effects of salinity on l ife history traits of amphibians reporter: wan-tso hsu advisor: dr....
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Effects of salinity onEffects of salinity on llife history traits of ife history traits of
amphibiansamphibians
Reporter: Wan-Tso Hsu Reporter: Wan-Tso Hsu Advisor: Dr. Yeong-Choy KamAdvisor: Dr. Yeong-Choy Kam
ContentsContents
Amphibian life history traits Amphibian life history traits
Effect of salinityEffect of salinity
The adaptation to salinityThe adaptation to salinity
ContentsContents
Amphibian life history traits Amphibian life history traits
Effect of salinityEffect of salinity
The adaptation to salinityThe adaptation to salinity
Amphibians have a Amphibians have a complex life historycomplex life history
Postmetamorphic life stage could be affected bPostmetamorphic life stage could be affected by an associated trait from premetamorphic life y an associated trait from premetamorphic life stage experiencing a different habitats.stage experiencing a different habitats.
““The time of larval period and weight at metaThe time of larval period and weight at metamorphosis can be predict adult amphibian’s sumorphosis can be predict adult amphibian’s survival and success of matingrvival and success of mating.”.”
(Deban & Marks, 2002. Relyea & Hoverman, 2003)
Traits at metamorphosis Traits at metamorphosis are very important to future fitnessare very important to future fitness
(Smith & Gill, 1978)
Adults can escape the extreme environment, Adults can escape the extreme environment, but larvae can not.but larvae can not.
http://www.tooter4kids.com/Frogs/life_cycle_of_frogs.htm
Environmental factors influencing Environmental factors influencing life history traitslife history traits
FoodFood TemperatureTemperature pHpH PredatorsPredators DensityDensity
(Newman, 1992)
Environmental factors influencing Environmental factors influencing life history traitslife history traits
SalinitySalinity
(Gomez-Mestre & Tejedo, 2005)
In a high salinity In a high salinity environmentenvironment
Salt : Na, Cl,
K, Ca …
Permeable skin makes ionic balance difficult
ContentsContents
Amphibian life history traitsAmphibian life history traits
Effect of salinityEffect of salinity
The adaptation to salinityThe adaptation to salinity
ContentsContents
Amphibian life history traitsAmphibian life history traits
Effect of salinityEffect of salinity SurvivalSurvival Development and growthDevelopment and growth MetamorphosisMetamorphosis
The adaptation to salinityThe adaptation to salinity
ContentsContents
Amphibian life history traitsAmphibian life history traits
Effect of salinityEffect of salinity SurvivalSurvival Development and growthDevelopment and growth MetamorphosisMetamorphosis
The adaptation to salinityThe adaptation to salinity
Survival in different salinities Survival in different salinities Litoria ewingii
(Chinathamby et al 2006)
http://www.frogsaustralia.net.au/frogs/display.cfm?frog_id=151
48-hr survivorship of tadpoles Rana limnocharis
0 3 5 7 9 11 130
20
40
60
80
100
Su
rviv
ors
hip
(%
)
Water Salinity (ppt)
Green Island Orchid Island Guoshin Tongsiao
(Wu, Unpublished)
ContentsContents
Amphibian life history traitsAmphibian life history traits
Effect of salinityEffect of salinity SurvivalSurvival Development and growthDevelopment and growth MetamorphosisMetamorphosis
The adaptation to salinityThe adaptation to salinity
(Gomez-Mestre & Tejedo, 2003)
Ionic concentration in Ionic concentration in different salinities different salinities
http://www.herpetofauna.at/amphibien/bufo_calamita.php
Bufo calBufo calamitaamita
Increase as salinity rises
0ppt 6ppt 8ppt P
Na(μmol) 3.86 ± 0.18 4.30 ± 0.17 5.07 ± 0.18 <0.001
Cl (μmol) 5.20 ± 0.20 5.89 ± 0.19 6.74 ± 0.20 0.04
(Gomez-Mestre & Tejedo, 2003)
Glucose and protein Glucose and protein concentration in different concentration in different
salinitiessalinities
Decrease as salinity rises•Spend a lot of energy in osmoregulation•Lower metabolic rate in saline water
Glucose (μmol) 0.55 ± 0.4 0.43 ± 0.5 0.36 ± 0.4 0.012
Proteins (mg) 0.92 ± 0.5 0.60 ± 0.4 0.6 ± 0.5 <0.01
0ppt 6ppt 8ppt P
(Gomez-Mestre & Tejedo, 2003)
Development in different salinitiesDevelopment in different salinities
0 ppt
6 ppt
8 ppt
a
b
b
(Gomez-Mestre & Tejedo, 2003)
Larval period in different salinitiesLarval period in different salinities
0 ppt 8 ppt6 ppt
a
bb
Tadpole growth in different salinitiesin different salinities Rana limnocharis
0 1 2 3 4 5 6 7 8 9 10 11 120.00.10.20.30.40.50.60.70.80.91.01.1
0 ppt 3 ppt 5 ppt 7 ppt 9 ppt 11 ppt
(Wu, Unpublished)Time (weeks)
Wei
ght
(g)
Tadpole development in different salinitiesin different salinities Rana limnocharis
0 1 2 3 4 5 6 7 8 9 10 11 122224262830323436384042
0 ppt 3 ppt 5 ppt 7 ppt 9 ppt
Dev
elo
pm
enta
l sta
ge
Time (weeks)(Wu, Unpublished)
ContentsContents
Amphibian life history traitsAmphibian life history traits
Effect of salinityEffect of salinity SurvivalSurvival Development and growthDevelopment and growth MetamorphosisMetamorphosis
The adaptation to salinityThe adaptation to salinity
Thyroid hormone is important to Thyroid hormone is important to metamorphosismetamorphosis
Thyroid Thyroid gland gland
Thyroid hormone T3 Thyroid hormone T3 in in different salinitiesdifferent salinities
(Gomez-Mestre & Tejedo, 2003)
T3 decrease as salinity rise at Gosner 38 and 42
Thyroid hormone T4 Thyroid hormone T4 in in different salinitiesdifferent salinities
(Gomez-Mestre & Tejedo, 2003)
T4 increase as salinity rise at Gosner 38 and 42
Metamorphic time & mass in different salinitiesMetamorphic time & mass in different salinities
(Chinathamby et al 2006)
a
*
aa
aa
bb
b
bc
A B
0 3 5 7 90
10
20
30
40
50
60
70
80
Tim
e (d
ays)
Water salinity (ppt)
BCBC
AC
A
A
0 3 5 7 9
0.0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
Water salinity (ppt)
Siz
e (g
)
D
CDAC
B
A
Time Size
(Wu, Unpublish)
Metamorphic time & mass in different salinitiesMetamorphic time & mass in different salinities
When is the best time for metamorphosis ?
MIN
Time
Siz
e
High salinity
Low salinity
MAX
When is the best time for metamorphosis ?
MIN MAX
Metamorphic size and time are Metamorphic size and time are plastic to amphibian larvaeplastic to amphibian larvae
MIN
MAX
plasticity
Time
Siz
e
Extreme high salinity
Low salinity
high salinity
0 3 5 7 90
10
20
30
40
50
60
70
80
Tim
e (d
ays)
Water salinity (ppt)
BCBC
AC
A
A
0 3 5 7 9
0.0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
Water salinity (ppt)
Siz
e (g
)
D
CDAC
B
A
Time Size
(Wu, Unpublish)
Metamorphic time & mass in different salinitiesMetamorphic time & mass in different salinities
Benefit and cost of plasticityBenefit and cost of plasticity
Plasticity helps to avoid rapid change in enviroPlasticity helps to avoid rapid change in environmental conditions.nmental conditions.
But small adult amphibians may not survive beBut small adult amphibians may not survive better or have lower reproductive succees in the ftter or have lower reproductive succees in the future.uture.
(Semlitsh, R.D. 1987)
When a population is restricted at a When a population is restricted at a brackish habitatbrackish habitat
ContentsContents
Amphibian life history traitsAmphibian life history traits
Effect of salinityEffect of salinity
The adaptation to salinityThe adaptation to salinity
How to test plasticity or How to test plasticity or adaptationadaptation
“Distinction between genetic variation and environmentally induced phenotypic variation is best made using reciprocal transplant experiments.”
