The Secret Lives of Wild Animals — Text-only | Flash Special Report
Watch scientists attach miniature transmitters to dragonflies to learn
more about their migratory habits.
BIRDS MIGRATING, CAMERA MOVES ALONG RIVER COASTLINE
NARRATOR: The migration of birds and monarch butterflies are natural phenomena studied worldwide. Now, for the first time, scientists are able to study migration in individual insects—
CLOSEUP OF GREEN DARNER DRAGONFLY
green darner dragonflies. Professor
MARTIN WIKELSKI WORKING ON SMALL AIRCRAFT
WIKELSKI: There are millions of dragonflies migrating every year,
CLOSEUP OF DRAGONFLY
probably up to about 50 species, and virtually nothing is known about these migrations.
HAND HOLDING RADIO TRANSMITTER-ZOOM IN FOR CLOSEUP
NARRATOR: Now, that’s changing.
WIKELSKI: Our collaborator, Jim Cochran, from Sparrow Systems has developed small radio transmitters at a weight of between 250 and 300 milligrams that allow
CLOSEUP OF DRAGONFLY ON LEAF
us to study at least large insects during their migratory flights.
CLOSEUP OF SCIENTIST HOLDING DRAGONFLY BY WINGS
So, we teamed up with Rutgers University and caught a total of 14 dragonflies in the fall, in New Jersey, and we know that those animals are on their way south.
CLOSEUP OF DRAGONFLY-TRANSMITTER ATTACHED TO UNDERBELLY
We attached transmitters to their thorax using superglue and eyelash adhesive.
DRAGONFLY RESTS ON MAN’S FINGER, THEN FLIES AWAY
And then, we let these animals go. They take off and then
SCIENTIST ON BEACH WITH TRACKING ANTENNA
we track them from the ground or
WIKELSKI PILOTING SMALL AIRCRAFT
EXTERIOR OF PLANE SHOWING STRUTS
from small airplanes with antennas attached to the struts.
SIDE VIEW OF DRAGONFLY RESTING ON LEAF
NARRATOR: What they found was that the dragonflies have migratory behavior similar to that of birds.
DRAGONFLIES IN FLIGHT
They fly some days, rest on others. And like birds,
DRAGONFLY ON RESEARCHER’S FINGER AT BEACH LOCATION
the decision “to fly or not to fly” seems to be based on temperature and wind speed.
TWO RESEARCHERS CHECKING DRAGONFLY
The darners only migrated when the wind speed was less than about 15 miles an hour
TWO CLOSEUP SHOTS OF DRAGONFLY WITH TRANSMITTER ATTACHED
and when a night was colder than the one before it—signaling a cold front with winds from the north.
DRAGONFLY TAKES FLIGHT FROM RESARCHER’S HAND
It looks as if these kind of migratory rules, these simple rules, that potentially could be innate, as has been shown by birds,
AERIAL SHOT OVER FARM LAND
are sufficient to help these darners go south. We calculated that
CLOSEUP OF DRAGONFLY WITH TRANSMITTER ATTACHED
within about a month or two-month period, they can get a southward advance on a population level of about 700 miles. The longest flight we had was about 100 miles per day.
CLOSEUP OF DRAGONFLY ON TREE STUMP
NARRATOR: Dragonfly and bird migration do differ in one important way: dragonflies migrate in one direction only,
DRAGONFLY ON BRANCH CLOSEUP - SLOW ZOOM OUT
with the next generation making the return trip. The dragonfly study
SCIENTIST USING TRACKING SYSTEM ON BEACH
demonstrates the viability of radio tracking of large-scale insect movement.
EARTH FROM OUTER SPACE
In the future, transmitter signals could be picked up from space by special satellites.
AERIAL SHOT OVER FARMLAND
Birds, bats and insects could be tracked over huge distances,
with implications for anticipating the spread of diseases and for pest control.
DRAGONFLY RESTS ON RESEARCHERS FINGER AT BEACH LOCATION
Martin Wikelski, Princeton University
Dave McShaffrey, Marietta College
Lori Dieter, Gray Lodge Wildlife Area
Dave Moskowitz, EcolSciences, Inc.
Tom D. Schultz
National Park Service
Cliff Braverman, National Science Foundation
Susan Bartlett, National Science Foundation
Gwendolyn Morgan, National Science Foundation
S2N Media, Inc.