PSY 2364 Red Deer lower their formant Animal Communication ...assmann/PSY2364/ancom_lec11.pdf · 0.1 Forest shade, sunny GREEN Irradiance 400 600 0 0.05 0.1 Woodland shade, sunny

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PSY 2364Animal Communication

Red Deer lower their formant frequencies in response to rivals

Midterm

• Wednesday October 2 – midterm exam

• Midterm exam review sheet is posted on the course web page:

http://www.utdallas.edu/~assmann/PSY2364

Optical signals for survival

• Aposematic signals: warning signals associated with the unpalatability of a prey animal to potential predators


• Mimicry– An animal species (the mimic) has evolved to

share the visual properties of another animal (the model) through the selective action of a signal receiver (the dupe).

Monarch Viceroy


• Batesian mimicry– one species has evolved to mimic the warning

signals of another species directed at a common predator.

Monarch Viceroy

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• Batesian mimicry: one species has evolved to mimic the warning signals of another species directed at a common predator.

• Müllerian mimicry: convergence between two or more species to warn predators of their unpalatability.


Milk Snake(Lampropeltis triangulum)

Coral Snake(Micrurus tener)

Example: Rapid color changes

Anolis carolinensis – Green Anole lizard

Source: http://animaldiversity.unmz.umich.edu/index.html


Sepioloidea lineolata – Australian cuttlefish

Kingdom: AnimaliaPhylum: MolluscaClass: CephalopodaOrder: SepiidaFamily: SepiadariidaeGenus: SepioloideaSpecies: lineolata

Source: http://www.cephbase.dal.ca/index.html


Sepia officinalis– male squid display zebra stripes only during aggressive conflicts; normal pattern is mottled or blotchy

Kingdom: AnimaliaPhylum: MolluscaClass: CephalopodaOrder: SepiidaFamily: SepiadariidaeGenus: SepiaSpecies: officinalis

Blue-ringed Octopus(Hapaloclaena lunulata)

1. Warning coloration(blue rings signal danger)

2. Concealing coloration (body colors match coral surroundings)

3. Disruptive coloration(blotches on the skin disguise the outline of the octopus’ body)

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Hawaiian sepiolid squid(Euprymna scolopes)

• Camouflage (keeps a "sand coat" on its dorsal surface)

• Counter-shading (a symbiotic bacteria lives in the sepiolid's light organ to produce a weak light under the body of the animal)

Vampire Squid(Vampyroteuthis infernalis)

• Lives in the dark oxygen minimum layer (600-800 m)

• For its size, it has the largest eyes of any animal

• Named for its jet-black skin (but color varies from black to red to purple depending on light conditions)

• Has photophores; lights all over its body; bioluminescent organs at the tips of each arm

Source: http://www.cephbase.dal.ca/index.html

Bioluminescence

Scyphomedusa, Atolla vanhoeffenihttp://www.lifesci.ucsb.edu/~biolum/organism/photo.html

https://ocean.si.edu/ocean‐life/fish/bioluminescent‐animals‐photo‐gallery

Bioluminescence

Deep sea squid,Histioteuthis heteropsis

http://www.lifesci.ucsb.edu/~biolum/organism/photo.html

Bioluminescence (lantern fish) Bioluminescence (firefly)

Kingdom: AnimaliaPhylum: ArthropodaClass: InsectaOrder: ColeopteraFamily: LampyridaeGenus: PhotinusSpecies: ??

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Deceptive signaling

“Femmes Fatales”

Males are attracted to the species-specific flashing patterns emitted by females.

Predatory fireflies of a different species, Photuris, mimic the species-specific flashing pattern of a Photinus firefly to attract and eat the male.

A female Photuris firefly eats a male Photinus ignitus to obtain defensive compounds called lucibufagins which are distasteful to predators.

Proceedings of the National Academy of Sciences (Sept. 2, 1997, Vol. 94, pp. 9723-9728)

Visual systems

• Vision provides a means of detecting objects in an animal’s surroundings.– Luminance (intensity differences; brightness)

– Reflectance (spectral composition; color)

• Vertebrate visual systems contain two types of receptors:– Rods are more sensitive in low light conditions

– Cones function in daylight and provide the basis for color vision

Vision

• Visual systems have evolved to detect light.

• This requires trapping the electromagnetic energy and absorbing it by a receptor molecule. This process triggers an electrical response in the receptor neuron.

Properties of color

• Brightness (intensity)

• Hue (dominant wavelength or frequency)

• Chroma (degree of saturation or purity of the dominant frequency)

Rods and conesTrichromatic Color vision

• Human color vision depends on interactions of three types of cone cells in the retina of the eye, each sensitive to a range of wavelengths of light.

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Color vision

• Cone cells in the retina contain a pigment derived from a protein (opsin) linked to a small molecule called retinal. The pigment absorbs light energy (photons) which activates retinal neurons, generating action potentials in the optic nerve.

Color vision

• Two different wavelengths of light can produce the same pattern of activation in a cone cell. The outputs of the cone receptors are combined and must be compared at a higher level of the visual nervous system. Color vision result from a decoding of the outputs of the color receptors by the brain.

Color vision

• Color vision in birds, lizards, turtles and many fish is based on four types of cone cells (tetrachromatic color vision). These animals can distinguish colors in the near ultraviolet range of the spectrum.

• Old World primates and humans have three color receptors; most mammals have only two types (dichromatic color vision).

