Migration and Navigation Flashcards
Define migration
“The periodic movement of an animal from one region to another region”
What are the 5 traits associated with migration?
1) Prolonged movement
2) Straight course of movement
3) Undistracted by usual stimuli
4) Distinct departure and arrival behavior
5) Reallocation of energy in advance of migration
What are the two advantages of migration?
1) Increased REPRODUCTIVE success
2) Increased NUTRITIONAL opportunity
What is the most common method of migration? Why?
Flying- because it is a lower cost of transport than running, but is more rapid than swimming (a key compromise)
Name four birds and their migration distances:
- Sooty Shearwater (a marine bird): 65,000 km
- Bar-tailed Godwit: 11,000 km (Ak to NZ)
- Hummingbird: 1000 km (Gulf of MEX)
What bird migrates over the Himalayas?
the Bar Headed Goose
Name two insects that migrate. How far do they fly?
1) Monarch Butterfly: 2000-4000 km
2) Dragonflies: Canada to Mexico
How far can a dragonfly fly in a single day? How do we know this?
100 mi. Tag them with radio transmitters.
What is one marine mammal that migrates? From where?
Grey Whales… Canada to Mexico
What is a marine animal that migrates (stays in saltwater)?
Great White Sharks
What is the longest shark migration ever completed? Geography, distance, time
Africa to Australia, 20,000 km, 9 months!
What is the order of fuels that mammals generally use during exercise?
Use carbohydrates first, then use fats
What is the order of fuels that birds generally use during exercise?
Use fats first, then carbohydrates
What kind of fuel do migrants use?
Fat
Why do migrants tend to use fat?
It is 9x more energy dense than other substances!
What three things does a migrant need to do to use fat for migration?
1) Increase caloric intake
2) Store lots of fat!
3) Increase FATTY ACID TRANSPORTERS
What percent of body mass can birds and butterflies carry as fat?
50% and 60%
What are two issues with the fat gain for migration?
1) Behavioral changes
2) Increased predation risk
What is one migratory bird that doubles its body mass for migration?
Semi-palmated Sandpiper
Do birds just eat all kinds of fat, or do they increase specific fatty acids? Name two key ones
They increase specific fatty acids (EPA and DHA)
What bird migrates from Swedein to Sub-Saharan Africa? How long is that, and how long does it take? What is the average speed?
Great Snipe… 9,000 km in 2 days (average speed of 60 m.p.h.)
If fuel gets low toward the end of the journey, what do birds and fish do?
They use up muscles that are not key to travel (e.g. white muscle in the fish). The fish may even CATABOLIZE its gut
What is the order of energy sources that salmon use on their migration?
Lipids, then proteins, then glycogen/carbohydrates
What special adaptation allows the Bar-Headed Goose to migrate over Mt. Everest?
Their hemoglobin has high affinity for o2
What coordinates behavior and physiology in migrating animals?
Changes in the ENDOCRINE SYSTEM
Name a change in the endocrine system in migrating insects
JUVENILE HORMONE stimulates flight at intermediate levels, suppresses migration at high levels
Name a change in the endocrine system in migrating fish
THYROID HORMONE (T4) increases swimming activity and lipid mobilization. CORTISOL stimulates lipid metabolism and salt water tolerance
Name a change in the endocrine system in migrating birds
THYROID HORMONE (T4) increases fattening and restlessness CORTICOSTERONE regulates metabolism
What happens in fish that migrate from freshwater to seawater?
CORTISOL levels rise, down-regulate PROTON PUMP (reduce Na uptake), upregulate CHLORIDE CELLS (pump Na into surrounding seawater).
What happens in fish that migrate from seawater to freshwater?
PROLACTIN levels increase. This decreases the number of CHLORIDE CELLS and increases Na/H (PROTON) PUMP activity. Also, PARACELLULAR GAPS CLOSE.
Name two changes that occur when migratory birds stop to feed? Why do these occur?
1) Larger crops
2) 20% increase in the length of the intestine
Happens b/c of a change in diet
When birds do not stop, what do we see?
Atrophy of the G.I. system
Where do freshwater eels migrate to/from? How far is this? What is remarkable acout these eels? What happens to their gut during the migration?
England to Bermuda (3500 km)
They have a low metabolic rate (only 2x resting when swimming), so transport cost is only 20% of what would be expected. Gut atrophies during migration (lose 20% of body weight)
What characteristic do we find in salmon that complete their migration?
Stronger cardiovascular systems!
- Larger hearts, better coronary blood supply, higher Vo2 max, more Beta receptors in heart
How far and how much elevation gain do salmon achieve?
1000 km, 1000m
Why is a V-Shape the best energetic flight formation?
It allows the birds to capture the UPWASH from one another’s wings
As we get further out in the V, birds become positioned further _______ from one another
back
What three things does animal navigation involve?
1) sensory integration
2) motor control
3) learning and memory
What are the five main navigational strategies that animals employ?
1) Trail following
2) Piloting
3) Path Integration
4) Compass Navigation
5) Map and Compass Navigation
What are the four methods of compass navigation?
a) Sun compass
b) polarized light compass
c) Star compass
d) Magnetic compass
What are two ways that animals can follow a trail?
Visually or olfactory
How do you describe piloting?
Animals follow a discontinuous series of learned landmarks that they use to determine where they are with respect to their destination
How does path integration work?
Animals keep track of past directions and distances traveled, and then integrate this information to determine how to get back to where they started
What is one animal that uses path integration? How can we prove this?
Ants! 1) see how they reorient after facing a barrier 2) attach stilts to their legs or make them shorter and see that it changes the distance that they end up traveling!
What is one insect that uses a sun compass? What it its movement called, and describe it
Bees
They do a BEE DANCE, where they fly in two loops with a squiggly line in the middle pointing at the pollen. The other bees note the angle between the line and the sun.
What is one bird that uses a sun compass? How can we test this experimentally?
Homing Pigeons!
We can test this by setting their biological clock off by keeping them inside, then releasing them.
What are two animals that use a polarized light compass? How does this work?
Birds and bees
Electromagnetic light that reflects off of particles in the atmosphere becomes polarized at a certain orientation. As the sun moves in the sky, the direction of this polarization changes.
Name two animals that use star compasses
Birds that migrate at night and Dung Beetles
Name a bird that migrates at night. Why would it want to migrate at night?
Indigo Bunting
Reduced Predation
How do birds navigate using the night sky? How can we test this?
Birds learn a “star map” around the north star. We can test this by putting them in a planetarium.
What do dung beetles recognize in the night sky? How can we test this?
the Milky Way
We can test by putting small caps on their heads.
Name four animals that use magnetic fields to navigate. How can we test this?
Bees, birds, butterflies and turtles
We can test this by causing magnetic disruptions (with devices attached to them, or with geological formations e.g. iron)
What are two ways to use a magnetic field to navigate?
1) Detect north-south polarity
2) Detect “dip angle” of lines relative to Earth’s surface
What two kinds of compass does the Monarch butterfly employ on its migration?
Sun Compass and Magnetic Compass
What protein is crucial for sensing a magnetic field? Where is it located? What sort of light can it sense?
CRYPTOCHROME (CRY1, CRY2)
Located in the ganglion cells of the retina
Blue light
What are the two locations where monarchs have light sensors?
Eyes and antennae
What else is cryptochrome important for?
Producing circadian rhythms (in both plants and animals)
Is human cryptochrome (CRY2) sensitive to magnetic fields? Do humans sense magnetic fields?
Yes. Don’t know.
Do humans wander in circles if we don’t have a visual reference point?
Yes
