Slideshow 8

Question 1

What is the Manly-Chesson index

Answer 1

measure selective feeding or resource preference by a consumer when multiple resource types are available. It accounts for changing resource availability, which makes it especially useful in experiments where resource abundance decreases due to consumption.

Question 2

What is the Manly Chesson index formula

Answer 2

Alpha i= (di/Ni)/ksum (dj/Nj)

Question 3

What does k represent in the Manly-Chesson Index

Answer 3

number of prey categories

Question 4

What does di represent in the Manly-Chesson Index

Answer 4

is the proportion if prey of type i in the predators diet

Question 5

What does Nirepresent in the Manly-Chesson Index

Answer 5

Ni is the proportion of the prey type i in the environment

Question 6

What does alpha i = 1/k mean

Answer 6

No preference

Question 7

What does alpha i > 1/k

Answer 7

Positive preference

Question 8

What does alpha i < 1/k

Answer 8

Negative preference

Question 9

What is the optimal foraging theory

Answer 9

What foraging decisions lead to the most efficient
energy capture

Question 10

What is the formula for the optimal foraging theory

Answer 10

En/T = E/Th + Ts

Question 11

What does E represent in the Optimal foraging theory

Answer 11

energy gained during feeding
period of length T

Question 12

What does Ts represent in the Optimal foraging theory

Answer 12

search time

Question 13

What does Th represent in the Optimal foraging theory

Answer 13

handling time

Question 14

What does En/T represent in the Optimal foraging theory

Answer 14

net rate of energy gain

Question 15

What are 2 predictions about the Optimal diet model

Answer 15

1) Foragers should prefer the
most profitable prey
2) An efficient forager should broaden its diet to include more low value prey as the abundance of high value prey decreases

Question 16

How was should Foragers prefer the
most profitable prey represented

Answer 16

crab feeding on mussels graph,
shows optimal size of muscles to be middle of the pack in size.

Question 17

How was An efficient forager should broaden its diet to include more low
value prey as the abundance of high value prey decreases

Answer 17

Great tits feeding on mealworms. and bluegill graph

Question 18

What are 2 predictions about prey selection

Answer 18

1) The zero one rule: Prey are either always eaten when encountered
(Pi = 1) or they are never eaten when encountered (Pi = 0)
2) Inclusion of a prey type in a diet depends only on its own
profitability and that of higher profitability prey types.
i.e. it doesn’t depend on its own encounter rate

Question 19

What are some limitations of the optimal diet theory

Answer 19

1. Mobility of prey had a negative effect on the ability of ODT to
   predict observed diets

Question 20

1. Prey handing time increases with the ratio of prey size to
   predator size
2. Prey energy value is positively related to prey size
3. Predators prefer the most energetically rewarding prey

Answer 20

yes

Question 21

What percentage of predator-prey links in 4 real-world food webs

Answer 21

65%

Question 22

What are 3 probabiliets of predation

Answer 22

encountered – attacked – consumed

Question 23

What happens when the density of the prey decreases

Answer 23

predators diet should
broaden to include more prey types

Question 24

What is an example of Consequences of selective predation

Answer 24

Periwinkle Littorina littorea

Question 25

How is Periwinkle Littorina littorea food chance between habitats

Answer 25

* In tidal pools its preferred food is competitively dominant * On emergent substratum its preferred food is inferior

Question 26

What is a Consumptive effects

Answer 26

predator kills and eats prey

Question 27

What is a Non-consumptive effects

Answer 27

non lethal effects 1. Habitat shifts 2. Life history evolution 3. Activity levels 4. Morphological changes

Question 28

how are Paramecium aurelia affected in presences of Stenostomum virginianum

Answer 28

wider and swim slower in the presence predator

Question 29

what happends to Paramecium aurelia and Stenostomum virginianum when undefended and defended

Answer 29

undefened, Stenostomum virginianum lags behind its prey Paramecium aurelia Defended , Paramecium aurelia thrives and Stenostomum virginianum slowly increases

