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Visual Mimicry

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Objectives

• 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

• 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

Aposematic examples

jefferson.unl.edu/waterskunk.htm http://www.tropical-rainforest-animals.com/image-files/poison-dart-frog.jpg

Aggressive mimicryAggressive mimicry

““Duping the prey”Duping the prey”

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Cookie-cutter Shark

• 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>

(Widder, 1998)(Widder, 1998)

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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://www.youtube.com/

watch?v=RitJe16c3sM>

http://tolweb.org/Ceratiidae/22010

Reproductive mimicryReproductive mimicry

““Duping the mate or donator”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 ibaguenseEpidendrum 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.

Mutualistic mimicryMutualistic mimicry

““Help Each Other”Help Each Other”

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Orange and Black Coloration

• 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,

Two unpalatable species, (a) lycid beetle (Coleoptera), (b) arctiid moth Two unpalatable species, (a) lycid beetle (Coleoptera), (b) arctiid moth (Lepidoptera) with mutualisitc mimicry (Sherratt, 2008). (Lepidoptera) with mutualisitc mimicry (Sherratt, 2008).

Mutualistic mimicry in Peruvian Dendrobate Frogs

               

                    

           

                        

           

                        

               

                    

           

                       

           

                       

http://www.ucl.ac.uk/taxome/jim/Mim2/dendrobates.html

Protective mimicryProtective mimicry

““Camouflage”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 (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– Flatfish/Flounder– Lion-fish– Sea-snake – Sea anemone– Jellyfish

(Norman (Norman et alet al., 2001).., 2001).

Mimic Octopus Video:< http://www.youtube.com/watch?v=H8oQBYw6xxc >

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Audio Mimicry?

• Tiger Moths hunted by bats 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-) Various Tiger moths with/without a chemical defense (C+ or C-) and with/without a sound strategy (S+ or S-) (Hristov and Conner, and with/without a sound strategy (S+ or S-) (Hristov and Conner, 2005).2005).

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• A-C = Bees• D = Fly• The fly generally has bee-

like:– 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

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Summary

• 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?