Songbird Odor Predicts Reproductive Success

Danielle J. WhittakerNicole M. GerlachEllen D. Ketterson

Photo by Marine Drouilly

Preen oil is an odor source

Oil secreted from the uropygial gland contains volatile compounds that give birds an odor

Volatile compound concentration increases during breeding season

1-Dec

anol

1-Und

ecan

ol

1-Dod

ecan

ol

1-Trid

ecan

ol

1-Tet

rade

cano

l

1-Pen

tade

cano

l

1-Hex

adec

anol

1-Hep

tade

cano

l

1-Oct

adec

anol

0

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Breeding Non-breeding

Co

nc

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Soini et al 2007, J. Chemical Ecology

Whittaker et al 2011, J. Chemical Ecology

Odor varies with sex and population

MANOVA

Sex p<0.001

Population

p=0.022

Sex * Population

p=0.03Whittaker et al. 2010, Behavioral Ecology

Birds can detect and differentiate among odors

Whittaker et al. 2011, Behavioral Ecology

Does odor predict reproductive success?

Photo by Flickr user Enjoy Every Sandwich

Dark-eyed Juncos (Junco hyemalis)

Seasonal breedersSocially monogamous~30% extra-pair

fertilization (EPF) rate

Females incubate eggs, both males and females feed nestlings

Field Methods

Mountain Lake Biological Station, VA

Summer 2008Captured birds for

measurements, blood samples, and preen oil

Monitored nests

Photo by Dustin Reichard

Photo by Dawn O’Neal

Lab Methods

Genotyped at 8 microsatellite loci to assess parentage

Analyzed chemical composition of preen oil with GC-MS

15 volatile compounds

Photo by Flickr user wvsawwhet

Relative proportions of volatile compounds

Previous studies found relationships between relative proportions and sex, population differences

More “male-like” and “female-like” blends due to different proportions

  PC1 PC2 PC3 PC41-Decanol 0.131 0.927 -0.078 -0.1421-Undecanol 0.257 0.925 -0.081 -0.1381-Dodecanol 0.63 0.663 -0.251 0.11-Tridecanol 0.805 0.123 0.115 0.0151-Tetradecanol 0.663 -0.548 -0.292 -0.0781-Pentadecanol 0.486 -0.402 0.425 -0.141-Hexadecanol 0.494 -0.801 0.016 -0.012-undecanone -0.043 -0.081 0.066 0.9712-dodecanone -0.112 -0.075 0.156 0.962-tridecanone 0.147 0.009 0.89 0.2842-tetradecanone -0.008 -0.016 0.727 0.6182-pentadecanone 0.193 -0.162 0.935 -0.049DodecanoicAcid -0.955 -0.05 -0.156 0.187TetradecanoicAcid -0.98 -0.041 -0.147 0.029HexadecanoicAcid -0.964 -0.036 -0.172 0.029VARIANCE EXPLAINED 32.82 22.11 17.70 16.29

Principal Components Analysis: Relative Proportions

-1.2 -1 -0.8 -0.6 -0.4 -0.2 0 0.2 0.4 0.60

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8Female Odor and Reproductive Success

PC3 (Relative Proportions)

Nu

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of

off

sp

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g p

rod

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ed

Pearson’s correlation = -0.639, p = 0.019n = 13

-1.5 -1 -0.5 0 0.5 1 1.5 2 2.50

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8Male Odor and Genetic Reproductive Success

PC3 (Relative Proportions)

Nu

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of

Off

sp

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urv

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Pearson’s correlation = 0.572, p = 0.005n=22

  PC1 PC2 PC3 PC41-Decanol 0.131 0.927 -0.078 -0.1421-Undecanol 0.257 0.925 -0.081 -0.1381-Dodecanol 0.63 0.663 -0.251 0.11-Tridecanol 0.805 0.123 0.115 0.0151-Tetradecanol 0.663 -0.548 -0.292 -0.0781-Pentadecanol 0.486 -0.402 0.425 -0.141-Hexadecanol 0.494 -0.801 0.016 -0.012-undecanone -0.043 -0.081 0.066 0.9712-dodecanone -0.112 -0.075 0.156 0.962-tridecanone 0.147 0.009 0.89 0.2842-tetradecanone -0.008 -0.016 0.727 0.6182-pentadecanone 0.193 -0.162 0.935 -0.049DodecanoicAcid -0.955 -0.05 -0.156 0.187TetradecanoicAcid -0.98 -0.041 -0.147 0.029HexadecanoicAcid -0.964 -0.036 -0.172 0.029VARIANCE EXPLAINED 32.82 22.11 17.70 16.29

Principal Components Analysis: Relative Proportions

Male Female-0.5

-0.4

-0.3

-0.2

-0.1

0

0.1

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0.3

Sex

PC

3 S

core

Volatiles contributing to PC3 are associated with sex differences.2-tridecanone2-tetradecanone2-pentadecanone

More “male-like” males have higher RS

More “female-like” females have higher RS

-1.2 -1 -0.8 -0.6 -0.4 -0.2 0 0.2 0.4 0.6

0

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PC3 (Relative Proportions)

-1.5 -1 -0.5 0 0.5 1 1.5 2 2.5

0

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PC3 (Relative Proportions)

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Ge

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*One-way ANOVA, p = 0.04

Photo by Flickr user wvsawwhet

Absolute measurements of volatile compounds

Concentrations change seasonally

Total amount may convey information 1-

Decan

ol

1-Und

ecan

ol

1-Dod

ecan

ol

1-Trid

ecan

ol

1-Tet

rade

cano

l

1-Pen

tade

cano

l

1-Hex

adec

anol

1-Hep

tade

cano

l

1-Oct

adec

anol

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Breeding Non-breeding

Co

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-2 -1 0 1 2 3 40

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Male Odor and Apparent Reproductive Success

PC1 (Absolute Concentration)

Nu

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er

of

So

cia

l O

ffs

pri

ng

Su

rviv

ing

to

Fle

dg

ing

Pearson’s correlation = 0.512, p = 0.015n=22

Volatiles associated with RS in males (Absolute concentrations)

  PC11-Decanol 0.2031-Undecanol 0.2831-Dodecanol 0.4861-Tridecanol 0.6951-Tetradecanol 0.8641-Pentadecanol 0.8841-Hexadecanol 0.9292-undecanone 0.082-dodecanone 0.0852-tridecanone 0.6752-tetradecanone 0.6752-pentadecanone 0.815Dodecanoic Acid -0.003TetradecanoicAcid -0.034HexadecanoicAcid 0.017VARIANCE EXPLAINED

32.145

}

}But what are these?!

Associated with “maleness” – more “male-like,” more RS!

Photo by Flickr user Super Bay

Pearson’s correlation = 0.558, p = 0.025n=16

-1.5 -1 -0.5 0 0.5 1 1.5 20

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PC3 (Absolute Concentration)

Nu

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er

ex

tra

-pa

ir o

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in n

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Male Female-0.5

0

0.5

1

PC

3 (

Ab

so

lute

)

Odor predicts paternity loss

More “female-like” males lose more paternity

*One-way ANOVA, p < 0.001

  PC3Dodecanoic Acid 0.911Tetradecanoic Acid 0.952Hexadecanoic Acid 0.928VARIANCE EXPLAINED

19.699

Photo by Flickr user Dave W

ConclusionsOdor is a strong

predictor of RS in both males and females

Females may evaluate potential social mates and EPF mates using different cues

No other traits correlated with RS

AcknowledgmentsMilos NovotnyHelena SoiniThe Ketterson Lab and

United Junco Workers

National Science Foundation Indiana University Faculty

Research Support ProgramIndiana Academy of ScienceAmerican Philosophical

Society

Photo by Marine Drouilly