What is predicted when offspring will win parent/offspring conflict?
- Piglets do better
eg. example with piglets and sow in confined or get-away pens. When piglets are in control, they go for their optimum, when parents are in control, they go for their optimum.
Conflicting selecting pressures on parents and offspring.
What’s a signal?
Any adaption whose function is to affect the behaviour of other animals or provide stimulus for other animals
- Doesn’t really address fighting .
- IE. deer can use antlers as weapons (eg. pushing) OR as a signal (eg. showing them off)
What are the five components of a signal (in order)?
- Sender
- Signal
[Transmission] - Receiver [detection, recognition and meaning]
- Response
Signal gets to the receiver, and the receiver has to make a behavioural decision. There’s processing of the signal at the receiver. Meaning is referring to appropriate content for that receiver.
What influence the form of signals?
The environment and mediums that they have to pass through
Eg. sticking tail straight up in open grassland for visual signal vs. tactile/olfactory signals.
Might want something that’s not volatile and won’t spread through environment (eg. scratching certain area) or something that is volatile (eg. spraying wide area)
What happens to sound as it passes through an environment?
Attenuation (loss of energy/volume with distance)
- From absorption/spreading
- Worse for higher frequencies
Is attenuation worse for higher or lower frequencies? How does bird song demonstrate this?
Higher
Eg. Bee Gees getting soaked up by walls, but not bass.
Bird song is lower frequency in forests or dense environments.
How do animals make sure that their signals are detected and recognized? (3)
Conspicuousness
- Eg. having low/high frequencies in call
Repetition
Stereotypy (signal stays relatively constant each time)
What is the evolution of signals called? Why?
Ritualization
Because many signals look like rituals (eg. peacock fanning feathers or gazelle hopping)
What are some common features to signal evolution?
Like an arms race (opposing selective pressures)
- Senders manipulate receiver behaviour
- Receivers anticipate sender behaviour
Signals are honest (on average)
Do signals evolve as cues or responses first?
- Signals start as undetected signals
- When it’s the receiver’s advantage to detect cue, he evolves response
- When signaler then benefits from receiver reception, you get signal specialization
What ensures signal reliability?
- If interests coincide, none is needed
- If no reliability, there is manipulation
- If it can’t be faked, index?
- If it’s too costly to fake, it’s a handicap
- If fakes are caught, it signals status
What are two factors in the transmission of sound?
- Attenuation (loss of energy from absorption and spreading)
- Degradation (loss of form from reverberation)
Both of these are worse for higher frequency sounds
How can songs fit the transmission features of a habitat?
Open environment
- Broad bands
- Fast changes (high frequency)
Dense environments
- Lower frequencies and slow changes
What three factors influence detection and recognition once a signal arrives at a receiver?
- Conspicuousness
- Repetition
- Stereotypy
