Featured Research

from universities, journals, and other organizations

Emory Study Finds Monarch Health Tied To Migration

Date:
March 11, 2005
Source:
Emory University
Summary:
Monarch butterflies in eastern North America have one of the longest migrations of any species, with a survival-of-the-fittest trek that can take them thousands of miles from Canada to Central Mexico. A new Emory University study has found that these journeys may be the key to maintaining healthy monarch populations at a time when habitat loss and other environmental issues could curb the ability of the butterflies to make the trip.

Emory researchers have discovered that monarch butterflies infected with a protozoan parasite flew slower, tired faster and had to expend more energy flying than healthy monarchs.
Credit: Photo courtesy of Emory University

Monarch butterflies in eastern North America have one of the longest migrations of any species, with a survival-of-the-fittest trek that can take them thousands of miles from Canada to Central Mexico. A new Emory University study has found that these journeys may be the key to maintaining healthy monarch populations at a time when habitat loss and other environmental issues could curb the ability of the butterflies to make the trip.

Emory researchers discovered that monarch butterflies infected with a protozoan parasite flew slower, tired faster and had to expend more energy flying than healthy monarchs. These results, published in the March issue of Ecology Letters, may explain why parasite burdens are much lower in migratory monarch populations compared to year-round residents -- an effect that possibly occurs in other migratory species as well, explains Sonia Altizer, lead researcher of the study and an assistant professor of environmental studies at Emory.

"We know that several species of birds, insects and other animals undergo two-way migrations of several thousand miles or longer. These journeys can be thought of as animals essentially running a marathon every fall and spring. So if animals are infected with parasites, this would be like a distance runner trying to run a marathon with the flu. In this case, parasitized animals will drop out of the race, and across the whole population, prevalence of disease will decline," Altizer says.

However, monarch migration in eastern North America is threatened by several environment factors such as habitat loss at wintering sites, climate warming trends and an increase of tropical milkweed species in milder climates. These dynamics could ultimately cause large migratory populations to be replaced with smaller remnants that stay put and breed year-round, she says.

"The results of our study add one more reason to protect monarch migration east of the Rockies. If this migration collapses due to climate warming, habitat loss, pesticide use or other reasons, we probably won't lose monarchs as a species, but we'd be left with remnant, nonmigratory populations that are heavily infected with parasites, which could have several negative effects, from higher mortality rates, smaller body sizes and deformities, to more virulent strains of the parasite," Altizer says.

Altizer's experiments, conducted with graduate student Catherine Bradley, showed that parasitized monarch butterflies had 10-20 percent lower flight ability while on the "butterfly treadmill," and that the parasite affected their ability to fly long distances. Although the infected monarchs looked the same, weighed the same and had nearly identical survival rates to adulthood when they were not migrating, the flight trials in the laboratory essentially "unmasked" an effect of the parasite that normally would have been hidden. "The experiment demonstrates that seemingly small effects of parasites on their hosts can have a larger impact when combined with the stresses of migration," Altizer says.

###

Emory University is known for its demanding academics, outstanding undergraduate college of arts and sciences, highly ranked professional schools and state-of-the-art research facilities. For more than a decade Emory has been named one of the country's top 25 national universities by U.S. News & World Report. In addition to its nine schools, the university encompasses The Carter Center, Yerkes National Primate Research Center and Emory Healthcare, a comprehensive metropolitan health care system.


Story Source:

The above story is based on materials provided by Emory University. Note: Materials may be edited for content and length.


Cite This Page:

Emory University. "Emory Study Finds Monarch Health Tied To Migration." ScienceDaily. ScienceDaily, 11 March 2005. <www.sciencedaily.com/releases/2005/03/050309105725.htm>.
Emory University. (2005, March 11). Emory Study Finds Monarch Health Tied To Migration. ScienceDaily. Retrieved October 1, 2014 from www.sciencedaily.com/releases/2005/03/050309105725.htm
Emory University. "Emory Study Finds Monarch Health Tied To Migration." ScienceDaily. www.sciencedaily.com/releases/2005/03/050309105725.htm (accessed October 1, 2014).

Share This



More Plants & Animals News

Wednesday, October 1, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Earth Has Lost Half Its Vertebrate Wildlife Since 1970: WWF

Earth Has Lost Half Its Vertebrate Wildlife Since 1970: WWF

Newsy (Sep. 30, 2014) A new study published by the World Wide Fund for Nature found that more than half of the world's wildlife population has declined since 1970. Video provided by Newsy
Powered by NewsLook.com
Dolphins Might Use Earth's Magnetic Field As A GPS

Dolphins Might Use Earth's Magnetic Field As A GPS

Newsy (Sep. 30, 2014) A study released Monday suggests dolphins might be able to sense the Earth's magnetic field and possibly use it as a means of navigation. Video provided by Newsy
Powered by NewsLook.com
How To Battle Stink Bug Season

How To Battle Stink Bug Season

Newsy (Sep. 30, 2014) Homeowners in 33 states grapple with stink bugs moving indoors at this time of year. Here are a few tips to avoid stink bug infestations. Video provided by Newsy
Powered by NewsLook.com
California University Designs Sustainable Winery

California University Designs Sustainable Winery

Reuters - US Online Video (Sep. 27, 2014) Amid California's worst drought in decades, scientists at UC Davis design a sustainable winery that includes a water recycling system. Vanessa Johnston reports. Video provided by Reuters
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:

Strange & Offbeat Stories


Plants & Animals

Earth & Climate

Fossils & Ruins

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins