Featured Research

from universities, journals, and other organizations

Migrating Monarch Butterflies 'Nose' Their Way To Mexico, Neurobiologists Discover

Date:
September 25, 2009
Source:
University of Massachusetts Medical School
Summary:
Since the late 1970s scientists have studied the fascinating annual migration of monarch butterflies from across eastern North America to a single location in Mexico. Neurobiologists have now found that a key mechanism that helps steer the butterflies to their ultimate destination resides not in the insects' brains, as previously thought, but in their antennae, a surprising discovery that provides an entirely new perspective of the antenna's role in migration.

Monarch butterfly.
Credit: iStockphoto

The annual migration of monarch butterflies from across eastern North America to a specific grove of fir trees in Mexico has long fascinated scientists who have sought to understand just how these delicate creatures can navigate up to 2,000 miles to a single location. Neurobiologists at the University of Massachusetts Medical School (UMMS) have now found that a key mechanism that helps steer the butterflies to their ultimate destination resides not in the insects' brains, as previously thought, but in their antennae, a surprising discovery that provides an entirely new perspective of the antenna's role in migration.

"We've known that the insect antenna is a remarkable organ, responsible for sensing not only olfactory cues but wind direction and even sound vibration," said Steven M. Reppert, MD, professor and chair of neurobiology and senior author of the study. "But its role in precise orientation over the course of butterfly migration is an intriguing new discovery, one that may spark a new line of investigation into neural connections between the antennae and the sun compass, and navigation mechanisms in other insects."

In a paper to be published in the journal Science, Reppert and his colleagues Christine Merlin, PhD, and Robert J. Gegear, PhD, have demonstrated that the butterflies' antennae —formerly believed to be primarily odor detectors—are actually necessary for sun-related orientation, a critical function commonly thought to be housed solely in the insect's brain.

"Previous studies have shown that butterflies use their circadian clock, an internal timing device such as the one that controls our own sleep-wake cycles, to correct their flight orientation and maintain a southerly course even as the sun moves across the sky," Reppert said. The time correction factor of the sun compass mechanism was assumed to reside in the brain, where the sun compass itself is located, although this presumptive role of brain clocks had never been tested directly.

Recalling an observation from 50 years ago—made even before the discovery that millions of monarchs fly to specific wintering grounds in Mexico—when it was noticed that migrating butterflies became lost in free flight when their antennae were removed, Reppert and colleagues sought to unravel the role of the antennae in migration.

In their studies, the investigators removed the antennae of a number of butterflies and tested their ability to fly south while tethered in an outdoor flight simulator rigged to calculate the insects' flight direction. They found that the antennaeless migratory butterflies could not orient themselves to the proper southerly direction, while butterflies with intact antennae could orient correctly. They also showed that the molecular cycles of the brain clocks were not altered by removing the antennae and that the antennae actually contain circadian clocks that function independently of those in the brain.

The researchers next covered the antennae in black paint, effectively blocking light sensing by the antennal clocks. Those butterflies homed in on an incorrectly fixed direction: the insect's brain could sense light but couldn't adjust the timing of the sun's movement across the sky in order to steer towards the proper destination. However, when the team used clear paint—which did not alter antennal light input—the butterflies accurately established the southerly flight orientation, indicating that the antenna's reading of light is key to navigation.

The Science paper, "Antennal circadian clocks coordinate sun compass orientation in migratory monarch butterflies," will be published September 25. Reppert, who is also the Higgins Family Professor of Neuroscience at UMMS, has been a pioneering force in the effort to understand monarch butterfly navigation and migration and hopes to trace the neural connection between the antennae clocks and the brain's sun compass. In addition, his team is investigating other functions of the antennae that they believe are critical for successful migration.


Story Source:

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


Cite This Page:

University of Massachusetts Medical School. "Migrating Monarch Butterflies 'Nose' Their Way To Mexico, Neurobiologists Discover." ScienceDaily. ScienceDaily, 25 September 2009. <www.sciencedaily.com/releases/2009/09/090924141736.htm>.
University of Massachusetts Medical School. (2009, September 25). Migrating Monarch Butterflies 'Nose' Their Way To Mexico, Neurobiologists Discover. ScienceDaily. Retrieved July 29, 2014 from www.sciencedaily.com/releases/2009/09/090924141736.htm
University of Massachusetts Medical School. "Migrating Monarch Butterflies 'Nose' Their Way To Mexico, Neurobiologists Discover." ScienceDaily. www.sciencedaily.com/releases/2009/09/090924141736.htm (accessed July 29, 2014).

Share This




More Plants & Animals News

Tuesday, July 29, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Rodents Rampant in Gardens Around Louvre

Rodents Rampant in Gardens Around Louvre

AP (July 29, 2014) Food scraps and other items left on the grounds by picnickers brings unwelcome visitors to the grounds of the world famous and popular Louvre Museum in Paris. (July 29) Video provided by AP
Powered by NewsLook.com
Deadly Ebola Virus Threatens West Africa

Deadly Ebola Virus Threatens West Africa

AP (July 28, 2014) West African nations and international health organizations are working to contain the largest Ebola outbreak in history. It's one of the deadliest diseases known to man, but the CDC says it's unlikely to spread in the U.S. (July 28) Video provided by AP
Powered by NewsLook.com
Traditional African Dishes Teach Healthy Eating

Traditional African Dishes Teach Healthy Eating

AP (July 28, 2014) Classes are being offered nationwide to encourage African Americans to learn about cooking fresh foods based on traditional African cuisine. The program is trying to combat obesity, heart disease and other ailments often linked to diet. (July 28) Video provided by AP
Powered by NewsLook.com
Asteroid's Timing Was 'Colossal Bad Luck' For The Dinosaurs

Asteroid's Timing Was 'Colossal Bad Luck' For The Dinosaurs

Newsy (July 28, 2014) The asteroid that killed the dinosaurs struck at the worst time for them. A new study says that if it hit earlier or later, they might've survived. Video provided by Newsy
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:
from the past week

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