Insect-level intelligence

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Insect-level intelligence
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Information for performing tasksLearning about
home a routine for acquisitionExploration and
the return from newly discovered sitesLearning
routes scaffoldingMultiple routes and memory
retrievalRepresentation of space routes not
maps
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Behaviours generally evolve within a specific
ecological niche and the strategies and
underlying neural systems may only operate
effectively in that niche.
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Predator avoidance categorisation using simple
features
Zeil and Hemmi, 2006
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Crabs live on a flat surface where all objects
above the horizon are classified as predators
Zeil and Hemmi 2006
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• Unexpected sophistication
• Crabs at first run to their burrow whenever they
  spot movement above the horizon.
• But, if objects are presented repeatedly,
  their escape attempts habituate, unless the
  object is a dummy bird.
• (Hemmi and Zeil)

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Behaviour is also guided by complex information

• Burrows are a valued resource and fiddler crabs
  keep their burrow under constant surveillance.
  They return rapidly to it if an intruder
  threatens to take it over.

Zeil and Hemmi 2006
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A crab starts to rush home when an intruder comes
within a set distance of the burrow. How does it
gauge this distance when the hole is invisible?
Crab can know the distance of the intruder from
retinal elevation and of the burrow from path
integration. These egocentric measures must be
combined to give the allocentric distance of
intruder from burrow.
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• Ants, social bees and wasps collect food for
  their nest. Individuals stick to one or few
  foraging sites and learn fixed routes between
  these sites and their nest.

Cataglyphis bicolor
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Collett, Dillman, Giger and Wehner, 1992
Homeward routes of Cataglyphis bicolor
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Behavioural routines for learning

• A bumblebee leaving its nest for the first
  time may be gone for an hour and then return to a
  small nest hole with a load of pollen.
• On departure. the bee performs an elaborate
  flight that helps acquire landmark information
  that can guide its return.
• The structure of such learning flights reveal
  efficient strategies for acquiring visual
  information.

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Collett (1995)
Learning flight of Vespula vulgaris leaving feeder
10 cm
10 cm
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Two learning flights from one wasp
Moments during six of the wasps flights when it
faces the feeder ()
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Return flights to feeder
Note consistent body orientation when is close to
the goal
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Body orientation in learning and return flights
Wasp 1
Wasp 2
Learning flight (when facing feeder)
Return flight (when close to feeder)
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Wehner, Meier, Zollikofer (2004)
Route learning in Cataglyphis starts with
exploration.
Successive foraging trips of an unsuccessful ant
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Wehner, Meier, Zollikofer (2004)
A luckier ant
White numbers show successful trips
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Wehner 1982, 1990
Path integration encodes the coordinates of an
ants current position relative to the nest so
providing it with the information to go straight
home.
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Ants encode the path integration coordinates of a
newly discovered feeding site into long term
memory and so can return directly to the site
through path integration.
Collett, Collett, Wehner, 1999
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Such straight routes due to path integration are
modulated by innate visuo-motor responses to
objects.
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Collett, Collett and Wehner (2000)
Route modulation by barrier
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Graham and Collett (2002)
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Graham and Collett (2002)
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Graham, Fauria, Collett (2003)
Route modulation by beacon
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• Scaffolding allows route to be acquired
  simultaneously along the whole sequence.
• It also means little chance of learning the
  wrong thing, so no danger in acquiring routes
  fast.
• Why does the ant bother to learn routes if it
  can reach its destination through path
  integration?

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• Route memories are linked to motivational state

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Food-ward and homeward routes overlap
Wehner (2003)
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Formica rufa
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Harris, Hempel de Ibarra, Graham and Collett
(2006)
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Harris, Hempel de Ibarra, Graham and Collett
(2006)
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Wehner et al. (2006)
Food-ward route not recognised by ant in homeward
motivational state
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Memories primed by panoramic context
Collett, Fauria, Baron, Dale 1997
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Honeybees in a 2 compartment maze in one place
Collett, Baron, Sellen,1996
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Spatial representation

• Ants use visual landmarks in a procedural
  rather than a map-like way.
• They are attracted towards places defined by
  landmarks or they associate motor commands with
  landmarks.
• But landmarks are not labelled with positional
  coordinates.

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Independence of PI and landmarks PI coordinates
are not reset by encountering familiar landmarks
Collett et al. 2003
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Routes are independent of PI state repeated
homeward routes (red and black) do not differ
from normal trajectories (grey).
Kohler and Wehner 2005
But home vector changes. After 1st repetition of
homeward route there is no home vector. After 2nd
repetition, home vector points away from nest.
Andell and Wehner, 2005
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• In mammals robust and flexible navigation is
  ensured by combining path integration and visual
  information.
• Separating the two strategies also gives
  robustness, one strategy can take over when the
  other fails, and errors in one strategy do not
  contaminate the operation of the other.
• A possible hallmark of insect intelligence is
  that it comprises smart, but specific and
  independent modules.