3/25/2014

Professor Donald McFarlane

Mimicry and Defense

 Protective Strategies  Camouflage (“Cryptic coloration”)

 Diverse Coloration

 Diversion Structures

 Startle Structures

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Camouflage (“Cryptic coloration”) Minimize 3d shape, e.g. flatfish

Halibut (Hippoglossus hippoglossus) 3

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Counter‐Shading

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Disruptive Coloration

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Polymorphism – Cepeae snails

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Diversion Structures

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Startle Structures

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Warning Coloration (Aposematic coloration)

Advertise organism as distasteful, toxic or venomous

Problem: Predators must learn by attacking prey; predator learning is costly to prey.

Therefore strong selective pressure to STANDARDIZE on a few colors/patterns. This is MULLERIAN MIMICRY.

Most common is yellow/black, or red/yellow/black

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Warning Coloration (Aposematic coloration)

Bumblebee (Bombus Black and yellow mangrove snake (Boiga sp.) Sand Wasp (bembix oculata) dendrophila)

Yellow‐banded poison dart frog (Dendrobates leucomelas

Fire salamander ( Salamandra salamandra) 11

Warning Coloration (Aposematic coloration)

coral snakes (Micrurus sp.)

~ 50 species in two families, all venomous

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Batesian Mimicry

1862 –Henry Walter Bates; “A Naturalist on the River Amazons”

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Batesian Mimicry

Batesian mimics “cheat” –they lack toxins, venom, etc. but imitate toxic/venomous species to gain the advantage of predator deterrence.

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 Batesian mimicry involves an unpalatble/dangerous MODEL and a palatable MIMIC.  Disadvantage is that mimics must be rare compared to models, otherwise predator learning will be reversed.  How much rarer?  How unpalatable/dangerous is the model?  What is the shape of the predator learning curve?  What proportion of the predator population is experienced versus naïve?

 Automimicry  Danaus plexippus  Monarch butterflies feed on milkweed and accumulate toxic cardenolides.

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 Cardenolide concentration varies greatly between individuals (only 12 of 50 collected caused vomiting in Blue Jays)

 WITHIN the species, palatable individuals mimic high‐cardenolide individuals.

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Three examples of female‐limited polymorphism in Batesian mimicry. Hypolimnas misippus: across western India and Africa, males are monomorphic and nonmimetic whereas females are trimorphic, each mimicking a different form of the model, Danaus chrysippus. There are no male‐like nonmimetic females in this species ( Ford, 1975, Smith, 1984 and Wynter‐Blyth, 1957). Papilio polytes: across their distributional range in the Oriental Region and in several subspecific variations, P. polytes males are monomorphic and nonmimetic whereas females may be polymorphic, with one male‐like nonmimetic form and usually one but sometimes two form(s) mimicking locally abundant Pachliopta models. The subspecies Papilio p. romulus in Sri Lanka and peninsular India has trimorphic females, with a male‐like form (cyrus) and two mimetic forms (polytes, also known as stichius, and romulus) ( Ford, 1975, Kunte, 2000 and Wallace, 1865). Papilio dardanus: males of this African species are monomorphic and nonmimetic in several subspecific variations whereas females in most populations are polymorphic, mimicking Danaus, Amauris, Acraea, Bematistes and day‐flying moth models. Only the subspecies in Madagascar (illustrated in the bottom row), Grande Comore Island and Abyssinia have male‐like nonmimetic females

Island of Trinidad

Auto‐ Auto‐ mimicry mimicry

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Wassmanian mimicry

Ant‐Mimicing spiders (right: Synemosyna formica)

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Rove beetle: Paederus littoralis

(Wassmanian mimic of ants)

Aggressive Mimicry

Photuris sp.

Female Photuris attract male Photinus as prey.

Photinus sp.

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