Practical 2 - crickets Flashcards
What is habituation?
Innate responses to a stimulus decrease after repeated exposure to the stimulus
Why is habituation important?
Ensures behavioural responses are accurate and not caused by fear or stress as well as it being ethical
Cricket natural behaviours to look out for
Walking, running, antenna movement / fencing, stridulation (singing), harsh chattering, chasing, mandible fighting
What is an ethogram?
A catalogue of behaviors defined
Why is an inter-observer reliability test important?
Represents the extent to which data is collected accurately with each observer describing behaviours the same way
What to do if the chi-squared of your inter-observer reliability tests is < 0.8?
Look back over ethogram and redefine behaviours / make definitions more clear
Issues with taking cricket body mass?
Movement on scales, missing appendages, don’t know when last fed
Why do we measure the pronotum?
Good proxy for size
How did we assess aggression?
Observe frequency and level of aggression of fights in a period of time
What did we use to tell crickets apart?
Marked each with a different coloured spot of non-toxic paint
How to tell the loser and winner apart?
Loser walks away from encounter, winner chases loser, body jerking and singing
Important hypotheses
Greater difference in pronotum size = increased aggression, larger males start more fights to assert dominance, more likely to win if the crickets starts the fight
How were the crickets prepped?
Weigh body mass on scale in petri dish, measure pronotum width using digital callipers, left for 5 min to habituate
Tinbergen’s 4 questions about animal behaviour
Ultimate (why), proximate (how)
Tinbergen’s ultimate questions
Function (what is the behaviour for?) and evolution (where has the behaviour come from?)
Tinbergen’s proximate questions
Development (how does the behaviour develop?) and mechanism (how is the behaviour achieved?
What is a display?
Any behaviour pattern especially adapted (i.e. modified through evolution) in physical form or frequency to function as a social signal in communication
4 kinds of signals which animals use to communicate?
Auditory, olfactory / chemical, visual, tactile
Response rate to signals
Immediate (e.g. alarm calls), gradual (e.g. courtship) or both
Discrete signals
All or nothing (e.g. fixed action patterns)
Graded signals
Varying intensity and / or frequency
What is a fixed action pattern?
A discrete behavioural unit that is sterotyped, innate and is performed in an all-or-nothing fashion when the animal is triggered by a certain stimulus
What happens when a stimulus is detected?
It triggers an Innate Releasing Mechanism within the nervous system that generates the FAP motor output
Statistical tests used?
Correlation (Spearmans Rank) and T-test / Mann-Whitney U
