Summary Results Draft

In order to ascertain the origin of the monarchs, hydrogen isotope (δ²H ) data was collected, knowing that it decreases northwards. Infected monarchs had higher average δ²H values, showing that such individuals originated in southern latitudes, while those born further north had lower δ²H values. As well, monarchs originated from northern areas had larger forewings, but the correlation between δ²H values and wing area was not significant in infected individuals. Regarding parasite loads, butterflies from southern populations closer to their wintering grounds were more heavily infected. Finally, citizen science data indicates that there is no significant effect of latitude on the odds of infection.