Colour strategies in Nature

7/29/2019 Colour strategies in Nature

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COLOUR STRATEGIES IN NATURE

ABOUT THE USE OF COLOUR IN NATURE

STRATEGIES BETWEEN MIMICRY AND PROTAGONISM

a text by Francesca Cremasco

MIMICRY / CAMOUFLAGE / IMITATION

The word ‘mimicry’ is derived from the Greek ‘mimetizo’ which means ‘imitation’. In nature it indicates the phenomenon

in which an animal takes colours, forms, behaviors and other characteristics to be similar to the environment around it,

or to another animal. Mimicry is one of the most interesting and complex phenomena within environment adaptations

aimed at survival.

If an individual does not adapted to the environment in which it lives, its chances of survival and reproduction are

minimal. A very similar colour to the surrounding environment is beneficial in escaping predators, but also to avoid being

noticed by an animals’ potential victims. Body color is often linked to the needs of the struggle for existence.

Animals may

have

two

types

of

camouflage,

one

with

the

aim

to

hide

(survival,

protection)

and

the

other

with

the

aim

of

modifying appearance and recognition (predation and reproduction).



The first is known as cryptic mimicry (from the Greek kriptòs = hidden) and refers to the process of a subject physically

adapting to its surrounding environment, or becoming part of it, in order to hide or become invisible. Some animals

authentically mimic the colors and the shapes of leaves, flowers, wood or rocks.

The second type is known as the faneric mimicry (from the Greek phaneros, manifest) and occurs when an advantageous

feature is “copied” from other species for predation. Faneric mimicry may be ‘batesian’ and ‘müllerian’ .

With batesian mimicry (the name derives from Henry Bates who first discovered and reported this phenomenon) a

harmless species

is

protected

by

its

resemblance

to

one

or

more

dangerous

species,

noxious

or

unattractive.

This

type

of

mimicry functions as a defensive strategy. This type of system may evolve if models and mimes coexist in time and space,

and share a similar lifestyle.

With mullerian mimicry (from Fritz Mulller) two or more species assume similar shapes and colours in order to not be

distinguishable, and thus by having similar colors predators quickly learn to chase both. Such “cooperation” allows a

mutual advantage to these species, as the predators must learn only one signal. In this way every single species is preyed

on in smaller quantities.

FUNCTION / TYPES OF STRATEGIES

In order

to

understand

mimicry

in

its

true

sense,

it

is

important

to

look

at

each

function

of

the

various

camouflage

types,

and their effects . The function connects and organizes all the parts into a system and identifies a strategy. Each part

(such as the form, colour, motion etc.) can have different meanings depending on the specific context of relationships.

This is crucial because similar pattern types (e.g. blotches, stripes) may have entirely different functions in different

animals and circumstances, ranging from camouflage to warning and sexual signals.

The main forms of visual camouflage1:

Background matching: where the appearance generally matches the colour, lightness and pattern of one (specialist) or

several

(compromise)

background

types.

When

a

subject

has

the

same

color

(monochromatic)

as

its

environment

there

is

an identification of figure and background (examples are frogs, caterpillars etc. ...). This process can happen even with

the borrowing of materials from a context (like fish camouflaged in the sand). Another example is when the livery

matches several background types. This can happen in two ways, one considers the subject and its environment (like a

leopard in the savannah), the second regards a group of subjects rather than the individual. This difference leads to

specific configurations of livery. In the first case the pattern takes colours and forms from the surrounding context, but in

the second case the pattern performs its function through the dynamics of the group, through the multiplication of

subjects. For example, the striped pattern of the zebra produces an optical illusion, which makes it difficult to recognize

the single subject. The “disguise” is optimized not only for the environment but also for group behavior of herd animals.

Counter shading (obliterative shading and self ‐shadow concealment): a counter‐shaded animal possesses a darker

surface on

the

side

that

typically

faces

greater

light

intensity

and

a lighter

opposite

side.

