Bio 281 EXAM 2

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Background:

Experimental Design:

Observations:

Conclusions:

Redshank flock paper:

Background: Testing the selfish herd theory (idea that animals group to lower individual predation risk). Wanted to know how location in herd, spacing, distance from predators affected predation risk and vice versa.

Experimental Design: Recorded video of surprise attacks on the redshanks, compared the successfully attack redshanks to data on their position and distance from neighbors.

Observations: Redshanks more spaced from neighbors were the most targeted. There was variation in response time for attacked birds, but this affect was also explained by spacing. Closer on riskiest side of flock.

Conclusions: Validated selfish herd theory. Behavioral trade-off (prey change spacing based on risk).

Frog mimicry paper

Background: Testing predator learning of mimics based model toxicity and mimic and model frequency. Mimic frog species A zap. mimics two poisonous frog species: more toxic E parv and less toxic E bili.

Experimental Design:

• Tested which model the mimic resembles in areas of allopatry and sympatry.

• Tested predator learning with different models.

Observations:

• Predators learned faster on the more toxic model.

• Predators trained on the more toxic model generalized to avoid all mimics, while predators trained on the less toxic model only to avoid mimics of less toxic model. This made mimicking the less toxic model more beneficial.

• Also allowed the mimic to be more prevalent than either model by gaining protection from both

Conclusions:

• Mimicking the less-toxic model is an adaptive strategy because it exploits how predator psychology generalizes risk, providing cumulative "cross-protection"

• toxicity based learning

• mimic frequency in allopatry

Butterflies residency effects paper ***main takeaways

Background: testing residency effect in territoriality. Question of why do territory owners typically win fights over the territory. Testing the three hypotheses.

Experimental Design:

• Set up territory contests in natural and semi natural arenas. They tested who would win in natural set up and if the reversed the roles.

• tested thoracic temperature to see if warming from sunbasking encourage

• They recorded prior win/loss sequences to isolate whether past victory created a psychological or physiological momentum (self-reinforcing effect) independent of the physical spot itself.

Observations:

• Residency was not neutral/arbitrary. Whoever originally won would win again.

• Intrinsic Aggression & Winner Effects: More aggressive or highly motivated males tend to secure and hold territories first, and the psychological/physiological boost of winning a prior fight (self-reinforcing winner effect) makes them progressively harder to defeat.

• no thermal advantage

Conclusions:

• Residency effects in this case based on RHP

• Owner-intruder success is driven by a combination of intrinsic quality/aggression (sorting into residency) and prior winning experience (self-reinforcing feedback loops) rather than passive location rules or simple thermal quirks.

Cochran Songbirds thrushes migration direction paper **(how to read the expectations graphs)

Background: Songbirds navigate twice a year during seasonal changes. researchers wanted to know how they manage to do this. Testing hypothesis of a) star based compass, b) time compensated star compass (compass which is set by twilight cues and maintained with stars), c) magnetic compass, d) compass set by twilight and maintened magnetically, e) compass set by magnetic cues at twilight and maintained by stars

Experimental Design:

• thrushes held in outdoor cages with altered magnetic field. Released and observed for first night and following night.

• 
  

Observations:

• Found Magnetic compass calibrated daily from twilight cues

• Birds during treatment would incorrectly set a heading relative to magnetic field based on where they saw the sun and intrisicn instinct to go a certain # of degrees from sun.

• After release they would continue with this incorrect heading, now facing a different direction as they based of true magnetic fields

• Night two at twilight they had an oppurtunity to adjust their angle to magnetic field using sunset, now going correct direction

Conclusions:

• Geographical Adaptation: Daily recalibration helps birds adjust for local changes in the Earth's magnetic field, magnetic declination, and shifts caused by crossing the magnetic equator

• Example of migration using multiple cues to set directionality.

• Shows how songbirds orient

Songbirds funnel paper star**

Background: investigates how young pied flycatchers, Ficedula hypoleuca, and blackcaps, Sylvia atricapilla, interpret and use celestial cues (star based cues)

• wanted to test if songbirds use true star navigation, a time-compensated star compass, a time-independent star compass based on learned geometric star configurations to find true north

Experimental Design:

Observations:

Conclusions:

Spiny lobster paper

Background:

• Testing spiny lobsters for true navigation: the ability to ind the way from ones origin to ones destination when displaced not using cues from displacement journey(not simply retracing steps)

• Testing use of magnetic field for oreientation and tru navigation

Experimental Design:

• First trial, lobsters displa

Observations:

Conclusions:

Crows Shell dropping paper

Background:

Experimental Design:

Observations:

Conclusions: