1
Q
define cryptic colouration
A
morphological colouration that matches the colour of the environment to reduce detection by predators
2
Q
why are predators less likely to notice slow-moving or stationary prey?
A
bc predators often use motion detection to find prey
3
Q
explain the experiment on the proximate explanation for the behavioural changes in lizards
A
- manipulated the corticosteroid hormone levels in male ornate tree lizards and observed their behavioural responses to sight of a predator
- corticosterone levels elevated for half males through dermal patch
- control males had patch on w/oil only (no corticosterone)
- lizards exposed to caged collard lizard (predator) - measured latency to respond first, time spent hiding and plasma corticosterone levels after exposure
- results showed experimental group had significantly hgiher levels of elevated plasma corticosterone levels compared to control group
- individuals w/high corticosterone levels reacted more quickly (lower latency to respond) and spent more time hiding
- concluded such hormonal response can facilitate more rapid antipredator behaviours if and when future encounter w/predator
4
Q
in vertebrates, how happens during exposure to a stressor?
A
often causes increase in the plasma concentration of corticosterone - stress hormone affecting both physiology and behaviour in ways that reduces predation risk
5
Q
how can the defenses to avoid predation of caterpillars be categorized?
A
aggressive or evasive
6
Q
what are some aggressive defense behaviours of caterpillars?
A
biting and regurgitation
7
Q
what are some evasive defense behaviours of caterpillars?
A
- thrashing and twisting
- head flicking
- dropping from an elevated perch
8
Q
what does regurgitation mean
A
bringing swallowed food up into mouth again
9
Q
what does latency mean?
A
state of inactivity/dormancy
10
Q
explain the experiment investigating the effectiveness of antipredator behaviours of caterpillars
A
- tested response to a parasitoid attack
- scored each individual for types of behavioural defenses employed during a simulated parasitoid attack - gently brushing caterpillar and gently squeezing it
- then all caterpillars developed in captivity
- results found significant relationship between antipredatory behaviours exhibited by a species and its level of parasitism
- species least parasitized uses aggressive bites and dropped when attcked
- high rates of parasitism showed no antipredatory behaviour or only thrashing
- aggressive defense and dropping when attacked were associated w/enhanced survivorship
11
Q
A
11
Q
explain the startle display in swallowtail butterflies experiment
A
- wanted to see wether sudden reveal of brightly coloured dorsal wing surface when predator is nearby is effective startle display to discourage great tit?
- collected wild birds, grew butterflies in lab - half were killed when became adult other half kept alive
- birds trained to eat mealworm on wooden surface
- had two wooden surfaces w/mealworm - one had dead butterfly other had alive
- single bird released into experimental room, its behaviour and behaviour of live butterfly was recorded
- of birds that attacked, most attacked dead butterfly first - latency to attack differed significantly
- live butterfly responded w/startle display majority of time bird came to visit
- majority of birds that visited live buttefly quickly flew away or hopped back - appeared to be startled and wary to attack butterfly
- very little live butterflies killed - suggests important antipredator function of wing-flick startle display by butterflies
12
Q
what is the startle response in butterflies?
A
abrupt changes in behaviour often involving sudden exposure to conspicuous colours that may be accompanied by a sound
13
Q
what is a behavioural trade off?
A
sacrificing one activity for another
14
Q
define vigilance behaviour
A
a behaviour in which an individual scans the environment for predators
15
Q
what does ubiquitous mean?
A
present, appearing,, observable everywhere
16
Q
what can be predicted about vigilance behaviour and the environment?
A
as predation risk increases, so should vigilance
17
Q
explain the vigilance and predation risk in elk experiment
A
- wanted to see how elk behaviour was affected by the presence of wolf
- recorded behaviour of elk herds: proportion of time spent feeding, moving, bedding, or vigilant w/presence of absence of wolfs in the drainage
- results showed elk spent majority of time foraging and very small time vigilant
- stronger effect of presence of wolk on females; significantly more time vigilant and less time feeding when wolves nearby
- male behaviour largely unaffected by presence of wolves
why? 1) - maybe bc bulls larger than cows & represent more dangerous challenge to predators
2) maybe bc reproductive success largely dependant on maintaining high body mass - males have more to lose by reducing feeding time, even if consequences is higher predation risk when wolf nearby
18
Q
what two research questions can be asked about animals in terms of patches richness and risk?
A
- how often will animals be willing to accept higher predation risk in order ton feed in richer patches
- what factors might favour animals feeding in richer but riskier patches?
19
Q
explain a bit about redshanks
A
- medium-sized wading birds
- long straight bill used to find insects, earthworms, mollusks and crustaceans buried in soil
- found in salt marshes and mudflats
20
Q
explain the environmental conditions and predation risk in foraging redshanks experiment
A
- studied how weather conditions and predation risk affected daily feeding rate during winter
- observed predator (sparrowhawks) more common in salt marsh than mudflat, concluded salt marsh was risker; but observed on some winter days redshanks fed more in the riskier salt marsh than mudflat
- since birds are endotherms, predicted - energetic requirments and predation risk affect redshank feeding behaviour; outside low temp, birds cannot find sufficient food by feeding only in mudflat
- predicted - salt marsh has more food than mudflat, ambient temp affect where redshanks will feed
- exp: collected samples from both env and counted # of invertebrates found - results showed more intervetrabtes in salt marsh than mudflast
- exp 2: recorded # of redhanks feeding in salt marsh in low and high tides and temp for some days - as temp decreased daily, more redshanks fed in salt marsh
- concluded more food in salt marsh and when is cold, feed in riskier salt marsh bc more food present and should results in higher energy intake rates
21
Q
explain the mating and refuge use in fiddler crabs experiment
A
- wanted to see if males would emerge from their refuges more quickly after an attack if mating opportunities available
- exp: created plots, put active female in half of the plots, other half control
- when all males came aboveground, flew model predator over burrows
- recorded how long birds stayed in their burrows after attack
- compared averages for both groups - results showed some males did not go into burrow w/female present, others that did reemerged very quickly, control took longer
- concluded males adjust their refuge use based on its benefits and costs - trade off safety for increased mating opportunities when receptive female present
- when no female present, use burrows much more
22
Q
explain the perceived predation risk affects reproductive behaviour in sparrows experiment
A
- wanted to see if changes in perceived predation risk could also affect song sparrow life history
- exp: protect nests from direct predation through electric fencing and seine netting
- recorded behaviour of females in breeding season; treatment - played vocalizations of predators for 4 days, silent for 4 days
- control - vocalizations 4 days, silent 4 days of nonthreatening species
- results showed treatment females nested in denser vegetation, laid fewer eggs, fewer offspring and more nestlings died - perceived predation risk can affect reproductive behaviour
23
Q
how do fiddler crabs attract females?
A
- wave one large claw back and forth
24
at what cost does risk reduction come at?
reduced feeding or reproductive activity
25
what is a way to reduce predation risk?
living w/others (dilution effect), stay near the centre of group (selfish herd hypothesis), vigilance behaviour (group size effect)
26
define social group
a set of individuals that live near and associate w/one another
27
define the dilution effect
a reduction in the probability of death as a result of associating w/others
28
explain the relationship between dying an N number of individuals in a group
as N increases, probability that any single individual dies decreases
29
what is the only behaviour required for the dilution effect to occur?
an individual to join others in a group
30
define the selfish herd hypothesis
the hypothesis that a predator is more likely to kill a member on the outside of a group because it will encounter outside individuals first
- individuals can lower predation risk by placing others between themselves and an approaching predator
31
define the group size effect
a commonly observed patter in which the vigilance behaviour of an individual declines as group size increases
32
what are the two factors that are though to be the cause of the group size effect?