Counter

shading

appears

to

be

involved in several functions, including the compensation of the animal’s own shadow (self ‐shadow concealment),

simultaneously matching two different backgrounds in two different directions (background matching), changing the

three‐dimensional appearance of the animal (obliterative shading). In self ‐shadow concealment the creation of shadows

is cancelled out by counter shading, and obliterative shading, where the creation of shadow/light cues for the three‐

dimensional form of the animal are destroyed.

Disruptive coloration: being a set of markings that creates the appearance of false edges and boundaries, which hinders

the detection or recognition of an object’s, or part of an object’s, true outline and shape. A typical example is a body

coloration that consists of high‐contrast markings that tend to break up the appearance of an animal.

1 Here the term camouflage is used to describe all forms of concealment, including those strategies preventing detection (crypsis) and those recognition

(e.g. masquerade).



Flicker‐fusion camouflage: where markings such as stripes blur during motion to match the colour/lightness of the

general background, preventing detection of the animal when in motion.

Distractive markings: which direct the “attention” or gaze of the receiver from traits that would give away the animal

(such as the outline).

Transparency: where part of an animal’s body is transparent, reducing the likelihood that it will be detected.

Silvering: common in aquatic environments and where an animal’s body is highly reflective (like a mirror) making it

difficult to

detect

when

light

incidence

is

non

‐directional

(such

as

due

to

strong

scattering

by

water

‐borne

particles).

Masquerade: prevents recognition by resembling an uninteresting object, such as a leaf or a stick.

Motion dazzle: markings that make estimates of speed and trajectory difficult by the receiver.

Motion camouflage: movement in a fashion that decreases the probability of movement detection. An animal appears to

be stationary, ‘tricking’ the receiver’s visual system by moving in a certain way.

MAIN ASPECTS

The first important aspect of mimicry is the function (what it does), which is resolved through the synergy of many

different matters. The technical aspect of visual camouflage provides a specific solution to a desired function.

Function always

moves

from

some

foundational

aspects.

The

first

and

foremost

is

communication,

the

need

to

transfer

a

message. The color is the most effective mean to communicate and create an emotional state (attraction, fear,

protection, etc.). This fact implies the involvement of at least three subjects : an active subject, a passive subject

(receiver) and the environment, and each subjects can be single or a group. The first two subjects are involved in an

empathic relation and the space is used passively, it has a role of utility. The result is always a relation, which stems from

the specific needs and characteristics of the subjects.

Mimicry processes occur in a space and generate a space (of relations, of attraction, of warning etc.). What happens

during the process is perceived only by subjects involved, or by external parties capable of decoding the phenomenon,

therefore of having the same cognitive abilities.

The

strategy

of

imitation

in

nature

is

based

on

the

existence

of

a

model,

an

imitator

and

a

receiver

(the

subject

deceived

by the imitator). This process is in continuous evolution because the imitator tends towards a complete imitation of the

model, and the receiver evolves towards an increasingly accurate distinction of the characteristics of the imitator.

The cognitive abilities of the receiver are constitutive part of the process of mimesis. In the process of natural selection

what is decisive is the viewer’s perception, not our own, because it has created the selection pressure on the animal’s

coloration.

bibliography:

Animal camouflage, edited by M. Stevens and S. Merilaita, Cambridge University Press, 2011

Exploring Life Set, G.Brum, L. K. McKane, G. Karp, Wiley & Sons, Canada, 1994

Il mimetismo

animale,

Ward

P.

, De

Agostini,

Novara,

1979

web resources:

http://en.wikipedia.org/wiki/Mimicry

http://en.wikipedia.org/wiki/Animal_coloration



exampleofcrypticmimicry

time

adaptationtotheenvironmentmaybecontingent

colour,

form

and

pattern

colour

someexamplesof

background

matching.

opticalillusion-falseeyes

Largespotsthatresembleeyesisafrequentdrawingon

thecoatofanimals.

