Chapter 5 - 8: Optimality models and Feeding/Habitat Flashcards
1
Q
How do circadian rhythms work?
A
- Suprachiasmatic nucleus (SNC) is the master clock that coordinates many behaviors–also based on light sensitivity and light activated
- SCN should use chemical signals that are pulsed in a timed manner
- Target tissues should have appropriate receptors
- Adding a chemical messenger to the target tissue should disrupt behavioral timing
2
Q
What happens to animals without active per genes?
A
They do not show distinct circadian rhythms.
3
Q
What happens when rat brains are injected with PK2?
A
Their activity cycle shifts by twelve hours, or is twelves hours off the normal.
4
Q
How did ground squirrels demonstrate that hibernation is a long term cycle of behavior?
A
When held in constant darkness and temperature for four years (e.g., no outside indicators of hibernation were available), they still showed annual patterns of hibernation and activity at fairly normal rates. These were consistent w/ animals that were exposed to other triggers of hibernation.
5
Q
What is a hormone?
A
- Chemical messenger secreted and released by endocrine glands into bloodstream
- Affects target tissues with appropriate receptors
- Coordinates behavior and physiology
6
Q
What do hormones do to target tissues/receptors?
A
- Specific effect on target tissue
- Usually lower (change) threshold necessary for behavior to occur
- Multiple targets of action (fewer with neural mediation)
7
Q
What three areas do hormones affect?
A
- Sensory systems
- Central nervous system
- Output systems (effector organs, e.g., muscles)
Their modulation causes a feedback loop b/w all three of these integrate systems, which results in a behavioral response.
8
Q
What are associated reproductive patterns?
A
A seasonal change in reproduction which is highly correlated with a change in gonad and associated hormone.
9
Q
What are dissociated reproductive patterns?
A
When the change in gonad and associated hormone is not highly correlated w/ a change in reproductive behavioral patterns.
10
Q
How is testicular growth in stonechats an example of long term cycles of behavior?
A
- When under constant light-sensitivity and temperature conditions (e.g., in the dark w/ regulated temperature), stonechats still showed testicular growth and shrinkage. They also molted.
- The periodicity of these behaviors changed slightly, but they still demonstrated them without the need of any exogenous cues
11
Q
What are two examples of physical environment impacting long term cycles?
A
- Some animals match foraging patterns to lunar cycle (kangaroo rat)
- Some animals match reproductive activity to longer day length (white-crowned sparrows)
12
Q
What did white-crowned sparrows demonstrate about long term cycles of behavior and receptivity to environmental cues?
A
The SNC is able to detect changes in photoperiods b/c it is light sensitive. The clock re-sets every morning. It insensitive to light in the morning and becomes more sensitive later in the day.
- Reproductive system becomes activated when daylength exceeds 14 hours; testes grow
13
Q
What does reproductive cycles in crossbills demonstrate?
A
Even if the birds are sexually receptive when food is plentiful and present in an environment, it does not change the underlying processes or behaviors significantly. No matter how much food is made available to them, the birds still will never be able to breed in winter b/c winter is not their biological mating season.
14
Q
How does testosterone change mating behaviors in garter snakes?
A
Even if males do not make testosterone/sperm during the spring when they actually mate, its absence does not actually change their mating behavior or season. Mating is activated by temperature; in castrated snakes, they were only able to mate if they had the testosterone surge (artificially stimulated) in fall. As the experiment continued into its second and third year, mating behavior dropped off in castrated snakes.
- Testosterone is necessary for courtship behavior to develop; not necessary for courtship behavior to occur
15
Q
What is the relationship b/w prey and predator?
A
- Predators exert selection pressure on prey
- Prey evolve to avoid/evade predators
- Predators evolve to overcome prey adaptations
16
Q
What is the adaptationist approach to behavior?
A
That behavior is the product of natural selection, or hereditary selection as genes are passed through the genepool.
17
Q
What are the constraints on perfect adaptation?
A
- Failure of mutations to occur by chance
- Pleiotropy: genes have multiple effects
- Coevolution - interactions b/w individuals that affect each other’s fitness (e.g., evolution favors counter responses over direct changes b/c mixing genes still favor ambiguous traits, environments, and expectations)
18
Q
What are important features of the cost-benefit approach?
A
A.) Fitness Benefits - increase # of offspring or alleles passed on
B.) Fitness Costs - negative effects of trait on reproductive success C.) Trait is adaptive if the benefits of the trait > than the costs of the trait
19
Q
Is mobbing behavior in seagulls an adaptive behavior?
A
- Benefits - predators are distracted and less likely to find eggs
- Costs - crows don’t retaliate against mobbing gulls; costs are relatively low
- Yes, it is; predation decreases and fitness increases if the gulls are inside the colony
20
Q
What is another example of mobbing being an adaptive behavior?
A
In arctic Skuas, birds raised more chicks in larger colonies as opposed to smaller colonies. This implies that mobbing increased survival b/c more Skuas were able to protect the eggs. However, chicks grew more slowly in denser colonies.
21
Q
Is fitness measured directly in either of the mobbing behavior examples?
A
No. A proxy is used instead (e.g., egg survival, hatching survival, etc).
22
Q
What is the comparative method for testing adaptationist hypotheses?
A
- Compare species under similar/different selection pressures
- Separate effects of current environment and phylogeny
- Find closely related species w/ different selection pressures to check for divergent genes or behaviors
- Find distantly related species w/ similar selection pressures to check for convergent evolution (i.e., same traits that evolved independently) and increases the chance that the behavior is adaptive
23
Q
How are Kittiwake seagulls a demonstration of divergent evolution? What behavior do they not do and why?
A
- They are cliff-nesting seagulls, so they do not show mobbing behaviors
- They are smaller than ground seagulls; more individually vulnerable to predation, which increases costs of mobbing
- As a result, they do not mob b/c there is not a higher benefit to mobbing in Kittiwake seagulls
24
Q
How is mobbing an example of convergent evolution in ground squirrels?
A
- They have partial immunity to snake venom, which decreases the costs of mobbing and increases benefits
- They also demonstrate mobbing behaviors to distract and scare off predators, like the seagulls; this is convergent b/c it is the same type of trait evolving from a similar evolutionary scenario
25
Why is comparing divergent and convergent behaviors/traits important?
- It provides increasing confidence about the adaptive nature of certain behaviors
- Various types of evidence can help determine whether or not a trait is an adaptation
- Accumulated evidence leads to greater confidence that it is an adaptation
26
What is the dilution hypothesis in the Cost-Benefit approach to predation?
Forming large groups reduces the chance that a predator will get any single individual
27
What are two examples of the dilution effect in action?
1. Butterflies - form larger groups overtime, and this causes the predation rate to drop to lower than 0.1 if the group is above 10 individuals
2. Mayflies - have a swarming behavior; the more hundreds of mayflies that emerge per day, the more predation drops; it will drop to approximately less than 50% and then level off
28
What is another possible benefit of grouping living in animals?
Group attack against predators - occurs in Africanized Ants, Ants, and Sawfly larvae; the Sawfly form a grouping that looks like bird’s feces and discourages predators from consuming them
29
What must be true in order for camouflage to actually benefit animals?
The the type of camouflage match the environment the animal lives in. This encourages crypsis, which is proper selection of microhabitats within the larger environment that are well-suited to the animal’s camouflage.
30
What is an example of this adaptive demonstration of crypsis?
In moths, they gravitate towards tree areas that match their colors. Green moths hide in moss; black moths hide against darker tree stumps; and lighter moths hide in the trunk and branches that are also lighter in color.
31
How do bugs that hide in environment cues change their fitness with or without this camouflage?
- If the bug is hiding in dust and with “backpack” of various ground-level items, it is completely camouflaged and most predators ignore it
- If the bug is hiding only it dust, its predation rate increases
- If the bug is naked, it is eaten at a very high rate
32
How are sponge crabs an example of camouflage?
The sponge crabs hide in a piece of a sponge at the ocean floor in order to confuse predators and blend into their environment.
33
What is an example of a predator evolution to camouflage?
In wasps that eat skipper caterpillars, they are able to distinguish b/w shelters that are clean and that have more waste pellets. If there is more waste, they spend more time investigating it under the impression that a caterpillar likely lives there. This implies a sensitivity to the environment of the skipper caterpillar.
34
What are Darwinian puzzles?
Traits with costs that seem to outweigh the benefits of having the trait itself. Three examples are:
1. Brightly colored species that are conspicuous to predators
2. Conspicuous behaviors that attract predators (stotting/pronking; rabbit screaming)
3. Male traits that appear to have fitness costs (sexual selection)
35
What about bright coloration is actually adaptive?
It advertises toxicity, and predators develop a conditioned taste aversion and avoid all individuals if exposed to a toxic species once.
36
What about the tephritid fly’s dance is an adaptive behavior?
When dancing, the body resembles a spider, which is an insect predator. This attention-grabbing dance intimidates other predators and requires both bright coloration and wing display.
37
What about stotting/pronking in gazelles is an adaptive behavior?
Pronking signals good physical condition. Predators will often abandon or avoid a pronking gazelle b/c it is an advertisement of being difficult to capture. It is an honest signal of physical condition.
38
What about push-ups in lizards? How is this adaptive behavior similar to pronking?
It is also a signal of good physical condition. Lizards use it warn off competitors or possible predators that they can respond aggressively. The more push ups the lizard does, then the better physical condition that it is in.
39
What is one possible explanation for why screaming may be an adaptive behavior?
When an animal screams, it may attract competing predators and thus encourage the predators to fight amongst themselves rather than kill it. This was experimentally shown when birds in dense areas screamed, but those in open areas did not.
40
What are the two approaches to cost-benefit analysis of evolution of behavior?
1. Optimality
2. Game theory
Both are forms of mathematical modelling.
41
What do optimality models stress as core components?
1. Consider multiple behavioral phenotypes
2. Look at all costs and benefits of behavior
3. The adaptive behavior is the one that provides optimal benefits and out-competes other phenotypes
42
What is the concept of the “selfish herd?”
In large groups, individuals are uniquely trying not to be spotted. As a result, they use the other members of the group as “living shields” in hope they will be predated rather than other individuals.
43
What is the cost of selfish herd behaviors?
The group is more conspicuous.
44
What is the benefit of selfish herd behaviors?
There is a lower chance of attack from predators on individuals.
45
How does the selfish herd result?
A behavior that causes sociality could spread in population of solitary (e.g., selfish) individuals. This means the individuals are interested in their own fitness, but not necessarily in other animals of same species.
46
What is murmuration?
The creation of flocks that avoid each other and are able to effectively avoid other members of the same flock during motion.
47
What is a bait ball?
A huge mass of fishes that have gathered into a ball and are mass predated until only few survivors remain. Is fitness-adaptive b/c at least some will survive, and species that form bait balls are often already prolific.
48
What does optimal foraging behavior have to take into account?
1. Where to find food
2. When to forage
3. How long to forage
4. How long to spend finding and processing each type of food
49
What are the result of optimal foraging behavior in crows?
1. Larger prey requires less drops to open
2. Greater height drop increases chance of breakage up to a point and then levels off
3. Prey that doesn’t break after several attempts is unlikely to do so
4. Larger prey results in more calories per processing time/effort
50
What does crow behavior imply about their foraging behaviors?
- Crows focus efforts on prey that maximize return per unit of effort
- Adaptive behavior
- Suggests that by maximizing calorie return, there is a fitness (offspring) payoff
51
What about in oystercatchers?
These birds sometimes choose mussels that are larger than average, but do not focus on them. This violates the assumptions of the optimal foraging theory.
52
What was the problem with the modelling of the oystercatchers foraging behaviors?
1. It contained false assumptions
2. Larger mussels are taken, and can be preferred
3. Some mussels have barnacles and are harder to open
4. Increased handling time to remove barnacles costs more than the benefit of eating a larger barnacle
53
How are models of pike cichlid also problematic?
Optimal theory ignores the time of handling, time to attack, and of capture rate. This creates a more inefficient modelling of the actual process of catching food. When handling is difficult, cichlid fish ignore the larger prey and choose a more medium sized prey for better payoffs.
54
What are problems with optimal foraging theory?
1. Predicts animals will always make the best decision in terms of return for effort, but animals are not always efficient as is possible
2. Modelers need to make correct assumptions about animal’s behavior and options
3. May not consider other important factors that affect foraging, like predation or handling time
55
What tradeoff emerge in skink behavior when raised near snake scent?
The skink lizards foraged less and grew more slowly, as well as avoided being out in the open compared to skink raised without snake scent present.
56
What tradeoff emerged in leafcutter ants as to night versus day foraged?
The ants are targeted by parasitic flies which occupy the fungus gardens that the ants live in. Nocturnal foragers did not have to fear being predated by the flies, which were inactive at night.
57
What does frequency-dependent selection explain?
Why two different hereditary phenotypes can coexist, such as feeding through hunting or stealing prey.
58
What happens in frequency-dependent selection?
When fitness of each phenotype depends on frequency of other type, both will have equal fitness at some point (equilibrium). They are both useful enough to be selected for, b/c they both have equal benefits in different situations.
59
What forces phenotypes back into equilibrium during frequency-dependent selection?
Changes in relative frequencies will result in frequency- dependent selection, which will drive phenotypes back to equilibrium.
60
How are scale-eating fish an example of frequency-dependent selection?
These fish attack either the right or left sides of prey. The prey then becomes focused on whichever side is more likely to be attacked (e.g., the higher occurring left or right side bias) and ignore the fish attacking it from the other side it cannot defend from. As time goes on, the amount of left or right side focused fish will “switch” b/c there will be too many genes for one or the other type. This puts it back in equilibrium.
61
If the behavior is non-hereditary, how does it develop during foraging?
There is flexibility in foraging behaviors, and the inherited mechanism or foraging-style can modify behaviors depending on different circumstances (e.g., one animal being dominant and forcing other animals to choose less optimal strategies for foraging).
62
What is an example of non-hereditary behaviors in foraging?
In osprey colonies, they are more likely to forage after a neighbor returns w/ food. They will follow the other osprey’s flight direction and path, and are typically more successful at catching food than others.
63
Can groups be used as information centers?
Yes.
64
What is an example of this outside of osprey colonies?
Crows that are captured and later released found food if they were related by roosts that located a dead animal carcass. Crows that were released away from other birds never located this carcass.
65
What is cooperative hunting?
When a group of animals works together to kill or capture prey and then splits it amongst the different hunters in the group as a whole.
66
What are examples of cooperative hunting?
1. Crocodiles forming groups to kill wildebeests
| 2. Killer whales forming groups and periodically attacked seals until they die
67
What do the snowy owl pellets made of animal bones and etc. indicate about foraging?
Different foraging strategies, types of animals eaten, and possible locations where the animals were more profitable to hunt.
68
Why are some webs more conspicuous than others?
They attract UV-sensitive insects, and thus capture more insects than undecorated webs.
69
Why can some female spiders make more elaborate webs?
If they have better web locations, than they capture more insects and thus have more energy to spend building decorated webs.
70
What happens in sites where insect productivity is low?
More decorated webs capture less insects than webs that do not have decoration. In this, ornate webs can have an energy-cost.
71
What are some other possibilities as to why spiders might make decorated webs?
1. Less damage from birds (visibility).
| 2. Camouflage for spiders, who might resemble the webbing and etc.
72
What do praying mantises do in regards to decorated versus undecorated webs?
They prefer to hunt by decorated webs, b/c decorated webs attract more insects in general (or at least have the potential to do so).
73
Why do humans consume alcohol?
Fermented fruit are sugar high and have a benefit to be consumed. Very ripe fruit creates alcohol, which explains the attraction to alcohol. There are some sex differences in the breakdown of enzymes in alcohol; women break it down less easily, as do indigenous Native Americans.
74
Why do humans eat spices?
They have antibacterial properties. Rotting is inhibited; probably helped preserve food in evolutionary history.
75
Why do people eat dirt?
It neutralizes acids in the stomach. This behavior is not necessarily for nutritional value.
76
What is bee waggling, what does it indicate, and when does it occur?
1. A dance bees do to communicate b/w one another and with the rest of the hive.
2. It communicates distance according to the length/time of the dance, distance according to the angle of the sun, and the type of flower
3. It can be done to either direct other bees to food or when the hive splits into a second hive
77
What is innate and what is learned in bee waggling?
The dance is innate and sense of direction is learned.
78
What two parts does total time spent foraging have?