(Reznick and Travis 1996)
Transplant experimentsTransplant experiments
Fresh Saline
Fresh water population
Saline water population
Three outcomesThree outcomes Population genetic basis
low high
survival
salinity
high
low
Saline water population
Fresh water population
Three outcomesThree outcomes Environment phenotypic plasticity
low high
survival
salinity
high
low
Saline water population
Fresh water population
Three outcomesThree outcomes
Interaction Local adaptation
(Alonso et al. 2001)low high
survival
salinity
high
low
Saline water population
Fresh water population
Local adaptation of an anuran amphibian to osmotically stressful environments
Fresh Saline
Fresh water population
Saline water population
(Gomez-Mestre & Tejedo, 2003)
Embryonic survival
Fresh 6 ppt 8 ppt
Embryonic survivalEmbryonic survival
Fresh 6 ppt 8 ppt Fresh 6 ppt 8 ppt
Fresh 1
Fresh 3
Fresh 2
Saline
CV=80.9 CV=132.1
CV=90
CV=37.6
Larval survivalLarval survival
Fresh Saline Saline
P = 0.943
P = 0.09 P < 0.001
Larval survivalLarval survivalfresh brackish brackishfresh
Fresh 1
Fresh 3
Fresh 2
Saline
Salinity–population interaction Local adaptation
low high
survival
salinity
high
low
Saline water population
Fresh water population
SummarySummary
Water salinity represents an environmental stress for many species of amphibians
High salinity decrease larval survivalHigh salinity decrease larval survival
Metamorphic time and size of amphibian Metamorphic time and size of amphibian larvae are plastic in different salinitieslarvae are plastic in different salinities
SummarySummary
Larvae at a low salinity will metamorphose at Larvae at a low salinity will metamorphose at the maximum size.the maximum size.
Larvae at a extreme high salinity will Larvae at a extreme high salinity will metamorphose at later at a minimum size.metamorphose at later at a minimum size.
Larvae at a high salinity will metamorphose Larvae at a high salinity will metamorphose earliest at a smaller sizeearliest at a smaller size
SummarySummary
When population migration is restricted, selectWhen population migration is restricted, selection under extreme habitats lead to local adaptaion under extreme habitats lead to local adaptation.tion.
Results of transplant experiments showed population–salinity interactions, suggesting local adaptation in R. calamita.
Thanks for your attentionThanks for your attention
DevelopmentDevelopment
Adult amphibians increase in their osmotic conAdult amphibians increase in their osmotic concentrationcentration urine retentionurine retention accumulation of electrolytesaccumulation of electrolytes enhanced urea synthesisenhanced urea synthesis
(Gordon 1962; McBean and Goldstein 1970)
0 3 5 7 90
10
20
30
40
50
60
70
80
ABABABB
A
Tim
e (
day
s)
Water Salinity (ppt)
Orchid Island: As salinity increased, size at metamorphosis decreased
0 3 5 7 90.0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
C
BBB
A
Siz
e (
g)
Water Salinity (ppt)
Time Size
(Wu, Unpublish)
PlasticityPlasticity
Environmental heterogeneity tends to increase the phenotypic plasticity of traits, with phenotypes optimized to the particular conditions on each environment.
(Rawson and Hilbish 1991; Sultan and Spencer 2002)
PlasticityPlasticity
When gene is affected by variation of environWhen gene is affected by variation of environments, genotype will lead to multiple phenotypments, genotype will lead to multiple phenotypeses Life historyLife history Metamorphic size and timeMetamorphic size and time behaviorbehavior physiologyphysiology
(Miner et al. 2005)
High salinity tolerant speciesHigh salinity tolerant species
http://www.hlasek.com/bufo_viridis_da1531.html
Bufo viridis
http://www.britannica.com/eb/art/print?id=4886&articleTypeId=0
Xenopus laevis
http://www.froghome.idv.tw/html/class_1/rana_cancrivora.html
Rana cancrivora
AdaptationAdaptation
““Different phenotypes among populations can Different phenotypes among populations can be considered adaptive if they have a genetic be considered adaptive if they have a genetic basis, and they confer fitness advantage in a basis, and they confer fitness advantage in a given environment.”given environment.”
(Endler 1986; Sinervo and Basolo 1996)
Wilbur and Collin’s modelWilbur and Collin’s model
W > b
dW
Wdt
Additional growth
Initiate metamorphosis
W > b+cno
noyes
yes
yes
no
> g