Moving About the Environment Flashcards
orientation
organism positions itself in the environment on the basis of external cues
navigation
orientation over greater distances; process by which organism uses external cues to determine its position in reference to a destination as it moves about the environment
can involve both map sense + compass sense
migration
involves navigation: periodic movement from one location to another
homing
involves navigation: the ability to return to a home site or locale after being displaced
kinesis
non-directed movement in response to environmental factors such as light, moisture, temperature
ex. pillbugs - lack humidity –> moves in non-linear pattern until 70% humidity
taxis
directed movement: the source or a gradient of some factor are detected and the organism moves in the appropriate manner
ex. “questing” tick - seeks host @ top of grass blade –> go against pull of gravity (hairs stimulated)
phototaxis
attraction to light
ex. moths
chemotaxis
attraction to biological chemical substance
ex. moths - male antennae more alborate to sense female pheromones
map sense
made up of memorized landscape “snapshots”
ex. honeybees - sugarwater –> young will get lost, experienced will know way back after disorientation
Cues for Orientation, Navigation, & Migration
- landmarks (Tinbergen’s digger wasps, bees, arctic tern migration)
- sun (bees, ants, birds)
- stars (birds (indigo bunting planetarium))
- lunar/tidal (fiddler crabs, grunions)
- magnetic fields (pigeon, sea turtles)
- chemical cues/olfactory (salmon)
- sound cues (ducklings, bats)
- electric cues (electric fishes)
- ocean currents (lobsters, sea turtles)
Cues for green sea turtle migration
currents, magnetic fields, chemical cues
Pigeons - magnetic field detection & use
back-up orientation mechanism is based on the ability to detect Earth’s magnetic field (ex. during cloudy days)
if distorted, bird will be disoriented (only on cloudy days)
arctic tern
longest migration ever recorded, can rest + feed on journey
monarch butterflies
2 populations divided by Rocky Mountains, different migration patterns
Distinguishing compass and map sense in honeybees
bee get sugar water –> move sugar water 400 mi E –> experienced can head home, novice will follow og pattern
Why don’t green sea turtles breed on mainland?
Small islands (Ascension Island) has fewer predators + if it worked for my ancestors, it’ll work for me
Desert Ant Cataglyphis (Wehner)
- Sahara desert (simple enough to find causes for behavior)
- Ants (easy to find way home)
- Wehner (develops machine that falsifies sun –> ants follow false sky)
- Follow-up: fitted w/ stilts –> travel 50% further than normal distance & get lost from home (internal system to calculate steps)
Lohmann (2004)
coil aparatus to generate magnetic fields to identify navigational cues of green sea turtles
Hays (2003)
Adult turtles traveling long distances to remote isalnd targets tend to travel directly to the general vicinity of their island target using geomagnetic cues but may then need local cues (e.g. winds) for final island approach
All downwind placed female sea turtles able to navigate, 2/3 upwind took very long (1 lost)
Salmon migration (Hasler)
Adult salmon return to sam tributaries where they hatch 2-3 years before + young salmon stay in gravel nest area for about 2 months –> set up feeding territories for 14 months –> journey downstream into ocean
Hypothesized that odors led salmon home –> young hatchlings reared in holding tanks + expsed to diff smells –> marked + released into wild –> baited streams w/ various chems hatchlings were exposed to –> went home to most familiar smell
Clock Shifting Effect on Pigeons (Keeton)
2 groups: some clock-shifted (lights on at midnight + off @ noon)
Both groups released at 6 AM at point west of home –> clock-shifted go North (Sun is East) rather than East
Pigeons - magnetic field detection & use
Back-up orientation mechanism: use Earth’s magnetic field when X see Sun
only on cloudy days
Mora et al (2004)
Pigeons trained to go on one end of tunnel is magnetic-emitting coils switched on and other when off (follow field)
Misinformed leaders for pigeon flocks
Artificial light applied –> leader notices wrong pathing –> readjust
OR
group notices –> readjust + abandon leader
Froy, O. et al (2003)
Clock-shifted monarch butterflies behave similarly
Indigo bunting
Use star positions to navigate during migration
experiment: raised birds in planetarium
Dacke et al (2013)
Dung beetles navigate via stars
able to keep straight lines via sun and moon cues
Honeybees: waggle dance
of waggles & orientation of straight run provide info on distance + direction of food
Wenner & Wells’ concerns
Workers secrete phermones from Nasanov gland when marking source of nectar/water –> 87% of marked bees observed to follow forager dance + fly off failed to appear at any feeding dish
Gould: further tests of “dance language”
Scented sugar water experiment: array of sugar + fresh water –> bees smell like sugar water –> drones follow –> recruits more likely to appear at og spot –> olfactory not a significant factor
Misinforming bees: paint bee’s eyes to limit light –> still find way back to hive –> hard to see while in hive –>dance for recruits + force flashlight (forager X see light) –> recruits prefer to respond to light directly rather than vertical –> go to different food source in respect to vertical
Riley et al (2005)
newly recruited bees fly directly from hive to vicinity of food source –> search for exact location using odor + other cues
Honeybee swarm in search of new nest site
new queen –> 50% stay, 50% leave to find new nest –> foragers find new nest –> dance on other bees –> others convinced by majority (election)