1. Search time: Ts
| 2. Handling time: Th
79
What is search time/waiting?
How long it takes between prey encounters.
80
What is handling time?
How much time it takes to catch and eat the prey.
81
What are factors to consider?
Failed capture, how long it takes to follow prey from area to area (or during migration), size of prey, injury during capture, and overall energy expenditure.
82
What is profitability?
Profitability = net energy per handling time, or E/H.
83
What do wagtails show about how size of prey influences predation?
They prefer mid-sized prey, b/c larger prey have a high cost handling time and smaller prey have a low nutrient return. Size is a very important factor during predation.
84
What does travel cost?
Energy.
85
What is an example of this tradeoff?
Bee eaters bring only one prey item to the nest at a time. The farther they have to travel, the fewer small insects they bring back. Only large insects make the longer trip worthwhile. The energy cost to travel is too high for smaller prey to merit it.
86
How can animals compensate for energy expenditure?
By switching prey types.
87
What does the curve demonstrate about leaving a patch to find a different food source?
1. Initially, food is easy to find and energy gain is rapid.
2. Later, “easy” food is gone; more effort and time required to get additional energy.
3. Eventually, no additional energy is found, total energy levels off.
88
When would be the most optimal timeframe for animals to leave and find a new patch?
Immediately when the curve begins to level off. This will reserve energy needed to look travel to another patch.
89
What are giving up times?
An animal’s assessment of when it needs to leave to find a better patch to forage in.
90
What do predators need to be mindful of during foraging?
1. They have predators/can be prey to other species
2. They need to avoid being eaten while hunting
3. Need to reduce time spent hunting to reduce exposure time
91
What happens if the foraging patch is risky?
The animal is afraid and spends less time foraging irrespective of how much food is at the patch.
92
What are giving up densities?
How much food is left behind because an animal chooses to leave before patch is depleted (indicates predation risk).
93
If there is higher food depletion/more foraging, what does this mean with respect to predation?
The animal was less afraid and foraged more.
94
If there is lower food depletion/less foraging, what does this mean with respect to predation?
The animal was afraid and foraged less. They gave up sooner.
95
What are two examples of exploitative foraging behaviors?
1. Drongo birds mimic warning calls to steal food from meerkats.
2. A chimp can take advantage of social behaviors to steal tools to open nuts from other chimps, as can other animals.
96
What qualities vary w/ habitat quality? What factors should be taken into consideration when trying to evaluate habitat quality?
1. Food availability
2. Nesting sites
3. Predators
4. Competing species
97
What are two elements of habitat selection?
1. Habitat preferences are adaptive
| 2. Individuals that can live in preferred habitat should leave more offspring
98
What do European Blackcaps demonstrate about habitat preference selection?
A.) Reproductive success is not guaranteed just b/c the animal occupies a preferred habitat.
B.) The stream-edge habitat may be more preferred than the conifer habitat, but it is also dense in competition (4x as high).
C.) Competition is reduced in lower-quality habitat.
D.) Net result: equal production of offspring in both habitats despite the preference.
99
What does the side-blotched lizard demonstrate about habitat selection?
- Territory quality = number of large rocks for basking, cover from predators
- Rocks attract females
- Males with rockier territories attract more females
If rocks are removed, males increase territory size to compensate for lower quality. If rocks are increased, males reduced territory size to decrease extra energy cost of defense b/c more males might patrol a larger area.
100
What was the net result of this rock experiment in side-blotched lizards?
Either large territory with a few rocks or smaller territory with many rocks resulted in same number of females. End result was equal b/w territories.
101
Why do bees move farther away than necessary after splitting a hive?
Greater distance reduces competition with original hive.
102
What happens in Europe when bees do this splitting behavior?
Bees in cooler climates disperse farther than those in warmer climates, whereas larger colonies move farther away than smaller colonies.
103
What do female flying crickets demonstrate?
That calories and muscle movement come at a cost. Flying females have less ovary mass (or smaller gonads) in order to make flight more possible. This results in lower reproductive rates in exchange for higher mobility and defense.
- In other words, when one system is produced, another system should suffer to preserve energy.
104
What are the possible benefits of dispersion?
1. Finding a better habitat
| 2. Higher fitness in that new habitat
105
What are the possible costs of dispersion?
1. Pay energy cost
2. Pay travel cost
3. Pay time and predator exposure cost
106
How are male and female offspring in Belding’s an example of sex differences in dispersal?
- Male Belding’s ground squirrels disperse ~3x farther from natal burrows than females
- Males disperse in order to find potential mates, avoid inbreeding, and b/c they want to move away from stronger same-sex rivals (e.g., father, uncle, other male Belding’s)
- Females stay closer to get help defending territory from their original family unit and to help their mother w/ raising other offspring
107
How are male and female lions also an example of sex differences in dispersal?
Females have advantages to staying w/ the pride. These advantages are:
1. Good hunting grounds
2. Familiarity
3. Safe, known breeding sites
Males also have advantages to dispersing from the pride. These advantages are:
1. Less competition for mates
2. Avoid inbreeding depression
108
How might migration have evolved?
Short, regional migrations may have lengthened to longer, trans-continental ones over many generations.
109
What do thrushes demonstrate about the evolution of migration?
Migratory behaviors can evolve both from separate species within a population which also do not migrate (i.e., sedentary species).
110
What are the costs of migration?
1. Extra body mass needed for trip
2. Increased predation risk
3. May run out of energy and fail to complete trip (die)
111
What does the optimality approach to migration assert?
1. Costs of trip will be outweighed by benefits
| 2. Costs of trip will be minimized by behavioral adaptations
112
How are pelicans an example of behavioral adaptations minimizing the costs of migration?
Pelicans gliding behavior is very energy efficient, but actually fight alone is not. There is a high cost (in heartbeats) to flying alone, but this cost is significantly reduced when flying in a group. Grouped pelicans use about the same amount of energy as used when gliding.
113
How can body condition influence migration behavioral choices?
A.) If the body is in poorer condition, an animal can choose to take the route w/ less risk of energy expenditure in order to finish their migration. This route is longer, but the chance of death is ultimately lowered b/c the birds can rest rather than fly without stopping. These birds fly over land rather than water, b/c water has more open space and the possibility of falling into the ocean.
B.) If the body is in good condition, animals can choose to take a higher risk route that is shorter. Birds, in this case, choose to fly over the Gulf/the ocean in order to reach their migratory destination. Although there are less predators, the energy exerted is much higher b/c the flight is continuous.
114
What are the benefits of migration?
1. Seasonal food resources (e.g., bugs increasing in the US to a point where migrating in the spring is more worthwhile than staying in South America)
2. Longer days: more time for foraging
3. Longer days: more time for finding mates and nesting
115
What benefits does migration offer monarch butterflies?
1. Habitat is cool, but rarely freezes
2. Higher elevations are cooler and more moist
3. Less energy spent
4. Less moisture lost
5. Resource conservation
In other words, the temperature is more balanced in the migratory locations than their original home. This preserves body temperature and makes it likely they will freeze to death, and is therefore an adaptive behavior.
116
How does deforestation impact this body temperature equilibrium in monarch butterflies?
It causes them to not have the forest’s protection, which means they lose more body heat and ultimately are more vulnerable to death.
117
Why have both migratory and nonmigratory forms persisted in many species?
Both strategies must have equal fitness:
- Lifetime fitness of types should be the same
- Migratory/sedentary behavior should have a genetic basis
118
What is a conditional tactic and what does this imply when species “switch” their strategies?
1. Non-genetic
2. Conditional strategy based on social/environmental conditions that encourage the animal to switch strategy from one to the other
119
How should individuals choose their behavioral strategies?
Individuals should choose tactic that gives higher fitness given their social status.
120
What type of animal is most equipped to choose/make the optimal choice?
Dominant animals.
121
What strategies do animals of lower social status adopt?
Lower-ranking animals adopt tactic with lower reproductive payoff but less risk to them.
122
How are crows an example of this choice behavior in conditional tactic strategies?
1. The preferred strategy is to stay “a resident,” or to not migrate when conditions are good for male or female crows. This is b/c territory can be preserved.
2. Low-ranked crows will migrate, but prefer to be residents if the choice is available.
3. All animals should make the optimal strategy choice if and when it is available.
4. If the optimal choice is not possible, the lower-ranking animal will choose to migrate, or will pick the less preferred choice.
