Next Monday Review

Next Wednesday (Feb 14) Exam I

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Recognition Systems:

1. What are they (types of recognition)?2. How do they work?3. Optimal Threshold Models

The Major Transitions

Maynard Smith & Szathmáry 1995

1. Replicating molecules ---> Molecules in protocells

2. Independent replicators ---> Chromosomes

3. RNA as gene and enzyme ---> DNA genes, protein enzymes

4. Bacteria (prokaryotes) ---> Eukaryotes (organelles)

5. Asexual clones ---> Sexual populations

6. Single-celled organisms ---> Multicellularity

7. Solitary individuals ---> Eusocial colonies

8. Primate societies ---> Human societies (language)

The Major Transitions

Maynard Smith & Szathmáry 1995

1. Replicating molecules ---> Molecules in protocells

2. Independent replicators ---> Chromosomes

3. RNA as gene and enzyme ---> DNA genes, protein enzymes

4. Bacteria (prokaryotes) ---> Eukaryotes (organelles)

5. Asexual clones ---> Sexual populations

6. Single-celled organisms ---> Multicellularity

7. Solitary individuals ---> Eusocial colonies

8. Primate societies ---> Human societies (language)

Recognition Systems

Self / Non selfKin Recognition

MateIndividualSpecies

Prey/Predators

Recognition Systems

Self / Non selfKin Recognition

MateIndividualSpecies

Prey/Predators

Recognition vs. Discrimination

Recognition Systems

Allorecognition systems

Self / Non self auto immune systems (MHC)self incompatibility (plants)sex determining locus (hymenoptera)

Genetic basis, highly variable (many alleles - most alleles known for almost any gene).

Recognition Systems

Intraspecific recognition

Kin Recognition formation of social groupscooperation / altruismmating behavior

Distinguish others based upon their degree of genetic relatedness.

Can be learned or innate. Self-referent or phenotype matching.

Recognition Systems

Intraspecific recognition

Kin Recognition formation of social groupscooperation / altruismmating behavior

Recognition Systems

Intraspecific recognition

Mate Recognition finding mates (right species) mate choice (right individual)

Individual Recognition pair bonds neighbors/territoriality

Species Recognition conspecific attractionterritorialitymate choice

“The grossest blunder in sexual preference, which we

can conceive of an animal making, would be to mate

with a species different from its own […]”

Ronald A. Fisher (1958)

Recognition Systems

Interspecific recognition

Species Recognition predator avoidanceprey capture (foraging)host / parasite association

naïve prey responding to cues of introduced predators

learned response innate response

New Zealand Robin and mustellids

Maloney & McLean 1995

Rana aurorabullfrogs and crayfish

Pearl et al. 2003

Conspecific Recognition and Social Development in

Brown-headed Cowbirds (Molothrus ater)

“[…] Brown-headed Cowbird behaviour is strongly influenced by learning, just as in other species. The Cowbird’s trick is to delay learning until it has become independent and has followed a genetic predisposition to seek company with its own kind. This means that […] it avoids the problems encountered by Lorenz’s geese and the cross-fostered Zebra Finches

Davies (2000)

“Brood parasites seem to know just who they are at an early age. Brown-headed Cowbirds join flocks of their own kind after they gain independence from their foster parents. This species recognition is most likely under genetic control and is a necessary precondition of brood parasitism.”

Ortega (1998)

Conspecific recognition in parasitic cowbirds

Recognition Systems

Other types of recognition

Abiotic conditions habitat choicenest site selectionprecipitation / temperature

Recognition Systems

Other types of recognition

Abiotic conditions habitat choicenest site selectionprecipitation / temperature

Lesser Prairie-Chicken

Components of recognition systems:

Evaluator (receiver, discriminator, actor):Individual whose behavior is modified by a signal.

Signaler (target, cue-bearer, recipient):Individual creating a signal to illicit a response.

(usually different individuals except in self recognition)

Components of recognition systems:

Label - a signal, cue, or stimulus that is perceived by the evaluator.

(can include chemical odors, cell surface proteins, songs, color patterns, stereotypic displays)

Template - what the evaluator uses to compare the signal.(can be genetically “hard wired” or acquired during development through learning or imprinting)

Referent - basis for a template when not genetically based

Components of recognition systems:

Decision rules - Different types of recognition systems may employ different matching rules.

Exact match for acceptance - foreign label rejectionPartial match is sufficient - shared label acceptance

Behavior can very depending on degree of match.

evaluatortemplate signal

signaler

Components of recognition systems:

1. Production - the nature and development of labels (cues) in signalers.

2. Perception - the sensory detection of labels by evaluators followed by a comparison of labels to a template. (includes the ontogeny of templates)

3. Action - modification of behavior in response to an assessment of the signaler’s label relative to the evaluator’s template.

Nest mate recognition in social insects

Label

Template A E

A E

Label

Template ABCD EF

A E

AB

AB

Nest mate recognition in social insects

Diet (C)Nest material (D)

Signal = cuticular hydrocarbons:acquired from genes, diet and nest

Label

Template ABCD EF

A E

AB

AB

Nest mate recognition in social insects

Diet (C)Nest material (D)

Signal = cuticular hydrocarbons:acquired from genes, diet and nest

Referent

Foreign label rejection

Label

Template ABCD AB

C B

AB

CD

“reject”“accept”

1

2

3

4

0.6 0.7 0.8 0.9 1.0

Y = 8.227 - 7.044 * X; R2 = 0.58

Correlation of hydrocarbon profiles between nests

Ave

rage

agg

ress

ion

s cor

e

Optimal Threshold Model

adapted from Reeve 1989, Starks 2003

Optimal Threshold Model

adapted from Reeve 1989, Starks 2003

signals you want to accept

signals you wantto reject

acceptance errors rejection errors

TAccept Reject

Dissimilarity between template and cues

Fre

quen

cy

Ideally, there would be no overlap between signals you want to accept or reject.

Dissimilarity between template and cues

Fre

quen

cy

However, the distribution and variation of signals (cues) can be constrained by selection or the environment.

TAccept Reject

Dissimilarity between template and cues

Fre

quen

cy

Moreover, the threshold of response may also be constrained by ability to distinguish among signals, or can evolve rapidly in response to selection.

TAccept Reject

Dissimilarity between template and cues

Fre

quen

cy

Moreover, the threshold of response may also be constrained by ability to distinguish among signals, or can evolve rapidly in response to selection.

TAccept Reject

Threshold shifts to the left (more stringent) to reduce acceptance errors if they are too costly.

Dissimilarity between template and cues

Fre

quen

cy

Moreover, the threshold of response may also be constrained by ability to distinguish among signals, or can evolve rapidly in response to selection.

Threshold shifts to the right (less stringent) to reduce rejection errors if they are too costly.

TAccept Reject

TAccept Reject

0 1Dissimilarity Score

Flexible Threshold Model(change in acceptance threshold)

Fre

quen

cy

Rejected Non-Nestmate

Accepted Non-Nestmate

Accepted Nestmate

TAccept Reject

Decrease in Genetic Diversity

Fixed Threshold Model(change in labels)

Rejected Non-Nestmate

Accepted Non-Nestmate

Accepted Nestmate

Fre

quen

cy

Dissimilarity score0 1

Mate Kin

Possible overlap of recognition cues/perceptual filters:

SpeciesIndividual

Species

Mate

Kin

Individual

Recognition: Production Perception Actioncue brain response

Mate Kin

Possible overlap of recognition cues/perceptual filters:

SpeciesIndividual

Species

Mate

Kin

Individual

Recognition: Production Perception Actioncue brain response