Looking at adaptive significance of behavior

Heuristic

Measures of fitness for alternative behaviors (ideally number of offspring reaching reproductive age)

Mobbing in black-headed gulls

Colonial nesting in skuas

Probablility of egg predation decreases as mobbing increases - adaptive

In arctic skuas, high-density nesting means more chicks hatch, but individual chicks are smaller (competition)

Mutations have not occurred (changing environment)

Pleiotropy

Coevolution (opposing selective forces)

Idea of adaptation

short-term optimality (optimize aspects of everyday life)

Long-term optimality (leaving the highest number of viable offspring in a lifetime)

Short-term provides insight into natural selection

long-term explains why behavior was favored in the past

Natural selection acts to maximize fitness (fitness depends on design features, which must be optimized)

Optimized = biggest difference between cost and benefit

Net benefit = benefit - cost

Optimal covey size = 10-15

smaller worse b/c less vigilant, larger b/c of competition

larger and smaller also have to move more (to find resources or competition)

1. Encounter
2. Detect
3. Identification
4. Approach - attack
5. Capture
6. Consume

intensity for prey is greater

if predator fails, loses a meal - if prey fails, gets eaten

Rarity

• apostatic behavior
• doesn't work too well

Apparent rarity

• change daily/seasonal activity
• hiding
• polymorphism

Prey more sensitive to predator than pred. to prey

Blue jays and apparent rarity (polymorphisms)

Blue jays in skinner boxes were shown digital moths

if they peck at the right moth, got mealworms

wrong moth, had to wait for a long time (operant)

birds choose specific morphs that change over time based on which get eaten

3 times for 50 generations

not one moth 'species' went extinct

• Immobility (can't see something still)
• Crypsis/camouflage
• Confusion (random mmt., flicker fusion)
• Mobbing
• Lures (killdeer)

• Masquerade (resemble inedible object)
• Mimicry (Batesian)

• Batesian: resemble a distasteful object (i.e. bird droppings, monarch and viceroy)
• Mullerian: two harmful species resemble one another

• Aposematism - warning coloration (and mullerian mimicry)
• Startle response
• encourage premature attack
• Speed - advertising unprofitability (gazelles)

Thompson's gazelle behavior

jumping straight up, indicating unprofitability of chase - if stutting does not occur, something is often wrong with the gazelle.

• strength to escape
• Mechanical methods (shells, slime, spines, autotomy)
• Attract secondary predator
• dilution (prob. of capture decreases in large group)
• Selfish herd (use others as living shields)

• Misdirecting attack (predator bites in the wrong place)
• Noxiousness (chem defenses deter predators)
• Aggressive mimicry - one organism acts like something important to another, attracts, and eats (i.e. katydid mimicking cicada)

glandular secretions (i.e. bombadier beetle)

Reflex bleeding (increase pressure to squeeze blood from joints)

Nobel prize - info. transfer in bees

Round dance

wiggle dance

fan test

Bee dances

fan test

round dance indicates short distances to resource (<50m)

Wiggle dance indicates longer distance - wiggle rate shows distance, wiggle indicates angle from sun

fan test: train foragers to location F - put out 7 equally attractive sites at different angles relative to F, count new recruits (same test for distance)

birds living in groups gain foraging info from others (i.e. osprey)

after successful bird returns, depatures should be clumped and should increase foraging success

Currency assumptions (How are alternatives evaluated; what is maximized?)

Constraint assumptions (What are the costs of the alternatives?  What limits payoffs?)

Decisions assumptions (What are the alternative choices? Behavior)

Oystercatchers will select the largest mussel that they can frequently open

Crows will drop whelks from a specific height that minimizes costs

Diet models (what prey included in diet)

Patch models (How long to stay in patch)

Optimally foraging animal must decide when to leave patch to search for a new one

cost-benefit ratio

individuals will stay longer in a patch as distance between patch increases and when a patch is more profitable

Optimal time in patch = when line from search time is tangent to energy gain curve

patch type instantly recognized

travel time known by predator and is the same between patches

gain curve is smooth and decelerating

Patches variable/stochastic (largely predictable but individually unpredictable)

variablilty introduces probalistic element

animals do not maximize profitabillity - instead minimize probability of death and increase probability of survival

If requirement (R) is less than mean, risk averse.  If R>mean, risk prone, more variable patch

Shrews

Traveling from established home range to another

Costs: Energy, inc. predation

Benefits: Increased fitnesss

Males competitive and often fight

inbreeding avoidance

Traveling between suitable habitat over unsuitable habitat

Usually long-distance, often return to orig. site

Evolved from short-range migration (Catharus thrushes)

Costs

• Energy (prevailing winds and V formation)
• Predation risk (travel in large groups)

Benefits

• Mult. reproductive seasons
• Multiple food resources
• Decrease chances of death (cold)

Follow milkweed from TX to Canada over 2-3 generations.  Last one flies back to Mexico

Navigate using magnetite

r (magnitude of mean vector) =0 if no magnetic field is present, r=~1 if field is normal or reversed.