Behavioral Ecology - Exam 2

ZOO425 Exam 2 - Spring 2025

predator-prey interaction sequence

way to escape predator-prey sequence at 1

activity of timing, spatial incongruence, both

way to escape predator-prey sequence at 2

vigilance (ex. sleeping ducks brain activity based on group location)

way to escape predator-prey sequence at 3

maximize cripsis or change spatial location (seek refuge)

way to escape predator-prey sequence at 4

convince predator of low quality or high capture costs

way to escape predator-prey sequence at 5

initiate flight (flee)

way to escape predator-prey sequence at 6

active defense, be distasteful, play dead (all last stops)

life-dinner principle

prey are running for their life, predator running for their next meal

• higher cost for prey, so evolution works stronger on prey

flight initiation distance

distance from predator where flight is initiated depends on distance to refuge, prey experience, and predator effects

combining predation and MVT

patch quality influenced by predation risk determines energy yield in patches

• how long in a patch is influenced by predation risk

giving up density equation

GUD = P + C + MOC

information

reduces ambiguity regarding the state of the environment, clarifies risk

cue

some component of the environment that can be perceived by a focal organism (by any sensory modality) and provides information

direct cue

produced by the predator or the act of predation

indirect cue

associated with predation risk, but not produced by the predator or the act of predation, typically raises or lowers risk no matter whether the predator is there or not (ex. time of day, presence of refuge)

predator facilitation

one predator benefits from anti-predator behavior from another predator, cost of risk-adversion

quality of information depends on

• quality - how much it disambiguates

• cost of gathering information - time, energy, risk, MOC

• discrimination - ease and costs or benefits of determining different states

• environmental change

error management theory (smoke detector principle)

there are two ways to be wrong, err towards the least costly way

false-postive

assumes risky when actually safe, costs of unnecessary defense

false-negative

assumes safe when actually risky, costs of forced attack defense

decision threshold

where the organism decides to accept false-positives or false-negatives

consumptive effects (CEs)

effects created by predation (by eating the prey)

non-consumptive effects (NCEs)

effects created by the risk of predation

risk allocation theory

prey in acute risk environments are more responsive to pulses of risk than prey in chronically risky environments

• depends on background and duration of the cue

• must eventually accept some level of risk due to the cost of safety becoming too high

induced defense

a defense mechanism induced by the environment

• typically morphological (ex. daphnia shape in presence of fish), chemical (ex. plants predation and MeJA exposure), or behavioral

crypsis

prey defense where prey matches the background

• avoids detection

• prey must choose correct background

masquerade

prey defense where prey is mistaken for background

• avoids identification

• requires predator experience being not interested in the background (ex. chickens and sticks)

aposematic (warning colors)

prey want to be detected and identified as a threat

• identified as a threat

• predator must have innate or learned recognition

  • innate more likely in high risk situations

mullerian mimicry

two dangerous species mimic each other

• both species benefit

batesian mimicry

a harmless species mimics a dangerous one

• reduces protective value of dangerous one unless mimic is very rare or the dangerous one is very dangerous

aggressive mimicry

a dangerous species mimics a harmless one

arms race

a strong reciprocal selection, coevolution with natural enemies and what they attack

• needs extreme interactions between species

  • less strong with asymmetric or opposing selection

asymmetric selection

selection that is stronger in one species than another (ex. life-dinner principle)

opposing selection

selection for one thing causes a decrease of fitness for another

probability of arms race

predator-prey < host-parasite < host-pathogen

hosts change behaviors

parasitoids

ecology of disgust

why things provoke disgust may be due to innate parasite avoidance

parasites change host behaviors

ex. increased predation risk to move parasites to next host species

interspecific competition

competition between different species

intraspecific competition

competition within species

exploitation competition

one competitor uses a resource better

interference competition

one competitor prevents another species from using or accessing a resource

patch

a spatial subset of a habitat that is treated as a single homogenous unit by the behavior of the individual

• depends on the individual’s use of a habitat subset

habitat

a spatially bounded area with a subset of physical and biotic conditions within which the density of interaction individuals, and at least one of the parameters of population growth is different than adjacent habitats

habitat selection

the process whereby individuals preferentially use or occupy a non-random set of available habitats

Ideal Free Distribution (IFD)

a model of exploitive, intraspecific competition

IFD assumptions

individuals are ideal (have perfect knowledge of available habitats) and free (have no constraint on selection the optimal habitat) and fitness is negatively related to density (competition decreases fitness)

IFD predictions

1. fitness is equal among habitats if the density is such that both habitats are being used

2. density differs, but fitness doesn’t

   1. F₁ = F₂ but D₁ ≠ D₂

3. correlation between density and quality

   1. acute indicators of each other

   2. higher density = higher habitat quality

Aphid galls on leaves

• same average number of aphids per gull with a different number of gulls

• however, within a leaf the gulls interfere with placement on a leaf

  • not free

whether IDF applies may depend on the scale

Isodars

when D₁ and D₂ are based on equal fitness, you can predict fitness from the densities or predict the densities based on equal fitness (ex. pike)

territoriality

the economic defendability of a resource, depends on the environment

territoriality requirements

many intruders, has resources distributed across space and time in clusters of high and low abundances

signs of territoriality

non-overlapping space use held by an individual or group of individuals that can be always held or seasonally held

costs and benefits of territoriality

benefits - sole access to a resource

costs - defense (time and energy)

Ideal Despotic Distribution

IFD where the individuals are not free

• territoriality stops free choice of habitat

  • cannot make IDF assumptions

determining IFD or IDD

must measure whether a population is free or not

• measure fitness between populations, territoriality, demography (age, size reproductive status)

  • ex. higher quality habitat held by dominant individuals who are older/larger/highly reproductive

source-sink population

organisms from the source migrate to the sink, what happens to the populations depends on the state of the source, sink, and the ability to migrate between them

• source: lambda < 1 (increasing population growth)

• sink: lambda > 1 (declining population growth)

source-sink populations with territoriality

ex. source is territorial and only the very best get good quality territory and pushes others out to the sink

• individuals not free! (cannot choose to go back to the sink, forced out) - IFD assumptions do not apply

• population of source < population of sink

• must gain more information to determined whether it is a source or sink population

costs and benefits of group living

depends on the environment and group/social structures and can change in space and time (ex. information sharing or reproduction as a cost or benefit)

• benefits - predation risk (vigilance, dilution, predator defense), environmental stress, mate location, social or shared information

• costs - competition (resource of reproductive interference), disease or paratisms, social or shared information

Lima and Dill 1990

meta-analysis on predation risk trade-offs and decision making when exposed to a CE, highlighted predation influence on ODM and MVT

Morris 2006

Ideal Free Home Theory and pike

Pravosudov 2009

chickadee cache location and ability to recognize pilferer species