BRS Sonia Altizer: Migrating Monarchs and Disease Dynamics in a Warming World

https://ubc.zoom.us/rec/share/RZZwqTHhKdn_pGB5ItobTbwSnRPfcJAz5lU9qOAGrY3JOze_1BFQsZkJfyEmtExU.yUygjrDbHGFV5O8i

Passcode: b*UtuLm4 

host: Jonathan Davies

Title talk: Migrating Monarchs and Disease Dynamics in a Warming World
 

Abstract: Migratory animals undertake seasonal and often spectacular movements that connect ecosystems across space and time and provide important ecosystem services. Yet human activities are altering migration in many species: animals may travel shorter distances, arrive earlier in spring, or form resident populations where they were once migratory. Such changes in movement behavior can profoundly affect infectious disease dynamics. Migratory animals can transport pathogens across vast distances, but migration can also reduce disease risk by separating animals from contaminated environments or disrupting pathogen transmission. This talk examines how changing migration shapes infection dynamics, with a particular focus on the monarch butterfly and its debilitating protozoan parasite, Ophryocystis elektroscirrha (OE).

Field, modeling, and experimental studies during the past two decades show how environmental change can alter the balance between migratory and resident monarch populations. Mild winters and human planting of non-native milkweeds have created opportunities for year-round breeding in the southern United States. Resident monarchs experience high levels of OE infection and can serve as sources of infection for migratory populations, potentially altering disease dynamics across the annual cycle. Coupled migrant–resident interactions further suggest that changes in residency can influence both future monarch abundance and infection patterns. Climate warming introduces additional complexity because temperature affects hosts and parasites through multiple, often nonlinear pathways. Experimental studies of monarchs and OE show that warming has contrasting effects on host performance, parasite development, and infection, underscoring the importance of considering host and parasite thermal biology together.

Together, these findings illustrate how environmental change can reshape migration and parasite infection across scales of organization, from individual physiology to population-level and regional dynamics. As monarchs and other migratory species respond to a rapidly changing climate, understanding feedbacks between movement, residency, and infection will be critical for predicting the future of animal migrations in a changing world. 

Short biography: