New subject: King snakes, milk snakes and viceroy butterflies: Honesty and deception

28 Aug 2007

Deception has a long and distinguished history.  Mimicry and
camouflage are common in the animal world among predators and prey
alike - to hide, to pretend to be dangerous, to lure prey into a false
sense of security, etc.

Batesian mimicry occurs when two or more species are similar in
appearance, but only one has the trait (e.g. being poisonous) being
signaled.  Coral snakes have alternating stripes of red, yellow and
black.  So do king snakes and milk snakes.  However, coral snakes are
poisonous, but king snakes and milk snakes aren't.  The plain tiger
butterfly is poisonous, containing alkaloids that make predators
vomit.  They also fake death when attack, oozing nauseating liquid,
enabling them to often survive such attacks.  The palatable indian
frittillary females and danaid eggfly females look much like plain
tiger butterflies.  Alligator snapping turtles have tongues which look
like worms; if a fish tries to eat such a tongue, the fish is eaten
instead.

Muellerian mimicry is the same thing, except that the two species do
in fact share the trait being signaled.  Monarch butterflies and
viceroy butterflies look much alike, and both taste bad to predators.
Poison arrow frogs and Mantella frogs tend to have bright coloured
spots against a black background, and they are all poisonous.

Self-mimicry is where one body part imitates another.  Prey can use
this to increase chances of survival if attacked, and predators can
use it to lure prey into a false sense of security.  Owl butterflies
have spots on their wings which looks like eyes.  They are more likely
to survive an attack on their wings than an attack on the main part of
their body.  Pygmy owls have false eyes in the back of their heads to
fool predators into thinking they are seen.  The two-headed snake of
central Africa has a head which looks like a tail and a tail which
looks like a head, fooling prey into believing the attack will come
from the tail rather than the head.

Camouflage involves imitating the appearance of the environment to
avoid being seen by predators or prey.  Katydids look like leaves or
sometimes sticks.  Countershading involves a light underside and a
dark top, to counterbalance normal shadowing, and is employed by grey
reef sharks and pronghorn antelope.

Deception is not some barbaric human invention - it is ingrained in
use by evolution for a reason - because we need it, to survive.
Deception is often as natural as breathing, and we lie not only to
others, but to ourselves.  Honesty often requires actual effort.

Notice a number of the examples above involve colour, which is not a
hard signal to fake, making such signals conventional signals.
Basically, it is much like signaling that you are strong by wearing a
'Weight lifter' t-shirt - not hard to fake, and if too many do fake
it, the signal may become worthless.

According to the handicap principle, a signal may be difficult to fake
if producing it requires the trait being signaled.  Having muscles
tends to require being strong, hence having big muscles is an
assessment signal for being strong.  Moose have large antlers, which
requires strong bodies to support, hence antlers are an assessment
signal for strength.

The following questionnaire is helpful:
1.  What is the cost of sending the signal if honest?
2.  What is the cost of sending the signal if deceiving?
3.  What are the advantages to the deceiver?
4.  Statistically, how reliable is the signal?  (May require experimentation.)
5.  What is the cost of observing the signal?
6.  What is the cost of being deceived?

If the cost of sending the signal if deceiving is significantly
higher than the cost of sending it if honest, and the advantages
to the deceiver are not too great, it should generally be
fairly reliable.  However, the cost of observing the signal relative to the
cost of being deceived and the reliability of the signal itself is
important to deciding whether to bother.

References

* 'The Arts of Deception: Mimicry and Camouflage'.
http://rainforests.mongabay.com/0306.htm
* Zahavi, Amotz.  'The fallacy of conventional signaling'.  1993.
http://links.jstor.org/sici?sici=0962-8436%2819930529%29340%3A1292%3C227%3A…
* Donath, Judith S.  'Identity and Deception in the Virtual
Community'.  Communities in Cyberspace.  MIT Media Lab.  1996.
http://smg.media.mit.edu/people/Judith/Identity/IdentityDeception.html