Question 30

How does Temporary habitat shift affect population

Answer 30

No real impact on population dynamics

Question 31

How does Population consequences habitat shift affect population

Answer 31

Predation risk can change with body size * Ontogenetic niche shift – changes in pattern of resource use as an animal grows to maturity

Question 32

What is an example of a habitat shift

Answer 32

* Small size-class bluegills are at high risk of predation by large mouth bass * The largest individuals are not susceptible to predation * In the absence of bass habitat use was similar across size-classes * In the presence of bass smaller-size classes were restricted to sub optimal habitats

Question 33

How can habitats shifts affect populations

Answer 33

Habitat with a lower predation rate may be less good quality * ‘Safe’ areas may have higher competition for fewer resources * Trade-off between reduced mortality and energy gains

Question 34

How does Zooplankton experience habitat shift

Answer 34

Daylight - zooplankton stay in deeper, colder darker areas to avoid visual predator Night - zooplankton move to the surface where phytoplankton (prey) is more abundant at a time when predation risk is lower

Question 35

What type of effect is Vertical diel migration of zooplankton

Answer 35

Non-consumptive effect - reduction in birth rate due to time spent in the colder, deeper parts of the lake

Question 36

How can predation of Tadpoles effect life history

Answer 36

Metamorphose when fitness in larval habitat drops below achievable fitness in the terrestrial habitat

Question 37

When does the optimal life history evolution switch happen

Answer 37

μ1/g1 > μ2/g2 where μ is size-specific mortality rate and g is size-specific growth rate

Question 38

What is Gilliams rule

Answer 38

Life history evolution rule * Only applies to stable populations with no time constraints * Useful tool to understand behavioural decisions under predation

Question 39

What is the example of Life history evolution in mayflies

Answer 39

* Adult mayflies are short lived (2 days ) and can’t feed * Must maximise energy gain for reproduction in their larval phase before metamorphosis * Trade-off between remaining a larva and maximising energy and avoiding predation * Adults emerge earlier and at a smaller size if trout are present in the stream

Question 40

How was the mayfly experiment conducted

Answer 40

* Were changes in metamorphosis due to the presence of the trout or could that be induced by chemical cues * Streams that were treated with tank water had earlier metamorphosis of smaller adult mayflies compared to controls * 13% - 20% reduction in size and 24%-35% loss of fecundity Non-consumptive effects on population growth were larger than the effect of being consumed by the predator

Question 41

How does predation effect activity levels

Answer 41

* If you’re hiding you’re generally not feeding and gaining energy * Trade-off between growth rate and predation * Species will differ in how to prioritise and resolve these issue

Question 42

How was activity level of green frogs experiemnt created

Answer 42

* Green frog larvae prefer pools where the bullfrog is absent, but will inhabit a full range of temporary to permanent pools * The presence of bluegill was experimentally manipulated * A series of choice experiments using 3 known larva predators: bluegill, dragonfly larva Anax junius, the salamander Ambystoma tigrinum * Bullfrogs survived in the presence of bluegill, but did not survive when it was absent * Green frogs survived both , but did better when bluegills were absen * Bullfrog have higher activity levels result in higher predation risk * Bluegills predate both dragonfly larva and salamanders and reduce this predation risk * Bluegills also predate green frog larvae which reduces competition with bullfrog * Bulldogs are limited to bluegill pools as they trade-off lower predation risk for a faster growth rate * Neither bullfrog or green frog are able to dominate the environmental gradient due to these trade-offs

Question 43

How does predation effect morphological traits

Answer 43

Changes traits to allow for better survival

Question 44

how was Morphological changes in carp changed by predation

Answer 44

* In the absence of predator it is narrow bodied and lives in dense populations * In presence of predators (pike) there are fewer individuals and have a deep body

Question 45

How do carp reeduced their predation risk

Answer 45

changing body shape

Question 46

What is the tradeoff of carp changing body size for predation

Answer 46

Deep bodied fish expended 30% more energy when swimming