-4450/10/8/253 |
| _version_ | 1819090254507802624 |
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| author | Ania A. Majewska Sonia Altizer |
| author_facet | Ania A. Majewska Sonia Altizer |
| author_sort | Ania A. Majewska |
| collection | DOAJ |
| description | Background: North American monarchs (<i>Danaus plexippus</i>) are well-known for their long-distance migrations; however, some monarchs within the migratory range have adopted a resident lifestyle and breed year-round at sites where tropical milkweed (<i>Asclepias curassavica</i>) is planted in the southern coastal United States. An important question is whether exposure to exotic milkweed alters monarch migratory physiology, particularly the ability to enter and remain in the hormonally-induced state of reproductive diapause, whereby adults delay reproductive maturity. Cued by cooler temperatures and shorter photoperiods, diapause is a component of the monarch’s migratory syndrome that includes directional flight behavior, lipid accumulation, and the exceptional longevity of the migratory generation. Methods: Here, we experimentally test how exposure to tropical milkweed during the larval and adult stages influences monarch reproductive status during fall migration. Caterpillars reared under fall-like conditions were fed tropical versus native milkweed diets, and wild adult migrants were placed in outdoor flight cages with tropical milkweed, native milkweed, or no milkweed. Results: We found that monarchs exposed to tropical milkweed as larvae were more likely to be reproductively active (exhibit mating behavior in males and develop mature eggs in females) compared to monarchs exposed to native milkweed. Among wild-caught fall migrants, females exposed to tropical milkweed showed greater egg development than females exposed to native or no milkweed, although a similar response was not observed for males. Conclusions: Our study provides evidence that exposure to tropical milkweed can increase monarch reproductive activity, which could promote continued residency at year-round breeding sites and decrease monarch migratory propensity. |
| first_indexed | 2024-12-21T22:20:54Z |
| format | Article |
| id | doaj.art-76a194cc3e3d4da9bd41352b015e1096 |
| institution | Directory Open Access Journal |
| issn | 2075-4450 |
| language | English |
| last_indexed | 2024-12-21T22:20:54Z |
| publishDate | 2019-08-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Insects |
| spelling | doaj.art-76a194cc3e3d4da9bd41352b015e10962022-12-21T18:48:21ZengMDPI AGInsects2075-44502019-08-0110825310.3390/insects10080253insects10080253Exposure to Non-Native Tropical Milkweed Promotes Reproductive Development in Migratory Monarch ButterfliesAnia A. Majewska0Sonia Altizer1Odum School of Ecology, University of Georgia, Athens, GA 30602, USAOdum School of Ecology, University of Georgia, Athens, GA 30602, USABackground: North American monarchs (<i>Danaus plexippus</i>) are well-known for their long-distance migrations; however, some monarchs within the migratory range have adopted a resident lifestyle and breed year-round at sites where tropical milkweed (<i>Asclepias curassavica</i>) is planted in the southern coastal United States. An important question is whether exposure to exotic milkweed alters monarch migratory physiology, particularly the ability to enter and remain in the hormonally-induced state of reproductive diapause, whereby adults delay reproductive maturity. Cued by cooler temperatures and shorter photoperiods, diapause is a component of the monarch’s migratory syndrome that includes directional flight behavior, lipid accumulation, and the exceptional longevity of the migratory generation. Methods: Here, we experimentally test how exposure to tropical milkweed during the larval and adult stages influences monarch reproductive status during fall migration. Caterpillars reared under fall-like conditions were fed tropical versus native milkweed diets, and wild adult migrants were placed in outdoor flight cages with tropical milkweed, native milkweed, or no milkweed. Results: We found that monarchs exposed to tropical milkweed as larvae were more likely to be reproductively active (exhibit mating behavior in males and develop mature eggs in females) compared to monarchs exposed to native milkweed. Among wild-caught fall migrants, females exposed to tropical milkweed showed greater egg development than females exposed to native or no milkweed, although a similar response was not observed for males. Conclusions: Our study provides evidence that exposure to tropical milkweed can increase monarch reproductive activity, which could promote continued residency at year-round breeding sites and decrease monarch migratory propensity.https://www.mdpi.com/2075-4450/10/8/253<i>Asclepias curassavica</i><i>Danaus plexippus</i>gardenreproductive diapausephysiologymigrationsedentary |
| spellingShingle | Ania A. Majewska Sonia Altizer Exposure to Non-Native Tropical Milkweed Promotes Reproductive Development in Migratory Monarch Butterflies Insects <i>Asclepias curassavica</i> <i>Danaus plexippus</i> garden reproductive diapause physiology migration sedentary |
| title | Exposure to Non-Native Tropical Milkweed Promotes Reproductive Development in Migratory Monarch Butterflies |
| title_full | Exposure to Non-Native Tropical Milkweed Promotes Reproductive Development in Migratory Monarch Butterflies |
| title_fullStr | Exposure to Non-Native Tropical Milkweed Promotes Reproductive Development in Migratory Monarch Butterflies |
| title_full_unstemmed | Exposure to Non-Native Tropical Milkweed Promotes Reproductive Development in Migratory Monarch Butterflies |
| title_short | Exposure to Non-Native Tropical Milkweed Promotes Reproductive Development in Migratory Monarch Butterflies |
| title_sort | exposure to non native tropical milkweed promotes reproductive development in migratory monarch butterflies |
| topic | <i>Asclepias curassavica</i> <i>Danaus plexippus</i> garden reproductive diapause physiology migration sedentary |
| url | https://www.mdpi.com/2075-4450/10/8/253 |
| work_keys_str_mv | AT aniaamajewska exposuretononnativetropicalmilkweedpromotesreproductivedevelopmentinmigratorymonarchbutterflies AT soniaaltizer exposuretononnativetropicalmilkweedpromotesreproductivedevelopmentinmigratorymonarchbutterflies |