Goldsmith TH (2006). What birds see. Sci. Am. 69-75

Color vision

• Evidence suggests that the progenitors of mammals lost two of the four types of cone cells during a period in their evolution when they were mainly nocturnal (and color vision was less important for their survival).


Color vision

• African monkeys, apes and humans “reclaimed” a third cone through duplication and subsequent mutation of the gene for one of the remaining pigments.


Ruby-throated Hummingbird

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Further reading

Acoustical communication

• http://sites.sinauer.com/animalcommunication2e/summary02.html

Optical communication


Properties of light

• Different frequencies of light are perceivedas different colors.

• Light also varies in intensity (brightness)

• Light shows wavelength-specific and medium-specific attenuation (selective filtering)

Ambient light spectra in forest

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W oodland shade, sunnyBLUE-GREY

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Forest, woodlandshade, or cloudy

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Small gapRED

W avelength (nm)

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Large gapW HITE

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Low sun anglePURPLE

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Ambient light spectra in forest habitats

Properties of light

• Light is directional

• Light follows the inverse square law

• Unlike sound, light requires no medium fortransmission and in fact travels fastest in avacuum

• Light speed varies depending on the medium

Properties of light

• reflection: light bounces off a surface at thesame angle as it strikes the surface

• refraction: light bends as it travels fromone substance to another.

• diffraction: the slight bending of light as itpasses around the edge of an object

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Properties of light used in animal communication

• spatial characteristics - variations in

shape, size, surface features, color pattern

• temporal characteristics - changes in

pattern of color, surface, color change,

apparent size and shape over time

Optical communication

• Specializations of the sender (body structures modified to generate or reflect light for the purposes of communication)

• Specializations of the receiver (visual system is designed to pick up electromagnetic radiation)

• Adaptations to the channel (properties of the signal are selected to maximize the likelihood of unambiguous reception)

Trichromatic color vision

• In humans and related primates, color vision is based on three types of cone cells in the retina of the eye, each sensitive to a range of wavelengths of light.

Dichromatic color vision

• Most other mammals are dichromats (two color-sensitive cone receptors). Evidence suggests that the progenitors of mammals lost two of the four types of cone cells during a period in their evolution when they were mainly nocturnal (and color vision was less important for their survival).

Color vision

• Evidence suggests that the progenitors of mammals lost two of the four types of cone cells during a period in their evolution when they were mainly nocturnal (and color vision was less important for their survival).


Color vision

• African monkeys, apes and humans have trichromatic color vision and “reclaimed” a third cone through duplication and subsequent mutation of the gene for one of the remaining pigments.

Goldsmith TH (2006). What birds see. Scientific American 69-75.

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Dichromatic color vision

• Dichromacy occurs in humans when one of the cone pigments is missing and color is reduced to two dimensions (color blindness). – Protanopia (no red receptor)

– Deutanopia (no green)

– Tritanopia (no blue)

Tetrachromatic color vision

• Several groups of animals (birds, reptiles, fish) have four distinct types of cone cells in the retina, adding a cone type sensitive to wavelengths in the ultraviolet range.

Pigments

• Pigments are chemical compounds whose molecules selectively absorb certain light wavelengths (mostly short wavelengths; yellow, orange, red)– E.g., carotenoids, melanins, porphyrins

Structural coloration

• Many animals use structural coloration rather than pigments. These involve microscopic surfaces that interfere with visible light, sometimes in combination with pigments (e.g. the iridescent colors of peacock’s tail feathers)

http://sites.sinauer.com/animalcommunication2e/chapter04.03.html

Structural coloration

• Ultraviolet / blue colors often involve coherent scattering (using layered structures or gratings) to produce a narrow range of wavelengths

http://sites.sinauer.com/animalcommunication2e/chapter04.03.html

Ruby-throated Hummingbird

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Further reading



• http://micro.magnet.fsu.edu/optics/lightandcolor/index.html

Ultraviolet sensitivity

• Bees, like humans, have three receptor types, although unlike humans they are sensitive to ultraviolet light, with loss of sensitivity at the red end of the spectrum.

Ultraviolet (UV) receptors in birds

• Fruits and berries often reflect UV light to advertise their presence.

• Eurasian Kestrels can see UV reflections in the scent trails made by voles.


Ultraviolet (UV) receptors in birds

• Male Blue Grosbeaks with the most intense UV components in their plumage are larger in size, control a larger territory, and feed their offspring more often than other males.


Source: Schaefer, Schaefer and Levey (2004)Trends in Ecology and Evolution

Spectra of a blueberry Vaccinium sp. (peak in the UV part) and willowleaf cotoneaster Cotoneaster salicifolia (peak in the human red part of the spectrum) according to the colour perception of humans (a), birds (b) and bees (c). The colours do not represent the actual colour sensation of each group but rather serve as an approximation to illustrate differences in visual abilities. Solid black lines denote the spectral sensitivities of the four (birds) and three receptor types in bees and humans based on physiological measurements and behavioural tests resulting in models of colour vision [25–27]. If at least two receptors are excited by photons of a given wavelength, wavelength discrimination is possible. Vertical lines denote this range for each group.

Sexual deception by plants!

Documents

PSY 2364 Red Deer lower their formant Animal Communication ...assmann/PSY2364/ancom_lec11.pdf · 0.1 Forest shade, sunny GREEN Irradiance 400 600 0 0.05 0.1 Woodland shade, sunny