An investigation of behavioral syndromes and individual differences in exploratory behavior in prairie voles, Microtus ochrogaster

An Investigation of Behavioral Syndromes and Individual Differences in Exploratory Behavior of Prairie Voles, Microtusochrogaster
Danielle N. Lee
Department of Biology
University of Missouri

Intra-specific behavioral variation
2

Animal personality research
Behavioral Syndromes: Suites of related behaviors across situations or contexts
Correlation of behaviors
Behavioral plasticity limited
Stability
Context
3

Behavioral Stability
State response (Unstable)
Behavioral responses that occur in a specific situation (not consistent from one situation to another)
Trait response (Stable)
Behavioral responses that are consistent from one situation to another
Kopp, Voge & Misslin 1999
4

Behavioral Stability
Behavioral Context
Domain specific
Correlations of behavior within a single context or functional behavioral category
Broad
Correlations of behavior across different contexts or functional categories
Trait response (Stable)
Behavioral responses that are consistent from one situation to another
State response (Unstable)
Behavioral responses that occur in a specific situation (not consistent from one situation to another)
Kopp, Voge & Misslin 1999
5

Domain-specific Behavioral Syndrome
Correlations of behavior within a single context or functional behavioral category
Verbeek et al. 1994
Great tits, Parus major
Single Context (Exploration)
Fast novel room explorers are also fast novel object explorers
Image credit: http://www.thebirdsofsussex.co.uk/
6

Broad Behavioral Syndrome
Correlations of behavior across different contexts or functional categories
Wilson et al. 1993
Pumpkin-seed sunfish, Lepomis gibbosus
Multiple Contexts (Exploration & Social)
Bold fish were more likely to approach novel objects and swim in closer proximity to other fish compared to shy fish
Image credit: Encyclopaedia Brittanica
7

Early Research Efforts
8

Behavioral Syndromes Hypotheses Hierarchy
H0: no correlations of behavior responses across situations or contexts = no syndrome = STATE RESPONSE
H1: correlations of behavior response across situations or contexts = syndrome = TRAIT RESPONSE
H1a: correlations of behavior responses within one context = DOMAIN SPECIFIC
H1b: correlations of behavioral responses across two or more contexts = BROAD
9

Experimental Design
OBJECTIVE
To examine individual variation in a single context – EXPLORATION
QUESTIONS
Is variation in individual behavior consistent across different tests?
If so, then do these consistent differences in behavior contribute to a behavioral syndrome?
10

Chapters
Examining individual differences and exploratory behavioral responses in prairie voles: In search of a behavioral syndrome.
Open-field and with novel objects
Novel choice apparatus
Complex maze apparatus
11

Domain specific behavioral syndromes: Hypothesis
H0: behavior responses across different tests are not correlated
H1: behavior responses across different tests are correlated
Exploratory Behavior
12

Exploratory behavior
Tendency to investigate novel environments and/or objects
Functional behavior category widely studied
Spontaneous behavioral responses
Indicates how animals might gather information about local environment and its resources
13

Microtusochrogasterprairie vole
14

Prairie vole characteristics
Socially monogamous
Colonial
Bi-modal dispersal
Short life span
Variable litter size
Variable and complex social environment
Induced ovulation and inbreeding avoidance
15

Methods
Three Exploratory tests
Open-field with novel objects
Two-way novel choice apparatus
Complex maze
17

Open-field with Novel Objects Test
1 m
1 m
Dependent Variables:
Latency
Time in the novel environment
Time with novel objects
Returns
Instantaneous scan of location
a) Total squares
b) Visits to each section
18

500 mm
Novel Choice Test
Latency
Time to reach the first terminal
Time to reach the second terminal
Total time to complete the test
19

Complex Maze Test
396 cm
610 cm
Latency
Number of times each arm was entered
Returns to the start box
20

Statistical Analysis
PCA analysis for each exploratory test
Identified the key dependent variables
PC1 accounted for the highest % of variance
All dependent variables that scored above .80 that explained PC1 – called Key Dependent Variables
Ranked each Key DV
Computed the overall Exploratory Score for each individual in each test
Correlate Exploratory Scores across tests
21

Overall Predictions
less exploratory more exploratory
Lower latency
More time spent interacting with novel stimuli
Higher spatial scores
Higher latency
Less time spent interacting with novel stimuli
Lower spatial scores
22

Exploratory Scores Continuum
lower exploratory scores higher exploratory scores
Open-field with novel objects test
Novel choice test
Complex Maze test
23