- as group size increases, each individual is safer because of dilution effect - can reduce level of vigilance
- as group size increases, each individual can afford to scan less frequently bc more individuals are scanning - collective vigilance high, ind. vigilance low
33
explain the group size effect and selfish herd hypothesis in dove experiment
- wanted to see if 1) if exhibit reduces scanning as group size increases (group size effect) 2) if ind. at perimeter exhibit higher scanning than those at centre of a flock (if doves at edge exposed to greater danger - SHH)
- observed focal individuals in dif. flocks - recorded location, scan rate, scan durations, total amnt time spent feeding - also note of position shifts
- results showed ind. vigilance decreased greatly as group size increased - yes to group size effect
- also saw ind. at centre exhibited lower scan rates and higher feeding rates than those at perimeter
- most position shifts from edge to centre
- concluded trade off btn scanning and feeding: scan decreases as feeding time increases w/group size
- supports idea of SHH that individuals at edge experience higher threat of predation than at centre
- suggests that dominance hierachy maintains group position; dominant at centre, subordinate forced at edge
34
define predator harassment
interactions with a predator to deter attack. Such behaviour can involve rapid movements, loud vocalizations, and throwing or kicking objects at the predator.
35
define mobbing behaviour
the harassment of a predator by two or more individuals
36
explain the predator harassment in ground squirrels experiment
- wanted to see if harassment of rattlensnakes had an infrared component and if such harassment causes snakes to be more defensive
- staged encounters w/dif. stimuli - rattlesnake, adult gopher snake, control (ground squirrel) separated by mesh cage
- recorded trials w/infrared camera - quantified amnt of heat coming off squirrel w/dif. stimuli
- also measured the temp of bodies and tails of squirrels
- results showed tail flagging w/snakes only
- squirrel tail temp higher during encounter w/rattlesnake
- squirrels add infrared component only w/rattlesnakes that can detect change
37
how do ground squirrels harass rattlesnakes?
rapid movements, engaging in vigorous tail-flagging (rapid wagging of the tail), kicking dirt and rocks
38
explain the second part of the ground squirrel experiment
- to determine how infrared signal of squirrels affected rattlesnakes
- used model squirrels - could do trail flagging behaviour and alter the temperature of tail
- trained snakes to retrieved food from artificial squirrel burrows
- put model squirrel next to burrow
- 2 treatments: cold tail and warm tail (w/infrared signal)
- found snake showed more defensive behaviour and moved less w/warm tailed squirrel
- shows adding infrared component to predator harassment behaviour is effective to hinder snake predator
39
what is advertisement behaviour?
advertising to predators - making oneself more seen/obvious
40
why might an animals indulge in advertising behaviour?
pursuit-deterrence hypothesis, alarm signal hypothesis
41
define the pursuit-deterrence hypothesis
the hypothesis that advertisement behaviour informs a predator that it has been detected and so pursuit is not likely to be successful
42
what does the pursuit-deterrence hypothesis predict
animals close to predator should exhibit tail-flagging behaviour more often than prey close to predator
- bc far away means is relatively safe, can benefit by deterring an attack w/little success possibility
- risk of capture higher if close, so should not advertise itself
43
define the alarm signal hypothesis
the hypothesis that advertisement behaviour functions to warn nearby conspecifics of danger
44
explain the tail-flagging behaviour in deer experiment
- tested both hypotheses
- alarm signal hyp - solitary deer exhibit less tail flagging than deer in social groups
- pursuit deterrence hyp - tail flagging should occur more often as distance btn predator and deer increases
- researchers acted as predators, once spotted - recorded # of deer nearby, if any aware of their presence
- selected focal animals, stalked animal - recorded # of times had tail-flagging behaviour, distance btn observer and deer, once fled also flight distance, flight time and tail-flagging behaviour
- results showed no diff. in tail flagging behaviour in social and solitary deer
- deer showed more tail flagging behaviour as distance increased
- observed deer that ran into dense forest stopped tail wagging, but standing in open continued it - maybe bc easier to spot in forest w/bright tail
45
what is an erratic drop?
drop in any direction bc of wind or other environmental factor to avoid being caught by preator
45
what does the alarm signal hypothesis predict?
solitary prey will rarely display advertising behaviour bc there is no one else to signal about danger
46
when are evasive actions taken by prey?
too slow to escape predator
47
how do tiger moths escape bats?
stop flying and initiate erratic drop just before attack to avoid capture
48
what is an evasive action
a range of maneuvers or strategies employed by prey animals to escape or avoid capture when they are detected by a predator. These actions are part of the prey's defense mechanism to increase chance of survival.
