sperm competition and sexual selection
DESCRIPTION
Leigh Simmons from the Centre for Evolutionary Biology at the University of Western Australia presents the tenth installment of the Environment Institute's Science Seminar Series at the University of Adelaide. The presentation is titled: Sperm competition and sexual selection.TRANSCRIPT
The Environment InstituteWhere ideas grow
Professor Leigh Simmons
Sperm competition and sexual selection
Sperm Competition and Sexual Selection
Leigh W SimmonsCentre for Evolutionary Biology, University of Western Australia
“…… [sexual selection] depends, not on a struggle for existence in relation to other organic beings or to external conditions, but on a struggle between the individuals of one sex, generally the males, for the possession of the other sex. The result is not death to the unsuccessful competitor, but few or no offspring.” (chapter iv)
The Origin of Species, 1859
The Decent of Man and Selection in Relation to Sex, Darwin 1871
Sperm Competition and its Evolutionary Consequences in the Insects, Parker 1970
• behaviour
• morphology • physiology
Sperm Competition and its Evolutionary Consequences in the Insects, Parker 1970
70’s 80’s 90’s 00’s
Num
ber o
f pub
licat
ions
Year
100
200
300
• ISI July 2009
Sperm displacement and optimal copula duration in the yellow dung fly, Scatophaga stercoraria
• Behaviour
• Image from Hosken 1999
• Parker 1970
Sperm displacement and optimal copula duration in the yellow dung fly, Scatophaga stercoraria
Small males
Large males
P2
tl* ts*156.5 min
• Evolution, 46, 366
• Behaviour
• Image from Hosken 1999
Sperm displacement and optimal copula duration in the yellow dung fly, Scatophaga stercoraria
• Evolution, 54, 924
-200
20406080
100120140160180200
5 10 15 20 25 30 35 40 45 50 55
Cop
ula
dura
tion
(min
)
Hind tibia length 3
• Behaviour
• Image from Hosken 1999
t*
expenditure ongaining matings
n matings
ejaculate expenditure, x
gain v per matingW = n.v
TotalReproductiveExpenditure
Modelling the ESS ejaculate expenditure
• Parker 1998
• Physiology
Modelling the ESS ejaculate expenditure
0.00 0.20 0.40 0.60 0.80 1.000.00
0.10
0.20
0.30
0.40
0.50
r =1.0
r =0.5
r =0.1
r =0.01
A
ES
S e
jacu
late
exp
endi
ture
Probability of double mating, q • Parker et al 1997
• Physiology
• Physiology
Evolution of ejaculate expenditure
• J. Evol. Biol., 15, 347
-.6
-.4
-.2
0
.2
.4
.6
.8
-1.2 -1 -.75 -.5 -.25 0 .25 .5 .75 1 1.25
Contrasts in sperm competition indexCrinia georgiana
• Physiology
Evolution of ejaculate expenditure
• unpublished
Crinia georgiana1.51.31.10.90.70.50.30.3
1.2
1.4
1.6
1.8
2.0
2.2
log Maximum male density
g
A
• PhysiologySperm competition games between sneaks and guards
ES
S E
jacu
late
exp
endi
ture
0.0 0.2 0.4 0.6 0.8 1.00.0
0.1
0.2
0.3
Probability of a sneak mating
Behavioural biology of onthophagine dung beetles
• Physiology
Testis size variation across alternative mating tactics of dung beetles
• Evolution, 61, 2684
-.2
-.15
-.1
-.05
0
.05
.1
.15
-.4 -.3 -.2 -.1 0 .1 .2 .3 .4
-.4
-.2
0
.2
.4
.6
.8
1
-.6 -.4 -.2 0 .2 .4 .6 .8
X 6
X 60
50
50
Mating Brooding Incubation Maturation
Experimental evolution: breeding regimes
Px3
Mx3
Ne ~ 106
Ne = 100
10 10
• Physiology
Evolution of ejaculate expenditure
• Evolution, 62, 2580
22201816141210864-0.12
-0.08
-0.04
0.00
0.04
0.08
0.12
Generation
Enforced monogamy
Sperm competition
• Physiology
Evolution of ejaculate quality
• Evolution in press
monogamy polygyny-1.5
-1.0
-0.5
0.0
0.5
1.0
1.5
Monogamous polygamous
Selection history
Mating regime:
A
Monogamous Polygamous
• % motile• VAP• Longevity
• Morphology
Evolution of male genital morphology among Onthophagines
O. vacca
O. furcusO. sticticus
O. hirtusO. punctatus
O. taurus
• Morphology
Evolution of male genital morphology among Onthophagines
5
1
• Biol. J. Linn. Soc., 93, 257
• Morphology
Evolution of male genital morphology among Onthophagines
• Curr. Biol., 19, 1442
• Morphology
Evolution of male genital morphology among Onthophagines
-4.0 -2.0 0.0 2.0 4.0
0.00
0.50
1.00
Aedeagus shape (PC2)
• Curr. Biol., 19, 1442
• Morphology
Evolution of male genital morphology among Onthophagines
1 2 3 1 2 3-0.8
-0.6
-0.4
-0.2
0.0
0.2
0.4
0.6
0.8
Monogamy Polygamy
• Curr. Biol., 19, 1442
• Clarissa House• John Hunt• Paco García-González• Joseph Tomkins• Michael Werner• Phil Byrne• Martin Dziminski• Dale Roberts• Renée Firman• Maxine Beveridge
Acknowledgements
The Environment InstituteWhere ideas grow
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Dr Damien Fordham
Predicting ecological turmoil: modelling the dynamics of global change on biodiversity