Transcript Visual Mimicry

Visual Mimicry
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Objectives
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Explain why animals use mimicry
Describe some of the categories of mimicry
Describe the three participants of mimicry
Explain aposematic and give examples
Understand the difference between aggressive,
sexual, mutualistic, and protective mimicry
Describe an example of audio mimicry
Why do animals use eye mimicry
Explain how imperfect mimicry is still successful
Describe the speed versus accuracy relationship in
mimicry
Provide an example of human mimicry
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Key Terms
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Mimicry
Bioluminescence
Photophores
Pollination
Pollenator
Aposematic
Unpalatable
Sexual dimorphism
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What is Visual Mimicry?
• 3 Players
– The Model
• Produces stimuli
– The Mimic
• Copies the model
– The Dupe
• Deceived by the mimic
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How do we categorize visual
mimicry?
• Aggressive Mimicry
– Allows mimic to avoid detection by prey
• Reproductive Mimicry
– Mimic propagates its own species
• Mutualistic Mimicry
– Mimic and dupe help each other
• Protective Mimicry
– Avoids detection by threat
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Aposematic
• A “warning” signal:
– Color
– Sound
– Smell
• Advertising to a predator to avoid because:
– Unpalatable taste
– Poison / Toxin
– Noxious Odor
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Aposematic examples
http://www.tropical-rainforestanimals.com/image-files/poison-dart-frog.jpg
jefferson.unl.edu/waterskunk.htm
Aggressive mimicry
“Duping the prey”
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Cookie-cutter Shark
(Widder, 1998)
• Bioluminescent shark
• Photophores on bottom (ventral side)
– Mimics the ambient light in dim, deep oceans
• Counter-illumination
– “Dog collar” band lacks photophores = mimics a small silhouette to
predators below
– As predator investigates the silhouette, the shark bites out plugs of
flesh from the swimming predator  hence the name “cookie-cutter”
– Watch this video: http://www.youtube.com/watch?v=syISlRJTaw4>
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Deep-sea Anglerfish
• Family Ceratiidae
• Fishing Pole
– Dorsal spine
– Only females
– Luminous tip ‘mimics’
small animal
movement to lure prey
– Large mouths quickly
consume prey
– Video:
http://tolweb.org/Ceratiidae/22010
• <http://www.youtube.com/watch
?v=RitJe16c3sM>
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Reproductive mimicry
“Duping the mate or
donator”
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Duped Pollinators
• Some plants attract
pollinators of other plants
using color
– Epidendrum ibaguense,
flower has no nectar, but
‘dupes’ the pollinators of
other flowers
• Lantana camara
• Asclepias curassavica
– Some orchids ‘dupe’ the
lamellicorn beetle
– The beetle mistakes
flowers for similarly colored
Cistus flowers
Epidendrum ibaguense
http://www.sbs.utexas.edu/quedensley/epidendrum
%20radicans%20TQ-4904-1.JPG
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Giant Australian
Cuttlefish
• Male cuttlefish ‘sneaks’ to mate
• A: Unpaired male (m) assumes
female coloration and posture and
approaches the paired female (f); the
consort male (c) displays to an
approaching male (top right);
conspicuous
– Consort and approaching male
have large white arms, a sexually
dimorphic male character
• B: female accepts a mating attempt
by the female mimic as the consort
continues to repel the other male
• C: the consort allows the mimic to
finish mating, even when he is not
distracted by an approaching male
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Spotted Hyenas
• Sexual organs mimic the male reproductive
organs
– Female cubs more at risk from aggression than male
cubs.
– Aggressors should have difficulty distinguishing the
sex of their potential victims
– Sexual mimicry is the greatest during the period of
highest risk.
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Mutualistic mimicry
“Help Each Other”
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Orange and Black Coloration
Two unpalatable species, (a) lycid beetle (Coleoptera), (b) arctiid moth
(Lepidoptera) with mutualisitc mimicry (Sherratt, 2008).
• Mullerian mimicry
• Two unpalatable species evolve a similar appearance
– Reduces predation mortality by training predators to avoid
– Orange and black coloration: lycid beetles, arctiid moths,
parasitic hymenoptera, and flies
– Predators avoid two distinct unpalatable prey at similar rate,
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Mutualistic mimicry in Peruvian
Dendrobate Frogs
http://www.ucl.ac.uk/taxome/jim/Mim2/dendrobates.html
Protective mimicry
“Camouflage”
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Decorator Crab
• Wears its environment
• Found near Australian
coastline
– Spider crab family
– Small hooks to attach
algae and seaweed
– Uses oral secretion to
bind camouflage to
hooks
– The algae continues to
grow
The decorator crab covered with algae and seaweed
(http://farm3.static.flickr.com/2007/2256514518_2e71f0c6c8.
jpg?v=0)
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Mimic Octopus
• Thaumoctopus
mimicus
• Found in Indonesian
Archipelago
• Can impersonate
several different
animals
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Flatfish/Flounder
Lion-fish
Sea-snake
Sea anemone
Jellyfish
(Norman et al., 2001).
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Mimic Octopus Video:
< http://www.youtube.com/watch?v=H8oQBYw6xxc >
Audio Mimicry?
• Tiger Moths hunted by bats
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at night
Use an audio aposematic
signal
Answer the bat echolocation
with high-frequency 'clicks'
from vibrating membranes
(tymbals) on the bottom-side
portion of the thorax.
Bats avoided the moths when
the sounds were paired with
defensive chemistry.
– No jamming
– Acted as audio warning
Various Tiger moths with/without a chemical defense (C+ or C-)
and with/without a sound strategy (S+ or S-) (Hristov and Conner,
2005).
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Eye Mimicry
• Confuse a predator
• Allow enough time for escape
http://www.flickr.com/photos/21514016@N08/2287685332/
http://www.flickr.com/photos/53817483@N00/2623073478/
http://www-user.zfn.uni-bremen.de/~kochzius/pictures/chelmon.jpg
Imperfect Mimics succeed?
• Some mimics are successful, even though
they only generally look like a model
• Possible explanations:
– mimic has not converged fully on the model
– Models and mimics engaged in evolutionary arms
• Model under pressure to evolve away from the
mimic
– Degree of similarity related to frequency of mimic and
model
– Conflicting energy demands on color patterns
• Compromises between signaling and constraints
of thermoregulation
Hoverfly
• Loosely
resembles
common
European bees
and wasps
• A-B = wasp
• C-F =
imperfect
mimics
(Chittka and Osorio, 2007)
Fly
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A-C = Bees
D = Fly
The fly generally has beelike:
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Body
Morphology
Integuments
Stripes
Predator Speed versus Accuracy
• Predators must make a decision on prey either:
– Quickly pick the prey
– Accurately discriminate between palatable and
unpalatable
• A quick decision may allow imperfect mimics
enough time to escape
• Categorization of prey
– Very different prey share common character(s)
– Different predators may form different categories
• Lab-raised birds attack bees, wasps, and mimics
– Learn to reject them all once they consume an
unpalatable prey
Summary
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Why do animals use mimicry?
What are the four general categories of mimicry?
What are the three participants of a mimicry system?
What does aposematic mean? Provide examples.
Describe aggressive mimicry.
Describe sexual mimicry.
Describe mutualistic mimicry.
Describe protective mimicry
Can animals use audio mimicry?
Why are animals that use imperfect mimicry still successful?
What is the relationship between the speed and accuracy of a
predator’s cognitive ability and mimicry?
• Can humans use mimicry? How?
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