49
what are some evasive actions?
fleeing, hiding, camouflage, deception, group defense, defensive weaponry, mimicry, freezing
50
explain fleeing
Running away from the predator to create distance and reduce the likelihood of capture. Some prey animals are adapted for swift, agile movements to increase their chances of escape.
51
explain hiding
Seeking cover or concealing themselves to make it difficult for the predator to locate them. This may involve finding shelter, burrowing into the ground, or blending into the environment.
52
explain camouflage
Some prey animals have evolved to blend in with their surroundings, making it harder for predators to spot them. This includes colouration and patterns that match the environment.
53
explain deception
Employing tactics to confuse or distract the predator, such as false alarms, sudden changes in direction, or vocalizations meant to startle or mislead the predator.
54
explain group defense
Prey animals may band together in groups for safety. Larger numbers can make it more challenging for predators to single out and capture an individual.
55
explain defensive weaponry
Some prey species have evolved physical defenses like spines, horns, or other structures to deter predators. When cornered, they may use these structures to defend themselves.
56
explain mimicry
Some prey species mimic the appearance or behaviour of other organisms that are unpalatable, toxic, or dangerous to predators, deterring them from attack.
57
explain freezing
In some cases, prey animals may freeze in place when detected, relying on the hope that their lack of movement will make them less conspicuous to the predator.
58
explain nocturnal activity
some species are primarily active during the night to avoid diurnal predators
59
explain crepuscular activity
some species primarily active during twilight (crepuscular) to avoid diurnal predators
60
explain vigilance and alertness
animals may remain vigilant and alert to detect predators early, allowing them to flew or take defensive action
61
what are some ways animals modify their behaviour to reduce predation risk?
noctural and crepuscular activity, synchronization of breeding, hiding and shelter use, escape behaviour and warning calls or signals
62
explain synchronization of breeding
Some species time their reproductive activities to coincide with periods of abundant resources, reducing the need to expose themselves to predators frequently.
63
explain hiding and shelter use
Animals may seek refuge in burrows, nests, dens, or other shelters to avoid predation during vulnerable times, such as when giving birth or molting.
64
explain escape behaviour
Rapid and agile escape behaviours, such as flight or fleeing, help animals evade predators.
65
explain warning calls or signals
Many animals use alarm calls or signals to warn others in their group about the presence of a predator.
66
what are some benefits of group living?
group acquisition of food (hunt together), access to mates (in group itself), shelter, protection from predation, social thermoregulation (huddle together, take advantage of e/o body temperature during extreme weather)
67
what are the anti predator benefits of group living?
dilute risk of attack (swamping predators; selfish herding), predator confusion, communal defense (take turns vigilancing, work together to hunt and protect), improved vigilance for predators
68
what are the foraging benefits of group living?
better food finding (information centres where scouts bring info or food, share responsibility), better food capture (group hunting - bigger food)
69
explain the selfish gene idea
idea suggesting individual will behave in way to maximize survivorship of gene – behave way we do bc of genetic level – genes drive behaviour bc want to continue in future generations – more reason for being in herd
70
what does an evolutionarily stable strategy suggest?
if all members adopt a specific strategy, it cannot be bettered by a different strategy
- if group gets larger, amnt of time of time spent in vigilance per individual decreases
- for cheaters, likelihood of getting cause increases w/more members
71
71
how can grouping improve foraging?
- can work together to take down large prey
72
what is a coalition?
- adult male lions in a pride usually related to eo
- coalitions usually composed of brothers or closely related males that have formed an alliance to work together in controlling a territory and its associated prides of lionesses
73
how does cooperative hunting in lionesses occur?
- individuals specialize in their preference for either being at the wings or centre
- the wings tended to stalk the prey
- the ones at the centre were typically the largest and heaviest and also made the final kill as the prey were directly towards them
74
explain the optimal group size model
- as group size increases, benefits and costs increase
- eventually benefits start to decrease and costs accelerate
- cost will exceed benefit
- model shows optimal group size is an intermediate group size
75
what is the optimal group size for lionesses?
- w/increasing group size, capture success also increases
- but food available decreases
- data shows 3-4 ind. per hunting group makes most sense
76
LifeSci 2D03
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