As many as 2 billion monarch butterflies migrate every year to winter in Mexico.
Scientists from the University of Georgia capture and collect these butterflies and, by rigging them to a flying treadmill, study the influence of a common protozoan parasite on their flight performance. Butterflies infected with the parasite -- Ophryocystis elektroscirrha -- fly 20 percent less well than those without it and often drop out during the long-distance journey.
For insects, long distance travel means lower infection rates, which means reducing migration could increase the risk of disease, said Sonia Altizer of the University of Georgia in Athens. Yet human activities, such as habitat disruption, affects their migration patterns, reports NewsHour science correspondent Miles O'Brien.
"If we take their migration away, and we're left with smaller migration populations that don't migrate, we could actually see infections build up in those populations," Altizer said. "And that could possible increase the risk of pathogens jumping over into people and their domesticated animals."
Miles O'Brien reports for the National Science Foundation's* latest Science Nation.
*For the record, the National Science Foundation is an underwriter of the NewsHour.