Simulatepartsofthebodyindifferentpositionsserves

tolookbiggerandscarethepredator.

exampleoffanericmimicry

falseidentity

Smalldifferencesoncolourand

patternforappearhowotherspecies,

inadefensivestrategy

Someanimalstaketheappearanceofdangerousanimalsforintimidatepredators.Inothercases

thestrategyistheopposite.Somepredatorsmimictheprey(usuallythefemale)forapproachit

andcapture...



CONTACT POINT

POSSIBLE MIGRATION OF FUNCTIONS AND TECHNIQUES

The concepts outlined above may suggest new perspectives on our environment. Changing one’s approach leads to a

reinterpretation of the places that belong to a vision almost codified, but also suggests ways for defining new functions

and relationships.

Below

I want

to

suggest

some

architectural

aspects

of

mimetic

processes,

and

how

they

could

lead

to

new territories of experimental design.

With regards to the spatial qualities of mimetic processes, in many cases we can see that the active subject aims to

simulate “other” spatialities (of the background, of the surrounding elements), or to conceal its three‐dimensionality. It’s

a sort of dematerialization and depersonalization, in order to assimilate the characteristics of spaces surrounding the

subject, through a complex flattening process. Background matching, countershading, disruptive coloration, flicker‐fusion

camouflage, transparency, silvering and masquerade all fall under this category. The constant element in these processes

is the interaction between active subject and the background or surrounding space. The active subject adapts itself to an

environment that is used in a passive way. Changing point of view, the subject is always in relation with surfaces, even if

the interaction is not functional and not designed. In mimicry, the colours and forms of livery are the most important

elements, supported also by the orientation of subject and the arrangement of its body parts in space.

Their position is linked to the point of view of the receiver, which can be directed in particular either to the horizontal

(from top to bottom), or to vertical planes (from high to low). The quality of surfaces (colours, shapes, developed along a

dominant axis) has an important role on perception of dimension ‐real, dilated or restricted. As explained above, in

nature the relationship status, determined by the specificity of the subject (defensive, aggressive, attraction etc.), is the

driver of the form of mimicry. In other words the type of relationship is the driving force of the project. Shifting the

concept to architecture, project development and design, relationships of various natures could emerge, i.e. elements,

people, places, and thus influence people’s reactions and behavior in relation to the various functions.

Position and

behavior

are

two

closely

related

concepts,

not

only

in

the

animal

world.

The

arrangement

of

subjects

creates

spatialities with different characteristics. Spaces of proximity, attraction or repulsion are generated through location and

orientation. The communication assets of colour helps to define the quality of the movement between the parts,

attraction, repulsion or distance. A signal of danger induces a user to keep his or her distance and vice versa, attractive

colours induce rapprochement. The qualities of the livery interact on the perception of the receiver, creating a

conditioned view. Strips, patches, “decorative” motifs guiding vision, sometimes cause a “distorted” perception, but

correspond exactly to the required function.



SUGGESTIONS

In the subway there are spaces allocated to different functions (spaces where people walk and spaces for waiting) but usually the aspect does not

change. Surfaces are the background of these conditions. Rethinking the surfaces as places of interaction with figures could lead to new scenarios

and a new territory of exploration.

This type of situation is very common in urban places. The rear side of road platforms, tramlines or trains is a horizontal surface which dominates the

environment. A different treatment of these could affect the perception of spatiality. Acting on perception means acting on space. Urban margin

spaces could

be

converted

to

places

of

many

different

functions

or

just

evolve

into

something

suitable

for

human

environment.

case_1

relation

subject/background/

movement

case_2

countershading/orientation of surfaces



Road barriers are a visual protection (to hide the road from the surrounding environment) and anti‐noise filter (cushion the impact of traffic noise).

