Lecture 4- Animal Signals Flashcards
example of complex signalling
facial expressions and gestures in primates
example of more clear signalling
large displays- frog warnings, etc
example of false signalling
batesian mimicry- e.g. in frogs, flowers
why might dishonest signals stay evolutionarily stable?
are only a small part of an honest system- generally advantageous for responders to take signals as honest- density-dependence
4 issues with signalling
need to get past bacground noise, signal degradation, avoid confusion, and lead to the correct response
how is the challenge of background noise/signal degradation overcome?
highly repetitive or very noticeable signals, sich as repetitive bird songs, pill bugs looking the same the whole way around to make it noticeable from different angles more easily
how can confusion be overcome?
creating signal diversity between species
example of useful intra-species variation in signalling
gazelle jumping- uniform signal to set a standard, but the variation can provide the actual information
what does ‘typical intensity’ mean
the idea that animal signals have a threshold to eliminate confusion about where they begin- signal ‘switches on’ after a certain threshold after which the other party can judge intensity
how did Dawkins and Krebs theorise that manipulation could help exaggerated displays evolve?
receiver evolves reduced sensitivity to a stimulus following manipulation- ‘sales resistance’
signal intensity is escalated
evolutionary arms race, leading to very conspicuous traits
what does ‘mind reading’ refer to?
receiver understanding actions which could give away future behaviour
how did Dawkins and Krebs theorise that mind reading could help more subtle displays evolve?
-receiver ‘mind reads’
-signaller reduces the conspicuousness of an action
-receiver gets more sensitive
-arms race based on stealth and concealment, or leading to ‘conspiratorial whisper’ behaviour
example of a ‘conspiratorial whisper;
honey bee waggle dance- signals quite a lot of information in a relatively quiet and non-costly way
what is the handicap principle
for signals to be effective, they must be reliable, and to be reliable, they must be costly
types of handicap
revealing handicap or ‘index’- sometjing correlated to the actual trait it is signalling, e.g. frog croak depth, which is impossible to fake
‘strategic choice handicap’- producing a disohonest and exaggerated signal isn’t worth it
