About MonarchHealth
Project Participants
Project Results

Overall Participation

From 2006-2013, we examined a total of 17,300 samples from 318 observers across all volunteer locations. Sampling locations spanned 28 different US states and 2 Canadian provinces. Most samples were from monarchs collected from the wild as larvae and reared by volunteers.

We would like to thank all our volunteers for some tremendous sampling efforts--7 of you have sampled all for 8 years with us!!! Special thanks to our 7 volunteers who have sampled all 8 years: Richard Breen, Sondra & Blaize Cabell, Sharon Duerkop, Ilse Gebhard, Cathy Leece, Bruce Parker, and Sharon McCullough.

To look at differences in infection, we have organized the data into 3 regional populations: the western N. American migratory population, the eastern N. American migratory population (Midwest in yellow, Northeast in light purple, and Southeast in green), and the Gulf coast population. Monarchs in the Gulf Coast were separated from the the migrating population because butterflies in these locations could potentially breed year-round and not migrate. The Gulf Coast population includes monarchs in areas 60 miles off the coasts of GA, SC, AL, MS, LA, monarchs 180 miles off the coast of TX, and monarchs in the entire state of Florida.


2013 Results

In 2013, results from 1549 samples received from 88 citizen scientists across 19 states and 2 Canadian provinces indicated that 7.5% of the eastern migratory monarchs, excluding sites where monarchs breed year-round, were infected with O. elektroschirrha across the entire sampling period (May through October). This is a lower than in 2012 when 16.6% of monarchs were infected. Overall, the proportion of infected butterflies decreased throughout the breeding season (from mid-season to late in the breeding season). In contrast, data from past years showed an increase in infected monarchs later in the breeding season, likely due to the building of OE in the environment. The monarch migration in 2013 was also unusual, with monarchs arriving in Mexico later than expected and at historically low numbers; winter 2013 had the lowest number of overwintering monarchs ever recorded. The low number of monarchs may have stopped the buildup of OE in the environment

Volunteers in the southern coastal areas also sampled 396 monarchs at sites where year-round breeding may occur. Monarchs in these areas show a higher OE prevalence than in migratory monarchs. When combining all Monarch Health data for 2013, including the southern coastal areas, prevalence was 26.3% as reported in the newsletter from 2013.

South= Arkansas, North Carolina, Georgia, South Carolina, excluding coastal sites
Northeast=New Jersey, New York, Pennsylvania, Virginia, Ontario
Midwest=Iowa, Illinois, Indiana, Michigan, Minnesota, Ohio, Wisconsin, Manitoba
Sites in southern Ontario were included in Northeast, and sites in Manitoba were included in Midwest just for the purpose of this analysis
Early= April 1-June 30
Middle= July 1-August 15
Late=August 16-October 31

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2013 Newsletter

 

2012 Results

In 2012, results from 1936 samples collected by 56 observers showed that 16.6% of eastern North America monarchs sampled in the breeding season (April-October) were heavily infected with OE. This is a slightly higher percentage than in 2011, which showed a prevalence of 11.2% in eastern monarchs. The results indicate that OE prevalence increased from April through October, as seen in previous years. This patterns shows that monarchs experience a higher risk of OE infection later in the breeding season, as OE might build up in the environment.  

Results from 196 total samples by 3 volunteers from the western United States show an increasing trend of OE prevalence from January through December. Two sites were located in northern Arizona and one site was located in southern California. The increasing OE prevalence throughout the year is most likely due to continuous breeding in non-migratory populations.

*No data available for April-June

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2012 Newsletter

 

Historical Results

From 2006-2010, we examined a total of 9715 samples from 164 observers across all volunteer locations. Sampling locations spanned 27 different US states and 2 Canadian provinces. Most samples were from monarchs collected from the wild as larvae and reared by volunteers.

We would like to thank all our volunteers for some tremendous sampling efforts--9 of you have sampled all for 5 years with us!!!

To look at differences in infection, we have organized the data into 3 regional populations: the western N. American migratory population, the eastern N. American migratory population (Midwest, Northeast, and Southeast sections), and the Gulf coast population. Monarchs in the Gulf Coast were separated from the the migrating population because butterflies in these locations could potentially breed year-round and not migrate. We also separated monarchs captured and sampled west of the Continental Divide, as these are individuals considered part of the western N. American migratory population. As a result, we analyzed data from these different populations to observe trends in parasite infection.

Over the past 5 years, we have observed similar trends in infections levels of O. elektroscirrha in eastern migratory monarchs, with the highest levels of infection in the later part of the breeding season:

2011 Results

In 2011, a total of 78 citizen scientists from 21 states tested over 2,000 wild monarchs for the protozoan parasite Ophryocystis elektroscirrha (OE). In the eastern United States, 11% of monarchs sampled in 2011 were heavily infected with OE. This is lower than in 2010, when 22% of eastern monarchs were heavily infected. In the western U.S. in 2011, only 6% were heavily infected with OE.
     From April through October, the prevalence of OE in the eastern region increased as the breeding season progressed: Eastern monarchs sampled earlier in the year had an infection rate of 8.2%, and monarchs sampled later in the year had an infection rate of 11.7%. This build-up of OE in the eastern U.S. monarchs before fall migration and the decline of OE after migration have been observed in previous years and highlight how migration may enhance monarch population health.

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2011 Newsletter

 

2010 Results

We received the most samples of the history of the program in 2010. Thank you for your participation! Results from 4320 samples showed that across the entire sampling period (from May through October), 29.5% of all eastern migratory monarchs were infected with O. elektroscirrha. The proportion of infected butterflies increased over time throughout the breeding season. Prevalence late in the summer was high similarly across all regions (below). In the Gulf coast population, total prevalence was 48% (from 120 samples) and in the western migratory population, 13.5% were infected (from 59 samples).

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2009 Results

Results from 2388 samples showed that across the entire sampling period (from May through October), 10% of all eastern migratory monarchs were infected with O. elektroscirrha. The proportion of infected butterflies increased over time throughout the breeding season. Prevalence late in the summer was highest in the Northeast (below). In the Gulf coast population, prevalence was 57.3%.

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2008 Results

Results from 1056 samples showed that across the entire sampling period (from May through October), 13.1% of all eastern migratory monarchs were infected with O. elektroscirrha. The proportion of infected butterflies increased over time throughout the breeding season. Prevalence late in the summer was highest in the Northeast (below). In the Gulf coast population, prevalence was 60%.

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2007 Results

Results from 1553 samples showed that across the entire sampling period (from May through October), 24.0% of all eastern migratory monarchs were infected with O. elektroscirrha. The proportion of infected butterflies increased over time throughout the breeding season. Prevalence late in the summer was highest in the Southeast (below). In the western population, prevalence was 44.4%, whereas in the Gulf coast population, prevalence was 64.7%.

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2006 Results

Results from 449 samples showed that across the entire sampling period (from April through October), 10.5% of all eastern migratory monarchs were infected with O. elektroscirrha. The proportion of infected butterflies increased over time throughout the breeding season. Prevalence throughout the summer was highest in the Midwest (below). In the western population, prevalence was 77.8%.

Click here to view a table of results for each participant