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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 considerd 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:
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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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%.
Click here to view a table of results for each participant
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%.
Click here to view a table of results for each participant
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