Animal Behaviours Chapter 7

Front 1

Catfish Track the Wake of Their Prey (Question, Hypothesis, Prediction, Methods)

Back 1

Question: How do nocturnal (Silurus glanis) catfish find food in the dark

Hypothesis: Catfish use their lateral line system to detect cues provided by the wake of their fish prey

Prediction: Catfish will follow the wake of their prey while hunting

Methods: -Observed catfish hunting individual gupppies

-Used an infrared video system to track the movement of both predator and prey in complete darkness

-Classified movement sequences as "path following" "head-on encounters" or "attack on stationary guppy"

Results: 80% of attacks were on moving guppies majority following), this leads us to our next experiment

Front 2

Catfish Track the Wake of Their Prey (Question, Methods, Results)

Back 2

Question: Do catfish use chemical or hydrodynamic cues to track their prey in the dark?

Methods: -Used an infrared video system to track the movement

-Manipulated either the lateral line or external gustation

3 parts of experiment:

Intact

nonfunctioning lateral line

external taste ablated

-Classified hunting success and movement sequences of treatment fish

Results:

Everything intact: 65% capture rate

Nonfunctioning lateral line: 17% capture rate

External taste ablated: 60%

Conclusion: Lateral line system very important for wake following. Gustation not as important.

Front 3

Bees Use Multiple Senses to Enhance Foraging Efficiency (Question, methods, Results, Conclusion)

Back 3

Question: Is foraging more efficient when multiple senses are used?

Methods: Trained individual bees to feed on artificial flowers. 3 treatments used,

-One exp only flower shape indicate reward

-One exp only odor used to indicate reward

-Both used (multimodal) to indicate reward

Had the bees pick flowers for correct choices after they were trained

Results: Visual was least correct, then olfactory. Multimodel had most correct choices.

Conclusion: Multimodel helps with foraging

Front 4

Define: Search Image

Back 4

The visual distinctive features of a single prey type that once learned, can enhance prey detection

Front 5

Blue Jays Use a Search Image to Find Prey? (Question, Methods, Results, Conclusion)

Back 5

Question: Do blue jays use a search image to find a cryptic prey?

Method: -Trained birds to search for moth images on a computer

-Scored correct and incorrect responses to images (moth present or absent on screen

Two Treatments

Run 8 negative and 8 positive treatments of same moth species

Nonrun 4 positive, 4 positive, 8 negative, different moth species

Results: Increase number of correct responses in the run treatment

Conclusion: Therefore search imaging must be a factor

This was confirmed but other experiments with other types of moths.

Front 6

Main assumption of Optimal foraging theory

Back 6

Fitness while feeding increases with energy intake rate

Front 7

Behaviour that maximizes fitness is called __________?

Back 7

Optimal behaviour

Front 8

Two well-known Optimal foraging theories (OFT's)

Back 8

Diet model

Patch use model

Front 9

Optimal Diet Model assumptions (3)

Back 9

1. Foragers maximize fitness by maximizing energy intake rate

2. Food items are encountered one at a time in proportion to their abundance

3. Food items can be ranked by their profitability

Front 10

Define: Profitability

Back 10

energy/handling time

Front 11

Define: Optimal behaviour

Back 11

behaviour that maximizes fitness in an optimality model

Front 12

Define: Generalist

Back 12

Forager that consumes a wide variety of items in its diet

Front 13

Define: speciallist

Back 13

Forager that has a narrow diet

Front 14

Who has a shorter search time, generalist or speciallist

Back 14

Generalist

Front 15

Define: Zero-one rule

Back 15

Optimal diet model, prediction that each food type should either always be eaten or always rejected

Front 16

Define: Partial Preference

Back 16

Acceptance of a food item some fraction of the time

Front 17

Diet Choice in Northwestern Crows? (Question, Hypothesis, Prediction, Methods, Results, Conclusion

Back 17

Question: Why do northwestern crows reject some clams while foraging?

Hypothesis: Crows attempt to maximize energy intake rate according to the optimal diet model

Prediction: Crows should eat all clams greater than 29mm in size and reject all clams <29mm in size

Methods: -Recorded the size of clams that were eaten and the size of clams picked up but not eaten (rejected)

-Measured handling times of differently size clams (timed crow opening shell and measured size of the shell)

-Measured energy content of differently size clams

-Measured encounter rates

Results: Energy and handling time increased with size

Profitability was maxed at the highest size

Found, almost always at clams greater than 30mm, always rejected less than 26mm

Didn't follow the zero-one rule, exhibited partial preference

Conclusion: Energy intake close to predicte of the optimal diet model

Front 18

Define: Diminishing returns

(Patch model topic)

Back 18

When a forager enters a food patch, it initially harvests food at a high rate.

As the patch is depleted, its harvest rate declines

Front 19

Define: Marginal Benefit: In foraging, thru benefit obtained by feeding for one more instant

Back 19

In foraging, thru benefit obtained by feeding for one more instant

Front 20

Optimal Patch model assumptions (4)

Back 20

1. Foragers attempt to maximize energy intake rate

2. All patches are identical

3. Travel time between patches is constant

4. The instantaneous harvest rate declines as a forager depletes a patch; the forager experiences diminishing returns in each patch

Front 21

Marginal Value Theorem

Back 21

Forager will stay in patch until its marginal benefit of feeding declines to equal average energy intake rate from environment

(look at slides for other definition)

Front 22

As travel time increases, forager should spend more/less time at the food patch

Back 22

more

Front 23

Patch Use by Ruddy Ducks (Prediction, Quick method, result/conclusion)

Back 23

Prediction: As travel time between patches increased, forager time at patch should increase

Method: Tome put 2 patches at bottom of a tank and had the ducks dive to them for food for another experiment. After finding time all the times in the first experiment he wanted to compare the amount of food eaten at each patch if he were to change the distance between the patches

Results: When increasing the space between patches found that the ducks stayed longer/ate more at each patch

Conclusion: significanly more food was eaten (time taken) at patch when increasing the space between them

Front 24

Optimal Patch Use: REVISED

Costs included are: (3)

Hint: when feeding

Back 24

Energetic costs: E used to exploit patch

Predation risks costs: Fitness cost associated with being killed by a predatory

Missed opportunity costs: costs of forgoing other activities that might yield increase in fitness (eg.mating)

Brown's patch-use model

Front 25

Brown's patch use model (REVISED) predicts that patches with identical benefits and costs should be harvested down to the same _______________________?

Back 25

Quitting harvest rate