11 Flashcards
What is a signal? What does it involve
Basic info
Sender and receiver
Both benefit
Stable if both benefit
Alters behaviour of receiver but receiver has evolved to respond also
3 communication types
And example
Coercion - camouflage
Cue- co2 guide mosquito
Signal - honey bee waggle dance
Show weight not cue
Funnel web spider
Weight is indicator of fighting ability but the signal is vibrating web to give info about weight
Same thing can be signal and cue
Tungstate frog song
Signal song to female
Cue song alerting itself to prey
Trade off
Classification types 4
Modality and medium
Information content
Honesty guarantees
Context
Modality
Sound light chemical electric field touch seismic
Medium
Air water solid
Info content 3
Sender -identity sex size Dom toxicity
Receiver- detection
3rd party- presence/ location/ qual quant
Honesty guarantees 3
Index signals- reliable can’t be fakes
Handicap- reliable -costly to fake
Conventional common interest - sender and receiver have common interest
Often seen in monogamous pairs
Context 4
Enviro presence and location of resources, conflict or aggression, mating / courtship or social group co ird
Indices two examples
Red deer stags
Assess fighting ability or oarallel walk to avoid heavily unmatched fights and reduce fighting costs - locking antlers is rare
Buck bufo Toad
Breed in pond, f there for few ayes so in demand , pitch of croak indicates body size is fewer attacks when deep croak ( limit is that strength of kick is also important)
Vary with qual induces and handicap?
Indices vary gradually with quality
Handicap signal means high quality individuals are favoured to make signal
Handicaps examples (4)
Stalk eyed flies
Badges of status
Harris sparrow
Honer wasps
Zahavi handicap principle
Makes can ridine costly ornaments only if good qual as if a low qual cost would outweigh benefit - the cost is lower for high quality males
Stalk eye male flies
High qual make allocates more resources to eye span and steeper decline with food than wing size so honest signal
Harris sparrow
Larger black bibs dominate and displace others from food but if faked a signal would have high social cost due to increased aggression and punishment
Honer wasps
Black facial spots
Like Harris sparrow faking signal would lead to high social cost of aggression
Handicap not only energy costs but also 3
Social cost - badges of honor if faked have aggression
Efficacy cost- required to ensure info reliably perceived
Strategic costs- to maintain honesty if handicap signals
Common interest 4 examples
Honey bee waggle dance
Quorum sensing bac
Fruit flies
House sparrows
Common interest
No point deceiving receiver
Kin selection
Honey bee waggle dance shows
Kim selection Alba shows distanc and angle of food source by dancing
Worker gains kin selection as dancer relatives will be fed
Quorum sensing bacteria
Between cells
Switches behaviour if high pop density
High pop density - use of common good
Problem with honest signals
Individuals that don’t respond to signal can invade pop as get benefits ie in quorum bacteria
Fruit flies
Courtship and receipt ability drosophila female if mates stops the male wasting his time dancing by extruding her ovipositor and bending her a do towards him and stopping this
Honest signals are common in spp where f mates once
House sparrows
Non relative signalling
Vocalisation when food source found
Icrease S number mean reduced predation risk
But sparrow chirrup call shows this depends on situ
If predator not preset and food easy to share less call
Dishonest signals examples 4
Fork tailed drongos
Fiddler crab
Angkerfish
Mantis shrimp
Fork tailed drongos bird
Makes fake alarm call to makes meerkat abandon food so eat it - but not all calls are false
1/4 food is stolen
Fiddler crabs
Low qual make can lose claw and Regrow weaker that is dishonest indicator of fighting ability
Angler fish
Lures other fish using LURE looks like work
Bayesian mimicry is also dishonest signal h
Mantis shrimp
Forelimbs covered in exoskeleton moults every 2 months but can still use as threat even when has moulted it
This is rare as less than 15 % are moulting at any one time
Intentionality of communication unintended (2) and examples
Eaves dropping m fiddler crabs and Siamese fighting fish
Exploitation - bats crickets and humans and parasitoids
Eaves dropping
M fiddler crabs - see makes and see other mail waving conspicuously but can begin waving before f visible
F Siamese fighting fish- If audience m make no Sig difference in way males displayed but if audience female m increase intensity of conspicuous displays
Audience effect -info to make and female
Exploitation
Parasitoids- as makes are usually more signalling sex they are usually more at risk of predators that locate by sex signals
Bats exploiting neutropical all frog calls - eavesdrops in advertisement if m tungaa fm frog and exploits frog sing to predate it
Parasitoids flies exploiting cricket calls- acoustically orientates via phonotaxis to m cricket sing so singing is therefore costly as attractive to mate as well as predator
Human language - honesty could be maintained by social cost of lying - did selectio factors lead to dif communication forms
Cost benefit if honesty
Strategy and currency
How much to invest in a sexual trait in order to attract mates benefit given the cot is producing it
Long term maximisation of fitness
Honesty cba
Assumption
As trait gets larger it becomes more disturbing to produce therefore cost is energetic
What determines the cost for particular value of T (trait)
Cost coefficient alpha
W=
Benefits - costs
W of L(T)
T - alpha L T^2
Or
T-2T^2
W of H (T) =
T - alpha H T^2
Or
T-T^2
Lec overview 6
Basics Classification Honesty hypotheses Dishonest signals Intentionality Cost benefit of honesty
More examples (lec 12)
