Sensory Ecology 2: Predation and Aggression

Find Food - Predator-Prey Interactions
1. Visual cues can be used to detect prey
  1. Thee cues may be obscured by the complex habitat
  2. Prey is also under selection pressure to not be detected
    1. Use camoflage or crypsis
      1. Prey that is detected show rapid response times
  3. Predators use many different senses to detect prey
2. Predation strategies
  1. Ambush Predators
    1. These predators will wait for mobile, abundant prey to come into their active capture area
      1. E.g. spotted stargazers who hide in burrows and use their lateral line to detect wake of prey in water
  2. Criise Predation
    1. Predators move through the water to capture less abundant prey
      1. Prey is normally evenly distributed throughout water column
3. Saltatory Predation
  1. Predation where predator will move and wait, move and wait.
    1. eventually prey will move into the animals active capture area
    2. Basset et al (2007) looked into the predation strategy of scorpionfish
      1. Porcelain crabs are small and uptake water through scathognathies
        fish have to move and wait so as to detect crab breathing (interference)
      2. Prey is not abundant so cant ambush
      3. Scorpionfish detect water currents through lateral line
Avoid Detection
1. Background matching
  1. Hermit Crabs occupying empty gastropod shells
    1. Given choice of either light or dark shells on an either light or dark background.
    2. Initially crabs just pick whatever shell is closest regardless of background match
      1. After 24 hours crabs have changed choice to shell that matches background.
      2. In dark backgrounds crabs only changed shell to match when there was a predator cue
2. Counter-shading
  1. Reef sharks have two different colourations on their bodies
    1. Light underneath so prey below cannot see when they look up.
    2. Dark topside so that prey/predators above cannot see from above
3. Disruptive colouration
  1. Animals trying to break up their colouration (stripes)
    1. E.g. Spotted Drumfish
  2. This breaks up the outline of the animal in complex habitats
    1. Useful for avoiding detection
4. Colour change in Cephalopods
  1. Cephalopods have been known to change colour based on their background
    1. Carry out this process using chromatophores
    2. Eg Cuttlefish
Decision making and Competition
1. Briffa et al (1998) Decision to give up in hermit crab fights.
  1. Successful attackers rap on shell more vigorously than ones that give up
  2. When a crab is evicted the last rapping bout will have been strongest
    1. If a competitor doesn't give u shell rapping strength decreases
2. Hypoxic conditions cause attackers to rap slower and causes them to give up easier

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Sensory Ecology 2: Predation and Aggression

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	Created by Connor Joesbury over 6 years ago