Chapter 8: Foraging behaviour

Question 1

sensory modality

Answer 1

mechanism in which information gets to the animal

Question 2

what do fish use mechanoreceptors for?

Answer 2

detecting body position and information about water pressure/movement

Question 3

lateral line system

Answer 3

used by fish for “hearing”, detecting their body position and for information about water pressure/movement. made of neuromasts, which are mechanoreceptors that provide hydrodynamic information

Question 4

catfish prey tracking research questions

Answer 4

how to nocturnal catfish find food in the dark?

do catfish use chemical or hydrodynamic cues to track prey in the dark?

Question 5

catfish prey tracking hypothesis

Answer 5

catfish use their lateral line system to detect cues provided by the wake of their prey

Question 6

catfish prey tracking prediction

Answer 6

catfish will follow the wake of their prey while hunting

Question 7

catfish prey tracking methods

Answer 7

use infrared video to track movement of both predator and prey
classify movement as path following, head on, or attack on stationary guppy

manipulate lateral line or external gestation, classify hunting success and movement sequences of fish

Question 8

catfish prey tracking results

Answer 8

intact catfish relied mostly on wake following
lateral line inhibited (ablated) fish used a head on attack mode. hunting success SEVERELY reduced
taste ablated used more head on and wake following. hunting success mildly reduced

Question 9

what’s interesting about research into snakes’ heat sensing abilities

Answer 9

help inform tech for military, search and rescue, police

Question 10

bees foraging senses research question

Answer 10

is foraging more efficient when multiple senses are used?
(bees tend to use colour + shape along with odour to find flowers)

Question 11

bee foraging senses methods

Answer 11

trained individual bees to feed on artificial flowers
treatments:
- visual cue
- olfactory cue
- shape and olfactory cue

Question 12

bee foraging senses results

Answer 12

bees trained to use both visual and odour cues (multimodal) had highest feeding performance

Question 13

bee foraging senses conclusion

Answer 13

use of multimodal cues facilitates efficient feeding

Question 14

evolutionary arms race and visual predation:

Answer 14

natural selection favours more cryptic prey, behaviour or morphology that avoids detection.
natural selection favours predators that can better detect hidden/cryptic prey

Question 15

trout foraging research question

Answer 15

how does cryptic prey colouration affect trout foraging efficiency

Question 16

trout foraging hypothesis

Answer 16

prey that match their background will be harder for predators to detect, and predator hunting efficiency will increase with experience

Question 17

trout foraging predictions

Answer 17

1. trout will find non cryptic prey faster
2. trout will find cryptic prey faster with experience

Question 18

trout foraging methods

Answer 18

2 aquaria, identical except for bottom: one was brown plastic + grains, other was green plastic + grains.
placed prey in aquarium. it was cryptic on brown, conspicuous on green.
record time until fish found food item
tested half with cryptic half with conspicuous prey

Question 19

trout foraging results

Answer 19

found non cryptic prey faster
search time decreased with experience

Question 20

trout foraging conclusion

Answer 20

background colour matching can benefit prey by reducing predator hunting efficiency
predator search
predator search efficiency for cryptic prey increases over time

Question 21

optimal foraging theory, and 2 common examples

Answer 21

assumes that fitness increases with energy intake rate
behaviour that maximizes fitness is optimal behaviour
diet model
patch use model

Question 22

diet model assumptions

Answer 22

1. foragers maximize fitness by maximizing energy intake rate
2. food items are encountered one at a time in proportion to abundance
3. food items can be ranked by their profitability (energy/handling time)

Question 23

diet theory variables

Answer 23

food items: define energy and handling time
diets: define how specialized or general the diet is
mean search time: how much search time for each food item
mean handling time: how much time each type of forager spends handling food

Question 24

optimal diet model solving

Answer 24

average energy equation

Question 25

optimal diet model graphical solution

Answer 25

find line that minimizes time spent on one item and handling time per item. middle is best, since theres some specialization to speed up handling time but not so much where the food is hard to find.

