Further Insights on the Migration Biology of Monarch Butterflies, Danaus plexippus (Lepidoptera: Nymphalidae) from the Pacific Northwest

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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Effects of the Protozoan Parasite Ophryocystis elektroscirrha on the Fitness of Monarch Butterflies (Danaus plexippus)

Journal of Invertebrate Pathology ◽

10.1006/jipa.1999.4853 ◽

1999 ◽

Vol 74 (1) ◽

pp. 76-88 ◽

Cited By ~ 80

Author(s):

Sonia M. Altizer ◽

Karen S. Oberhauser

Keyword(s):

Danaus Plexippus ◽

Protozoan Parasite ◽

Monarch Butterflies ◽

Ophryocystis Elektroscirrha

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Citizen Scientist Tagging Reveals Destinations of Migrating Monarch Butterflies,Danaus plexippus(L.) from the Pacific Northwest

Journal of the Lepidopterists’ Society ◽

10.18473/lepi.v72i2.a5 ◽

2018 ◽

Vol 72 (2) ◽

pp. 127-144 ◽

Cited By ~ 8

Author(s):

David G. James ◽

Tanya S. James ◽

Lorraine Seymour ◽

Linda Kappen ◽

Tamara Russell ◽

...

Keyword(s):

Pacific Northwest ◽

Danaus Plexippus ◽

Monarch Butterflies ◽

Citizen Scientist ◽

The Pacific

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The occurrence and effect of a protozoan parasite, Ophryocystis elektroscirrha (Neogregarinida: Ophryocystidae) on overwintering monarch butterflies, Danaus plexippus (Lepidoptera: Danaidae) from two California winter sites

Ecological Entomology ◽

10.1111/j.1365-2311.1992.tb01067.x ◽

1992 ◽

Vol 17 (4) ◽

pp. 338-342 ◽

Cited By ~ 25

Author(s):

K. L. H. LEONG ◽

H. K. KAYA ◽

M. A. YOSHIMURA ◽

D. F. FREY

Keyword(s):

Danaus Plexippus ◽

Protozoan Parasite ◽

Monarch Butterflies ◽

Ophryocystis Elektroscirrha

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Lipid reserves and immune defense in healthy and diseased migrating monarchs Danaus plexippus

Current Zoology ◽

10.1093/czoolo/59.3.393 ◽

2013 ◽

Vol 59 (3) ◽

pp. 393-402 ◽

Cited By ~ 14

Author(s):

Dara A. Satterfield ◽

Amy E. Wright ◽

Sonia Altizer

Keyword(s):

Danaus Plexippus ◽

Protozoan Parasite ◽

Parasite Load ◽

Immune Defense ◽

Eastern North America ◽

Energy Reserves ◽

Long Distance ◽

Phenoloxidase Activity ◽

Weak Support ◽

Ophryocystis Elektroscirrha

Abstract Recent studies suggest that the energetic demands of long-distance migration might lower the pool of resources available for costly immune defenses. Moreover, migration could amplify the costs of parasitism if animals suffering from parasite-induced damage or depleted energy reserves are less able to migrate long distances. We investigated relationships between long-distance migration, infection, and immunity in wild fall-migrating monarch butterflies Danaus plexippus. Monarchs migrate annually from eastern North America to central Mexico, accumulating lipids essential for migration and winter survival as they travel southward. Monarchs are commonly infected by the debilitating protozoan parasite Ophryocystis elektroscirrha (OE). We collected data on lipid reserves, parasite loads, and two immune measures (hemocyte concentration and phenoloxidase activity) from wild monarchs migrating through north GA (USA) to ask whether (1) parasite infection negatively affects lipid reserves, and (2) greater investment in lipid reserves is associated with lower immune measures. Results showed that monarchs sampled later in the fall migration had lower but not significantly different immune measures and significantly higher lipid reserves than those sampled earlier. Lipid measures correlated negatively but only nearly significantly with one measure of immune defense (phenoloxidase activity) in both healthy and infected monarchs, but did not depend on monarch infection status or parasite load. These results provide weak support for a trade-off between energy reserves and immune defense in migrants, and suggest that previously-demonstrated costs of OE infection for monarch migration are not caused by depleted lipid reserves.

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Western North American Monarchs: Spiraling into Oblivion or Adapting to a Changing Environment?

Animal Migration ◽

10.1515/ami-2021-0002 ◽

2021 ◽

Vol 8 (1) ◽

pp. 19-26

Author(s):

David G James

Keyword(s):

Pacific Northwest ◽

San Francisco ◽

San Francisco Bay ◽

San Francisco Bay Area ◽

Breeding Population ◽

Daily Maximum ◽

Monarch Butterflies ◽

Bay Area ◽

The Pacific ◽

Winter Breeding

Abstract Monarch butterflies in western North America typically migrate each fall from the Pacific Northwest to overwintering sites in California. Winter 2020/21 saw the lowest number of overwintering western monarch butterflies ever recorded, but was also marked by a winter-breeding population in the San Francisco bay area that appeared to be the largest ever seen. Recoveries of monarchs with wing tags from the Pacific Northwest suggested that many non-reproductive migrants in fall 2020 became reproductive in the San Francisco bay area and did not reach coastal overwintering sites. Mean daily maximum temperatures for San Francisco during fall and winter increased by ~1 °C during the past decade and were 2.5 °C above the 30 year mean during September-October 2020. Warm fall and winter temperatures along with the availability of non-native milkweeds likely caused the increase in winter breeding in winter 2020/21. The outcome of continued winter-breeding in the San Francisco bay area is uncertain. Whether it becomes a sink or source will be dependent on whether winter-breeding monarchs can re-enter their migratory state during spring. However, endemic levels of infection by the protozoan parasite, Ophryocystis elektroscirrha (OE), are often high in winter-breeding monarchs which can limit migration success. The eventual co-existence of winter-breeding and non-breeding monarch populations in northern and central California is probable, with an optimistic view suggesting that the adaptability of the monarch butterfly will allow it to persist in a changed environment.

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