Their condition is double (internal/external) in fact the perception and the utility is differently from inside and outside the street. The aspect of

surfaces could be designed for extend functionality. Through acting on shapes and colors of surfaces it is possible to determine a type of perceptual

relationship (concealment, decorative, communicative) . Outside the receiver could be near or far, standing still or in motion. This fact changes the

possible function and consequently the form of decoration (away from the barrier may indicate the presence of the road giving useful information,

but closely

the

decoration

can

be

viewed

in

a different

way).

In many buildings the appearance of the facade is dominant in urban spaces. There are many facades designed with visual codes now exceeded.

Acting on their appearance we could transform and deform the perception we have on them. Modifying figures, forms, colors, rhythms, it is possible

to guide the perception to something different without destroying the existing. Nature provides us with methodological examples and concepts (like

distractive markings, disruptive coloration etc.) so we can come up with new

techniques.

case_3

functions/movement/distance

case_4

affect the perception/re‐semantise

case_5

extend the

functions/space

in

the

shadows



Animals use shadow to change the perception of their volume or to disappear. In many cases (as in historical places) we need to make invisible

interventions or minimize the impact on the existing elements. The relation of light‐shadow on architecture is of primary importance, rarely do we

look at the shadow before we look at the building thus not exploring the visual opportunities and signals of shadows. Through shadows it is possible

to re‐think spaces, equipment, roofing and many other typologies of elements which may cause shadows to hide, to confuse, to emphasize

surrounding elements.

Pedestrian underpasses should be visible, attractive and perceived as safe, the opposite of what often happens. Visibility of subjects outside and

during the passage is the most important aspect of feeling safe in a place. This case has an analogy with background matching, the one about

relation between subject and background. Light‐shadow and colors are the primary elements upon which we can work to influence the perception

of underpasses.

Different conditions/functions coexist in the same. The relation figure/ background can help isolate the subject from its surroundings and amplify

the attention to it. Concentration is the most important aspect when we are talking with somebody for a few minutes in a public office. Also the

division of spaces (not only physical but also sensory‐perceptual) is important for both conditions (waiting and action). During moments of

concentration, the space tends to lose its three‐dimensionality. Visual perception focuses on the close up. Also the acoustic isolation, which is very

important in terms of concentration, deletes the perception on three‐dimensionality of space. Space planning should lead to a correct spatial

relationship (proximity, distance), not only physical but also perceived.

case_6

emotional perception of

space/figure‐background

case_7

functions/spatiality/flattening



CONCLUSION

Mimicry is a complex phenomenon that must be analyzed from many points of view, because simple and different

elements become the visual reply of complex interactions. Mimicry is a system of environmental adaptation, which from

time to time finds unusual functional expressions. The function is the place where elements are organized in a strategy,

which is the expression of characteristics and relations between the subjects involved in the mimetic process.

The subjects are of primary importance because they are the driving of the system. Every animal is an active and passive

subject at the same time, because each subject can be predator or prey for another subject. Mimicry primarily serves in

situations of conflict, where there is a contraposition of interest between individuals. The conflict take place if the

interest of a subject (active) precludes/conditions the interest of the other (passive subject).

Our environment (not only natural but also our built environment) has many places of contrast, some of which are not

immediately identifiable because of our ordinary vision. We often suffer the surrounding reality because we take for

granted the

modalities

that

have

generated

it.

Many

places,

spaces,

and

elements

that

appear

neutral

to

our

vision

are

instead actually strongly characterized. Mimicry often seems neutral, because of the visual depersonalization of the

subjects on the environment. It's a form of highly engineered neutrality.

Can harmonious coexistence come through a neutral project?

As social animals, which mechanisms can we actuate to adapt the environment to many different users?

Also, how could we be more adaptable to our current environmental circumstances?

In conflict conditions, which are the mimetic strategies that we normally use, and how much can our intervention

influence the environment?

Since our world is so strongly artificialized, is it still possible to refer to a natural world and adopt its strategies?

Documents

Colour strategies in Nature