Question 26

crow diet research question

Answer 26

why do crows reject some clams while foraging?

Question 27

crow diet hypothesis

Answer 27

crows attempt to maximize energy intake rate according to optimal diet model

Question 28

crow diet prediction

Answer 28

crows should eat all clams greater than 29mm and reject all clams smaller than this.

Question 29

crow diet methods

Answer 29

measured handling times of differently sized clams measured energy content of different sized clams

Question 30

crow diet results

Answer 30

clams over 30mm were almost always eaten, clams under 28 mm almost always rejected

Question 31

diminishing returns

Answer 31

when forager enters a food patch theres an initial high harvest rate, but as patch is depleted the harvest rate declines

Question 32

optimal patch use model assumptions

Answer 32

1. foragers attempt to maximize energy intake rate 2. all patches are identical 3. travel time between patches is constant 4. instantaneous harvest rate declines as forager depletes a patch (forager experiences diminishing returns)

Question 33

what does optimal patch use model predict?

Answer 33

the optimal time to spend exploiting each patch

Question 34

graphical solution to optimal patch use model

Answer 34

line that goes from start (beginning of travel time) will meet the curve. wherever it meets is the optimal time

Question 35

marginal value theorem

Answer 35

for fixed travel time Tt, energy intake rate is maximized when forager spends Tp time in patch short travel time = short patch time long travel time = long patch time

Question 36

costs when feeding:

Answer 36

- energetic costs -predation risk costs -missed opportunity costs

Question 37

updated patch use model

Answer 37

predicts that patches with identical benefits and costs should be harvested at the same rate

Question 38

give up density

Answer 38

amount of food remaining in a patch after foraging

Question 39

fruit bat research question

Answer 39

how do fruit bats exploit food patches that differ in food amount?

Question 40

fruit bat hypothesis

Answer 40

bats will attempt to maximize their energy intake rate

Question 41

fruit bat prediction

Answer 41

bats will equalize give up density across patches

Question 42

fruit bat methods

Answer 42

outdoor flight cage with feeding stations each station had 3 artificial feeders that differed in amount of food record give up density in all feeders for 3 days feeders had rubber pieces inside to make extracting food challenging

Question 43

fruit bat results

Answer 43

graph mimics the graphical solution for optimal patch use mode. as food harvested increased, so did time in patch but it began to level off. bats equalized giving up densities at 3 feeders in each station

Question 44

kangaroo rat methods

Answer 44

individuals feed from food patches filled with sand patches in open or covered with brush manipulated presence/absence of predator urine near patches measured give up density in patches

Question 45

kangaroo rat results

Answer 45

GUD lowest under shrub highest when predator scent present

Question 46

kangaroo rat conclusion

Answer 46

foraging behaviour is affected by predation risk costs as predicted by updated optimal patch use model

Question 47

food patch estimation

Answer 47

optimal patch use model assumes animals know quality of encountered patches, when in reality the animal will combine sample information about the patch with prior knowledge about other patch types using bayesian estimation

Question 48

bayesian foraging bees research question

Answer 48

can bees estimate food patch quality in a bayesian manner?

Question 49

bayesian foraging bees hypothesis

Answer 49

foragers combine prior knowledge of distribution of patch types with sample information to estimate patch quality

Question 50

bayesian foraging bees predictions

Answer 50

bees trained in uniform environment will exploit patches differently than bees trained in high variance environment

Question 51

bayesian foraging bees methods

Answer 51

trained bees to feed from artificial patches half in uniform, half in high variance environment observed propensity to depart a patch (estimate of patch quality)

Question 52

bayesian foraging bees results

Answer 52

high variance bees would have high propensity to stay in patch uniform bees would have low propensity to stay in patch

Question 53

bayesian foraging bees conclusion

Answer 53

bees appear to combine prior knowledge of patch type distribution with sample information to estimate patch quality (bayesian foraging)