Components
N = 102
58 females
44 males
PC 1 explains 46.9% of the variance
PC 2 explains 18.7 %
PC 3 explains 12.5 %
24

Novel choice apparatus test
Components
N = 141
83 females
58 males
PC 1 explains 54% of the variance
PC 2 explains18%
PC3 explains 13 %
25

Exploratory maze test
Components
N = 98
53 females
45 males
PC 1 explains 58% of the variance
PC 2 explains 19%
26

Correlations of Exploratory Scores across all three tests
N = 51
26 females
25 males
No correlated suites of behavior across test situations.
27

Exploratory Responses
lower exploratory scores higher exploratory scores
Novel choice test
Complex Maze test
28

Discussion
Behavior in one situation did not correlate or predict behavior in a different situation
Behavioral responses are distinct and stand alone
Animals interpret context differently
Null Hypothesis in hierarchy supported
29

Behavioral Syndromes Hypotheses Hierarchy
H1: correlations of behavior response across situations or contexts = syndrome = TRAIT RESPONSE
H1a: correlations of behavior responses within one context = DOMAIN SPECIFIC
H1b: correlations of behavioral responses across two or more contexts = BROAD
30

Calling behavior of roosters
Nelson et al. (2008). Roosters, Gallus gallus domesticus
Behavioral syndromes in stable social groups: an artifact of external constraints? Ethology, 114: 1154-1165
31

Calling behavior of roosters
Nelson et al. (2008). Roosters, Gallus gallus domesticus
Behavioral syndromes in stable social groups: an artifact of external constraints? Ethology, 114: 1154-1165
32

Fox et al. (2009). Mountain chickadees, Poecilegambeli,
exploration in a novel room and with novel objects
Dingemanse (2008). Sticklebacks
Adriaenssens & Johnsson (2008). Brown trout
Milderman (2008) Starlings
Snekseret al. (2008). Damselfish
33
Other studies

Historical contextStudies in Psychology
Context: Learning ability and cognition in lab rats in labyrinth mazes
No two trials of the exact same test correlated with any degree of reliability. Tolman (1924)
Learning ability is specific to the apparatus.
Tryon (1940), Searle (1949)
34

No single test can serve as a proxy for an entire domain
Behavioral syndromes may not be a general attribute, as previously proposed
Demonstrate domain-specific correlations first, then broad
Cautions
35

36
Behavioral Syndromes Paradigm
Image credit:
http://www.n-k-d.co.uk/images/balloon_pop.jpg

Heuristic Value of Behavioral Syndrome Framework
State responses still reveal high individual variation
37

Chapters 2, 3, 4
OBJECTIVE
To examine roots of individual variation in exploratory behavior responses of prairie voles
QUESTION
What are the shared characteristics of individuals who show similar exploratory tendencies?
HYPOTHESES
1: subjects from similar early social environments behave similarly
2: behavioral similarity is best explained by age or sex
38

Overall Results
Open-field
Litter size matters, litter sex ratio contributes
Sex differences are consistently different, but n.s.
Age matters
Novel Choice
No differences for any of the comparisons
Complex maze
Litter sex ratio matters
Sex differences are consistently different, but n.s.
39

Conclusions
Individual variation in behavior was observed across all tests
Individual behavioral plasticity is high in voles
Plasticity might be beneficial for this species
40

ACKNOWLEDGEMENTS
David Chisholm, Lyndell Bade, Tom Kent
Jasmine Clayton, Robert Clayton, Allison Clayton, MeitalLaks, Dominique Craven, Evyn Craven, AnnaLynn Harris, Dianne Voorhis, Angel Scarfino, Alecia Hoyt
Stan Braude, Karen Norberg, Lon Wilkens, George Taylor, Godfrey Bourne, Patrick Osborne, Maryann Hempenn
Elizabeth Congdon, GenaSbeglia, Laura Kent, Javier Hernandez, Tim Lescher
Darcella Craven, Piia Hanson
Family, Friends, Blog readers and SM supporters
NSF
AGEP Fellowship
Doctoral Dissertation Improvement Grant
G-K12 MO-STEP Fellowship
American Society of Mammalogists GIAR
TWA Scholarship for Environmental Science
UMSL – The Graduate School BRIDGE Fellowship
41

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An investigation of behavioral syndromes and individual differences in exploratory behavior in prairie voles, Microtus ochrogaster

by Danielle Lee on Mar 16, 2010

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An investigation of behavioral syndromes and individual differences in exploratory behavior in prairie voles, Microtus ochrogaster — Presentation Transcript