Award Abstract # 1754431
Collaborative Research: How do shifts from migratory to sedentary behavior alter host-parasite dynamics?

NSF Org: DEB
Division Of Environmental Biology
Recipient: EMORY UNIVERSITY
Initial Amendment Date: May 9, 2018
Latest Amendment Date: May 9, 2018
Award Number: 1754431
Award Instrument: Standard Grant
Program Manager: Kari Segraves
DEB
 Division Of Environmental Biology
BIO
 Directorate for Biological Sciences
Start Date: June 1, 2018
End Date: May 31, 2022 (Estimated)
Total Intended Award Amount: $378,459.00
Total Awarded Amount to Date: $378,459.00
Funds Obligated to Date: FY 2018 = $378,459.00
History of Investigator:
  • Jacobus de Roode (Principal Investigator)
    jderood@emory.edu
Recipient Sponsored Research Office: Emory University
201 DOWMAN DR NE
ATLANTA
GA  US  30322-1061
(404)727-2503
Sponsor Congressional District: 05
Primary Place of Performance: Emory University
GA  US  30322-4250
Primary Place of Performance
Congressional District:
05
Unique Entity Identifier (UEI): S352L5PJLMP8
Parent UEI:
NSF Program(s): POP & COMMUNITY ECOL PROG
Primary Program Source: 01001819DB NSF RESEARCH & RELATED ACTIVIT
Program Reference Code(s):
Program Element Code(s): 118200
Award Agency Code: 4900
Fund Agency Code: 4900
Assistance Listing Number(s): 47.074

ABSTRACT

Every year, billions of animals migrate long distances. If animals with parasites are less likely to reach their destinations, then migration may allow populations to escape habitats where parasites build up over time. Understanding how animal migration affects the spread of disease is important to predicting disease risk, including to humans. This study focuses on monarch butterflies as a model system and explores the impacts of parasites on butterfly populations that migrate and populations that have recently lost their migratory habits. This study will also examine how non-migrating populations may influence the risk of having parasites by the migrating forms in areas where they come together. Field and experimental studies will also examine how these microscopic parasites influence how long butterflies live and their flight ability. Through the high visibility and public appeal of monarchs, this project will support the participation of citizen scientists on a continental scale. The investigators will also mentor and train undergraduate and graduate students and will develop web and classroom based educational materials on host-parasite relationships and animal migration. This work will provide additional opportunities for middle school students and support k-12 activities. Finally, this work will inform efforts to conserve monarch butterflies and our understanding of how migration may influence the importance of parasites across many systems.

Using a monarch butterflies and protozoan parasite system, the goal of this study is to examine how migratory and sedentary behaviors influence transmission risk and severity of infection. Research activities will integrate (i) an analysis of continent-wide citizen science databases to monitor monarch butterfly abundance and infection; (ii) field and experimental studies to test how monarch migratory behavior depends on non-native milkweeds and infection status, and to quantify parasite transmission rates; (iii) molecular genomics to ask whether genetic changes in sedentary populations might reinforce the loss of migratory behavior; and (iv) mathematical modeling to track how host and parasite populations respond to migratory vs. sedentary strategies. Information on the mixing of non-migrants and migrants, inferred from stable isotope analyses of field-collected monarchs, will inform mathematical models of interacting sedentary and migratory populations, to explore the consequences for disease spread and the persistence of migratory populations. The project will develop theory for how overlapping migration strategies alter, and are themselves affected by, parasite infection, and will shed light on the evolution of migration by characterizing genetic changes that accompany the recent formation of sedentary populations.

This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

PUBLICATIONS PRODUCED AS A RESULT OF THIS RESEARCH

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Alaidrous, Wajd and Villa, Scott M. and de Roode, Jacobus C. and Majewska, Ania A. "Crowding does not affect monarch butterflies resistance to a protozoan parasite" Ecology and Evolution , v.12 , 2022 https://doi.org/10.1002/ece3.8791 Citation Details
Majewska, Ania A. and Davis, Andrew K. and Altizer, Sonia and de Roode, Jacobus C. "Parasite dynamics in North American monarchs predicted by host density and seasonal migratory culling" Journal of Animal Ecology , v.91 , 2022 https://doi.org/10.1111/1365-2656.13678 Citation Details
Talla, Venkat and Pierce, Amanda A. and Adams, Kandis L. and de Man, Tom J. and Nallu, Sumitha and Villablanca, Francis X. and Kronforst, Marcus R. and de Roode, Jacobus C. "Genomic evidence for gene flow between monarchs with divergent migratory phenotypes and flight performance" Molecular Ecology , 2020 https://doi.org/10.1111/mec.15508 Citation Details

PROJECT OUTCOMES REPORT

Disclaimer

This Project Outcomes Report for the General Public is displayed verbatim as submitted by the Principal Investigator (PI) for this award. Any opinions, findings, and conclusions or recommendations expressed in this Report are those of the PI and do not necessarily reflect the views of the National Science Foundation; NSF has not approved or endorsed its content.

Billions of animals undertake spectacular annual migrations, moving between different areas, and sometimes traveling thousands of miles. Parasites could have a major impact on animal migration, with infected animals being unable to complete their journey. As a result, migration could also help a population keep parasites at bay, by weeding out infected individuals on an annual basis. In this project, the researchers studied the impact of migration on parasitism in monarch butterflies. In North America, monarchs migrate from the eastern United States and Canada to overwintering sites in Mexico. Monarchs from west of the Rocky Mountains migrate to the California west coast instead. As part of this project, the researchers found that the prevalence of a debilitating protozoan parasite has risen from less than 1% in the 1960?s to around 10% at present. The researchers found that migration itself can reduce parasite prevalence, by weeding out infected monarchs as they try to migrate to their overwintering sites. However, because parasite prevalence has increased so much, the researchers estimate that tens of millions of monarchs can no longer complete their journey each year. The increased parasite prevalence could be due to increased local densities of monarchs at breeding sites. Monarchs have formed such non-migratory populations along the coast of the Gulf of Mexico and the Atlantic Coast, increasing caterpillar density and parasite prevalence. Experimental studies showed that the increased densities can increase transmission of parasites, but surprisingly can also reduce the disease suffered by individual monarchs: this is because competitor caterpillars can eat up the parasite spores that infected monarchs scatter onto shared milkweed host plants. Genetic analyses suggest that these newly formed sedentary populations are not much different from migratory monarchs, which indicates that ecological factors, such as the planting of exotic milkweed and warming temperatures, are responsible for the cessation in migration, rather than evolved genetic changes. This project has trained multiple postdocs and undergraduate students, and researchers have presented results at monarch butterfly festivals and school science nights.


Last Modified: 07/01/2022
Modified by: Jacobus De Roode

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